ESO Workshop: Coating and Cleaning Large

Mirrors

ESO Headquarters Karl-SchwarzschiidstraBe 2

8046 Garching Germany

7 and 8 October 1991

I---~-~~/!ection of contributed papers

ESO Libraries

I ~ "II' IIIIIII!II III II II In " I;, , " I,

M L 1,-, '-I 7' ,-. ..-....... -, ,-, '-I 7 7 . .:.. I.) I.} ... 7 I: .. :'

List of Participants at ESO Workshop: Cleaning and Coating Large Mirrors, 7 and 8 October 1991

Participant

A. Abraham P. Alvarez B. Atwood K. Birkle D. Cowley C. Del Vecchio A. Gilliotte T. Gregory N. Itoh M. lye D. Jackson K. Kissel B. Mack M. Maars L. Miglietta J. Montesinos M. Nakagiri H. Nicklas F. Perez H. Petrie K. Raybould P. Salinari V. Sanchez A. Schier J. Sovka R. Thicksten J. Williams R. Wolf S. Worswick

Affiliation/Project

Gemini 8m Telescope, USA Instituto de Astrofisica de Canarias, E Columbus Project, USA Max-Planck-Institut fur Astronomie, D Canada-France-Hawaii Telescope Arcetri Obs., Florence, I ESO La Silla Canada-France-Hawaii Telescope Japanese National Large Telescope Japanese National Large Telescope Royal Greenwich Observatory, UK AMOS/MOTIF Observatory, USA Royal Greenwich Observatory, UK Magellan Project, USA Arcetri Obs., Florence, I Instituto de Astrofisica de Canarias, E Japanese National Large Telescope Uni-Sternwarte Gottingen, D Carnegie Obs., Pasadena USA Palomar Obs., Caltech USA Gemini 8m Telescope, USA Arcetri Obs., Florence, I Instituto de Astrofisica de Canarias, E Carnegie Obs., Pasadena USA Canada-France-Hawaii Telescope Palomar Obs., Caltech USA MMT/University of Arizona USA Max-Planck-Institut fur Astronomie, D Royal Greenwich Observatory, UK

Summary and Presentation of Current Practice and Experience in Washing and Coating (Primary) Mirrors at existing Observatories

Contents:

1. Calar Alto 2. Kitt Peak 3. CFHT 4. La Silla 5. Mt. Palomar 6. Roque de Los Muchachos

K. Birkle A. Abraham J. Sovka A. Gilliotte R. Thicksten B. Mack

Calor Alto

Presentation by K. Birkle

Calar Alto Observatory

ESO Workshop: Coating and Cleaning Large Mirrors

Standard Procedures of Mirror Coating at Calar Alto Observatory K. Birkle, R. Wolf, G. Lingenfelder

Max-Planck-Institut fUr Astronomie, Heidelberg

Telescopes of the MPI fUr Astronomie at Calar Alto Observatory: 1.2 m RC, 2.2 m RC/Coude, 3.5 m Prime/RC/Coude, 0.8/1.2 m Schmidt. In addition, a 1.5 m RC/Coude is operated by the Instituto de Astrofisica de

Andalucia, Granada.

The MPI fUr Astronomie has installed two aluminization plants: (1) vacuum chamber of 2.6 m in diameter located at the 2.2 m telescope building (Fig. 1);

(2) since 1983 with completion of the 3.5 m telescope a 4 m vacuum tank at the 3.5 m building (Figs. 2 - 4).

Mirror Handling for Re-coating

In a series of illustrations (Figs. 5 - 12) the mirror handling is demonstrated. The whole procedure, in particular aluminizing is carried out with the (primary) mirrors in horizontal position.

For dismounting the mirror cell and lateron attaching it to the telescope again

a cart on a hydraulic platform is lifted underneath the cell (Fig. 5), Beside the

telescope, after protecting the mirror with a cover, the mirror is removed from its cell with the dome crane (Fig. 6) and lowered through the building to the ground floor.

In the metallization plant, with separate crane properly screened to prevent

grease or oil to drop from the crane onto the mirror, the mirror is lifted for washing into a tub made up of glass fibre reinforced plastic and from there after cleaning into the lower part of the vacuum chamber (Figs. 8, 9), At the 3.5 m telescope, instead of a washing tub a three-legged bench of

stainless steel is used (Fig. 10), By this, cleaning liquids freely flow to the drain in the floor.

The central support for lifting the mirror, which remains inside the vacuum tank during aluminization, is made up of stainless steel. It is different from

the radial definition support of the mirror inside the mirror cell and has to be interchanged with the latter before washing and before re-assembling the mirror in its cell, respectively.

1

Fig. 1.

2

Caler Alto Observatory

N-S sectional drawing of the 2.2 m telescope bUilding.

Aluminization chamber (2.6 m diameter) on the ground floor. Vertical coude spectrograph at left (northern side of building>.

Calar Alto Observatory

Fig. 2. N-S sectional drawing of the 3.5 m telescope building.

Below the telescope a 35 ton hydraulic platform for mounting cas­

segrain focus instruments and for disassembly of the mirror cell. The

aluminization chamber (4 m diameter) is located on ground floor.

3

Caler Alto Observatory

Fig. 3. The 4 m vacuum chamber; at the right the electronic rack for comple­

te control of pumping, cooling, glow discharge and filament firing.

In the foreground at right and left of the vessel 2 of the 4- mechanical supports for lifting the upper part of the chamber, so that the lower part can be moved horizontally.

In the vaccum chamber, it is important for mirrors of different thickness to

keep their optical surfaces at the same level to an accuracy of about ± 5 cm

for reasons of homogeneity of the aluminium film depositing on the mirror surface during evaporation ( Fig. 11).

There is only one step in mirror handling which needs special care because of

increased risk of mirror damage (only in case of the 2.2 m mirror): Connecting

the mirror baffle with the central radial definition support (Fig. 12) shortly

before the newly coated mirror in its cell is attached again to the telescope,

4-

v f' r ~ , ~ ,-

Calar Alto Observatory

,

Fig. 4. Side view of the 4 m aluminization chamber with the twin oil diffusion

pumping station; in the foreground the rotary vane pump, the roots pump is not visible.

as this can only be done after removal of the mirror protecting cover. The same holds for the reverse procedure after dismounting the mirror cell. The construction of another cover to avoid this problem was not possible because

5

Calar Alto Observatory

r Fig. S. Disassembly of the 2.2 m mirror cell using a transfer cart on a hydrau­

lic platform.

6

Calar Alto Observatory

Fig. 6. Before the mirror is taken out of its cell, the mirror surface is protec­ted by a cover.

of the special geometry of the baffle. To avoid this risk at the 3.5 m telesco­

pe the construction of the corresponding parts is completely different there.

All other steps of mirror handling are considered to be of no special risk

when carried out with normal care. For example, crane operations with the mirror are of no risk even in the case of the 14 ton 3.5 m primary, as accele­

rations are kept small « 0.1 g) when starting and ending crane motion at

slow-speed; due to elastic stretching of the twisted wire cables acceleration forces are also damped.

Normally, re-coating the primary means that the telescope is out of operation

for one night. When dismounting the mirror cell begins in the morning of the

first day, the telescope is operational again in the evening of the second day.

7

Calar Alto Observatory

About 5 persons are needed for mechanical work. Mirror cleaning, preparation of the vacuum chamber is done by 1 person, at times with 1 - 2 helpers.

cart weight ----\---1.5 Mp

mirror + cell total weight 30 Mp

dome floor

~ E

r-;-..-154 0

Fig. 7. In case of the 3.5 m mirror we use two identical carts, one on the do­

me floor which bears mirror and cell, the other on the ground floor

for transportation of the mirror only.

8

Calar Alto Observatory

Fig. 8. A view in the aluminization hall of the 2.2 m telescope bUilding.

In the middle the glass fibre reinforced PVC tub for mirror washing. In the foreground the lower part of the vacuum vessel.

Mirror Cleaning

First step washing is done with tap water at slightly increased temperature (350 C) with detergent added.

In case that some grease or oil (from lubrication of dome shutter elements) is visible on the mirror, these stains are removed first with acetone before was­hing starts in order not to distribute further the grease on the surface. The old aluminium film is removed using NaOH (8% solution) within about 15 minutes. If the removal of Al is not uniform or rather slow at some parts of the surface, NaOH solution at increased temperature (up to 40° C) is applied,

9

Calar Alto Observatory

Fig. 9. The 2.2 m primary (Zerodur) is lifted from the washing tub into the lower part of the vacuum chamber. The upper part of the chamber and the control electronics for evacuation, glow discharge, and firing are to the right.

and cotton wool soaked with NaOH solution is placed on the mirror surface

for about 10 minutes. In most cases, however, these additional steps are not necessary.

We do not use HCl. Even with special ventilation installations HCI gas cannot removed with sufficient efficiency. Use of breathing masks is not ideal. The main concern, however, is contamination and corrosion of electronics and other

sensitive devices present in the plant. No problems of bad adhesion of the Al coating could ever be observed by not applying any acid medium.

After complete removal of the old Al film the surface is cleaned further with tap water and detergent. Normally, no mechanical treatment is applied. If it is

10

Calar Alto Observatory

Fig. to. Part of 3.5 m aluminization plant showing cleaning facilities. The ion exchanger producing de-ionized water which we use instead of distilled water is to be seen in the background (box-type device with hose on the wall).

inevitable, wet cotton wool is used WlpIng in radial direction towards the cen­

tral hole in a single use mode, that is, for each radial strip on the polished surface new cotton wool is used. When the surface seems to be clean, further flushing with distilled or de-io­nized water in case of the 3.5 m plant is carried out (no disadvantages to distilled water used at the 2.2 m plant can be noticed).

Finally the surface is treated with pure alcohol (ethanol p.a. or isopropanol p.

a.>. In this final stage of cleaning with distilled water and alcohol a vacuum

cleaner is used at the inner rim of the mirror to remove any remaining partic-

11

Calar Alto Observatory

- -I':

Fig. 11. A 1.S m primary (Chinese 1.5 m telescope with 2 Nasmyth foci for the observatory of the Instituto de Astrofisica de Andalucia, Sierra Nevada, ' Spain) is brought into the 4 m vacuum chamber ready for aluminizing. It is placed on 6 supports of such a height to compensate for the dif­ference in thickness of the 3.5 m primary of the MPIA (one of the 6 supports for the 3.5 m mirror is to be seen at right [arrow]; the va­cuum sufficient rubber disks used to avoid direct contact between mir­ror and the metallic support are removed>. For thin mirrors or tests with thin glass probes other supports of aluminium or stainless steel

are used, see e.g. the support leant against the wall in the background in Fig. 1Q

les or dirt floating in the liquid at the flattest part of the mirror surface.

Moreover, this speeds up the drying process. Before putting the mirror into the vacuum chamber, the remaining not polished surfaces including the rear side are cleaned with alcohol.

12

, .-.,;---" , --j

-.'

Caler Alto Observatory

Fig. 12. Connecting the mirror baffle with the central radial definition support of the newly coated 2.2 m primary in its cell. This baffle serves also

as base for the mounting of the first coude flat mirror. Here, instead the compensation weight for this flat is mounted.

What are criteria for a clean optical surface, that is, clean at least for alumi­nization purposes? When the polished surface is drying, one can observe New­tonian interference fringes formed by a thin wedge of remaining distilled water and alcohol (Fig. 13), with the fringes slowly moving towards the mirror centre

(a few mm/sed as evaporation of the liquid is going on, leaving behind a dry surface which seems to be perfectly clean (right parts of Fig. 13), However, as

long as one can see nonuniformities in the illuminated layer of cleaning liquid (left parts of Fig. 13) the polished surface cannot be considered clean.

13

Calar Alto Observatory

Fig. 13. Final stage of cleaning of the optical surface (Chinese 1.S m primary of the lAA, Sierra Nevada) with Newtonian interference fringes formed by a thin wedge of cleaning liquid (see text). The best visible fringes have a distance of about S mm from each other.

- 14

Calar AI to Observatory

Most of these nonuniformities seen in Fig. 13 are not impurities (particles) in the liquid layer but small craters formed by breaking up the thin liquid film due to some kind of (chemical ?) inhomogeneities in the polished surface af­fecting the surface tension of the liquid film in a different way than further away from the craters. This (non-) v isibility of the nonuniformities is a qualitative criterion only but a rather rigorous one, which means that cleaning and flushing has to be repea­ted until these craters are reduced to a minimum in size and quantity.

Mirror Coating

The vacuum chambers at the 3.5 m and 2.2 m domes are equipped with 96 and 64 tungsten filaments, respectively, arranged in one circle along the chamber wall with radius of 1.8 m (1.15 m) and height = radius above the mirror surface (Figs. 14, 15). There are four electrical circuits, each of them connected with every fourth filament. All 96 (64) filaments can be fired simultaneously (nor­mal mode of aluminization), or separately one after the other of the four circuits with 24 (16) filaments each. Each of the filaments is normally loaded with a 2 mm Al wire (99.999% purity)

58 mm long (0.5 gL A load of up to three times this normal load can be used. Above this maximum load aluminium droplets are found.

The tungsten filaments are fixed outside the mirror radius. Two rings of hori­zontal shields with a gap between them are mounted below the filaments to protect the mirror from aluminium droplets. The glow discharge ring electrode and its surroundings as well as the regions around the tungsten filaments, baffles and shields are cleaned before each evaporation.

Using pure aluminium, the filaments have to be renewed after two to four ti­mes of firing. The aluminium foil cover of the glow discharge electrode is re­newed after about 10 discharge processes.

After closing the tank pumping, glow discharge, aluminization, and flooding in total takes about 4 hours.

The glow discharge process starts if the pressure is 10-3 mbar. The glowing time is 15 minutes at 3 kV, 1.5 Aj The pressure is 0.1 mbar controlled by a needle valve.

We begin with the evaporation at a gas pressure of 0.5 - 2 * 10-6 mbar sup­

ported by the additional pumping of a LN2 cooled Meissner trap. Firing takes 30 - 40 sec with 6000 A at maximum for the 3.5 m plant, falling down to 3500 A if all aluminium is evaporated.

Before flushing the tank it is important to heat the Meissner trap to ambient temperature. The heating is simply done by blowing out the nitrogen in it with compressed air. Quality control of the adhesion of the new aluminium film is carried out by

pressing a piece of scotch tape onto the aluminium surface and removing it suddenly.

15

glow discharge rin electrode

evaporation

--- -= -i -.: - ~

~ .-

Calar Alto Observatory

.,.. ,..

-f-

..;.

·1

o o o l..()

Fig. 14. Drawing of the 4 m aluminization chamber with indicated mirror posi­

tion in the lower horizontally movable part.

Cleaning Mirrors in situ the Telescopes

The 3.5 m mirror cell is constructed in such a way allowing mirror washing

inside the cell. However, experience has shown that the results of washing in

most cases are not very satisfactory. Therefore, the primaries and also auxilia­

ry mirrors wi th their refl ecting surfaces looking upwards are periodically re­coated about once a year (1: about 4 months) without washing in the meanti­me.

16

Calar Alto Observatory

Fig. 15. Inside view of the 2.6 m aluminization chamber. The tungsten filaments

are just loaded with aluminium wires. Annular shielding screens below the filaments and the Meissner trap are clearly visible. Part of the

glow discharge ring electrode covered with aluminium foil is visible above the head of the operator.

17

Kitt Peak

Presentation by A. Abraham

Canada France Hawaii Telescope

Presentation by J. Sovka

CF\1T

_Sov~­

C~~(e'1 6r~c)~,\

(!;;)\.t4Z-..... 'I tc.. w ~I/" F- S £) W ~ ('" ~C.,h~\' 0""- e. t eL~.v.i } {& ~ fAdU', t. M f.CI·.I~

t)~7-i-\'" 1 '0

, 2. .I ~t.., .. ~ ol\.)~*~ ~ O.\:>~r".~'-c,\l")

M~~ ~~ -th~_~c:t....\,..~ ,

3. SVW\~IJ"~ 04 ~l1'":oc:.·&..C:t~ ... ~ '?t~~~\.~ J Se~~~(~ ;

M\ ... ~~ ~~l,-~ .

c..'~'-'"~ I w~~, s.t.-)f'\,,'~ - Al~'n"\"'''':~\.~ Ch~~~

l<2~~5>«-..-.-~t7 -t- tAr l ~\-\..~;.. Ph:. .

Ou,

9c::. ~v6,e. :

Co..) -r-"c...t c..-;.~~~eC;o a1""c.. 'f~ ..... fe.",1to L ~e ~ L A.~ .. .foe. A~"r'·O"IOT"l7~ ~ (:.1~"'C...A, ~ )

S. I t..a.a' C ~eC!-~ ~:

M~.rM.\~G UP(ir1~

Mlt\Jll#A.l ~ -:D~W.IJ '7j' ~

. .

-- rt1~'MV""" S G' e,..,(J::'

1'c!"1Z'.

KCl-c - ~.~~, "'j ( \z. t) k 'PAof ~ k ~ ~ ~ .~.

\<"C$ )

~) A) '-' n"?\ ~~ ~~ ·.~i ?('o c..e;:;,~ C'" "lT~H1.·~ !.~'1i~.~

- ?~\W\~~'1 H~7''''''''''''': -It ~,,~ (14""'-1 ~ ,,~- .A-u,., k.~~ . ~r4q it c. j Pf"£e(,.~~~. 'r~-( pJ#~: , ( .

'- ~L"h~p-...'

L.~~~e.1 ",,~ .... :r u-s<..~~.,f G..1fv~i"1 " -£ ~-ff~ j

- l-t .".~~ f.~ "'''''''''.c -A-"a.~)-.. ':a.tt: :!. ~.,..~e-s S

> ~, IT r

. (, ,.1:2 _

1 . A !.. '"' ~ 1 1I.:t ! P- C) .c:;-\J tr. 'P'A'C4 4 iJ ~1.) ~,+1..l.y '. Yf:"l'~1T: :Oe A-1'~

..... .. pC i ~ I ;$ c,'J / -t.-L.<C'" ~ ~ ~ P 'J ~"r; v'~ {C4... r, c.~ ~. Ii d' \0\...1 _1 1_ .... '-- Pe.G 1;0 't"ne-'> _ \ 'r" \-'1 GlV ... , L.. "ToO VI.) ~ ; 6\...,..".,

. I . '-h . t; v \ J t~ I <:.. c. .

- chc..~~a..l d. ~Yfl't.~c.. C ~'1' ~~.r~t'" ~pr:!( - o~ ~h'iSL~ ,.J.4~e. ( ~.~. Wt\"":~' -....

.. .

-3 eo' ~t:PA-t~ { ~t..C':~ccP'ca

(~... ~"'l~

'P. 1'4. Su f'~bC.t" S"1f.r-~S ~rn4*- C04.l-ttli"r J

~t" -Yo~ST~C.~~ H' A-c::.e~)

i. 1( l ~k.t S+«.~

2· Good.... f"4-u ,'f'~~\41 ..

~" ?ro~~ .' ?ro~-e Gl~"'~

4 .. Eno~" ~ , rnt-

~ -G\ ~ ...,

Q

~ ..., P--

f--

.-. .. t\

-1ft. , I'i ~

r -, 11

- ----- --~--.--~---~---

.. C Ft+ r '% ('"I ~"''1 M\t"Y'.~ ~ ,,,,,,,,,,:,,,~,~~

Ac,..+'\1~~ 'VA. ... ) .. j J D 1 '2 3 4 '7 '- 7

~~vl.v tJ"if ... f&~ tJ~J~t\' • • t ,

·6 , .,

.// , .. · • y; •. ~fI7~1c 1(.k<fUf<,

,

Szm· .~ .-

I • , , •

t'I(.", 1.r-1. ~ Fi.., 'AiC."'~_ I ~

.tlZL , , • .. II \

I • t1,;~r • 1 ., ....

WA.4ih # S1,,~ IZZlit , , • , . .

-':;;'JI kIA-f" I fZJ

, , • •

I , ,

M.V'c. t. Y41~· C,,"" ..... ... f.,,,,p , • · • • • • ,Plat • -

~J c,l\'n, 1"\.;,. -rCbe.c.'e. ~4 t , V

.. ., • , , , - , • M<>v(. l'-i I"~ -t. ~-k. FI,

, • rm f

, • • , · -

~,,.t';,,,-ro t.l\ 1- ~"'. IH"f;' . • • , · , • B. • • • .

Ce.ll .n~ -r-t.l~~,~,.(. ., , t a • • • , • .. ..

tZc..(t.~cr7'7"'~ ~It$,.t''- '. , • .,

• t rzTI, ~ • • ~ • • .. -A-tt.·1~ C9rt ;,c, A,,&.~ It

, , 4

- • at! • , • \ ,

~ · • , .. "

N \ ~ "t S'~, Tc.s~ ~ 1 J .. • .. • t :! C , I • • i • , r "f '''' _ \ ( \( <c.lz o."t,. / (\(.~-.., • • ., • • VJ!D ., • • .,

f~ ~ r~'I!~~ (o.r o~~ • • • • • • Jzmt • • • • • • • · . . .. .. '" -~-- . ... .---- --

". WA-f~

- $pr~i - ~~ ?11t.~f,e (,"/,." .~ CO2 S"Qf..J .

- H~ - ...... - A ,;. ~,,-b. '" t ..... +&.: .... ~ ro~Jr~

'~\1'~;cf '*~ --r\-.,.0I011.. ... -t -rc.lc..s.-~~ . ..

·,41 \J m\"I~t.A S>Jr-fA..C.~

- <.)y\"'1P~~t.tA c:;h~+~w~C, ..... ~ ..... \ U ""',,.,, i ,.;., ~~ cS>?'hCS.

__ ___ ~;.. o __________ ~ s_z~ C.l«L-_=J~_\{' 1._(.) ______ --- --- -----

___ 4.1----"I~ ~_>_\_T'-' _____ ']'~I~llW_'1----I~t \HZvR--- _CL~t.0Q,

__ .___~_~e~~ ~~-~.:;_.:tC~~"l~:-t~h<U-1v~~\ _ _ _ _ ____ __ _ ____ ~)--~'~:-:Y-L.>J~':.~\f6- ~ L.0c,-h.<.. __ L ~ :-+~~-du-{",

_________________________________ s~_~Gf> :. i'~~~---~-~---~f,~-:s---p-~C-- .. -

- A.-(~ e...11:~-c:trc.~c~.f ~(J -. --- -- ... ------.---.-~---.~ .. - -------------------~-~-~-----,--.--. --- ~-. -- ... -- .'~--. - ---' ~

______________________________________ _______ ~=_ __ ~~:0?<z __ ____ _ _ _ _____ _ _ _ ____________________________________ ~ ~--·6y c~r __ :~l;\.~-,vl

kDX J/\C..rJ . ------ ----- ---------------------------

~ I ~ r-.OILf... - r r . ,~ ----.---- ------'L!-)~4~1--=-~-~-~~t~-p-·.

-~=.... •• .~~~_=:-:=----~~-t~:·-t;;t-~~~-~..- .•• -------------------------K)----CQ-z--S ~~ _ __==__!:2.~s;t _'£v __ t:1C_~ ________ _

'ff\ s~ <;'-0 P" 4' ,,,. --------~'Z- . f.{ E~~~J--- ------- -----

-"'f'{~--.~~,;&2 l--\",-";5>~"",-c s# ______ __ -------s..v~....tQ. ___ ~=r~-t'L<:-~ -<-- - (!::.- tY\ ~ L~')--~ . ..r I.! b~ _ U~

J .... I ZJ; -l <:.X:t

-------____ k)Q-\- ~-\~~~t--~--~--y'-.~,-~-.-C~-~d2~/--::f~JJ~ ___________ ~'f()&l~- _ D()~1-l)':·'~---~-C~a- _ :~ __ ~'":'ZO _ ~~~/_~t-=

------. --- - fl'~..yJ-- '~_'_.H._c<;, ... ~ ; - - rC~l-"I\..<.."""'.r"J'; 0_"'- -f-,l~_<.._:' __ ~_"'"~'o..J,/'.

______________ t'~ ~ __ ', ... __ ~~~ __ ¥~~ -~f-~~;C4.f.-- ____ _

. (ko.-~ ~l .. ':'GJ~~ u.-iL- .~ __ ~\-_ ~'-ct·~~9~,- !t.X;... ...... ,\

-1.~\~.d- e-L(1L' G.~- e->-. .A~~''"\~~{ :<.J'-~ I ~k . v-- -.. - r ~-t .. 1 0 ~ ---Cl Al r~ -~.-~ I I\. .... .J ) (

___ ~",,-\..e.~(1 a.-st~lrc-r~~vJ~ w.c~ .&..~~J.!. 701

___ ~,t._~.....,r_~ ,_~L ~_!'- b~O.{;~t-- ____ _

~'+<-(d. .I~~~~~A2.Ld c~~ ~ ~-V4--A-V i'l-'l f\.,,-,~ ,

.~c.s-{.."'s.~_ ~.<L! c.L ~·~-.rs~~\.d <--+f'~~,' V~c... '44 .. - 'SVh. ~

__ 5- .----- -~ E co G-'t- t':'L~,...J Y ~::Ct 0 ~;'~.LS__ - - - -

______ . _ __ ------- fss _~--:>i-- ~f ~-±-~\.~ ,- -Ct HT .. 1~. ~ 0,­

-,----- "~"'" . '" '> .;;FG~'~-, _nub '2Jk-A ,-SG_ ~ ~ .;;.5. +3'~Y -i

.l "'._ .. . \( - . ~ ~~~ U8~ -6oVd...-$e.e,~_.-.----J-q-~.:-h~~- .. - ... '-<;'

_____ t:;;rJ ~1:2t~ ~.c:..~--1~l~1-----u.;~---~-L---l~~~'J--'h'----~"~--_________ . ____ ._. __ ~_~~~~ ____ s~~~)- __ ~_~ __ ~-~~s.t.;;(!"'---- aj>o~ .

. _____ --------i~-.s-~OC-~l-~-~tc;.-'- -1 ~--- ~+-..;,.... -x- 1...;r':::- ___ ~~_CJ2~ f-~ --n---n--------~---4Dv-j-- _o~ ~~~_ -?f'.:...rI.V"'~~_ )""'-_\ ~~~ _. _

. ______ ~_e_"\""-)-.~ep-~ -f +~~---c1--~~-.D-f-t~~s---(-~~,d ____ ~-L'7~~-t-c-01t~<.-~-,-.~~ .. -}---- o_~_.~

____ ~~--:~-~~--~Q-.-~--.--.:.~A-!-?O----~-.!~-~---- .

_____________ ~~~_~~.J._a.._1__~-c . ____ ~_c9'"_L~-~~ r-·---we. ___ ~_::<__ (1..c~1\-W

______________ ~04-' '~-~ ~~~~-~--. -.-~:-----6~~:=~4--·--· _._. __ . __________ o~G_~_~~_<;_) _ c) ~c __ eC44--s.L~,~-(L.-3-r.;---.----------.

......... d+;-<,,:~p.e0,-__ d'th cS-_ . ~ """--~fo'd V'e-./ 10 '--If"-~ , .. ___ <':_rl-+--r: . ___ ~S~'-){·~·<'-.-~~<"l.... __ ~-:+kp...1. ~~ . lJ,..) \. U_ ru:;i CG>?1c.. e4<; ;/,

. _______ ~ ___ ):"+- c.-_c; __ Es~~/-..)T\~ __ ---\1:> CC9"?:t_~~:\'h~~~ __ _ D_,-~ __ ~c:.~.{~\f~

____ \J\~'-"~_~~u\ £)Vr?4" ]}l~ }..,{\("(o;- v~v"-~)~---''-----

.. _. _____ ~ __ . ________ . ....--.---:'Dt..a-C.~-~-L ~~-;.--------------.--.- _____ .

. ______ . ___ ._. ____________ ._-=-_~~~~-d::-I-. .a:.c::..?:-~-~--{-R~k~-4-~f=~~~_ --.... --------.-~--.----.- _u5~g(f-(Y't- <;. W=~ .. ~ .. -----~ -----------.-----~-:=.~--Ac..:.~~-r_-?_~~-~-\-(r-:""'-~ ~~~L'-

_______ ~~~~~~~o~\~.~ ________________ _

--------~~--Ae_x_- -0 \ __ ~~_I-v.:--~"'-_,_~M_u...,~--}~---~~ ., -____ .. ___ )_~ ...... ~ __ . __ b~~~-.---j-C>n--.~~~~~~o~~~-~ ___ . n

.----__ e .. t1 __ - __ t:.. ~ .... ~--"o---~~'- '1'r:':'c,o;.""--' ___________ _

i. Osc:. 'J~~r "'~-( ." ..... ;tl,«,;[ I ~~pe1"'«.~~~ »ES".ue0.. C --rbof"'~ ~~ n I ..pt"'oc&.Q. I dee \>, ffc'l.\ ~).e ...... , ~ ~e.e~ ~c\-l. -th r~"1~ 1(f:&&JL.Jt-tCLt I -F"tC~u.r1S Da-~"" rev,.

2· 1>e~,,~ +~ ~oT£cr ?oM. f'f"~ S"'It'~ Co,...sT~1Wl'AJ~-:r/O,.J ,.~ .I-'\INIM'i& 1\'''~OA''''~NC s .

3.

---'nc- •

3.6 METER PRIMARY MIRROR

ALUMINIZATION

SOP 51 1 October 1991

Page 1

3.6 METER PRIMARY MIRROR ALUMINIZATION

(Procedures followed since May, 1986)

A. Initial Inspection

The primary mirror is removed from the telescope and delivered to the aluminizing room and placed atop the mirror washing stand. Next day the mirror sides are cleaned and the radial support pads wrapped in polythene plastic for protection. The mirror surface is rinsed with tap water to remove loose dirt and then it is washed with a detergent solution of 100 parts water to 1 part Liqui-Nox concentrate. Sponges are used in a dabbing, up-down motion only so as not to scratch the aluminum surface. oily spots are carefully dobbed-up with xylene soaked Kaydry towels. Also, bubble holes in the surface are cleaned.

The surface of the cleaned aluminum is inspected for pinholes, abrasion and scattering due to environmental corrosion. The surface is examined by viewing a high intensity lamp in reflection from the surface. There was a significant amount, perhaps a few percent, of scattering of the specular reflection into a halo of diffuse light. At this point a decision must be made to keep the old coating or remove it and deposit a new one.

B. Removal of Old coating

The coating is stripped from the glass surface by flooding it with a solution of hydrochloric acid and cupric sulfate1 . After rinsing the mirror with tap water and drying it with Kaydry towels a solution of sodium hydroxide is used. This has little effect on the more stubborn residual aluminized areas. Finally the mirror surface is flooded with de-ionized water and then sprinkled with reagent calcium carbonate powder and rubbed with cotton pads. The calcium carbonate is sufficient to remove the last residue of aluminum from the optical surface. The mirror is rinsed with de­ionized water and then rubbed dry with Kaydry towels. Care must be taken not to allow the mirror to dry on its own by evaporation as water spots would be a likely result. After the entire mirror surface is gradually dried there still remains a large amount of Kaydry towel lint sticking to the glass surface as a result of the static electricity produced by the rubbing of the clean glass with the paper towels. This lint is removed with static-master anti­static brushes before placing the mirror in the vacuum chamber.

lSee procedure for stripping aluminum coating.

C. Aluminization

SOP 51 Page 2

Once the mirror placed within the vacuum chamber, the roughing pump and roots rotary lobe blower evacuated the chamber to a pressure of 5 microns in about 1 hr. After the cold trap LN2 chevrons are filled, the diffusion pumps is used to lower the pressure to below 5 x 10-5 torr. A glow discharge is performed to insure cleanliness of the mirror surface2 . After the glow discharge, the high vacuum diffusion pumps are used to bring vacuum to the 10-6 range. The meissner coil is filled to aid in the further reduction of pressure. Ultimately a pressure of 3 x 10-6 torr is reached in about 3 hours from the time of initial pump-down.

The individual tungsten filaments, each laden with aluminum clips are pre-heated together in a series/parallel circuit for 4 minutes to bring them all to approximately 10000C. When the Inficon crystal thickness monitor indicates 50A of deposited aluminum, the power to the filaments is increased to the maximum level. Within 30 seconds the Inficon monitor is reading 637A. This thickness, according to previous tests, corresponds to an actual coating thickness of 900-950A on the mirror surface. A deposition rate of 27A per second is indicated upon the Inficon monitor. Interferometric tests were performed upon test plates placed at the central hole and outside the circumference of the mirror. These tests, and others performed earlier at zones simulating the mirror surface showed the coating to be radialy symmetric and even in deposited thickness to within 150A. The probable wavefront error induced by the coating process is estimated to be less than or equal to A/15 at visible wavelengths. During the filament firing, no drops of molten aluminum fall upon the mirror surface. The resultant coating looked brilliant and very free of scatter over its entire area and showed no signs of bloom or diffusion pump backstreaming. No wipe marks or haze due to incomplete cleaning should be observed upon the mirror surface.

D. Adhesion Test

A scotch tape test is performed on the outer bevel and upon the actual mirror surface one inch inside the outer circumference. No aluminum should be removed by the tape at either site.

2See glow discharge procedure.

THICKNESS OF EVAPORATED ALUMINUM FILM

SOP 51 Page 3

During the month of April 1986 tests of the CFHT Summit Aluminizing chamber were carried out to measure the actual thickness and uniformity of Aluminum coatings produced by the 112 filament array of evaporation sources. A set of ten test plates were used to simulate the mirror surface. For the initial test all filaments were loaded with 10 loops with a weight of .065 grams each. (Loops are from Jori Resources and are of 99.99% purity).

The loaded filaments were heated for approximately 5 minutes while monitoring the amperage at Inner Ring #2 = 330 amps. The Inficon crystal thickness/Rate of deposition monitor at the end of the 5 minute preheat period was reading o-lA /second. The total accumulated thickness after the preheat was 40A.

At this time the array voltage was increased and monitored at the Inner Ring #2 = 25 volts. This voltage was maintained for approximately 80 seconds during which time the evaporation rate reached a peak value of 28 A/sec. After an elapsed time of 80 seconds the evaporation rate dropped to zero and all power to the array of filaments was stopped. A total indicated thickness of 652 A was obtained. When· the test plates were measured with the Angstrom-scope interferometer, the following thicknesses were obtained.

1. Test plates approximating the outer 1 meter annular surface = 884 to 913A .

2. Test plates approximating the inner 1 meter circular surface = 1148 k to 1207A .

It was concluded from these results that a superior coating uniformity could be obtained by loading outer ring filaments with 10 loops and inner ring filaments with only 8 loops each. Also, the Inficon crystal monitor readings are about 30% low presumably due to the proximity of the crystal sensor to the chamber wall (-150mm) .

During the primary mirror aluminization in May 1986, test plates were positioned around the circumference of the mirror and within the central hole. After evaporation the following thicknesses were obtained upon the test plates as measured with the interferometer:

a. Circumferential Test Plates = 842, 795, 795, 845, 825, 913, 913, 854, 756A .

b. Central Test Plate = 962 A+.

c. Inficon Measurement = 639A .

d. Maximum Deposition Rate = 27A /second.

SOP 51 Page 4

It is estimated that local mirror surface wavefront distortions caused by the coating process itself are less than A/15 at visible wavelengths. Another test is planned for the future as it is felt that the 3.6 meter mirror surface coating is not accurately depicted with only 10 test plates and that perhaps 30 plates are necessary. This is particularly important near the chamber walls.

CFHT Vacuum Chamber T. Gregory

22 April 1986

ffi Test Plate Height = 24 inches (.6096m)

o P #1 o P #2

e884A

652A 913A ffi

el178A

ffil178A

ffi 1207A + center

ffi1148A

81178A

ffi 884A

61178A ffi884A

Filament Loading: All loaded with 10 loops of .065 grams AI.

SUMMIT VACUUM CHAMBER PREPARATORY CHECKLIST

1. Inficon monitor operation.

2. Cold cathode gauge operation.

3. Chamber lift-jack operation.

4. Integrity of roughing manifold rubber connection.

5. Pre-aluminized test plates, 10 required.

6. 10 single edge razor blades required.

7. Test plate stands.

8. Static-master brushes, 6 required.

9. Check air pressure and control panel functions.

10. Glycol coolant, chiller fan and pump operation.

11. Back-up diesel generator checklist.

12. 3x160 liter dewars of LN2 required.

13. Viewpoint windows cleaned.

14. Torque wrench (15 in-lbs.) for filament installation.

SOP 51 Page 5

CFHT SUMMIT VACUUM CHAMBER CHECKLIST

Pump-down operation:

SOP 51 Page 6

1. Check Inficon Thickness Monitor for proper crystal oscillation.

2. Close tank after inspecting bottom plate "0" rings for smooth and very light lubrication with Dow Corning High Vacuum Grease.

3. Close Air-leak and vent valves. 4. Turn cycle selector switch to manual position (key switch). 5. Connect chamber foreline manifold to roughing pump. 6. Turn chiller condenser fan "ON" in equipment room with

chillers. 7. Turn on 2 glycol supply taps and adjust flow with glycol

return tap to flow gauge valve of 2 1/4 gpm. (The safety flow switch enables the D.P. heating circuit at flow rates in excess of 2 gpm).

8. Start stokes roughing pump. (10 minute warmup period) 9. Check rough pump flow and oil level sight glasses. 10. The Rootes Blower will start automatically after a few

seconds when p ~ 15mm Hg. (see gauge near holding pump) 11. Turn on air supply valve and air dryer. (plug in!) 12. Start the holding pump. 13. Open fore line valves #1 and #2 to evacuate the diffusion

pumps. Wait for valve to open, takes 30 seconds. 14. Turn on thermocouple gauges number 1 through 4. 15. The roughing pump will quickly evacuate the DP's to p ~ 10

microns at T.C. #2 and T.C. #4. 16. Open holding pump valves to D.P. 's 17. Close foreline valves #1 and #2. 18. Turn on DP' s #1 and #2. (These will heat up only if the

glycol safety flow switch senses greater than 2 gpm glycol coolant flow).

19. Turn on seal pump. 20. Open chamber roughing valve. (It will take approximately 30

minutes for the rootes blower to turn on at p=15 mm Hg. It will take an additional 30 minutes for the chamber to reach the range of p ~ 20 microns).

21. Turn on Varian Cold Cathode gauge (pressure should be low enough to be on scale wi thin 1 hr. after opening roughing valve. (p ~ 10 microns)

22. Connect LN2 supply to DP Chevron traps via LN2 manifold. (The liquid level in the traps is automatically maintained. The consumption of LN2 is 10-20 liters/hr) . Open trap valves.

23. Connect LN2 supply to Meissner trap. 24. While the chamber is roughing down it will be necessary to

monitor the fore-pressure of the hot DP's as their pressure may exceed 100 microns with only the small capacity holding

SOP 51 Page 7

chamber rough pumping after the interruption. (There is a 10 second delay built into the control circuit which delays the opening of the foreline valves after closing the chamber roughing valve) .

25. When the chamber pressure is approximately 10 microns close the roughing valve and open the foreline valves to the DP's.

26. Close the holding pump valves. 27. To start high vacuum pumping on the chamber through the

diffusion pumps open the high vacuum valves #1 and #2 in succession while monitoring the foreline pressure in each to not exceed 100 microns. (As a precaution against backstreaming D.P. oil into the chamber allow about one minute between opening of the High Vacuum valve #2 after high vacuum valve #1 is opened).

28. Shortly after both high vacuum valves are opened the chamber pressure should be in the low 10-5 torr range. (SEE GLOW DISCHARGE PROCEDURE) .

29. with the chamber empty it takes about 1 hr. after the high vacuum valves are opened to reach a chamber pressure of approximately 5x10-6 torr.

30. During the high vacuum mode of pumping the Meissner trap should be filled as follows. Turn on the LN2 supply to the Meissner coil by gently opening the LN2 supply valve less than one full turn to avoid pressure vibrations from LN2 evaporation inside the coil. Pressure rises occur within chamber if the coil is filled too rapidly. Trap fills in approximately 30 minutes. Close valve and re-f ill in 10 minutes.

31. The chamber is ready for operation at a pressure less than or equal to 5 x 10-6 torr.

Procedure for stripping Mirrors of Aluminum coating

1. Change water filters.

2. Prepare a Solution of Hydrochloric Acid as follows: 4 liters of deionized water

SOP 51 Page 8

4 liters of Reagent grade (1 Normal) Hydrochloric Acid 100 grams of Cupric Sulfate crystal, Reagent grade. (When diluting, always add acid to water!)

3. Prepare a solution of Sodium Hydroxide: 4 liters of solution at a concentration of 100 grams of Sodium Hydroxide pellets (Reagent Grade) to 1 liter of deionized water.

4. Protect radial supports attached to sides of mirror by duct taping polyethylene film around them.

5. Flush mirror surface with copious amounts of filtered tap water to remove loose particles of dust.

6. Use Xylenes to clean. any oil from the mirror surface with soft Balzer's cotton wool pads.

7. Wash mirror with diluted (1:50) Liqui-Nox detergent using natural sponges and a dabbing action without heavy rubbing. Repeat this washing after a thorough rinse.

8. After mirror is clean, dry it's surface with natural chamois skins and inspect coating for condition, i.e. pinholes, stains, etc ...

9. During washing operations, pay careful attention to cleaning out bubble-holes in the optical surface as these can conceal dirt.

10. If it is decided not to save the old aluminum coating and re-coating is necessary then apply the Hydrochloric/Cupric Sulfate solution to the mirror surface. Spread the solution by dragging soft cotton wool along the surface to even the flow of solution over the aluminum coating. (Always wear protective apparatus when working with acids & bases.)

11. After 5 to 10 minutes most of the Aluminum coating will have bee~ removed. Some rubbing action may be required.

12. Rinse with copious amounts of filtered tap water and then dry the surface with Kaydry Laboratory paper towels.

SOP 51 Page 9

13. Inspect the surface for residual aluminum or water marks and other hazy wipe marks which have stubbornly refused to be dissolved by the Hydrochloric/cupric Sulfate solution.

14. If the surface still does not appear to be perfectly clean of old deposits it is necessary to flood the surface with deionized water and to sprinkle a small quantity of Reagent grade Calcium Carbonate powder upon the surface of the water film. A light rubbing action should remove any residual stains or deposits. (Note: the CaC03 powder must never be applied dry or allowed to dry upon the mirror surface.

15. The mirror surface is once again flooded with copious amounts of filtered tap water. Finish the rinse with deionized water and dry with Kaydry towels. Repeat step #14 if needed.

16. Wash mirror surface thoroughly with diluted Liqui-Nox detergent using natural sponges.

17. Rinse well with plenty of filtered tap water and then deionized water.

18. Dry part of the mirror with Kaydry towels being careful not to allow the mirror surface to dry on its own as water marks will occur. Gradually, dry all the mirror keeping the portions not being dried at the moment wet with deionized water. Much rubbing is involved with this step and some residue of the paper toweling will remain on the mirror surface.

19. To remove the paper residue on the mirror it is necessary to brush the surface thoroughly with the set of six parallel anti-static brushes before placing the mirror inside the vacuum chamber.

20. As with all optical coatings, success depends upon obtaining an extremely clean substrate surface.

FILAMENT INSTALLATION

SOP 51 Page 10

Filament type: R.D. Mathis* (Order as 4 x .030 W RDM-F-16683A)

1. Install 112 new tungsten filaments onto the chamber electrodes using 10-32 x 3/4" stainless steel Allen Socket flat head screws. (1/8" Allen Socket opening)

2. Tighten all 224 screws using special torque wrench to insure equal contact resistance at joint.

Torque setting = 15 in-Ibs.

*The R.D. Mathis Company 2840 Gundry Avenue P. O. Box 6187 Long Beach, CA 90806 PH: (213) 426-7049

OUTGASSING OF FILAMENTS

SOP 51 Page 11

To perform high temperature (>2000 0 C), vacuum cycle of filaments.

1. a) b)

Pump chamber to 5xl0-6 range (see: Pump Down Operation). Perform a glow discharge as described in SOP 51 p. 13.

2. Turn Filament power switches to all 4 filament rings to "on" position.

3. Turn cycle selector switch to "manual" position.

4. Slowly raise power to all rings until current for inner ring #2 is about 330 amperes.

5. View all filaments or reflected light from filaments to insure they appear to heat equally and become incandescent together and with same apparent temperature.

6. After approximately 3 or 4 minutes rapidly increase the power to all filaments until there is 25 volts of potential across inner ring #2. Hold this power level for 10 seconds to degas all filaments of impurities (low melting point metal, etc.).

7. Lower power to all filaments until all ammeters read zero.

8. Turn off all 4 filaments ring power switches.

9. Turn cycle selector switch to "off" position.

10. End of Filament outgassing (See: Shutting down system).

(Note: Tungsten melts at 3,382°C)

Loading Aluminum Loops on Filaments

SOP 51 Page 12

1. Aluminum Loops: Jori Resources*-.065 gram loops-99.99% AI.

2. Loops are loaded only at the downward curves of the filaments near the ends where the electrodes connect to the filament. The central "pigtail" helix of the filament is left free of loops to discourage the possibility of a droplet of molten aluminum falling through the hole in the baffle plate and damaging the mirror surface. If a drop of molten aluminum does fall it will most likely falloff near the ends of the filament and will harmlessly cool and solidify on the baffle plate. Only a relatively thin layer of molten aluminum should be drawn by capillary action toward the central helix of the tungsten filament.

3. To deposit an even thickness of aluminum on the mirror substrate it is necessary to load 10 loops onto each of the outer ring filaments (those two concentric sets of filaments nearest the outer wall of the vacuum chamber) and 8 loops onto all the remaining inner rings of filaments.

*Jori Resources Corp. 2128 Knoll Drive Ventura, CA 93003 PH : ( 8 05 ) 64 2 - 2 2 66

GLOW DISCHARGE OPERATION

Theory-

SOP 51 Page 13

In order to condition the substrate surface to enhance the quality of the coated film, a glow discharge is caused to occur within the chamber which has been preevacuated to 5XIO-5 torr with the substrate inside the chamber. The glow discharge is ignited by a continuous AC high voltage arc across two insulated ring electrodes of aluminum after the pressure within the chamber has been increased by the introduction of air to a pressure of 25 to 30 microns.

The glow discharge has several beneficial effects which are:

1. The substrate surface is degassed through heating. 2. Conversion of organic substances on the substrate into their

volatile components through interaction with ionized residual gas.

3. Desorption of films on the substrate surface through electron impact.

Operation-

1. The chamber is evacuated to 5 x 10-5 torr •. 2. Close high vacuum valves. Shut off chamber ion gauge. 3. Open D.P. holding pump valves. 4. Close D.P. foreline valves. 5. Open air-leak pressure control valve. 6. When pressure reaches p= 25-30 microns open chamber roughing

valve. 7. Monitor chamber pressure at TC #1 while adjusting vernier

throttling valve until pressure is maintained between 25-30 microns (nominal setting = 10.2).

8. Monitor pressure at TC #1 throughout glow discharge cycle of approx. 10 minutes.

9. Turn powerstat located on glow discharge panel fully counter-clockwise until at the zero setting.

10. Turn on glow discharge. First turn on pressure control. 11. Turn powerstat clockwise slowly until .5 ampere is read on

the ammeter., Maintain this current setting throughout glow discharge cycle. (A powerstat setting of 40% should be sufficient to maintain the .5 ampere current at an electrode potential of 1,000 to 2,000 volts.

12. After 10 minutes return powerstat to zero position and turn off the power.

13. Close pressure control valve and vernier valve. 14. After chamber has roughed to a pressure of 10 microns close

the roughing valve and open the D.P. foreline valves. 15. Close holding pump valves. Turn off holding pump.

SOP 51 Page 14

16. Open high vacuum valves #1 & #2. After a few minutes the chamber pressure will again be at 5 x 10-5 torr.

To operate glow discharge without holding pump (not recommended but doable). Run glow discharge cycle before heating D.P. IS using this procedure.

run glow discharge cycle before heating D.P. IS

close rough valve open leak until TCl reads 25 millitorr open rough valve (now TCl will stay at 25 millitorr) turn on glow discharge turn on pressure control turn up glow discharge power to .5 amp (~40 on dial) (inspect visually the aurora) run ten minutes

MANUAL FIRING OF FILAMENTS

SOP 51 Page 15

To evaporate aluminum (M.P.=660 0 C) from outgassed tungsten filaments which are loaded with aluminum loops at each end.

Chamber pressure ~ 5xlO-6 torr.

1. Program the Inf icon thickness monitor with the following parameters: Aluminum Density = 2.70 g/cm3

z ratio = 1. 08 2. Turn cycle selector to "manual" position. 3. To fire all filaments simultaneously, turn all 4 filament ring

power switches to the "ON" position. 4. Slowly raise power to all rings until inner ring #2 ammeter

reads 330 amperes. 5. Within 5 minutes the aluminum loops will melt and the molten

aluminum will be drawn to the center of the filaments by the "wetting" action of the molten aluminum for the stranded Tungsten filament. As the molten aluminum reaches the hotter surface of the central region of the Tungsten filament it will begin to evaporate.

6. The Inficon crystal monitor will begin to read a rate of aluminum deposition of 1 to 2 Angstroms/second.

7. When the Inficon monitor reads a thickness of about 50 angstroms increase the power on all rings until the voltage on inner ring #2 reads 25 volts.

8. The Inficon monitor should now indicate a deposition rate of about 30/second.

9. When the Inficon reads a total thickness of approximately 600 to 650 the power on all rings should be returned to zero and all power switches turned off.

10. An Inficon reading of 650 Angstroms yields a coating thickness of 900 Angstroms measured with the Angstrom-scope, interferometer.

11. See: Shutting Down system.

SHUTTING DOWN ALUMINIZING SYSTEM

SOP Sl Page 16

After outgassing or aluminizing operations have been completed it will be necessary to follow these steps to discontinue vacuum chamber operation, prior to opening.

1. Start the holding pump. 2. Turn off LN~ supply and disconnect dewars from Meissner trap

and LN2 man1folds. 3. Close high vacuum valves #1 and #2. 4. Turn off chamber seal pump. S. Turn off chamber ion gauge and/or cold cathode gauges. 6. Turn off diffusion pumps. (Approximately 2 hr. cool down

required) . 7. Open holding pump valves to diffusion pumps. 8. Close foreline valves #1 & #2. 9. Turn off roughing pump. (Manually vent pump to atmospheric

pressure. Air venting of pump is accomplished via manual valve on roughing manifold).

10. Leave glycol cooling on for 2 hrs. (Do not use rapid cooling).*

If chamber is to be opened:

11. Check again to be certain high vacuum valves #1 & #2 are closed. (Rapid oxidation of hot diffusion pump oil can lead to a serious explosion)!

12. Slowly open chamber air-release valve. Total venting back to atmospheric pressure takes approximately 20 minutes.

13. Disconnect the roughing pump from the chamber vacuum manifold.

14. Raise chamber about 50mm after it has been brought back to atmospheric pressure.

15. Walk around chamber to be sure all hoses and wires are free and clear and that there is ample slack to permit full upward motion of chamber.

16. Check the position of the overhead crane bridge to allow clearance and then switch crane power to "off" position.

17. Raise chamber to fully open position against up-limit switch. 18. Carriage drive switch can now be used to move bottom of

vacuum chamber to desired position. 19. For best long term chamber performance it is necessary to

leave the chamber at a pressure of 10 to 100 microns. This is easily done with the roughing pump only. (See: Pump down operation summit vacuum chamber checklist).

*See manufacturers' data.

SOP 51 Page 17

MIRROR STRIPPING, CLEANING, AND COATING SUPPLIES CHECKLIST

Items:

1. 5 Natural Chamois3 , well washed in Liquinox solution.

2. 8 Natural sponges3 , purified by pounding and HCL acid soak.

3. 4 Acid Vapor MasksS

4. 4 liters Photrex Methanol Absolute1 (Baker Reagent)

5. 4 liters Trichloroethylene1 (Baker Reagent)

6. 4 liters Xylenes1 (VWR Reagent)

7. 4 liters Acetone1 (U.S.P.-F.C.C Baker)

8. 4 liters Liqui-Nox1 Detergent Concentrate

9. 1 Kg. Calcium Carbonate Powder1

10. 2 cartons of "Miracloth" material

11. 1 Kg. Potassium Hydroxide Pellets1 (Baker Reagent)

12. 1 Kg. Sodium Hydroxide Pellets1 (Baker Reagent)

13. 2 Kg. Cupric Sulfate 5-Hydrate1 , Fine Crystal (Baker Reagent)

14. 20 liters 1 Normal Hydrochloric Acid1 (Baker Reagent)

15. 2 Boxes "Pylox" glovesS

16. 2 Boxes Neoprene glovesS

17. 2 Boxes Nitrile-Rubber gloves S

18. 4 pair protective gogglesS

19. 1 face shields

20. 5 Nalgene Mixing Buckets1

21. 20 Boxes x 90 wipes each "Kaydry" paper towels (VWR) 1

22. 10 bags x 30 pads each cotton wipers (Balzers)

23. 10 PVC yellow Tyvek Jumpsuits 4 (Large)

24. 10 Tyrel White Jumpsuits 4 (Large)

25. 10 Surgeons Caps

26. 10 Surgeons Masks S

27. 6 pair of rubber bootsS

28. 1 box of plastic booties

29. 1 garden hose (50 ft.) with outlet end cut off

30. 40 gallons of De-ionized water

31. 4 water filters

32. 1 large roll of Polyethylene film4

1. VWR Scientific, P. O. Box 29697 Honolulu, HI 96820

SUPPLIERS

2. Cole-Parmer Instrument Co. 7425 North Oak Park Avenue Chicago, ILL. 60648

3. McMaster-Carr Supply Co. P. O. Box 54960, Los Angeles, CA 90054-0960

4. Consolidated Plastics Company, Inc. 1864 Enterprise Parkway Twinsburg, Ohio 44087

5. Lab Safety Supply P. O. Box 1368 Janesville, WI 53547-1368

SOP 51 Page 18

La Sillo

Presentation by A. Gilliotte

YJoIlKS~OP

ESC

o ~ C\Jft«.eAJT P~AC.""C.£

AWt)

E 111,.. ~/CN cE

ON

WASM,Aj(i. At-JC CO~;-'NC.

.,

Ic?,e..a :

® A c.ot-\ft-''''' --proc&.s.r: .!"" '0 _ Wlel""~" /AI.tJl1,'NeUl'f A~l-tofilfL.

_ C.O~T'·'" G "'0 cal .... ... ~NT'.s - tOA-r'NGt ?ttt. AA"'.~ - t:,oA"'~ & r'oca.. : t". c,eel"r.

41\ .s,C,M.: I. Tt/.stars.

TH'AI IS ,,~., HI"A. AI

ON~ --o~ ~A.61 """O.~"

3"'0 , ~.,..,. , &- 20

OT.... fro. ~HA'~t!".c ,."AItO.,.

ItM5" Z) , -4 ttI& So ,:. ',M"O ~l4r '-'c" ...... 'df:: I .,,~ 00,0 ..... 40 J)~~I...

o~ 's aoc.Lu,-, 0""'" TWo 0-..- So ~w, sal .

~ .s'L~ T.e"'AI,'t:.AL .,"""FF T~ ~

"!"ul...;ea! ~&.s-....r-ok ~rf."1:

"~C:""N! e!~~: Tel&'CorL t:L.'st..ov.,.""/­... ,'rl'Or ~o-".~

C?f.!'~~~ ~}: ~;-IoA. ~A. "':NG. ANa

Ac.,," .. N'~A n'oN.

'!.o. _ ~ ~,~~_~. f'-'.C ~~!: . ."!;-.s •

l\'rA«;O A.~. . AA' . ' IItI'A'LU"lN-;-&a. .

.~'A1 -,we ., "'1/."1.~AS

ACCOAO,'" c:. V,'3"AL IAII t-,e"'''ON 0"', , . ,

T"'6 ",.~ IN D~ .It •• ' , ( Ol£. ~ WAT'.-t ,&'''1)

t1A«.KS).

e~-rW6.N 'rWo ALuI1,'",; ~T"'ON. ,"'H~

".-~'S AAE WASN.O Two ","""S.

TM. O~~ weT ~pON~ ... .sOAp ". .- . . "

~AS""Nta M.\S &£f~ .-.. '~C£D ~'NC#

~ 11o,H14S 61 eo& .sNO·~ reCIJN,'C$.

-",,~-.oA. Ac.,vt-\;~i2....qT.'ON .• .s p.CFo-'''''1) ON 3 or &t Dl\yS ACC.OA.",Nc-.

eOM" .. e" ,'Tl .,. 111111.1&01C. ;t;>'S"'O~N""IVt;,

[~""'o 5 .. 01$ -~"-w_] ..

",~ItA"S A... t.M~DC.~~ e, 11~'tN. 0'

-rAANspO .. T ltiAlta 0'" .zf'O.1If. Ga~A ~

ti\, ~ __ ~S .et'e 1-«"A'MS '".,~"".. IN

·....,.0 ..,.. II "" .S;, •• '~'- CI.llfAJ ,,_1$" •

A\L" 11; AI; 2A "'t.,.j· ~,,*Jr

..,.""c "I.ANT$ IW.~ INSTAl-'ll> IN

T'H6 .3'-"0' AAlO A ..... So, -S ibtflA ••

AA6~ - T"'~1 ~, ~Or A .. &AN C*C

. '

6u'T '1.00~ I., "~",,, •• A Z/)Af

6e Fo~E ..,."" pltoe'$$.

A "~,\oA et.e~""N~ IJ ,plCoa"H-fTlc,., :

A c.e • ss, W" L L ftA. AI"- QtJ A " ''''7 I C AA AI E",

-At-l C LC A N"N C. ,.111,0 C'"~ 1$ ,-,_Fe.,.,. C'O$~ 'rO "I-N. COAT)tNG. C~"-'.'It. -$MA ..... "-«.0"'5 ~'" MlI-"t4U.,tI/fj OAi A

wA.lM .~e., eo""c.. I.OC,Arr'D UN~IIA

A~ A .... -fUC.T\ON "'00 C (ftOA c"""""~L. VA ~A • ",.. etllA TJON)

LA •• ' M:,-.".:a·, A·i.6 INI"---)iiJ'UC.

G".CA ! ~~ p., ...... "~OS· ON

"1''''£ Fl.oo A. (p't..f\,"'c.) • . / .. ··-L.·Aa.·.f e\.l fl "A'~ ·OOOc.~·· CLO.r~A

-rNa AA_A 0", IL' N G "'~I wAr NINt:;,.

LA S,L&,A TI:",,' S cop I ,.,'*o.~~ I41tI 00,., £: \N • .,... 'P,/ "6)1 ~.su .. " GA ( F", see»

(DiF'FIAI,.r. D.f,.,.JG) A~~, Z6,coDuA

"''''-'0& e, .... M;C,AL W~I"'WGa t. 'O.I4Ir,'CAL­

roa A\,,- 0" 'N eM. AJo .Jl'le' -41. ",. o~ ... ~~,o,,.y p."_~~T10N AIt.'

f e.-.FoILK£J> • -("OAT'N6 p .. oces.£ IS P~AFoII.HEA

W ,T't-C -ru IJ G.ST&N f eo, Ls i 11 f Allo&S

A-'C MO~JrCD ve .. T'I'CAur 1#11 "'He

vACOUf1 C"'AM".A..

._ .. ' ..

C G ~ or, N CIt tt ... c e,.. CM:'-C'IC4.-,.r :(1) M~"C 6C.~ • C", .,. A.O w,"''' "" •• 9","",&ltIr ravJ PO'NT.s we,., A«,TI Alo T'ltl To "'"~ ~~_~~,~O'NC. THe .-t-."'~~C'C'

3~'0 ~-rr wli. ~~""'tIt~o.7H"£e IN ,q~~ J A ... 60 ~N".a, 4r~"'''~S 'N '~'l.' _ r£-.I O~TA" .. S o,,.tr.c. ON r",£ p~Nr

UT • ... ,'.s~ T' 0 tJ .

-Q.\J Ie '-ITy 'o~T~OL I:) F ~O~ rlAl6 IS

P£,,~o .. ..,e.o &1' V'SU_L ,~. PRT.oN

AN 0 M~ PPING. of TM~ ,0£ F£c.TS .

Alv "'~t\J""" TWtc&-< NE.. ,~t1C!'~$u.eA

&y rN'-CIt F'CItO t'le-..-.'c.. t1 &THOO

ON ~rec,'A'" w,,,.~,.SS p~"""

t10u" T£ J:> OAi -rill "" 1I1etJA..

EGG#!' OU~'A.Ica "'N~ Pl'foC~4S

'.

11.-.& •• Oi.$HOtJ",,'P',N6 " A'wk\JAtLD

ANO -r-MC· C.OAllflHINtJ. "1I.0C'OfJl& ••

)1,-,-,A. IS "'ANO"'.O ""OM """'.,c.o,.e Fc..oo&. "-0 w~AOf T .... "lAST 11"00-'

6y WeAN.! 0" A ~u"o&'T ,c'~G . 11'-.-.0-. 'S l.o~.,.-eD CC-o",. ~ 'l-N,

"Ac,ucJf-\ P ~tJ'I ~MD A'lr o~ .... .s pAOS.

ALL 1)ooU A&f el.o.sllc (JTOI&A.6

M-IA ~ TM-' DooA. •••• )

WA''''t~6 Pa~,~ ~.,.,O~

ALt. wA£ ",.", 6 PI.o Ou~T'~ ~o 7boLs ItA,

tout-r.o ON A rItOl-. cl,ole Tb- ?'II, ,.,'AAott C~:M\cALS.., Ga~V" J "~'I<S ~~Tro'" wooL.

AN 0 Te'J.su ell 0(,'" CA c.., f'~pe ~ ...•

PAP'A. ,. '-0&"0.0 'by J.r 0' "". ~N.'''j AN. p'l-eo Uf ON .,.1tI1 """iJL6.

A. TANlc of' $. "' ...... ..,1"$ "-/"".'19';6'1... (~ "'~"'.A. .~ ""MT ....... JI ,. TN.

~ ..... Two WAT. __ Sfotl-r~A~' t:o~NIC"".

T. ~ '"''''''''''0 ('A"Te'C,L.~~) WATW.c.. ".'pl.

0fT;C.'AAJ .,. .. ,,~ D""~J "",.,'" V,~t. C I,oT"". S ~ 0 ,."~s,, &( A&",N'r.l C,N,'I1,'tAl.

&Aa..) .' . . . '- 1'&.,'''' AAE 1l611tJ,'/tCO :('-""Eao)

£to. 0r'Ti'e""4~ Fo-. W~I""·N.. . .t o'Tt-l .... '.s "0" p~OO".-r O,'''A,6.''~

o AI' 0rT':c-.'~t.J C.o e~: ON .,.11. 111NioA..

c"~,,,TItA I.. No L E " ..,.". .J' 'o-nleA ~ /Co.".,.,

A£o.,.,1) "'#I~ I'tII&AOA. t:ZfjC~_

A\,o N C, ...... eM. &.0" C,1f 4U~ A. e-fo ".

we Fo __ ",ec A.CG"bN~O'- ~,''''-I

To MA.HTA.", L"ftJ'O .. 0\1." A-r I.ct4"r ~ 3 0 F' H ........ ILIffJ/UJ.

A _ 'T~' .JATe.. ~'N Ie Oo)~/rAr.ie"El ~e:"'o",4t'­l100fMTE JiT F"o,. ... fO & r ~tNtDE~ ~.-r" T~f: Host'

~ to' ACCoe.D;v~ t1 t ~ .. o .. s ."l.E

t--1 AJo" Ar\of)r.JT flt rio v£o /1) ,~.·("'LT'''-o q vA .... ; f.1 o~ wET' $\II."AcIS

I ~ lo 1- NAOt-t $'/.

.... ACet:J"D/~6 ALv 1l't'\o~AL &.., e~'"'CAL , N,U4~ SIZ.t fl.octss. . L.; '1'" 0 I)$f 0 ~ ~ IS" L.T.us Acflo-'o 'N~ Atv -....',~TO'M,(.&. AAJO "v~c" .

C()Tfo~ wooL. ""'l,o\AJ ,,'9.;t'0 Srlll-A !) o~ .. ~

M.· .. -.o __ ~D .... - ON',! ~O".~ON"l"lt"".

ArO~NO q 0 1. oF' ALu".·~:VI-\ """'0 ~60 (J>EfINO.s 0.., ALu"' ..... ·\II't ADH~~I~I!).

3 _ r. £$T -. ,'IJ $ t.

Co TrON Wooc. o,·,,~ 1l.61'10tl60 ..

--rAt' "'AT<EA. A..'NI~ ., N4ol/ ..

~s -

,,_ "'y"'. C"'\ef:~ Ael~ IX·· ~ lo;® + Cv .s-'t . . .. ~&".~A\' At ~'"o"AL _. T I.,....,..! .$AI1£ fAOe.l~ AI NAON (eo-ro., WooL b"tlI)

C'.~ 'It. ~Ic II( (el ~ L 1'.' •• "'01/4,) A 't AL~", N:U'" A..et'lQ '-' £c:.

5 - .s.C.04N 0 A.,#.J~E

F.,.,'r .. , ...... TAp wATEA.

TMe~ ~,,.t-f O;,TI&£«o w~lA.. ~ 10 /

t1 t .~&. ,.s.; .. ~ Co £, Ae • 0 ~~uT"'-f ~ ,. ~ Tib..!

> t5 ':'CI'S

~ .. AteooL. (''''A~''- ''t.:rl.) 1I..i+I.r. S-'

WATfll. I ~f..r.·OvAL, .1I..~"o VA L - S /'T",S

ALco.t. J_A.'A~. O.,'/t T~I.ru~Ae~

W·-nt 0fT;eAt..... r~r,.1t . 1I~l-" ON ON" EP"~ AwO HQ~'O S"t;,H'I'L1 -ffAM'D (r:-'N',-,) eOAhAe-r· Avo'C>~D •

.,. ... ,·S I-\AN'," W.,.. .. QN 0·' ,.ltl' Cc, ,~ .bo#tJ I

W,.,.... &Aa.' tJ."6~AJ }I~ IJ f:jS

(TO AvOeO v INy l.. ~ 1.,.0 \Ie COAlT'!,., ;Ajf\IIOk

I ~, 10 AccotlOllv G.. T"O

ALCOO L. (p. 0 p ~ NO \.) "S ,PtIVO 11 "AI!.o~ SJ2.~ tON T, NUOU&L'I f:jl.srlt,GftI"~C OV'" Tt-II

S\J_·r~c,E F'~o"" ,.. ... C C,e'NTe:c.. T'OW~""O.l TN£"

I! o CaE. ' ("'0 1f.1'f1f'''' wEr AC,,, -rHE

Su-.FAe' ON T..-" S~Irf~ rll1E.)

3 0f~e"A.Js("" ONf. ON TilE t!~NTIIl) ItOTAT"£ ~A.oy,JD T+t" t1,a.aoc. WI"'''' 12.0·

• Rlw\ ""'\J" p06.T', 0 N~ •

opTIC.AL "A,e~ . .5 CtfAN,.ea .aEtlE&4L...

-r • .-,e.""o M'c...? .s",IlF-iACE O"','NG. -wlote... M.fttlo ~ $"'''J:~ e5 -rCIJ06,D-ro

0--., ,T .... P"P Eo- 1$ IU"LACeo 13'1 c.oTro ~ wOOL. TI.sS uS •

~1 .so~'" '" "AI ° e.oN'TAc:.' 0"'41t TilE

-PA1:> Tt-s.ru! tAl,""'" F!far c,~c.cJ'-A T,'oAl

MovE.s "'~6 H'~oll. 1$ c.tIANEo 0'

AL.L. 1l!$\OUAL. w e-r .s pOT.

M,It«ofl ,s C,Le.A~ • Sy ",~,,~c.. cl'l~c,<

w • .,. ... dT"oAl(i. 11.I.CI""/~lfr'ON £V~N~~I...

C.L~A,v'N6 ~TA'AI "'Af ltal-tA1,.,j -

A N~W pA.oees,5 0':- 1I',ooL" e.t.~IfN''Nt:.

'T~ • .s~cCe$l .,. AC.COOC-.O&Y'tAlG. -e,-cNos Mow "A~ .,. .. ~ C.AC\J ~-n.", ·oF ~o.".o~

"""·JJ",~S IS DONI.(W,.,-It/ At$O. A. FI4.tr I'fOV'

o r 0r""C'~N A£.O~ND T"~ MII&I&4~.

'By ~)I rE ..... AJCE. A SECOND "'''N,AltJ. IS

AI-WArS t!.ol1PIJLlo -"1 · -

" It

»1. il~ft. .. Ite-tr\A ,1tJ.$ 0f'ltJ

f~LT'''c,\.,c GoAJT'",,,,,'N,.TiOAi . UN", L ITs HOfJl4JT,'Nc. ON"H ~ VII CtAJ"" eN,.,.. t)E~ ,

J\JJ'- o6FoAe CLO.lING. rN~ e"''''1t4.46A.,

A 'fl,fO&o\JA'" OUIT' It rl10 vitI. II DON~

"",'T~ II ~o c.., 4t;I. ANTI n"1I.""c 81.uSI/ •

( $TJI& T,'ItItJ. O~ To,P of ~II,. VIti.. or, C4(.. )

n'&Ao~ • .

-

, ~ Ala

lEDGe.. A~oo~ THE t!~N7eAt • -

G f eMTt." .".,.. . IIJ,r-ANOL""'t.

1'1, ....... , A~. , o.~,.;~ L. .

.,...~. ON'-y 0."'" A'MC6 t!ONC,~II.NS

-r .. 1M, u.o.. ...~ 0 ... ,'1tJ ca. • 3~6o.-, f.#A-NO""AI G. ~'NGa N'IT/I.w.1o UAH'O'''~6 Noo~ ON ",,'«'oe.

et-lt-. •

AL.L 't-lA I.e.,. '" M '-'_£$ ""-.. UAalJD",'6

W."" Sr'O&1t. ·c;.AA6. TM.,.".&oA. /fi.I('nO-J ," C~_~.... IJ .ON6 ON""~ U'UOA.

£."~~, (".I'T,'t.L M, •• OA.)

,," , (!J):,','''' : ' ";.f'.

\_.,.\ . '-"~ .. ,] - '.

_ .... -,,- ,. -"

VA c,u\J,,' ~ • lit 0," G....p .. ~TOIJ "U"P (ItO""A~t fl.i'1bN)

\.(. AlN &1 • eo •• "." rooT.s ~"-f k/NN·Y

.. 0', Q"ptUJ/ON PultffJ \I~ &t'AN + L.A.lz. ~rL'

- Gtc.o.., O:'CMA .....

e.v~ po "ATo&.S - two IL,'AI.S

O..,TE.... ...... f.o~" "'"01"$

INN." II ~"' .. &C. "" __ ILI ~"'lo) - O..aTWa.. W.T" '0 CO"s _INN .... ," J' Coi's

ptoWl!a- \S .se"I4~"~o ' I~ ~ rAAT'1 _ pr.c.e.ss o,"c. A"~6 ' • '3 ~ 1.0 c."'s , .. proc .. ss IN~e .. AIN6 • 3 :w I L t:o;'$ •

O",T.'" &..~c.' : ~., 01 1o Twr-.S

~ Hoo ~s,tI, l. ~ II ...... I AJ~... It 'Al II.' 'c.O; I "/0 r&JI'''' I

~ HOOItI; I.S If I' ......

boTH 1l.~G.I, l-oAoeo F.~ -'1S

r-.:O&' AL\Jt-\: ~:1A""Ow - kEGp 10·"76,,. \lAC.v~M UNTeL, C. ... ~M61' ... 0f.wIN • fib ..

M,.&o~ L.oAO.tJGt

to\, .. aoA. Few A TI'ON . ~ "C&TICIi'-'1

51 t1eoA~$ 0' A C .N'rLAL Flltlf-nbA/

.s~rfOa."r ~OtlN".1> ON"'''' E C. ... ~~ 6'A 1>00"'.

V AcuCl", : -' ~O~CI'" P;ITo~ , , ... ~p' · (~"CD'VAc:)

.. O.c. 0. ""'U'I·.~ '''tT" WI\" •• CootaD ,'6AFFc.E .(.$'~I"~ItC)

. .'.' ;a "'.~:~J~:~~f!~"~,:' . · .. ~fif'., , s ....... ..

""wJtW. ·.·.N ·T.... O":e'" t-A·""."· ,. ... ' C"AMM ..

pow~A. : . £')f"" toi Is ON "Y &of CIrai IS toJTILe .....

ON·T ... « .rN-tC ,..,.. ••

• AC" COi/. oJ 10 TU,ttS LOAO'O w .... 11 6 1/001,1

. . ~ ,....... a.B .... 'o.i' 'OArO.N& IS ".II' •• If~O ,,~w ~Y~G.

'" 1"-.0" F,'" ~ ""'011\1 : ,",or; 10111" ~ "7 t "'''",I>''' Ooo&. "'o~"'o Ho4Lt'1AN'rA"r Fo&' H,·Uo/t. &.o~OtNC:. (J"tW& G.~6)

F.'JCI4.T"ON IS ~ON.ONTW' I¥,'UOA.

~O •• S (Jr' H6~N O".r"~''41,. .r~r,o"T"Au.oAD"~" .. 9' 11'''A4.c..

T""I ~ 1)00 A. ,'.. AO-rAT'O " •• "'.0/ To c.Lo s. .,N. a,H~"'6.:'4t. ,

VA4UUH t;"'~H.'I& • . ~""WAft UNA'"

10 -\. '1Or,. Wt-'CN IJ0-r. u/.o. I"ew o"y.a &6 'olt~ ,",,'CflA#'I •• " '.

0f4!~fJ) ItNO COI&,..A .. 6 '/fIC"ltNG,O

~NO c.o" D'D "tI • .,,., A I~"i N''''''' f.f.oolr ... O~& ?eOr,e IN elM .... 0" HA'N",41AMe,

e .... c '< TM' "' v • ., "'.4J-r.

WI NO .. M" .... '/ us~ cH,eN- t.,. .. r. Seve irA" pOINT. MA". G.'~ "'.IJ""'~o

~"O"O'NG. ~"~~A'C'~c,,~· ...

-'_'0 L~"- f" .... r,..,''''.cI .'" ."'c... '1,....... &.oc~.,.. D 'Nfl, D. .,.116 C#lIfHd~tt..

( e_It .... 'ro;,'''',.o.. ""'1 C.~"';If'" 'N~ TM£ .... AM"- ~U"PAC.) .

p~caC!~~~! :

- ftouG."'- fw""'r'~ "f't4.:e ... I11 ....... '

U~'T" 'P""&$..,&£ It f ACfof '0·" 1l"''''6t:' .' , .

a ... 6o pte-r: Bo· . I

~ ~ So rtC*tT: If 0

- Row J"- rv'""'r:"'s. 'f).'//u""o- ~Mf \N,"" 'o·~".rr 1 ... H«ATt~c. PuMP .'L. ,

S_60 rte--.f\ 6., A-..So I. ~ 40

~..r ~o' 104 • .r:-==e. ~ ... ,o ~ tAIL O~

~O &0' "... ~."\J"~~ Foe. CoOLING "'H~ aA".,E

.... ~. CON 0 tftA,1 PtJltffiM Cia .

tiNT,,. ~"""A' C.~eM.t lo-r ~,fN.tI a-..'O : $)0' '.-4", So : SO'

- C;Lo'~ t).'IC."~".£.

3---'0 ~ J.4!lI.., "AC"Wl1 "A'~. Clo.t~ A

A ~rr~~ VAC.,," '.1 o~,.,'O ~NO ~ t'o.v-r_L£O Ov"'J,'O~ ~ .... L ... w A&,Io-..l..r 5 10·&'71"

"00 V Ate.Arr l,teJ

o.s ~ DI"C."~" •• ew .. ,,~r , .

10 proC&$,$

.. r;"AL Py~ PINe.

3", '0 10 -r ('.C!~ Jo I , 'C ,

t' I A..,$". , 10· ro...~&. c lo ,

Pol. e~c'" ON~ , TH ~. Voc...-r"'.E '.$

INC&eA.raao(.t,,,,,&..,.A N"OtJ~1.7 0#01

TMI ~ "ecTor,· ./ 10 eoifJ ..... 0L...) ,st.:>""7 '!"MoT. 'tu4 .1 __ 71&1.

wATe. .. ,AJ G. T'I" fl'1"A""~ "'J1 TWo fULL ~1"S .. .~.

OtJf..y.J p:a.LAHeNT;£ M.f!I .,,'I\'-'LE,

AFTI! a.. ,.aw. JT~P I NClI.l!'ltSE ,

ALv"'; AI"Ut-\ "£&. r. oN I:. I'fY.I-r TII£II.I .. INC".t4tE' V€"y

.$ to.., ~ Z N· ~/''1 .. ' .'N;tt#.,({f);, ~ CeU:,.r ~,,,,,,,'N'illf,: "",·,r'NG 110& ~C.L Co"S (CtJt'.M.~ 411",cr...Je.

"''''..... ~t.u" •. .,."'" "r'" ;r~ 4;lt) t(: IS .

't .. !~ v .... .,..~ ... IS 'NC_'~Z~~ M.t7r,« (JwTI~ eo",.". rr ~V~ pO ~ TfoAl (efuckul o""y 0"'- .,. ... e. .a VI' II G'''' eolU)

o reM'1"\' _AI'S .& ,..rATI! () IoU.,.,... ,... t' 3" II. Co\\' of ....-. 'NNIA..A'~C.

ON'1 I/. t:oiu M. ~ rlttlE /fED

.s'lftJl. -rIltNUOfJJ':!, ."

.... ". 0r.MTro~ ,,'f-ff.1tJ DONE E.. T~ .... s 'TO ".ro .... ,-. ALL..

tCf eo'" s ' val 4;"''''', o~ ~,c. IJ~OtC., ~,.ty ·AN'J AlY"';Nt~,..· 11'''''''NG 'J

,., 0 A. E ~1'I.z .. Ly cl,. cke.J •

&.-r,-,- c~.·~ eN..,. A.' ,:Vh". c. ••

," ", .. ; ~ .,.,.,' H, AAo& A 'II"' 'N" ~ -r:"OI\l 9 ~ A c.. " , .t "I~""'l c,",u.&'cd • ....1 .,y",. ....... ",'-r/.cf·ir 1fttI.'1f'1- I'r. rcffol' • .J·

\U,Tr.-..&sJ' Ga&...\U 4&. ~.~ """""1). '~"''1 '7"b 1+"Ao", • .,., .. r8 N~

Dt! roIlT£.J:j AWI1; A/,'tJl1 .,.lIidtN,,,.r.

J".,,.,,TAnoNJ .-_ ,.... ",.a'" A &.&.. ~"':.' ,-.....

_ ",UO ~ '-ANO',-...,... C,OI4(J"~

ANo "H6 .,.,,,. CfMI'"'''' N6.

- "A"'O".~ C. .,....~ No'" .Il..,.r"y W"'''''~~ . .

.. A/o "A r. ,.O.,.~cnON .0'" ""1&4101&. ~,,~ce D~ ... 'NGa "'~O'.NA.

- D~.T'l A",.,'ANT' ....,

_ CoNTItC"-' C~"'N"N" ...,.:",. .. ~e • .$cA.lt ro". ~

- IAI~PFt'C ... ~-, ca.LOI4ID ""CHA ... 6

.. Tbo k,...y 40,,-_ ~ow ••• A ..s'''IIt. T'A N"."""Y' ... ~ .. "'Ic..",~ca CONT&oL. OtR=.cuc..r, __ po.s .. , ..... '. 0 •• r'.e:.s .... ".~., ~t. • . At.\I P'OJec,"'·OM.I

. LOIS .," ALU ..... a. Il"Na., -- Tbo ,.~ .1,.60 ~vlf"o&An04J

A v'J,T o~ Ou~ £~o Vf\c."ClI1 ..J,~e,'AL,~r

N£ .. ,. u~ To .sT~"'" "'oo; .. ,·~.,.,·o~,.

\~.'tIl." ,. M~.·~'f. _ C.L.A N .... M ... ,.,e_,r w • .,.~ . .

ptl"r Le .. ",..." Ow,..ltO'

_ A, __ ,.c.o W .00 t:- ~. L ". ,t AAo I&.

wAat+,'NCa P"".c"tO~ ~t.~INlr.Al.rr

_ DutT' IlRMO \lAc.. w,.,.... CO .. .lNO~

,. .. ,0" AL.tJ M, Alf ",,"'0-'" o.c.. P«,£c. 1T'A,p CO~ T,'~G (o..r Clt.~~ ;.;"" O.,,'rl 04L6"M'C., ....

11"0 ~L) - NON Co""tl1C."r ALeo 0(.. .0-, 'lilt;. - .$.~"tAA"'1 POW'I&,'Nta oP "ft,lHf~

CO""fI"'.~ &ONr&o "'''0 ( .5/".,...,. ... NtlOIJ' ", .. ,.,)i,6 4NO ~,,~,,)

....

AHo ~ C,ONT;~.,Otl. ""1&1&01& O""'~"N. WI'nf eol.. ,sIJOw ;lltilllO p •• ' -Off m.p eo At'f AJ CIa r. '4J e."" 6". " r,.", IF

p •• ,'01) I!J~TW6~N. ""'0 AI-tlI'I, NI ..... "ONJ

-

Mt. Palomar

Presentation by R. Thicksten

CALIFORNIA INSTITUTE OF TECHNOLOGY

PALOMAR OBSERVATORY

PROCEDURE FOR WASHING

AND

ALUMINIZING

THE 200 INCH MIRROR

Revised September 21, 1991

Edited from the notes of:

Earl Emery Bruce Rule Robert Thicksten

200 IIOi Au,,"'1 - Revised 9/21/91 - RPT

Preparation for Mirror Wash

Inspect the surface of the mirror to determine if there is any material which may have come in contact with the surface that may need special cleaning attention.

Oil is removed by using solvents before preceding with soap wash.

During the wash it is necessary to prevent water from getting into the cell area below the mirror where the delicate support system for the mirror is located. To prevent this, a Mylar dam is placed around the perimeter of the mirror and should protrude about 4 inches above the surface. A skirt is then taped below the dam to prevent any over-spills or leaks in the dam from reach­ing the cell. A pan is installed in the center of the mirror, and is sealed to the glass with an O-ring and· bol t-on clamp assembly. The pan is supported by the flange that carries the coude' pedestal. In the center of the pan is a lifting handle which, after installa­tion, is replaced by a drain assembly which passes liquids through the mirror and cell below.

Clean the outside perimeter of the glass with acetone and alcohol so that tape will adhere well.

Tape a plastic drop-cloth around the perimeter of the glass about 12 inches below the lip edge and let it extend down below cell.

Put double-sided, 4 inch wide masking tape around the perimeter as close to the lip as possible.

Attach/Install a single 8 inch wide Mylar (or similar acid resistant material) to double sided tape and the seal bottom edge wi th 4 inch wide gaffers tape. Note that Mylar should extend about 4 inches below and about 4 inches above the lip of the glass.

Apply second course of- gaffers tape over and extending about 3 inches below the first.

Install the center pan using O-ring and drain tube. Make sure the bottom pass-through plate has been removed for the tube to pass through.

Install the drain hose from the drain tube to floor drain.

Make sure all sponges, buckets and chamois are thoroughly cleaned in Orvus and distilled water before the wash.

\

2

MIRROR WASH

Soak

Mix ab·out 1/4 cup of Orvus soap with about one gallon of dis­tilled water in a plastic bucket. Make up 3 to 4 buckets. Have one person standing by to make fresh soap solution as needed.

Do not use tap water which might contaminate the sponges with particles that could scratch the mirror.

Wet the surface with the soap solution and period of 15 to 20 minutes to allow the soap away as much dirt as possible.

keep it wet to lift and

for a float

Note .that it is important that from now until the mirror is dried, it be kept wet in order to prevent drying marks.

Rinse

Rinse using filtered tap water at low pressure through an ordi­nary garden hose (all metal fittings removed) for about 10 minutes. Pay special attention to the Mylar to mirror gap as soap will collect there.

When the rinse is complete, a worker is placed in the center of the mirror. This worker, along wi th other members of the wash team gathered around the perimeter, begin patting the surface with sponges soaked with Orvus soap and distilled water.

The procedure is to pat the surface 3 to ~ times, turn the sponge over, pat 3 to 4 times again and then rinse the sponge in the soap bucket. The idea behind this patting procedure is that debris that might scratch the surface 1s picked up and discarded before doing so. Rubbing could, of course, carry the debris across the surface and scratch it.

Rinse

After the entire surface has been patted/washed 1 t is again rinsed for 10 to 15 minutes and then washed again. Be sure to change bucket solution, at the least, between every wash.

If the mirror is to be aluminized, proceed to ACID WASH section.

3

200 mOl Al.L\~ - Revised 9/21/91 - ~T

Clean Sponges

After the second wash, wash the sponges thoroughly to insure that no particles that might have been picked up by the sponges during the patting wash remain.

With clean sponges, apply the soap solution to the surface in a wiping motion - do not press down, but rather drag the sponge across the surface. Rinse in soap solution after 2 long swipes -one each side of sponge.

Rinse

Rinse with tap water 10 - 15 minutes.

Repeat wash, this time using light pressure in sponges when wiping.

Rinse with tap water a minimum of 20 minutes, during which time the man can be removed from the center of the mirror and the Mylar dam can be removed. Do not allow the mirror to dry!

Using distilled water poured from buckets, rinse the mirror with about 15 gallons.

Dry the mirror with clean chamois.

(00 lNOt Au...., - Revised 9/21/91 - RPT

ACID WASH

After·a hose rinse, respirators and protective clothing are put on by workers to protect them from the acids and caustic chemicals that will be used to remove the aluminum coating. Also, fans are set up to suck fumes from the work area and exhaust them outside.

Apply Green River Solution

A solution of 1 quart hydrochloric acid, HCl, mixed 'with 2 quarts water and 1 ounce cupric sulfate, CuS04' makes up what is referred to as "Green River" solution (the cupric sulfate having turned the diluted acid green).

This solution is carefully poured from plastic buckets over the surface from the perimeter. A dam of disposable, lent-free paper lab towels is normally placed around the mirror, about half way to the center. Another dam is placed around the center hole of the mirror. These dams will slow the flow of the acid from the surface and allow more time for the chemical to dissolve the aluminum. After a few minutes, have workers begin wiping the surface with lab towels to aid in the removal of the aluminum. This is a dangerous time in the aluminizing _process, as workers must stretch out over the glass to reach the" ,entire surface. The worker that is in the center pan must position himself in a squatting position as one cannot kneel in the acid that is flow­ing to the drain beneath him. Also workers must be careful that the fume masks and safety goggles are well secured - if they fall off and hit the surface, damage to the mirror could result. After about 5 to 10 minutes the honeycomb structure of the Pyrex glass is evident.

Rinse

After about 30 minutes or so, if there is no longer any evidence of aluminum, all lab towels are removed and a 10 minute hose rinse is begun.

Apply Potassium Hydroxide KOH solution, followed BY Calcium Car­bonate.

The next step is to apply a caustic solution to the surface to remove any aluminum particles which still may be adhering to the

_ surface.

Mix 1 part KOH with 25 parts water and apply evenly over the surface.

Again, dams are placed on the surface, and after application, the solution is agitated with lab towels. After 2 to 3 minutes, CaC03 powder is dusted/spread over the surface. Using lab towels, the

5

200 ltni ALI..M - Revise:] 9/21/91 - RPT

powder is mixed with the KOH solution on the surface and then this mixed solution wiped over the surface for about 5 minutes -rinse before drying starts.

Repeat.

Rinse

Rinse for about 30 minutes - pay special attention to the dam, the CaCo3 will want to stay between the glass and Mylar.

Apply nitric acid solution.

Mix 1 part HN03 with 1 part water and apply to the surface - do not leave this on the glass for more than 2 minutes.

-Apply the diluted solution of nitric acid over the surface -again dams are used and the solution agitated with lab towels.

Rinse

Rinse for about 30 minutes - again, pay special attention to the dam area.

All protective clothing can now be removed and returned for washing and storage.

At the end of the rinse the Mylar dam is carefully removed to insure that there is no splash-back from the wet Mylar to the glass surface. During "this, as well as preceding steps, no part of the surface is allowed to dry. If any portion of the surface dries, there will be some type of drying mark left which means returning to an acid wash.

Final Rinse .

Distilled water,. about 20 gallons, is: now poured over the glass. As some water will go over the outside perimeter, workmen standby to mop up any spills.

- The skirt which has protected the mirror cell is now removed.

6

200 lOOi ALl.l't1 - Revised 9/21/91 - RPT

DRYING AND ETHYL ALCOHOL WIPE-DOWN

Disposable lint free cotton gloves are put on and the mirror surface is dried using lint-free disposable paper lab towels. Towels are changed frequently.

Once the surface has been dried, immediately precede to wiping the surface with ethyl alcohol. A lab towel is held in one hand and a plastic squeeze bottle is used to apply a small amount of alcohol to the towel. The towel is then wiped across the surface in one pass and discarded. After about 20 minutes of wiping with alcohol, "black breath" tests are begun.

Breathing onto the surface should spread a even layer of moisture which will be evident for a few seconds when viewed against a distant light source (our fluorescent work-lights work OK for this). During the few seconds available, wipe marks or other sur­face defects will be apparent. When the breath test shows a smooth even surface stop wiping. The alcohol bath can take an hour or more.

W~~e the perimeter/side of the glass with ethanol.

The mirror is immediately placed into the tank and pumping begun.

7

200 IIOi AU..., - Revis~ 9/21/91 - RPT

PREPARATION FOR ALUMINIZING.

It is a good idea to test the system a month or so ahead of the engineering/aluminizing run to insure that the system is func­tioning properly, all gauges are working etc. In the past, opti­cians have even melted the aluminum on to the filaments during this test procedure. Experience has shown that melt-in is not necessary.

Verify that electrical leads in the tank lid have been changed from the melt-in mode (single filament firing) to the mode for pair firing and fast firing. At this point the tank lid should be on it's supports on the observing floor.

Inspect the filaments visually.

Replace broken filaments and its firing partner using filaments.

8 loop

Load filaments. Wearing clean cotton gloves, use the special long-nosed pliers to install 3 loops of aluminum per filament (315 filaments in all). Each loop is 0.47 inch long aluminum wire, 0.040 inch in diameter. For fast fire filaments (total 35) use 5 loops of aluminum.

Check for continuity and possible shorts of all filaments using an ohm meter.

Record which filaments were replaced in the filament log-sheet.

Clean the tank. Remove debris, clean surfaces with solvent (acetone) as needed.

Check that the tank-to-mirror a-ring is clean, greased (silicone vacuum grease) and properly seated.

Insure that the port windows inside the tank lid have been stripped and cleaned for easy viewin~ of the glow discharge and filament firing. ,

On the tank lid, clean and grease the main flanges that seal to the rubber grooves in the base. Also clean « grease the base grooves.

If desired, put several clean glass test slides/plates on the stainless steel plug in the Cassegrain hole and around the outer shelf for possible test purposes.

8

2CXl I~ ALlM - Revised 9/21/91 - ~T

Assemble Tank

With the mirror prepared, raise the four guide posts into posi­tion and lift the tank over the mirror. Lower the tank slowly until the O-ring mirror seal is a few inches above the lip of the mirror. Using a bright light source, watch to insure that the D­ring does not come off as the tank is lowered around the mirror. Stop - when the tank is about 4 inches from contacting the cart. Raise the cart until contact is made and slack is apparent on the lifting cables.

Lower the crane hook and disengage. i

Lower the cart so vacuum ports are ready for contact. At this point the tank is separated from the pumping manifold by 2 feet or so. Clean upper and lower flanges and clean and grease (light­ly) a-rings on manifold and roughing interfaces between tank and pumping s.ystem.

Move tank into contact with the vacuum ports; align and bolt upper and lower ports together.

Put the pair firing transformer (same as for 84" tank) and fast fire transformer on top of the tank at a convenient place towards the direction of the aluminizing console (control). Do not put these transformers on the tank before this step or the tank will be unbalanced for lifting.

9

m l~ ALlJtl - Revised 9/21/91 - RPT , ~

PUMP-DOWN

On the observing floor:

Activate all circuit breakers

Turn on air compressor for pneumatic valves

Turn on water cooling to all 3 roughing pumps

Make sure drain-hoses are properly located.

Make sure water is flowing through each pump.

At the Control Console:

Install water lines to intermediate and bypass D.P.s. Check water flow.

Install gauges to tank.

Install glow discharge and other electrical to tank.

Turn on main power.

Check control board to insure all valves are closed.

Turn on the TC gauges.

Prepare pump-down chart recorder to record tank pressure.

Turn on the 3 roughing pumps (Stokes, Kinney, eX LeBold) and moni tor their individual, isola ted base pressures. They should reach less than 50 microns in less that 15 minutes.

I

Open the Stokes pneumatic valve, RV2 ~o the D.P.s and fore-line. , Open the two mechanical gate hand valves, BV1 eX BV2 one for each pump at about foot level on the D.P.s.

When the D.P. fore-line pressure is less than 50 microns turn on D.P. 's and the 2 refrigeration compressors for D.P. cold traps (on observing level).

Turn on the 2 separate water valves for D.P. cooling. The water temperature should be stabilized, by ~egulating flow, at 115 -120 F. This takes about an hour.

The tank may be rough pumped whi I e the D . P. "s are heating up using the Lebold and Kinney to pump the tank. Open the pneumatic valves, RV1, FV2,RV3 eX RV4 between the pumps and the tank. Make ~ the valve FVl to the D.P.s from these pumps stays closed.

10

200 loo-! AWl - RevisEd 9/21/91 - (:$>T

While the tank is pumping down connect the firing cir­cuits. The fire lead of the small transformer connects to the inner or outer lug, with a shorting cable between inner « outer lug. The large transformer hot leads CORnect to lugs marked 1 through 10 on the Lucite bar. Both transformer ground leads connect to bolts on the steel structure. Make sure all Variacs are turned off and all knife switches are open.

When the tank pressure is below 1000 microns, (30 minutes or so) activate blower switch from time to time. When the pressure is low enough the blower will stay on. The pressure will fall fairly quickly (15 minutes) below 10 microns.

When the tank is below 50 microns, close valve FV2 and open valve FV1 to put the Kinney on backing for the D. P. 's along with the Stokes. This leaves only the Lebold roughing the tank.

When the 'tank is below 50 microns, turn on the emergency bypass and intermediate D.P. IS. Check water cooling and proper heater operation on these 4 pumps.

Turn on ion gauges.

Turn on the chart recorder.

Moni tor D. P. gauges ION 2 « ION 3 to enSUl:e they are w_'!fking properly - the pressure should be at or approaching 10 . "'-"-TCRR.. Gl'giAS.

When the bypass, intermediate and main D.P.s have come to tem­perature and the high vacuum io~auges ION 2 « ION 3 indicates a pressure of less than 25 *' 16 microns, open D.P. gate valve DPV1 or DPV2 making sure the fore-line pressure does not exceed 100 microns (GAUGE TC1) for more than 30 seconds. It. may be necessary to cycle the valves open and closed a few times.

, -5 The pump down will take about 5-6 hours to about 1 X 10 -3 -*-~~~ tII •• us. After the tank pressure has reached about 1 X 10 m.J,.-~ :IS (about 2 hours), fill the liquid N2 trap. Carefully monitor the filling of the large plate surrounding the filler hole. It has- an O-ring seal. Avoid spilling Ln2 around the filling hole. Ln2 could freeze the O-ring seal and cause a leak.

Glow Discharge

-5 ~.-e~ When the tank pressure is about 1 X 10 .~ ••• R8, initiate the glow' discharge procedure. connect an oxygen cylinder to the Kerotest valve on the tank feed-through. Set the pressure to 3-5 p.s.i. (Flush the air out of the hose before connection)

Isolate the tank by closing the main roughing valve RV1 and the gate valves DPV1 & DPV2 on both D.P.s. Crack the kerotest valve very slowly and let the pressure as read on gauge TC6 rise slowly to 30 microns.

11

200 JrDi All.f!l - Revised 9/21/91 - RPT

Turn on glow discharge (control console) and run current up to 10 amps (200 V) for 3 minutes. Monitor and control the current button (up - down) as the current can fluctuate fast and consid­erably. Observe the glow discharge through the port if the there is a lot of arcing, lower the current a bit, but not so low that the glow cannot be seen.

After glow discharge, open the roughing valve RV1. After a couple of minutes the pressure should be less than 10 microns Open the D.P. gate valves DPV1 &: DPV2 one at a time; the fore-pressure as measured at gauge Tel, should not exceed 100 microns - as before.

Repeat the Glow discharge 6 times. After each cycle, the pressure should return the previous value in 20 - 25 minutes or so. Pro­ceed to next cycle.

-5 After last glow discharge, wai t for vacuum to be near 2 x 10 m~1C

~:I;3S. Make sure the liquid nitrogen trap is full.

Filament Firing

Activate paired firing circuits. Set the Variac to 105 volts. Install clamp-on ammeter and the chart recorder clamp-on ammeter to monitor proper time on of filaments. Note: you will be moving the rotary selector though 360 degrees - 0 - 180 paired fila­ments, avoid getters marked G (obsolete).

Prepare chart recorder.

Attach the recorder's clamp-on amp meter to one of the firing lines. This meter will not give any indication while plugged into the recorder. Use another meter, attached to the same line, to calibrate/measure/check current as recorded on the chart.

Check that there is at least a 1(4 roll of chart paper in the recorder.

I , Put the 'v/mv' to the 'v' position.

Put the 'var/cal' to the 'cal' position.

Put the 'h/o/min' switch to the 'hI position.

Put the 'speed' selector to 'I' position.

Put the 'range' switch to the 10 volt position.

Put the 'm/o' to the '0' position.

Install recorder pen.

Turn on the Power

12

200 lOOi ALL.'I! - Revised 9/21/91 - I::?T

Use the green knob to align the pointer to zero on left side.

swttch the 'm/olswitch to the 'm' position.

Record the gauge readings on the log-sheet.

Set the Variac to 105 volts and turn it on.

Set the recorder speed to 10cm/hr and volts to 2V. This should give a recorded first spike that may be off the paper, but the melt-in/firing waveform will be large enough (peak to peak) to read easily.

When firing the filaments, switch the recorder speed from 'hr' to 'mini and then back - this saves paper.

Set the rotor switch to the filament pair to be fired.

While watching the recorder, press and hold the firing switch button. The current will surge and then drop and then slowly rise again as the aluminum melts and then begins to vaporize. As it starts to drop off linearly and gets just below the low point that was reached after the spike, release the button - this s6buld take about 8 to 10 seconds. A timer will turn off the supply automatically after 12 seconds.

Note the filament number on the recorder paper as each filament pair is fired.

Continue until all filament pairs have been fired.

13

200 l~ AlJ.l'I1 - Revised 9/21/91 - Ji?T , ':>

FAST FIRING OF FILAMENTS

Immediately after paired firing, prepare for fast fire. Put Variac at 68 volts and turn the Variac circuit breaker on. Throw the knife switches in prescribed pattern as below:

Tine (sec.) 0 1.7 3.3 5.0 6.6 8.3 10.0 11.6 13.3 15.0 16.6 18.3 20.0

~ife en 1-2 1-2-3 2-3-4 3-4-5 4-5-6 5-6-7 6-7-8 7-8-9 8-9-10 9-10 10

~ife off 2 3 4 5 6 7 8 9 10

Thus each knife is closed for 5 seconds, the time deemed correct to prevent filament being heated while bare of aluminum (1987).

This value was determined by activating the circuit - knife # 1 and watching through the window port for telltale visual evapora­tive process. This time may vary slightly according to filament age, aluminum contact initially etc. However in failure of 1987 aluminizing, the timing was grossly off. The filament was on for 9 seconds, for 4 of those seconds the filaments were bare of aluminum. - Earl Emery

14

200 ltci Al1."'1 - Revised 9/21/91 - RPT

SHUTDOWN

Close North and South gate valves DPVl & DPV2 to the manifold.

Turn off the North & South D.P.s as well as the Booster D.P.s.

Turn off the Intermediate and Safety bypass D.P.s.

Note - do not close the main roughing pump valve RVl until the intermediate and the emergency bypass D. P. s have cooled. The blower and roughing pumps must back these D.P.s. until they cool.

When all Intermediate and the Safety Bypass D.P.s have cooled:

Close main roughing valve, RV1.

Turn off the blower pump.

Turn off all ion gauges.

Introduce oxygen to the tank through the Kerotest valve at about 3-5 p.s.i. Use one bottle.

"& After oxygen, introduce air to the tank through the filter port.

Turn off water flow to D.P.s and roughing pumps.

Disconnect gauges to tank.

Disconnect water hoses to tank.

When temperatures of North, South and the Booster D.P.s reach ambient temperature.

Close valves IN THIS ORDER, BV1,BV2,FV1, RV2, RV3 and RV4.

Turn off the roughing pumps.

Turn off all TC gauges.

Turn off refrigerant condensors.

After 30 minutes, turn off water flow to roughing pumps.

15

200 I;fjj .:J:u.l - Revised 9/21/91 - f:FT

pump-down log sheet

ROUGHING (TC) GAGE READINGS

'I

TANK PUMPS ! I

Time Manifold, Inter- , High , Roughing' Stokes , Kinney , Leybold , , mediate , farside , I I I I , , I I I , , I I I I I I I

START I I I I I I I ! I f f I I I I I

00:30 I I I , I , I I I I ! f f f I I , 01:00 I I , , I I I ,

I I f I I I ! f I

I 01:30 I ! , ! ! I I I f I ' f I I I I I I , 02:00 I I I I I , I I I I I I I I f I I I 02:30 I , , I I , I , I ! I I I I I I I , 03:00 I , I I I I I I I I I I I I I I I I 03:30 1

" . , .1 I I I I , I I I I I f· I I I I 04:00 I 1 1 I I I I I I I I I I I I I I I 04:30 I I I I I , I , I I I I I I I I I I 05:00 1 I I , I I I I

I I I I f I I I 06:00 I 1 , I I I I I

I I I I I I I I 06:30 I I I I I I I I

I I 1 1 f I I I 07:00 1 1 I I I 1 I I I I 1 1 , I I I I I 07:30 I I I 1 I I I I I I I I I I ! I I , 08:00 I I I I I I I I I I I I I I I I I I , I I I I I I , I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I , I I I 1 I I : I I I I I I I I

I I I I I I I I I I I I I I I I

I I I I I I , , I I I I I I I I

»P

VI /'

ST

aK

ES

o

J)pv

a

NO

RTH

I~ ~

GA

TE

VA

LV

E

WlN

D'"

tLJI

20

0

INC

H

AL

UM

INIZ

ING

S

YS

TE

M -,

.--.

,,-,.

VI

RV

l -

MA

IN

RD

UG

HlN

Ii V

AL

VE

It

Ye

-S

TtI

KU

ItD

UG

HIN

G I

'UM

P

VA

LV

E

1tV

3 -

ICIN

NEY

R

DU

GH

DG

I'

tH"

VA

LV

E

DI'

Vl

-m

mt

JIJ'.

G

Att

VA

LV

E

Drv

e -

ND

RTH

JI

J'. G

Att

VA

LV

E

WI

-JD

DS

TD

t _

. G

AT

E

VA

LV

E

.VI -

.aD

ST

ER

_

. G

All

: V

AL

VE

FV

I -

f'DR

EU

NI:

VA

LV

E II

F

YI

-f'

QR

EU

HE

V

AL

VE

H

TC

I -

TC

G

IoU

GE

-S

TIl

CE

I PL

MP

TC

R

-T

C

GM

JGE

-1C

lN€Y

PU

lP

Tca

-T

C

GIo

UG

E -

LE

Y..

.. P

UM

P T

C4

-TC

G

AU

GE

-TA

NK

-

IIDU

GH

V

AC

T

CS

-T

C

GI\U

GE

-TA

NK

-

INT

EJI

ME

DlA

TE

V

AC

T

C6

-T

C

GI\U

GE

-T

AN

e -

HJG

H

VA

C

1C7

-T

C

GAU

GE

-IW

GF

DL

.D -

HIG

H

VA

C

ION

I

-IO

N

GA

UG

E -

MA

NJf

'DLl

I IO

N

I -

111M

G

AU

GE

-SO

UT

H

D.r

. IO

N a

-11

1M

GA

UG

E -

NO

RTH

_

.

DIN

4

-D

IN

GA

UG

E -

TA

N(

-H

IGH

V

AC

IO

N

II

-JO

N

GA

UG

E -

TAN

K

-IN

TE

R.

VA

C

KIN

CY

o·

HJG

H

VA

CU

UM

INT

ER

ME

J)lA

TI:

V

AC

UU

4

RC

UG

H

VA

CW

H MA

SH

R

OU

GH

ING

V

AL

VE

.LO

\(E

R ~ L

EY

KL

D o

TC

4 ,,-

Roque de Los Muchachos

Presentation by B. Mack

Summary Presentation: The Current Plans for Future Observatories

Contents:

1 . Columbus Project 2. Gemini Project 3. JNLT 4. Magellan 5. VLT

B. Atwood K. Raybould M. Nakagiri A. Schier M. GrossI

Columbus Project

Presentation by B. Atwood

The Columbus Report

ESO Workshop:

Cleaning and Coating Large Mirrors

Eso Headquarters, Garching

7 and 8 October 1991

Bruce Atwood and Barry A. Sabol

I Columbus Aluminization Configuration

II Aluminization Experiments-The Columbus List

ill Aluminization Experiments at Ohio State

1. Our equipment Diffusion Pump system Thickness monitor RGA Power supply and transformers Monochromator with

absolute reflectance accessory 2. Gas evolution during aluminization 3. Effect of background gasses on reflectivity 4. Pumping schemes 5. Filament geometry and source function 6. Power supply strategies

;: :.: · i · " · ~ ~, '"

99B5 9ZZ0 J6Z!l

" I':

lODntJ JUl l1l111 : III I I II !UIIII ii):,:'. T f;7 I i r ~

-

~ e <: -::

--I

I t

i

I I I I

I

r-W/~~' -/ci...--i" ~ I I 0168

ALilldINIZING EXPERTh1ENTAL AND DESIGN ACTIVITIES

(version 25 March 1991)

Improved Optimization of Filament Locations

• w / 0 baffles • w/baffles

.0". w / baffles and plasma • increase to 5 rings • optimize in single filament plane

Model Aluminum Distributions vs. Reality

O. comparison of model to chamber thickness measurements .

• thickness measurements by transmission

Verify the Properties of "higher density" and "astronomy standard" aluminum coatings

[samples from Las Campanas] [samples from Italy] [samples from Sunnyside] [samples from :MM:T small chamber]

• higher reflectivity • lower emissivity • washability (snowability)

Study Aluminizing in Argon

• reflectivity vs argon pressure • reflectivity vs oxygen pressure • profile variations from scattering • ionization of the argon?

Study Plasma-Assisted Aluminizing

• reflectivity and adherence measurements • ion assisted aluminum properties .• antenna design • special chamber requirements

Chemistry and Logistics of Coating Removal

• quantify the aluminum removal recipe from silica • quantify the silver, gold, chrome removal recipes • conduct experiments with potassium ferro cyanide • conduct experiments with Printed Circuit Board

etchant • quantify the effects of the silica recipes on E6

- long term damage tests - aluminum removal rates

• consider alternate removal schemes • integrate coating removal into cell design • design edge seal in detail (polish the edge) • design scheme to apply chemicals to the mirror • design scheme to clean the mirror

Impact of Mirror Support and Ventilation on Coating

• measure leak rates of mirror supports • measure leak rates of ventilation units • measure leak rates of the honeycomb structure • quantify the contaminants • estimate the tolerable leak rates in dirty vacuum • measure leak rates of butyl rubber seals • estimate the tolerable leak rates in clean vacuum

Filament Power Considerations

• measure filament transformer properties • price high current feedthroughs • design and build filament power supplies • estimate standard filament power and load • measure leak rates of transformers

Pumping Designs

• estimate required pumping speed • quantify getter pumping scheme • cryopanel design and test . • experiment with hydrogen gas effects • compare commercial cryopumps to cryopanels

Chamber Design

• specify number and location of ports • specify flange configuration • chamber testing requirements • interior coating (epoxy, AI, stainless, Ni ?)

Bell Jar Preparation and Handling • design fixtures for filaments and pumps • develop loading procedure • study integration of cleaning and coating procedure

ALUMINIZING EXPERllvIENT AL AND DESIGN ACTIVITIES

(version 25 March 1991)

Improved Optimization of Filament Locations

Model Aluminum Distributions vs. Reality

Verify the Properties of "higher density" and "astronomy standard" aluminum coatings

Study Aluminizing in Argon

Study Plasma-Assisted Aluminizing

Chemistry and Logistics of Coating Removal

Impact of Mirror Support and Ventilation on Coating

Filament Power Considerations

Pumping Designs

Chamber Design

Bell Jar Preparation and Handling

BASELINE liST OF ALIDv1INIZING SYSTEM FEATURES

250 -- 300 filaments, 400 -- 600 Watts each

··4 -- 5 rings of filaments

Filaments in a single plane

1.0 -- 1.5 meters above the mirror

Filament shutters and baffles

Dedicated low voltage wiring to each filament

Strip mirror horizon pointing

Install chamber horizon pointing

Clean mirror horizon pointing

Aluminize horizon pointing

Chamber divided into clean / dirty sections

Blowout valve between sections

Roughing Pumps: Roots blowers backed by rotary pumps

HiVac Pumps: Cryopumps or Cryopanels

Residual Gas Analyzer

Quartz Crystal Thickness Monitors (- 8)

Pressure Gauges

Bleed Valves

Edge Seals for ventilation, washing, aluminizing

Dual O-ring flange seal in keystone groove

3 . -- 4 one meter vacuUm ports on the top hat

Dummy mirror cell baseplate with 1.0 meter op'ening

Thermocouple readout system (shared with telescope?)

078 Ohio State/Colum:bus Proiect

1E ~----------------------------------------~ ~totaI ~a6E-7

2 3

: : · . : : · . · . · . · . : ~

4

· .-· ·

5 6

tE-iO+,----~----~--~----~--~----~--~~--~ 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00

Time (minutes)

101

Ohio State/Columbus Project 1E~6~------------------------------------~

-c- 1E-07 ~ ",. AMU16 0

1::.. CD

AMU15 "-::l en AMU14 en 1E~8 CD ~

a.. co t:: AMU13 co a..

(Ratios as expected for Methane)

1E-10+---~--~--~~--~--~--~--~--~--~ 0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00

Time (minutes)

'C" >-o l:::-CD '-::s U) U) CD '-a.. ca 1:: <1l a..

1.0~

Ohto State/CotulT-lDUS Project

AMU28

AMU29

AMU30

AMU27

1 E-1 a Initial total pressure 1 E-6 0.00 0.20 0040 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00

Time (minutes)

012 Ohio State/Columbus Project

lnitfaa total pressure 7.3E-7

1E-O ......... _-

AMU 78 (A/(OH) 3?)

1E~~~~~~~~----~------~----~----~ 0.00 0.50 1.00 i.50 2.00 2.50 3.00

Time (minutes)

1E-04

lE-05 :;:

Q) 1E-06 ... :: ::J en en Q) '--a.. . ttl t:: ttl 0..

:: ---

1E-07 = . : --

1E-08 ~ = : --

1E-09 0.00

104 Ohio State/Columbus Project

Jrnttab tofal! Pressure 9E-7 85& Angstroms deposited

H2

V H2O

J

~ - ..... V .

0.50 1.00 1.50 2.00 2.50 3.00 Time (minutes)

~ '--

~

087 Ohio State/Columbus Project

Initial total pressure 8E-6 Small ait ·feak Note 02 gettering

~ 1 E-06:::r--__ --9-

:::l en en CD "-

~ 1E-07 H~

t:: ctS a..

iE-08

1E-09+---~--~--~--~--~~--~--~--~--~ 0.00 0.50 1.00. 1.50 2.00 2.50 3.00 3.50 4.00 4.50

Time (minutes)

----0 c CD -:J

'UJ fI) CD -CL as 1:: as 0...

1E-05

1E-06

1E-08

1'00 Ohi:Q State/Col:umbu.s Project

H 2

1E~'+---~--~--~--~~--~--~--~--~--~ o. 00 5. 00 10. 00 15.00 20. 00 25. 00 30.00 35.00 40.00 45.00 50.00

TIm"a- (minutes)

106a1pt Ohio State/Columbus Project

Initial total pressure 7.8E-6

1E-08

1E~+---~----~--~--~----~--~----~--~ 0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00

Time (minutes)

c "-0 t::. CD "-::l tn tn CD "--a..

ctS t: <tS a..

1E-05

1E-06

1E-07

1E-08

1E-09

{)"o~ Qlaalpt

Ohio State/Columbus Project

Very low initial H2O

H 2

. ... _ ....

HO 2

1 E-1 O-t---,-----r--~----r-~--r____-~-_,__-_i 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50

Time (minutes)

Ohio State/Columbus Project 1.00E-OS_

- 0 --

-c--a C.

--& -:l -(I) (I) 0 CJ)

0 - 0 c-as 1.00E-06:

0 0 r

as 0 0 CL -- 0 CIt C -as ~ (ij --c

"-

1 . OOE-07-t-----r---....-.,--1..,--,.11--r-T""'"T'-'.------,I..----.---,,.---,---r"""T"""l~

1.00E+02 1.00E+03 1.00E+04 Reaction time (seconds)

I Columbus Aluminization Configuration

II Aluminization Experiments-The Columbus List

, "

m Aluminization Experiments at Ohio State

1. Our equipment Diffusion Pump system Thickness monitor RGA Power supply and transformers Monochromator with

absolute reflectance accessory 2. Gas evolution during aluminization 3. Effect of background gasses on reflectivity 4. Pumping schemes 5. Filament geometry and source function 6. Power supply strategies

Coating Thickness. Distribution Helical Fifament

1.20...,.....-----------i ------------, I 90

~ 1 oo~ ~ .... --... - G- ..... ----.--B- _-,ft} ... __ --.. e···---··---·-&-···----·-{ J ~ . '-p-............. -.. -.. -__ -e_.------.-B-··~~~~;==::::·-·-·8--... --__ ~z::.~. __ .... __ .-... -.t J

~ 0.80[~_ .. __ _.~/""~-. I ... ~.'''''''::-:---.-. 45 .-+h

~ 0° •. 4060

, "--=:~;? i::;~:~~~~~p E d ~ ~ i ~ 0.20- I

0.00 -90 -60 -30 o

Azimuth

• 30 60

- ... Elevation=90 ······8····· Elevation=67.5-··EJ····· Elevation=45

... 3-.... E1evation=22.5 ······8-·· Elevation=O

90

( .s

) i.J .... R.. -L . . {C

v';.' f: ~ ... tt, .~-J4... e,;.I''' ,

.r .' __ (_- ,-,.' ~l

~ L ... -I'(,..t.

t- :,., :-..: •• , ....... <>.:>.~~:-: .. :.'~' ',' .:.: .... :.~~": ... ~:.--: .... :~~ .. ~: . .;: ':"::~ ... ,. ::.:~.:: ::~'" V,';:::"': .~.~.

, ---- - -

{~rt ,1"'/1.

f ;4-, ~ oJ/. ~c I: Ie ( "c ." ... .(. .... ;-~J ",J ./ l .. .."." j/., ... ;- ~Q~1

1L ( .f- .- ~t..c. I. " IT.-- I"J t 4<:.- t:. J" I

t!~,:"",'t.''''''' { "' ......... ~ J

Ohio State/Columbus Project 6E-01 ,~

5E-01

-CD 0

4E-01-~

E -Cl) CJ 3E-01 c: as -.- (;) ~ "0 2E-01-c::

·0 0 0

0 1E-01- 0

c OC

OE+OO 0.00 100.00 200.00 300.00 400.00 500.00 600.00 700.00

Thickness (Angstroms)

:::J Optical Thickness * Mass Thickness

I

;: i I

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

• 1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

-0

.. _

--'v

..

J-,U

9

1/

40

0

.. ~.-;o

, ..

.. o

J .

...

o "-

,OX

) ,o

x)

'" OJ .., • OX

)

01' I

-... OX)

...

...

~

-

.----

---~--

~

I

~~

-.;: .2

u

.;; £

P.4

.' ]

.;;7

*.4

x ...

.

1 U

4

lb4

6

I 1

I -.

,

r ~~iE~

1 I ~

----

t71-

I i ~

'1 : !

I '

I I

1 I

~ f--

'-----L

----I-

' :

! ~:!

: ::.

1 !

I '{

I

i ii'

i ~

I I

\ I

;

Ir-~'

I 1

1 r

1"-I

;, v

II:

I IV-

I t

-1"

-G '

! e---------

--,-

-I

..

I iii

I ~

~ .t!

! !

,~ ~i~-~

~ ~,

i {ii I

,,

~'"

, ~

~ ~

! r~,

i !

\'~ '-

1\

J 1 ~

111'1

0 I~

I -I

;1:

~-,.

' g(]~

1 ~

(~

-~

~IT

J -

---,

i : i :

r [I

~-/

1/ i

0' -r~

_co,

'"

~I______

OX)I

k' 1

~ ~

~I J

'---/

III

v.,-

:.--

----

! -I

~Y

l '

~I

~ ,I

'I'loto

J ./

"'i:

I

I I

!'

1120

~ !

-..

.

.. -

-

65

9

51

50

85

0

ISE

(TIO

N

EI

OSS

ER

VA

TaR

IO

AST

RO

FIS

ICO

01

A

RC

ET

RI

DRAW

N BY

I SCA

I-'

PR

OJE

CT

: l

COLU

MBU

S PR

OJE

CT

2xB

.4 m

OPT

ICAL

TE

LESC

OPE

P

AU

LL

I 1:

50

W

ASH

ING

AN

D

AL

UM

INIZ

ING

E

QU

IPM

EN

T O

AT

[

~

~[Q)~

O'ii' §

.IU

£ S.

R.L

. 0

5-0

6-1

99

1

SIST

EM

I A

VA

NZA

TI

QA

AW

l","

~R

AD

S 0

10

33

3

'Ih

a'

PI)9

111

51

/8

22D~3

LE

eCO

le

ol

_. __ .

---

-

C\J >

~ ',~'~~.... -...... _ .. _- --.. .. . .. __ l~:~:········"··\

"" "".'I"'~~:'J;"~:""'('··(?~:":'.'·" :.·.'·>-I·"'¥~~:~~:=~~-~~~-~:=~:~:~-:~~~-~:-~~~':~2L __ , 'Z -, .. . ._ •.• _________ .. ___ .• ____ . __ . ____ • __ ~ _____ •. _. __ . _____ .. __ .• ___ .. ______ . ____ .:J"

rc;.: .. ·_ .. _·· .... · .. · .. ··_-_· .. ........... 'Y' ........... __ ........ -_ .. _ .............................. •....• --.-... -.--•.•. -.-., •.••••.• ~.-.-...... . \

,',I! ;1 l l ,

///'/ 1// i J ,( ,1 ( f

//1/ /// if i t i i / .,/ii Iii

;1/ ./ ./ ,. / / U I; ! I i

/1// iff /:'11/ 1//

/ ,.// / / / / ./ ;'.;' i / : I ,i .' j ~~ I ! ; t I :'i.i!/ jf." //1;' .:// f ; I j ! ! ,i

UI! 1/1 ;Yi/ //! ././ ,f (f i .. ,;

1/ ,l I·I / l / } . il",! iii ! I 1 /' t J I ,'I .. '\ I"}

// /! \. / l ! ; .. ! i .... ( I ,t

f .:' / / i '~,' / ,/

/ // / / // /. // / I / :'

.!/ / / .I / ! I ;' / I -' .___-.---.J

<:X/ F;;;;// . , ,f,:.:~j t _ 1;

-, .. "",',7":"7 l '. '. , "., !

" ~ '( . "!

i !

/ i

./ I

I I

i i

, {

i j

i

,~

\ ; , I 1 ! 1 1 l 1 1 1 1 ,

o

J ~I

-

, -f----

jF1

c=

~

'.

" ..

~ ~.

on ~ '"

<Xl

0111

'1 ~

~I

OSS

ER

VA

TO

RIO

A

STR

OF

ISIC

O

DI

AR

CE

TR

I CO

LUM

BUS

PROJ

ECT

2xB

.4 m

OPT

ICAL

TE

LESC

OPE

11

20

W

ASH

ING

AN

D

AL

UM

INIZ

ING

E

GU

IPM

EN

T

DRAW

N BY

I

SCAL

E

PA

UL

LI

I j:

50

OAT

E

r2fh

l /fo,

[Q) ~

~'ii' £

ILO

£ S

.R.L

. 0

5-0

6-1

'91

__

~

SIS

TE

MI

AV

AN

ZA

TI

A;;t~j~~3

$-v,.

01

P •• G

l 5

0/0

2

20

53

LE

CC

O

ICO

I S

HE

£T

1 O

F 7

/~

.~~

.. --.

- --~

'---.

--

. '/1t

~~.

/~,/?~O~;~~

/ /71

1 [~

r:o~

~'/ :/

I .1 \ -" /'

-./

~/.

/.

./"~

Df'A

WN

IY

:sou

: P

AU

lLl

1:25

0 I O

SS

ER

VA

TO

RIO

A

S T

RO

F/SJ

rQ_

Ql.;

"IK

EIR

L_

PR

OJE

CT

: CO

LUM

BUS

PRO

JECT

2.l!

8_"l.

..9fIl

CAJ,.

I~i

,.E;

~(Qf

:~-J

G

EN

ER

AL

AS

SE

MB

L Y

. _.

. ....... __ ._

t-

--o

.- TC--+

--

.~

fA ~ ~

U'ii' ~[6

a~

S.R

.L.

SIS

TE

MI

AV

AN

ZA

n

"" ..

MaG

I ~

n0

5) l~r(n t

rOt

17-0

5·19

90

DfII .

. wt"~

3006

25

t!'"

Ilf=

'CT

n

r:

Gemini Project

Presentation by K. Raybould

1. Start anagressive program, to de.n1onstate the· feasibility of producing durable lo.wemissivity coatings. . .

2. Investigate methods for cleaning the primary mirror in-situ.

1. SCIENCE REVIEW MEETING IN US 18119 JULY 1991 .' .. .

Concluded that one of the highest priority for the Gemini project is'the capabifity to' deposit low emissivity durable coatings.

Tef,escope emissivity specification 40/0 . (excluding scattering and sky contribution) .

..

Te~escope emissivity can degrade to 5% before the mirror emissivity must be reduced to the post coating level.

Target emissivity of 2%.

SCIENCE REQUIREMENTS· .

GEMINI DEVELOPMENT PLAN FOR LOW EMISSIVITY COATING

IN-SITU MIRROR- CLEANING

-

PROGRAM FOR DESIGN, PROCUREMENT, INSTALLATION AND COMMISSIONING

Primary mirror (silver coated)

Secondary mirror (silver coated) , C.' '

. . .;

O.Smm bevel around secondary mirror

. Secondary mirror support vanes (12mm) 0.40/0

Primary mirror bore (hole in centre) 0.00/0

Diffraction, at edge of secon.da,ry(1 0 microns)..O.2%

Scattering off mirror surfaces (APART) ? .

Other sources ? .

LOW EMISSIVITY DURABLE COATING I . DEVELOPMENT PROGRAM I

~:.;.:.;.;.:-:.;.:.:.:.;.:.;.:.:.:. ," '-:.- .:."': ',' {o ..... • ...... ,'. :.' '.' .................. .; ••••• ;. •• ;.;.; •••••••• : ... ;.:.: •••• :.:.:.: ..... x-............. ,':. ";';' ... :' ',' .. • ••• ,' ... ',' • .;.:.,' ..,." .... : .•.•.. ,' .•.•. : ...... ',' .••....• : •. { .. ·····ti::;:i:·:i<i·:·:·:f·:·:·:~f,.:-;k·:·:·:(ifu·:#?:.?,:. ·:"'f

AIMS-

1. Literature search on potential coating tech~iques. Silver is the prefered film for its low em'issivity in the IR.

2. Small scale testing of a few promising te~hniques. Durability of coating to be tested with accelerated environmental testing. .

3. Coat 1.3m IR telescope optics.

4. Ift-3 are. successful, investigate methods of boosting the relectance fn the blue and UV end of the spectr'um.

5. Develop methods for cleaning the primary mirror in-situ.

,PROGRAM FOR DESIGN, PROCUREMENT r :'

INSTALLATION AND. COMMISSIONING ; ":O;:::X:;·::;::·:-:::·:·:·:·;·;::~'~'··:·.~·· '.:.' '''; . .;>; •• : ..... ;.: '.:.:..:v:' .... .., :,:,,:-:.:.;.:« . • .,<. • • ,', ...... ;.0: • •••• ',.. •• •• :««.. . "'. :« . 'oX • y: "';:'.. .• . 'v..: :.:.;.: .. 0:-' ....... :.: ... : .... \.-:-».: ...... :-:.«;. :: .... :::

.1. Develop sputtering process hardware design for ~esting in the 4.2m chamber. ' . - .

2. Design and specification'

3. Procurement

4. Test assembly at manufacturers

5. Ship

6. Assemble on site

8. Coat primary mirror

uv LAS

ER-C

l.l~

ANiN

Q: O

F A

ST

RO

NO

MIC

AL

TE

LE

SC

OP

E M

IRR

OR

S

Con

tact

: .

Dr. W

ayne

:',K

imur

a:

STI

Op,

tron

ics.

27

55 .N

orthu

p,:W

@Y'

· . '.

Bell

e\iu

e~ W

A:':9

SQri4

,' USA

~"

. Pho

ne:

(206

) 827

-046

0 .

, FA

X:

(206

) 82

8-35

17 '

'; 'k

• .r~

_

_ .

_,,

' .~'::';,-,:;''-'.;

CU~RREMTSTATUS

• T

echn

ical

Iss

ues

Rel

ated

to

Las

er C

lean

ing

Ast

ron

om

ica

l Tel

esco

pes

Det

erm

inin

g o

ptim

um

tech

niq

ue

(e.

g.,

lase

r pu

lse

ener

gy,

# o

f sh

ots

/site

, p

uls

e r

epet

ition

rat

e) -

de

pe

nd

s on

co

nta

min

an

t

Sol

ving

eng

inee

ring

issu

es s

uch

as

be

st m

eth

od

fo

r de

liver

ing

lase

r be

am a

nd r

emov

al o

f exp

elle

d d

ust

• S

TI O

ptr

on

ics

is In

tere

sted

in W

orki

ng W

ith O

bs'e

rvat

orie

s to

Dev

elop

T

his

Ap

plic

atio

n

Col

labo

ratin

g w

ith

Uni

vers

ity o

f Was

hing

ton'

AS

tron

omy

De

pa

rtm

en

t on

join

t pro

po

sal'

In d

iscu

ssio

ns

wit

h N

atio

nal O

ptic

al A

stro

no

my

Obs

erva

tory

-P

leas

e co

nta

ct W

ayne

Kim

ura

at S

TI O

ptr

on

ics

for

mor

e in

form

atio

n

I

·.·STi·

to#mC

:>NI@

··

, BAC

KGR

:OU

,N:D

• T

ele'

seap

e M

irro

rs D

eg

rad

e'O

vert

ime

:

Incr

ease

of e

mis

sivi

ty a

nd s

catt

erin

g, d

ecre

ase

of r

efle

ctiv

ity

Rec

oatin

g la

rge

dia

me

ter m

irro

rs e

xpen

sive

and

ris

ky

Nee

d b

ett

er i

n si

tu c

lean

ing

tech

niq

ue

s

• P

ossi

ble

Sol

utio

n:

Use

Las

.er C

lean

ing,

Cap

able

of e

asy

and

sf:lf

e in

situ

cle

an

ing

.

Fre

quen

t cle

anin

g po

ssib

le (

e.g.

, da

ily)

-en

sure

s co

ntin

ual

op

timu

m te

lesc

op

e p

erf

on

na

nce

.

.

Cle

an d

uri

ng

da

ytim

e to

min

imiz

e te

lesc

ope.

do

wn

time

,

.',

• U

V L

aser

Cle

anin

g o

f Sm

all Diame~er M

irro

rs H

as A

lread

y B

een

Dem

onst

rate

d

UV

lig

ht b

ett

er t

han

visi

ble

or

IR l

igh

t

Exc

imer

UV

lase

rs r

eadi

ly a

vaila

ble co

mmer

cial~y STlt~IH _·_

.. CS

RE

VIE

W O

F B

AS

IC C

LE

AN

ING

ME

CH

AN

ISM

• M

elec

ular

Con

tam

inan

tFl$

.Alo

val '

P

hoto

chem

ical

dis

soci

'atio

n

• m

ole

cula

r bin

din

g e

nerg

ies

are

typ

ica

lly s

ever

al e

V

• ea

sily

bro

ken

by: ~V Ji

gta~

. P

hoto

ther

mal

pro

cess

es'

'.,

....

• d

ire

ct a

bso

rptio

n o

f UV

lase

r ene

rgy,

by

con

tam

ina

nt

• m

inim

izes

lase

r ene

rgy

need

ed t

o c

lean

sur

face

• P

artic

ulat

e R

emov

al

. . .

Ab

sorp

tion

of l

aser

lig

ht l

eadi

ng t

o v

ap

ori

zatio

n

Gen

erat

ion

of o

pto

-aco

ust

ic s

tres

s w

ave

• p

art

icle

s lit

eral

ly b

ou

nce

off

sur

face

. .

• re

quire

s pu

lsed

lase

r sou

rce,

suc

h as

an

exc

ime

r la

ser

I .

Ele

ctro

stat

ic b

on

d b

reak

in,9

bet

wee

n m

irro

r sur

face

and

pa

rtic

ula

te

• U

nifo

rm L

aser

Bea

m P

rofil

e Im

po

rta

nt f

or

Effe

ctiv

e R

emov

al

. S''F':t~PiRnN1es

C0MiF~RAT:I;V:E:E¥A!LtJATli0N-

:, C

02

AN

D

UV

EX

CIM

ER 'L

ASER

CLE

AN

ING

OF

-MIX

ED

CO

NTA

MIN

AN

T LA

YER

(PA

RT

ICU

LA

TE

S/D

IOC

TY

L P

HT

HA

LA

TE

) O

N A

I-C

OA

TE

D

Si

cte

an

ed

C

o-nt

amin

at-e

d

-5

0

urn

C02

(5

.5J/

cm

2)

(no

eff

ecti

ve

rem

ov

al)

1

--Cl'~~'

~'~d}-::

:::','

I" ',

'C-

:_,

-: ':"

,-"

--',

' ,

,:'

_

'I Co

n:fa

~ffi

i'B'

:a:t

'ea,

I

-'-, '

"-

-

, ---I

t'" ~~.~ ":

.~.;

~~:...

-(.~'::

i:~': "b

'~;"

\:.

,.,,--.-,

,

"'!*

"~ ,"

'41-

i~."

~:\'<;;'''''?'

~~:~

~~~~

: 5

0

un1-

"\J

V (

0.3

J /

c m

2 )

(co

mp

lete

rem

ov

al)

-,S-:1

!#.fOP

TRON

ICS_

KITT PEAK NATIONAL OBSERVATORY

SCHEDULES AND STAFFING

FOR MAINTENANCE OF TELESCOPE OPTICS

COATING SCHEDULES:

ALL TELESCOPE OPTICS ARE REALUMINIZED ONCE A YEAR EXCEPT

FOR THE 2.1 METER AND 4 METER TELESCOPES. DUE TO THE TIME . . .

AND EFFORT REQUIRED FOR REALUMiNIZING THE 2.1 METER AND 4

METER TELESCOPE OPTICS, THEY ~E BEING REALUMINIZED EVERY .

THREE TO FIVE YEARS.

WASHING SCHEDULES:

ALL TELESCOPE MIRRORS ARE WASHED A MINIMUM OF ONCE EVERY

SIX MONTHS.

STAFFING:

• PART TIME SERVICES OF ONE ENGINEER FOR SCHEDULING AND TECHNICAL SUPPORT.

• PART TIME SERVICES OF TWO TRAINED TECHNICIANS FOR WASHING, COATING, AND OVERSEEING ALL MIRROR HANDLING.

• PART TIME SERVICES OF REGULAR MOUNTAIN OPERATIONS TECHNICIANS TO ASSIST IN MIRROR REMOVALS.

KITT PEAK ALUMINIZING CAPABILITIES

2.4 METER & 4 METER COATING CHAMBER FACILITIES

I. Both coating chambers are pennanently installed in fixed locations

(aluminizing rooms) and all optics are transported to the aluminizing rooms

for coating.

. . II. The aluminizing rooms are fully equipped to handle all mirror operations.

Each room has overhead cranes to handle the optics and washing facilities

for stripping and cleaning the mirrors.

III. It has been· Kitt Peak's experience that the use of stationary coating , "

chambers and fully equipped aluminizing rooms has provided quick turn-

around times and minimum down time due to equipment failures. About

the only maintenance required on any. of the chambers is the standard

preventive maintenance activities.

NOTE

Originally, the 4-meter chamber was designed to be moved to the main floor of the 4-meter building for aluminizing the primary mirror and the mirror was to be installed in the chamber on its cell. In practice, it was found to be much easier, quicker, and safer to remove the mirror from its cell and transport the mirror to the chamber on the ground floor of the building.

COATING CHAMBER DETAILS

1. Only aluminum coatings are currently being done in both chambers.

2. Both chambers are only capable of using filament arrays for evaporations.

3. Both chambers are using diffusion pumps and meissner traps.

4. Only the 4·meter chamber has glow discharge capabilities which is not

currently in use.

s. Both chambers have never experienced any major mechanical problems in

over twenty years of use and the coatings produced in both chamb_ers are of

equal quality.

PERFORMANCE Of COATING CHAMBERS

4 METER CHAMBER

DESIGN PERFORMANCE SPECIFICATION;

Coating Uniformity: ±5%

Depositio~ Thickness: ~loooA

DELIVERED PERFORMANCE;

Coating Uniformity: ±27% thickness variation under the best conditions.

Deposition Thickness: Maximum thickness seldom approached 800A (Usually 400A - 600A)

CURRENT PERFORMANCE;

In 1985, modifications were made to the filament· arrays, the filament baffles, and power distribution circuit.

Coating Unifonnity: Better than ±lO%.

Deposition Thickness: Approximately loooA

2.4 METER CHAMBER

DELIVERED AND CURRENT PERFORMANCE:

Coating Uniformity: ±lO%

Deposition Thickness: 800A - lDOOA

4 METER CHAMBER MODIFICATIONS

FILAMENT ARRAY ARRANGEMENTS:

ORIGINAL FILAMENT CONFIGURATION

MODIFIED FILAMENT CONFIGURATION

BAFFLE ARRANGEMENT:

The baffles were catching much of the evaported material.

The baffles were raised closer to the filaments increasing the angle of incidence of the deposition on the substrate from 20 degrees to 45 degrees.

PERFORMANCE:

The ±10% coating uniformity achieved with these changes was adequate for all known NOAO coatings. The cost for further uniformity improvements was prohibitive.

MIRROR REFLECfIVITY MEASUREMENTS FOR REALUMINIZED MIRRORS

TELESCOPES CHAMBER 3500A 5500A ?JJJJ.JA

WIYN 3.5M 4 METER 91.7% 89.5% 95.3%

0.9M 4 METER 85.2% 87.1% 94.9%

U of A (2M) 41v1.ETER 88.7% 89.0% 95.4%

#1 VACUUM 2.4 METER 89.2% 90.3% 95.4%

#2 VACUUM 2.4 METER 88.1% 90.2% 95.7%

McMATH MAIN #1 2.4 METER 89.5% 90.3% 95.4%

McMATH WEST AUX #1 2.4 ME1ER 88.5% 90.5% 95.9% !

. r : ,

McMATH EAST AUX #1 2.4 MElER 90.0% 90.2% 96.2%

COUDE FEED #2 2.4 METER 88.5% 89.5% 95.7%

MIRROR CLEANING PRIOR

TO ALUMINIZING

1. ALL LARGE TELESCOPE OPTICS ARE STRIPPED AND CLEANED IN

THE ALUMINIZING ROOM.

2. THE MIRRORS ARE REMOVED FROM THEIR HANDLING CARTS OR

CONT A1NERS AND PLACED ON STANDS OVER THE FLOOR DRAINS

FOR STRIPPING AND CLEANING.

3. IMMEDIATELY AFTER THE MIRRORS HAVE BEEN CLEANED THEY

ARE PLACED IN THE CHAMBERS FOR COATING.

4. THE COATING CHAMBERS ARE PREPPED AND READIED FOR

FIRING PRIOR TO BRINGING THE MIRRORS INTO THE ROOM FOR

CLEANING.

PROCEDURE FOR STRIPPING AND CLEANING MIRRORS PRIOR TO ALUMINIZING

The following solutions are used in this process:

Solution "A":

Solution "B":

Solution "C":

Mix Hydrochloric Acid (HCL, 37%), Reagent grade, with distilled water in a ratio of 1: 1.· Then add 28 grams of Copper Sulfate (CuS04), Reagent grade, per liter. of solution and shake until dissolved. .

Mix distilled water with Potassium Hydroxide (KOH), Reagent grade, in a ratio 20: 1 and shake until dissolved.

Mix Nitric A~id (HN03' 70%), Reagent grade, with distilled water in a ratio of 1:1.

1. Rinse mirror' thoroughly with filtered tap water.

** Wear Protective Rubber Gloves for the Following Steps **

2. Remove any oil spots with Acetone or Xylene. 3. Apply Solution "A" to mirror surface. Using lint-free tissues soaked in solution

"A", rub the surface briskly to remove the coating. 4. Rinse mirror thoroughly with filtered tap water. 5. Repeat steps 3 and 4 until old coating is completely removed. 6. Apply solution "B" to mirror surface and rub briskly with lint-free tissues. 7 . . Rinse mirror thoroughly with filtered water. 8. Reapply solution "B", spread a light coating of Calcium Carbonate (Reagent

grade) over the entire surface, and rub the surface with lint-free tissues. 9. Rinse mirror thoroughly with filtered tap water.

10. Repeat steps 8 and 9 several times. 11. Apply solution "c" to mirror surface and rub briskly with lint-free tissues. 12. Rinse mirrior thoroughly with filtered tap water for 5-10 minutes.

** Remove Gloves **

13. Apply enough distilled water to thoroughly rinse off tap water. 14. Wipe surface dry with lint-free tissues. Do not let standing water air-dry on

surface. 15. Use filtered gaseous nitrogen (Nz) to blow off any dust or lint. 16. Mirror is now ready for aluminizing.

TELESCOPE MIRROR WASHING

CURRENT PRACTICE (ALL TELESCOPES):

1. Mask off surface of mirror from rest of telescope with plastic sheeting and tape.

2. Position telescope to permit wash solution to drain out holes provided for water removal.

3. Wash mirror in accordance with the approved wash procedure (see attachment).

4. Remove any excess water from the cell area with a wet or dry shop vacuum cleaner.

5. Remove plastic sheeting.

EXPERIENCE:

For several years strippable plastic coatings were successfully used for

cleaning mirrors, but has been discontinued due to the potentially

hazardous chemicals some of them contain.

CLEANING PROCEDURE FOR COATED MIRRORS

1. Required Supplies:

a. Two 20-liter, hand-operated, pressure sprayers. b. Two liters of reagent grade alcohol. c. One tablespoon of Alconox (Phosphorus-free detergent soap). d. . Ten liters of distilled water. e.One half liter of acetone or xylene. f. Several clean sponges. g. Several boxes of lint-free tissues.

II. Cleaning Procedure:

a. Clean spray containers thoroughly with distilled water and alcohol.

b. Fill "Rinse" container

c. Fill "Wash" container

d. Use acetone or xylene to remove any oil stains.

e. Spray mirror with "Wash" until all loose particles are removed and gently rub surface with wet sponges.

f. Spray with "Rinse."

g. Use tissues to tamp surface dry. DO NOT RUB!

PRIMARY MIRROR HANDLING

2.1 & 4 METER J'ELESCOPES

MIRROR REMOVAL AND INSTALLATION:

1. THE LARGE TELESCOPE MIRRORS ARE REMOVED AND

INST ALLED WITH THEIR CELLS ONTO MOBILE HANDLING CARTS.

a) 4 METER USES THE 4 METER COATING CHAMBER CART.

b) 2.1 METER USES A SEPARATE CART DESIGN SPECIFICALLY

FOR THE TASK.

MIRROR HANDLING FOR WASHING, AND COATING:

1. THE LARGE MIRRORS ARE HANDLED SEPARATELY WITH THE AID

OF OVERHEAD CRANES AND CENTER LIFTING FIXTURES FOR

MOVING THEM ON AND OFF OF THEIR CELLS, INTO THE

CLEANING BAY, AND ONTO THE COATING CHAMBER CARTS FOR

ALUMINIZING.

-I . I

"1 i

·j

· . .. " .. ::-... " .. :

:. ~:':'

: .. :

........ , ".'-.

· , .... , 1

-1 I ., , I

"OJ

· '1 .. ',1 '''1 .. :.j' 'j -, i

'j

.'j "1 '. 1 -I .. J

l __

.. _._---_.-------------

. __ ._._ .. _-.. _------

Japanese National Large Telescope

Presentation by M. Nakagiri

an 8 .. moptical .. infrared telescope project

·J,.c 0 t:

~ ·s

Q) u

>... a J-4 0 H

S O§

..... J,.c

~

e cc

.. I I f"" "i" ,- ':

r I ,..;/.: ...

I . i? f

IV ~ {- ':':7

"

+P ,.

I :':~:r-

fG " ~j t; " , >

I r-- .;~.~' • :-. ,

t..::'" "

Z

I ;

w " ,

m 0

I '-1 -'

w I ~-~

::r: ~ => w I ::r: ~-

..lJ ~

" ~. ~ .. -

" 1-

I ;'

"'-,

::> :J)

I L I :J

~I

: c;~~~~ . ~ :'-. ~ .. J ;'t:-~.

"" .~

"\"':~l~:t ":~r'J.{~~~~~~.~:~; "'~. ~ :·~~·_~.·~ti~·~~.~~-

'!

. ~ .. -;~ : ~.:,

Coating Procedure of SUBARU Telescope

m Outgasing the Vacuum Chamber

Lockup the Telescope

@ Carriage Uove in under the Telescope

@ Demount the MirroriCel If

Lower the Mirror/Cel If on the Carriage

® Move the Carriage on the Uirror Hatch

00 Li ft up the Mirror(CeI I)

@ Carriage Move out

@ Lower the Mirror to Vacuum Faci I i ty

@ Cleaning, Re~oval of Coating

Put the Mi rror in the Vacuum Chamber

Vacuum Pumping + Ion Bombardment

Reverse Operation

~ ~ ~ ~ ~~ ~m II!!

1m Ii

• jgl • m

~ ~

tI*

-9£-

.., :t;:

.~

"" ~

!!I Ifll.l ~~ ~~ IH2 ~\lKtd .i.i~ e!~ ~~II ="' ~< :t:: ~I!i 'r:t:: K: -LJ '" 8 {

I ________ -L ________ ~

!!I ~~

';'t«~ ~~IS :;:15

iJ

!iii l± ~ I--------~----------------~

JI!j l!j JI!j

f~ ~U!~ fr ~ ~~ tf ~ t~ ~

i,"~

!!! l±~ II!! ,\ ~

~ IK Y ~~ I!i ~ ~ '*'~ ill t1 ~ \t.lll:

cp

1 U

!'if S 4 S II!! .U~II!!

!'if t:nu~ II W s ~1l~1I!I .J.j ti!iill!f~.

i"~4tlt~_~ :..1:11110(';.

!L.

(+

JI!j f( ~ ~ ~ ~ Ii

:, , .... .. ~ c-'0 ~ .. -0<

II!! n

SS !f~ :S.!..

S 15~ I!!! " " 0 ' ,~ 5::::~ Kr<r<C'oo

o 0 0 ... - ............... .... " ~ ~ ,.. .... .... ......... rer<co-.co.r<

II!I 1.'(

, .. CIt . ~ rs ...... ... "

• S I!!! !t .' I!< !.. ••

t< ..... or .. M M -., . ~ ... <

• M

It

M

"' a

Ii

II

!S!$ I!!! I!!! I!(~

~1!\!1

-LJ

Ii: , ...

«

ill

III" HI: S 1Jj I!!! II!I

,\ 1:>( ';'!ilI f~ ~~ .. ;"m; ~!t:~~PIJ h~!H~lF

.:.

':-.

lit t~ = t~

t~ * t~ 1I1l

0-

~ . It Ii tI' t~

~~ tt (II! ~ ~ 1ID(ll.

:-LJ

illll!I I!Jf

I I I

II I i II

1~ II!!

"tl ':'1)(

... ~ < 18 "'-.. lit

!!f !t! t::

Ii IS ~

Ii! r.:I F3 lilF3~

I'- I'-~a!

4 1 "t!!1 :..:..tiII

I .J...LI !L.

SUBARU ~ ·JNLT~·~ 3l~ 1n- ~c

" R',mctV(j Hfv\-o\" g.3m. hQalAK 10em ~ck. . Su.pporG~ dI;.2by.. fOUtTs. ~ mP.cft. aCliia"liN:,

..• Co~ i~ . ~Ifl~ rfo-.. ~ ~ i •• .. . 5~'(j ... k nntt/k", Ctimf.

'* Hr~r I wit( ~ Gel ,n.llac~ ~. ~ ~ I(,Ll~) -~ - -

- - -

--- . < -. , --

~ GQQA~VlQ- Rlo.~ ..... .

• Tof2sw~rro- -6tc1nu.su;,& ___ ~ ~~

10 /{O~ QvIc( HAh.ti&z.... e In. UxiI:6c!((fJzgw, ~Jt~

• ~uiJL_.

H· Tyt Hr. N. ITo

s

Hr. ~. Nt1rAEt( Rl .pn~ ~~~V"' Cr-(6<..Cb)

Co~ ~dpJ2,:sr

I

~ e f-H ~ I!g

~ m ~ ~ t()

~

.h! ", \ ~

> z (t)

u; c--: {§1

~" ~ ,,~

~""

~~{ 0()

~ J-,

V\ , ---

~ ff '-

\i'\ ... "-

-

~1- f>... 4- ('()

J 1 ~ ~ ---- 0

::::::>

---f

~

~ ~ G

~ , ~

....

.... ,

.... z .. \. 'J) '\.

N ,

1-. ....---.

...

c5 <

t\j ___ 00 ----

"-~

V\ "

_0-.~

'\.

:c ~ ~. " § ~. C<'

~ ~t Cc

04-

h;

o?o

'£

~

-'"

~

ca ----

ll\ -,0

1 ~ i Q.. II) ~

V\

l o

I I

. J

~J

I I·· um m m

~31;.~ . I

I . Q.....L1..1 . -'''f'1

f . .. I'

:~

~ ,..f,'t>f1 ,'1'1'1

f..{ luJVlt11 'sWl

-

MrRRO~ STRESS DORNEr HANbLl~Er o StAfpori(V'\d to",d~ti Dt/\

I"s\ck Ed~ ;-

I t;>po,Y\.lS 0'1\ ()v.t~(cla. E.~

Upper 5th 0. 050 .... 0.067 fa/Ir-,>ttJ.. \

.J ~----.:....,;.\ Pad

~~=O,D?'lx 3 x Z ::;: CJ,4-6

t uf t/nd Shock (2(7)

5tn:z.ss c,.,.~1r«.t.~

Fo.c1e>r ~ to Ho!..e

< 6, ~ ~f /r... r'-f t.

( D, 0 S Iv1 Pa. )

All~weJ /'12 Str.e.S5

Magellan

Presentation by A. Schier

--

----.---. ~

:<-~-:--;/-; .~// --------- /-/ ---- /-./ .. /~

'-~" .~----

--

----I

-r-

--

T-

I --

-

; I

' ,

I I

I i

I;

Mag

ella

n ~.

5 !M~ter r

I'ele

scop

e P

rqje

ct

, j ;

! I Ii; :;

. I

MIR

RO

S H

AN

DLI

NG

FQ

R! R

lj:C

?AfI

NC

l! ;

i I

I!,

' I ii,

i !

! I

I I

! I

! !,

I I

I

6:5 ~EtER H

~NDU

Nr CO

~CEr1S

: I I

I i

I

!I! I

I :

'All'

0

' h

' dl

o I

I ,

I 'I

I I'

0 ii,

I I

, .:

; mlr

r.o r,

an

, In

g d~ne i.o

n l.o

ne

eve

Wit

.o?e

tra

nsp

qrt

~, ar

~.

, 'e

leva

t.ors

,' .o

r .fr

ayed

ner

ves.

'I

,II

'I I

I I

I I

: II

: j!

I II

I I

I I'

I ' II

I I

' I'

i "

I I

I I

I II

I '

I .

I ,

I

• :C

art

run

s .o

n' ra

ils

i I

I I

! !\

! !

i !

I I

i

I I'

: :!

I

: ;

: iii

I I

I 1

: I

I •

,Mir

ror

alum

iniz

ed li

n th

e ce

lie 1

.0 re

mov

al r

e ll1U

ired

.,

" '

"1

'I

I I'

:'"1

I I

J'

I '

, ,

I I

! I

':

;::

I :

I I

I I

I \

i !

! ,

I , iii

I I

I !

I I

I :

I .~irr.or c~l~

and

~ar

~ a~

e bl

.ott?

m ~ecfi.oqs .o

r v~c

u1;l

m ichain~~r.: C

ell ~tays

.0.,. c

~rt

In s

ame

.orI

enta

tI.o

n, on~e

rem

ove,

d ff

.o~ th

~ te

lesc

.op

e.,

' •

; !

: :

; "

i I:

i I

Iii "

I ill ':

i 'I:

/'

ii'

i I

' ,

' ,

I I

I!

, 10 :

' : ~!

; 0

I I

.1 I

h'

d I 0

hi I

I

°d

I 01

'd bl

II

: ld

•

A I

gnm

ent

l.or

reln

stal

:ah.

on ~c

~ev~

'f

It,

.ol,1g

gU

I i e

rial ~

an

,U

et-n

.ose

pi

ns b

etw

een

the

cell

and

tele

sc.o

pe.:

Car

t h

as a

dequ

,ate

c.o

mpl

ianc

e.

: ,

' I

I I

I :,',

. i!

I I

I '

I I iii

I iii

i •

Gro

ss v

erti

cal

pOsi

ti.on

Jng

!via

, p.o~e~ s

cre~ ja

~ksl F

ina~ p.

o,siti

~ning

ria:

ha

nd-.

oper

ated

hy

dra

uli

c ja

cks.

! , ':

' ,

, iii

I '

"i

I I

' !

"',

I

i I I

I !

, ;

, I

~.o ~r

aQes

,l

; !

I ,

, ,

Mag

ella

n 6.

5 M

eter

Tel

esco

pe P

roje

ct

, ,

j ~

j \

MIR

RO

R H

AN

DL

ING

FO

RR

EC

OA

TIN

G

, .

! '.

. P

RIO

RIT

IES

: :.

I·! Iii

' ,

I ,!

:

(Eve

ryth

ing

assu

mes

ad

equ

ate personn~l

safe

gu

ard

s ja

nd a

goo

d re

sult

ing

coat

ing)

• M

irro

rSec

uri

ty

• S

impl

icit

y'

. ;

I '"

Mec

hani

sms

and

str

uct

ure

s B

ette

r re

liab

ilit

y :

Ch

eap

er 'f

abri

cati

on

Ch

ea p

er m

aint

enan

ce

Op

erat

ion

s "

,i..

. Few

er v

aria

bles

(pl

aces

for

mis

take

s) i

n th

e pr

oces

s F

ewer

tra

ined

peo

ple

req

uir

ed i

:

i. i

i .

! i

' !

. .

I I

• C

onsi

sten

t op

erat

ions

/pro

cess

: ,

-: F

ew a

dju

stab

le e

lem

ents

-!

No

sens

itiv

e ad

just

men

ts r

equ

ired

any

whe

re

. :

I )

I I

! :

r I

, \

Mag

el1a

n q.5

¥et

~r T

ele,

scop

e rr

ojec

ti

CO

AT

ING

AN

D;C

OA

TIN

G E

QU

IPM

EN

T F

OR

6,5

ME

TE

R!

! i

:

i .

I' I Ii'

I iii

: iii

. .

. I

I"

I I

, i

! I

. "

' ;

, I

: ,

' i

I I

I i

1.1

I I

i I

I ill :

•

Pro

cess

bas

ed o

n cu

rren

tlv j

used

tec

hnIq

ues

(the

rmal

AI!,

eva

pora

tion

) .

I 'I

1 .11

I

I I

I I I!

iii

. 'I

I I' I"'.,

1 ill

! I

: .

i .

i ,.

C 1 h~

m~er ~es

;gn~

I

i I

I II

I j'

, I!

i ~

I I

f

-F

ixea

up

per

p~rti

:on'ls

talnle

ss ~te

~1 I

I j

l\1i

r~or

~ell:

and

h?n

dlin

g c~

rt fo

rm l

ower

por

tion

I Pp

mps

:,i

i I

I I

I I

I I

I !.

I

I

: 2 ~8-

I;nc

~ (5~,O~O

I{se

c N

2)

cryo

um

ps1

I ; 1

5hp

Roo

ts b

low

eli\

! :

' I

I I

I I

: 25 ih

p :o

il-,

sea~

ed !p

utnp

1

:

-3

ring

s ~f fi

la~ents, ~36!fiI~merts to

tal,

~re~

all a~

o~c

e! '.

. 36

get

tef fil:ament~

i I

I I

! I

I )

i !

: i ::

I

-S

impl

e ~e

alto

~egfeg~te r

p~er

!(c1~

an~ v

icu'

ljm

fh,m~er fr

of I~

w~r c

~a~b

er

: :

'I ill

I I

I i

I I

\ :

: •

••

••

1.,

I I.

I

• P

rlon

tles

: :,' (

wJt

hln

the

cons

tral

nt1o

f per

sonn

el a

nd m

Irro

r sa

fety

) i.

i:!!

I I

I I

I :

Cle

anli

ness

; iii.

I I

I I

I I

Fas

t ~e

nosi

tior

i of:

co~t

ing

I I

I ;

: .

; f

! II

\ I

: 1

!

iii

i I

I I

I .1

32-4'0.0 .

.... , ........... _- I _"'"

! ------------------------------r---------. ----~~:.

I ------_ I I -----___ _ __ --------

t---------~------=====t======---------------J

IVACUUM CHAMBER ASSEMBLyl

\ I

~-

I

5 III

>- III

~ ... Ul g ~ 0 I- ~ . • < ... III CD~

..J

.J W u--

. crti ~ ~!:..

a: :r

~,

§ ~ f- ~

0 Q.. x w

1 <=> 8'

>- W

..J

ill

r'1

IJ)

IS) ffi " ... (\J " .... ....

Pum

p-D

own·

Cur

ve

_,

... 1

04

. .

..... _-

p [T

orr

I 1

'I

I

102 1

-~

II'

L.·

____

__

I I

-----'"

: :

-L_~\::

0'

I 1

-I

I

10

-2

I I

i I

I :

r I

_ 1

10

-4

I .

I

-I

I

-I

I

10

-6

r I

I 0

__

_

I

--

--.

--

----1

--1

-

'"-

_ -

I I

10

-8

l 1

L

I l

I

o 2

0

~c

..35'

4

0

60

8

0

t [m

in]

2*A

PK

6000

0+

1*A

A90

01+

1*

RA

3001

+

2*

S6

30

FII

(6

0hz)

LE

YBO

LD

VACU

UM

PRO

DU

CTS

In

c ..

E

xp

ort

. PA

2

1-N

OV

-19

88

/J

G/

VLT

Presentation by M. Grossi

VL T MIRROR MAINTENANCE CONCEPT

GENERAL

OBJECTIVES:

• Maintaining High Optical Performance - specular reflectance - homogeneity - long term stability

• Safety - personnel

. - mirrors

• Reliability

ESOIVL TIMGRlwrkshpt 111. 1

VL T MIRROR MAINTENANCE CONCEPT

GENERAL

REQUIREMENTS for PRIMARIES (TERTIARIES) exposed to dirty environment

• Broad Band Reflectance (i < 1 OO) R > 86 % from 300 nm to 20 pm

• Homogeneity better 0 / -1 %

• in situ optical performance control

• Coating Renewal • in situ Cleaning

• Standard Coating: Aluminium

• Coating Options: - Improved Mechanical Stability - Improved Reflectance

ESO/VL T/MGR/wrkshpt 1/1.2

VL T MIRROR MAINTENANCE CONCEPT

GENERAL

REQUIREMENTS FOR OTHER MIRRORS placed in environment with contamination control

• Broad Band Reflectance R > 96 % from 500 nm to 20 Jim R > 80 % from 300 nm to 500 nm

• Long Term Stability > 15 a

• Wear (abrasive) Resistant Surface

• in situ optical performance control

• in situ Cleaning

ESO/VL T/MGR/wrkshpt1/1.3

VLT COATING RENEWAL

PRIMARIES (AND TERTIARIES)

REQUIREMENTS

• Handling Concept

• Coating Renewal Procedure - Coating Removal - Mirror Cleaning - Coating

• Safety

• Reliability

• Telescope. Down Time < 48 hours

• Consumables

• Investment

ESO/VL T/MGR/wrkshpt 1/2. 1

VL T COATING RENEWAL FOR PRIMARIES

HANDLING CONCEPT

REQUIREMENTS (Mirror Maintenance Building MMB 1.8 km for from telescopes)

• Procedures - Dismounting the Cell from telescope - Attachment of Coverage - Dismounting M3-Tower - Transfer Cell to MMB - Dismounting Mirror from Cell - Transfer Mirror to Coating Carrier

• Mirrors covered and horizontally face­up during all handling operations

• Handling Devices - redundant - self-aligning - force control for movements

• Reliability, Safety

• Duration: < 10 hours

• Personnel Requ: 2(1) mechanician 1 mech.operator 1 controller

ESO/VL T/MGR/wrkshpt 1/3. 1

/\ 1\ .. -*-.. -¥-of- -H--++-+--

vV .-

" \ \ r' "\ \"

L

'--"'==~'" .

L----I

\

'\

\ .\

"-'.

"­"-"-

I,

J-.-.. -

./",,?

-' . .... ~ .. ~

/ i

-- . "..---

VL T COATING RENEWAL FOR PRIMARIES

HANDLING CONCEPT

Out-ot-Cell Procedure: ADVANTAGES

• Simple single vacuum vessel

• minimum vessel volume (~ 80 m 3 for substrate + carrier)

• consequent high vacuum design of substrate carrier

• Simple long term storage

• high reliable vacuum quality and thus coating quality

• mirror washing on eye level

• No risk of chemical attack for the cell due to washing

• No vacuum requirements for M-Cell

• No delicate alignment and sealing procedure for the mirror

Out-ot-Cell Proc: DISADVANTAGES

• Dismounting the mirrors out of cells

• Mirror handling from cell to carrier

ESO/VL T/MGR/wrkshpt 1/3.2

VL T 8M-COATING UNIT

LOADING CONCEPT

DRAWER CONCEPT: Advantages

• Minimum Volume and vacuum exposed surface in loading section

• Simple Substrate Carrier integrated in vacuum vessel design

• All lubricated eleme.nts (wheels, drives, gears, damping elements) on atmospheric side

• Natural barrier against carry-in of dirt from floor

• No vacuum area safety risks for Personnel

DRAWER CONCEPT: Disadvantages

• Contamination risk during washing

• Prolonged air exposition for vac vessel

• Additional vertical movement for closing the coating chamber

ESO/VL T/MGR/wrkshpt 1/4. 1

fLT 8M (oafi)1g {)J111

LOAlJING CONCEPT

j)R4 ' 'J-' ;,-, J ",'

" . ...... . , [J •. }1;J-o ..

I I

• __ ,,! r

/ / / / /

[l /Is/-:'.';,l,r!" -; - ~ '! - r. , r", .,c. . / " <

...... _------ -----

I / / / / / / /

VL T COATING RENEWAL FOR PRIMARIES

FILM REMOVAL AND MIRROR CLEANING

CONCEPT

• Cleaning rear and side surfaces

• Automated front side treatment - purging away dirt, dust, bird

droppings, oil and grease - removal of old coating - chemical neutralizing - drying

• Particle contamination control - drying - mirror loading in coating plant

• Pre-cleaning prior to coating (in vacuo)

ESO/VL T/MGR/wrkshpt 1/5. 1

VL T COATING RENEWAL FOR PRIMARIES

FILM REMOVAL AND MIRROR CLEANING

PROCEDURE

• Cleaning rear and side walls, lateral pads, axial tripods: - manually with alcohol - in lifting area - while M 1 is hanging, prior to front

side treatment

• Crane operation: Setting mirror on Coating Cart, removal of lifting tool and top cover

• Moving mirror into Washing Area (coating carrier on rails)

• Allow recovery of contamination control

• Attachment of Washing Unit (manual) - mirror hole plugged tightly by

collecting tank - Spilling protection on outer mirror

edge

ESO/VL T/MGR/wrkshpt1/S.2

VL T COATING RENEWAL FOR PRIMARIES

FILM REMOVAL AND MIRROR CLEANING

PROCEDURE (cont'd)

• Machine process for AI-Coatings

- Soaking and large o Tap water rinsing, dirt removal: (recycled)

- Dirt removal, o 3x detergent, 50 0 C

(mechan .lchem.) Jet spraying

- Detergent o 2x Tap water rinse removal o 1 x Tap water spraying

- AI - film o 2x NaOH, 5% aqu. removal rinsing (recycled)

- Lie residues, o 1x HCI, 5% aqu. O-Iayers removal + CuSO 4, rinsing

- Neutralizing o 1 x buffer (e.g. NH40H)

5.5 < pHf < 6.5 o 3x H20 dist.,rinse

- Drying o 1 x Ethanol, rinsing

o 2x Ethanol> 96%, rinsing, fresh

o air draught support

(sucking or blowing)

ESO/VL T/MGR/wrkshpt1/S.3

". -

VL T COATING RENEWAL FOR PRIMARIES

FILM REMOVAL AND MIRROR CLEANING

PROCEDURE (cont'd)

• Motor driven removal of Washing Unit

• Opening contamination control area and loading Coating Unit

• Down-pumping to 1 x 1 0-3 mbar

• Pre-cleaning by Glow Discharge in air (~ 0.02 mbar)

ESO/VL T/MGR/wrkshptl/5.4

VL T COATING RENEWAL FOR PRIMARIES

FILM REMOVAL AND MIRROR CLEANING

MECHANICAL WASHING UNIT: Advantages

• Minimum wear load on mirror - well controlled mechanical purging

operation (spraying) - homogeneous permanent treatment

of surface - minimum duration (chemical action) - no contact of surface with solids

• stainless drying

• minimum liquid consumption (recycling)

• minimum particle contamination

• safe handling of aggressive chemicals and vapours

NOTE: Process can be fully automatic if no AI droplets have to be removed!

ESO/VL T/MGR/wrkshpt 1/5. 5

VL T COATING RENEWAL FOR PRIMARIES

FILM REMOVAL AND MIRROR CLEANING

MANAGEMENT PLAN

• Pilot Washing Unit (PWU) or < 3.6 m mirrors: Requirements

• PWU Engineering, • Manufacturing

external

• Process Development for AI Testing with 3.6m and NTT mirror

• Washing -Unit for 8 m mirrors: Requirements

• WU Engineering, • Manufacturing

external

• Installation in MMB

• Process Application and Tuning for VL T 8 m mirrors

ESO/VL T/MGR/wrkshpt 1/5.7

VL T COATING RENEWAL FOR PRIMARIES

FILM REMOVAL AND MIRROR CLEANING

CONTAMINATION CONTROL CONCEPT

• Washing in Clean Zone

• Clean Zone - completely separated from MMB - cleanroom class: < 5000 per cf - air exchange rate according to HEPA

filters « MAK requirements) - gowning and filter masks (MAK) for

personnel - starting procedure: complete cleaning

and switch on ventilation 3 days in advance

• Proper interface design: Clean Zone / Coating Unit

• Finishing washing with minimum personnel present (automatic removal of Washing Unit, automatic loading)

ESO/VL T/MGR/wrkshpt 1/5.6

VL T 8M-COATING UNIT

COATING TECHNOLOGY

C'()tsJ'~cfi(;)N Clean Zo,,~

tli"or tlaintel1C1nce Buildjng

ESO/VL T/MGR/wrkshpt 1/6. 1

Op

aci

ty o

f A

lum

iniu

m V

ap

ou

r D

ep

osi

ts

Re

fle

cta

nce

(%

1 96~, --~--~--~--~----~--~--~----------~--~--~---,

95

94

9

3 '-

"'''''

''''''

'''

92

91

90

89

8

8

87

-"'

"

86

85

84

83

8

2 I

I I

I I

15

20

2

5

30

3

5

40

4

5

50

5

5

60

6

5

70

7

5

80

ES

O/P

GII

07

.79

a

lth

ick

coa

tin

g t

hic

kne

ss l

nml

R1Ag RIlAg

1006 l.:g: _ ......... -' -b- - --6- - - - - ...... -_ -:.. -:.. -_ ± = ::. -=. -=. -6- - - ;;;..;.:fi:..:;..--~ _...b---l>- _-b-:1-6---6- ____ -Xt- ___ ~ _.-

-A- - --- _____ • -

t" - - -x- _x- - • ..::::::::. ---".,::::::::::..

80

---~ 60 Q) () c: cu ..... () Q)

..... Q) 40 a:

/ ,r --____ /. /'" -11_ x- -}l- -x_ -)C~ ./ --. RIAl

R~O'd -/ 7"- -x_ . / -lO-t /- -It-:- -x RIIAI

/ I' ---.. R"GOld

I · -0-- -0- --0- .....0- fo- /0- -<>- --0- -0- -0- --0- --¢- - - -<>- - - -0 R1C r

/ I / /

e I /1 i

-e - e--:::, --0- I-<>- --0- --0- -0- --0- --0-~ ---0- - - -0- - - -<> R II Cr -0---0- /

/ /

/ e

/

• / - - -.6- - -.6- -

-)C-X-l(-

-.- -.--e- _e ___ e -0---0-

Silver Aluminum Gold Chromium

20

450 550 650 750 800 nm

Fig.26b Spectral reflectance of opaque metal films at 45° incidence of linear polarized-~ light. (Films produced and measured by Carl Zeiss, FRG).

100

90

80

70

60

50

40

30

20

10

o

300 400 500 600 700 800 900 Wavelength ).(nm)

Spectral reflectance of various opaque metal films obtained at nearly normal incidence of the light beam. The films were deposited by evaporation in high vacuum. (according to Carl Zeiss, FRG).

r J 1--- -+---t-- I ! I ~ I J ~ L_ ' -.......... ,'" ~ ....... ... -~

-( f-' -~ ... - :,...../' V .-

"1 "ON 1 t v, /' I ;.1 I -"l.._ /' I ~ I . ~ .I' II

",' ~ . • I I I .

i I J . ,

V I

j f .. 0° J 1=

~- I I

",', Metallic mirror ALFLEX UV,!y.

/ - - - - - Metallic mirror ALFLEX 8®. _._._.- Metallic mirror ALFLEX A~ . .

~ I I I I I I I I I I

~

-

-

I 200 300 400 500 600 700 800 900 1000 1100

Wavelength (nm)

100

(

80

- ?f(

......... ~

60

c co .......

....... ~

40

c co

'- ~

3

" \

\ \ I

I I

•

I I \

81-0

W

ith i

on b

eam

(a

)!

\ I

I!

! (b

ri,dg

in,g

)

-~~i~~b~~f1l!(b)---

\ (JI.Si~O

I···;

---

----.

--.

--•

, J

----

--,-

.---

.. -.. -

---.

------

.. --

-t--

--1-

--l-(n

onbr

idgi

ng)

\ J.

; \

I 'I

-----·~-----'-·--·._. _

_ L

__

_ i.

__

__

l

--_

_ L

. __

_ i

-__

_ L

'-

-.(

... I

..

...

\ 1_

.

l __

~

o I

I I

I·

I 1

I L

_L

Sl0

2 __ J_

~_ .. ~l~~?

. __ -_J

-I

. 36

00

3200

28

00

2400

20

00

1600

12

00

800

400

Wav

enum

ber

(em

-')

Fig

. 5

Infr

ared

abs

orpt

ion

spec

tra

of S

i02f

ilms

depo

site

d w

ith (

a) a

nd w

ithou

t (b

) ac

tivat

ion

(oxy

gen

ion

beam

of 2

00 m

Al.

The

abso

rptio

n sp

ectr

um o

f the

latte

r fil

m e

xhib

it se

vera

l ab

sorp

tion

band

s in

dica

ting

an o

xyge

n de

ficie

nt f

ilm [

40].

VL T 8M-COATING UNIT

FILM SYSTEMS

NEW COATINGS DEVELOPMENT PLAN

• Film layer design

• (small) Sample manufacturing

• Adherence, wear test MIL 13508C ( cheese-cloth rubbing)

• Accelerated aging (80 a C, 20%RH, 5 x 3 days)

• 1: 1 Coating Process Development

• Reflectance Measurement

• Removal Procedure Development

• Film density Check (Pt/C replica)

• APPLICATION

ESO/VL T/MGR/wrkshpt 1/7.2

VL T 8M-COATING UNIT

COATING -TECHNOLOGY

CDoting rJeofYletty ·lJori ~ iacf-()p) I "/' \

Vac(jutlJ Reo!) itPtl!ents ..

Pre-\,

rUm Desigt~ , Yac./lessel ,'18!f'f'ia/,c;<_ COATING . __ lJesic;n

-f i I/lJ? () Ii a /il);~_ P'

(Thlck/leSSi /loJt!()­

·1f'tJ~/('V". )

TECIINOL06Y (dl'me;'.s;{jf!~ ',sf Jape .,.)

'-'

/'

, ; ,-

" ?

/ ,

i

S(a/e-u.p . ,:~ {'; /( I) if r. ft.' (/) ~·.C

~ (on,5umable.s

"). '. ,... / i \ , • 1It'.. ., , I ~ .

(Pow·er; If'afet~l( ,J

~ 51r! a .'! ,s c a/ e ~ \'j IYJ (j ! a f /0 I:'

(r /) ~.i. ,-.' (J !in it

ESOIVL TIMGRlwrkshpt116. 1

VL T 8M-COATING UNIT

COATING TECHNOLOGY

PVD TECHNIQUES used CURRENTLY on PRODUCTION SCALE for OPTICAL COATINGS

source type indicated substrate conditions

indicated

EVAPORATION Ion Plating (IP) Resistance heated Activated * Electron Beam heat * DC, RF Bias * Low Volt.Arc heat * Reactive * Hollow Cathode Arc Reactive IP (RIP)

SPUTTERING DC magnetron sp. RF sputtering RF magnetron sp. Ion beam sp.

Activated Reactive Evaporation Biased ARE High Rate Reactive Sputtering DC/RF Bias Sputtering

ESO/VL T/MGR/wrkshpt 1/6.2

VL T 8M-COATING UNIT

COATING TECHNOLOGY

COATING by EVAPORATION

• Emission characteristic of source type - coil (or basket) shape filaments

• Source arrangement after J. Strong - single source ring Osource > 0mirror - Os > 8.4 m - H > 4.2 m above mirror surface

• Moderate filament load (~ 1 5 mg/cm) minimizing droplet formation

• EI. Power .Requ: ~ 21 0 kW no. filaments: ~ 400

• Vacuum vessel (coating partition): D x H ~ 8.5 x 5.5 m

Volume ~ 300 to 340 m 3

vac exposed metal surface ~ 300 m 2

• Residual pressure: < 2 x 10-5 mbar

• In vacuo cleaning: Glow discharge

NOTE: AI alloys & wets; W stranded superior. No dielectric materials.

ESO/VL T/MGR/wrkshpt 1/6. 3

, , . ~ ,

Fig. 53 a Various types of resistance heated evaporation sources.

Fig

. 61

b

Rin

g sh

ap

ed

glo

w d

isch

arg

e c

ath

od

e a

nd e

lect

rod

es

for

the

sp

ira

l sh

ap

ed

A

I-e

vap

ora

tors

mo

un

ted

at

the

top

of

the

me

talli

zin

g p

lan

t.

Mir

ror

Alu

min

ium

Coa

ting

by r

ing

evap

ora

tors

on

oute

r ed

ge

req

u,e

l.p

ow

er

[kV

A]

fi la

me

n ts

/r in

g

22

0,1

--:-~--~-:---:--~~--~~--~--~~--~~----~

20

0

18

0

16

0

14

0

12

0

10

0

80

60

40

20

o 8

0n

m:

fil/

rin

g

50

nm

: fi

l/ri

ng

80

nm

: p

ow

er

50

nm

: p

ow

er

* O

BS

: p

ow

er

o O

BS

: fi

l/ri

ng

. ..

....

.,..

.\" ..

o

········

' ••...•••••• ?j

3~!f

il ..

'22

5

18

0

13

5

90

....

... :

....

. ..

:...

:·

····

·;.;

;;.l

\v

....

•.. c.~ ..

....

. ; .

....

....

~...J 4

5

01 ~

10

0,5

1.

0 1.

5 2

.0

2.5

3

.0

3.5

4

.0

4.5

5

.0

5.5

6

.0

6.5

7

.0

7.5

8

.0

8.5

dia

me

ter[

mm

]

ES

O/M

GR

/09

.91

e

vge

om

3

II

MI Line of exit

Area of erosion Line of entry

Magnetic field lines

Magnetic field and electron path in a planar magnetron.

Shield

~

Anode (grounded)

Insula tor

Erosion Zones

I o

" 0:: : 0::

~ ~

: : (l

~ Cf)

0 : ((ij "-

~ 0::

·s C) : :2

"""'" "-f-~

> "-

1/

0 Cf)

w

VL T 8M-COATING UNIT

COATING TECHNOLOGY

RESIDUAL PRESSURE REQUIREMENTS

Common performance rule for optical coatings:

current density < gas atoms r G

4.37 x 105

10 % current density of film material r F

OF ......... film density [g/cm3] M F ••...... molar mass of film [g/mol] MG ....... molar mass of gas [g/mol] PG ....... residual gas pressure [mbar] T G ........ gas temperature [K] rD ......... deposition rate [nm/s]

Example:

rD = 10 nm/s, of(AI) = 2.7 g/cm 3,

Air 20°C

Result: PG < 2 x 1 0-5 mbar

ESO/VL T/MGR/wrkshpt 1/6.5

100

90

80 ...- 70 ~ 0 ---Q) 60 () c 50 ~ ...... () Q) 40

'+-Q)

30 a:

20

10

0

Fig.11

- / t:/ \ -.......... v V

./ .L"

I f\ II '-7 sec at 1 '10-5 Torr

I I A

/1 1\ V . 260 sec at 1,5 . 10-4 Torr

j

1/

'/

0,2 0,4 0,6 0,8 1,0 3,0 5,0 7,0 9,0 11,0 Wavelength (~m)

Reflectance of two AI coatings prepared under extremely diffe­rent evaporation conditions in the wavelength region from 0,22 to 11 microns.

VL T 8M-COATING UNIT

COATING TECHNOLOGY

SPUTTERING: Advantages

• Vacuum vessel height/volume small HCh-SPUT ~ 2.5 m ~ 1/2.7 HCh-EVAP

V Ch-SPUT ~ 150 m3 ~ 1 /2.7 V Ch-EVAP

• Less foreline pumping capacity

• Low el.power requirement PSPUT < 1 /2 PEVAP

• Flexibility in film material Multi layer dielectric film stacks

feasible .

• No loading (high target lifetime)

• Reliable automatic process

• Excellent homogeneity (no droplets)

• Small scale simulation feasible

• Price (coating unit, transport, installations)

ESO/VL T/MGR/wrkshpt 1/6.6

VL T 8M-COATING UNIT

COATING TECHNOLOGY

SPUTTERING: Disadvantages

• Water cooling systems required

• Periodic Cleaning of sources (surroundings)

• Moving parts in vacuum close to mirror surface required

ESO/VL T/MGR/wrkshpt 1/6.7

VL T 8M-COATING UNIT

COATING TECHNOLOGY

PRECLEANING (in vacuo)

• By irradiation IR or UV - dedicated to substrate - dedicated to contamination

• By Glow Discharge - efficient - versatile . . - InexpenSive

ESO/VL T/MGR/wrkshpt 1/6.8

VL T 8M-COATING UNIT

PUMPING

REQUIREMENTS

• Residual pressure: ... < 2 x 10-5 mbar

• Working pressure (sputtering): ........... ~ 2 x 10-3 mbar

• Pumping Duration: ... < 4 hours

• Reliability (oil backstreaming)

SOLUTIONS

• Roughing with roots blower + rotary vane pump to > 0.08 mbar

• High vacuum pumping with High Vac Pump + Meissner Trap: - Bath-cryo pump - Diffusion pump with LN2 Baffle

(Silicon Oil DC 704) (- Refrigerator cryo pump)

- Throttle position for Sputtering

ESO/VL T/MGR/wrkshpt 1/B. 1

VL T 8M-COATING UNIT

PUMPING

CONSUMABLES (preliminary)

• Electrical power SPUTTERING EVAPORATION - Foreline pumps 65 1 25 kW

idle (low p) 45 90 kW - Diffusion pumps 1 00 - Bath-Cryo pumps 0

• Cooling Water - DIF System

- CRYO System

• LN 2 / 8 hour batch

125

5

100 kW o kW

130 I/min

10 I/min

- Pumps/Baffles 600 600 - Meissner Trap 1500

• LHe / 8 hour batch - CRYO 40(7) (JltsJ. c~srgi'lI1~ ~oJ­

'Wrcluded. )

·2000

40(7) I

ESOIVL T/MGRlwrkshpt1/8.2

VL T 8M-COATING UNIT

PURCHASE

MANAGEMENT PLAN

• Requirements 8m Coating Unit (loading concept, film requ., film quality, [coating technology], power requ., pumping system, precleaning)

• Engineering FEA • Design Substr. Carrier

• Manufacturing • Process Developmnt • EU Perform. test

FEA Vac Vessel

• Transport on site • Weight load tests, witness tests • Acceptance test with mirror

• Development alternative films

ESO/VL T/MGR/wrkshpt 119.1

VL T 8M-COATING UNIT

QUALITY ASSURANCE

PLANNINGS

• Activities prior to production - starting clean zone - 1 test run with witness plates

• Quality Control during production - film thickness check (witness) - adhesion tape test (at the edge) - reflectance measurement (in situ) - monitoring selected parameters of sequences for washing and coating

- final visual observation (dark field ilumination)

• Maintenance plan - weight load tests - cleaning coating equipment

ESO/VL T/MGR/wrkshpt 1/10. 1

Discussions on Topics for Future Observatories

Mirror Handling for Re-coating S. Prat

Coating and Coating K. Raybould Equipment

Cleaning Mirrors in situ P. Giordano the Telescopes

Mirror Handling for Re-coating

Presentation by S. Prat

\ "

~\ .. \.

'" \

~

~

'-' «> '" 0;:;

\

,..

/ /

. \

\

" ~

\ ...\. .. \

..)

/

'.

I

I

I

I

I

I

I

I

I

I

:i

., .... -_____ I _________ --r;...-________ ~i: (JIS! I,

Ii

to"

~-------~----.~u--------~

10([ 10((

" .1 i

I

1 !I' ·1

I'

/

, ',: '. '.'

'. ',\ .

, \ , ' . . '.

.. ....

' .. ".

'. ".

I !

! i I I 1 I

i I

i , i j I +h-'--...... __ -' -

Oi (\\1 ~I

8 ~

I

I j

I i I I I ; I

1 \ --"-

'-'I -,

1 j i i

, I ----_._-------_ ....... - ................ .

~::=:::c-:-+tl~

1--J. ________ ; ______ ~____ _______ ___ L ___________________ ------------- __ J : OIOe \ o~ c<i \ 015"3 ! I

111, • - I

l(

~'

I

!

~ '- i \, ~

L-,,.-- II I ~=3~ I

1 (

I \ I l I

I ~ "

'. ,

0156 j -_.- "'0'" Oc --- - --'-f-

" )

1 , ! I I

I !

: ~ ~ - -~, ' -

~.

ELEVATDR... / TAA-NSPoRT€/J...

ST1\7'OIJ l •

• •

..

•

S71tTIlHJ 2.

I)\\ct.SS 40 T~N.r

h i.~"" tor ~ 9~ bl)~ cf, s. ~,.,..

4 tJe.sCof~ l,'-4..dLI s -,:

h5:2.fN. ol,~~ ~ e. K lNa.~"" ~u81. D~~3 ~ 1,..2. ~

\N 10 A\.\

~u !;OO~ 1:0 2. ~ S~U2.~ pq.vJ /Load IY\\AX • sR.of~ 10 %

.5. R£QUI A.EM'E-tJTS .'

· d..W1..~tc.~ < 4 H

• fi!1e.\TO-ro~ ~r ~~~ o.-d ~ b~ f~ t:JJo.y

• lA.b~ ~ 6 ~tl.$ • SAFe7Y is cM..t~ !

- P.oo.J fAQ"->..sf~ - ~~ ~u~"-.e-1-- tN,.;v..$ f".J-

• }~ of ~ e~~t ~ses ~o f/LL1 .... oL~ • £.ro.-.J.~ ~ ~ ~~7 ~a..l-.tk,. .. a~c.tt

Q

g en

I }

/\ .

.

vV

~---' COOl. :

.~ ~

., , I i-I

~

I .~

g~ ,

,. ; , I

I

J ~: - I !

0101 o! O!

: ~; tOl <>,

, . , ' . .

: !

~ J .~ , /'

0006

.......'--'--"-.:', 1 Ii .

Iq---'._ ____ I I -. .-._-......

. -'- ' ............

I I -- - +_i,-1 . -. -.! .........

I I Ii \ I' I 'I \

ill ii I I:· \ :il'1-i- --' lfC- --.. ----.-.

: --_ ..... - ' i --- " +-.~ ..

i " -. , I -I ... . " . --.. -i ....... -: ! '-. -:

; i ... ! ....... , \

" \

\

I ,_1.- __

.. -

.. , ,r'-' G"" ~I jl"lji'l-r , '

-", I'" I --7'

\

1-·-t-m. ~~~I ~ I

"";1- -...!; ~ ;--11'··'

. ~.oj~~7-'.... ... ' ' .. _.'

:"j. ,- ", ~....+-

..... .' ... ;

i--l,t-'-l

~~ I:' . +-~ __ • .._J

""'1'-·' ~.:=-.. ~

I ,/ j

t •••••••• !

'--"1"'" _.?,.:.;..

_ .. loO;

. - -. ~ .. :

------~~ .. -

+

~ r ,--- -C

--

. __ .

--:(.

:..

_. -

--·1 t

. ::::~

._-:..

>" ~<;!

=-_< -

:?

i-Is

!>90

0 1 1

~

"U

0 <

l..

0 ()

\Il

N

Co"

,l"lI.

.ol

Sc",

8( ...

.. ,

;X~:~/·

.-I

I

"':1

I::::

....

<

' ",

,,><

' '~"

q

in W

'.

0

+-<'

•• '+;

.... ,--,

~ \:

'1

I ~=============-

'" q~/...

... ,<,.

~~ ~ 40

00

I -( -

-,

~~~

~T.I.

,,' r

--

81

0-

..n

I t I 1-

-

:J:

"I

.~

--

-,

1 .~l

_

. I

<"1

~ I

v '''I

"I

.~

I",'

ii

.§.

~ r g

-~ J

~

o~

·'!I

I a

1'-

>0,.1

E.

CO

II!)

I

I

~, L

--

J L

_..

J

\-, ,

'U'_'

r ,.1'

1' y

. __ .~o

~Q..._ ...

~_--

-1

PM

8T

OO

O

CU

~5TOOO

PT

e 5

3TO

OO

13

SO

kJ

>1\1

I

tran

smis

sion

e

lect

riq

ue

A

US

§ AU

TOM

OTE

UR

45

T Q

pla

te-f

orm

e ~Ievatrice

~~--~----------------------------

~

, ,;;;

) ;j.~ .:~

.~

.;! " 'l ~

§ {\V

NICO

lAS

I

~

89

29

0.C

HA

MP

S/Y

ON

N£

24

133

Ii ('

\\Pt

R~~

• f'

~\\~~ .. ,~ilY. .....

"r" ...... ' ............. ""'}~ ; ..

1''' .... ·-11'/ , .... _____ ~_----lIIl/1ll(/.

, , I

GI

1--- ---, 'I , 1 1 r 1 L ____ J

- -----

1- ----1 I I I I L ___ -'

I~Z -- --(; :- ---=*=-=-:=\------1---'

"II!!.C!ff---::I~~ Y

--- --, I I

I ~ L ___ .J I I

~~~ '==JJ==:::;~ - - - - - - - ---

SLI.bII\JG PLATEg SYSI€M

f:'DR LA7EAAL AJ7uSTMENI

'1

LoAD

/ U

p.JL

DA1

>

&£

NE

RII

L

MA/~reNltAJC£

AREA

fA r

I C W

ASH

It.JG

A

ReA

[L) Co

AT

ING

A

AE

:A

1 1

. ..n

....

..dIL

c

I .....

.. '-

t t

t ..

+ .

f L_

. ~

JI ~

W

I

'V ~~

Nt

\V

,~

r '-

f '"

~I

, l?'

" ~. ~J .. 1'-

r" I

. l::

:::::,

:.J

I '7

' I

·1

.. I

.·1

...

'I

/ /

/ ./

/ /,/ /

./ ,/ ./ /

/

.' /

,/ / // ./ ./

/ /

/ /.~.;

, ..

, ."

~

!..o

o"

I _

_

~.

J .~./

'.-

,.,. ~ ",.'

/'7./

7// ,:)-

~?7 ?

:?7

6'11

JJ rA

.'Y

C A

A "I

E

I 11

i '\ _..

.. 1-

''':lC''iH

~'~L_ ~~:

.......

... _

..

I/.-;. ~:::. --

... .!./.:::..

:~:~:::---

~ c /

Cd/

I'l.,

."--

-r·-"

~~

i /"-

<" ~:

~~-,.

t----------i

. --I

'\

. .

/'. ,

!, .'

Jt

\.\ /'-

-1--

---i77~--I---

.:~\

L'fh

'u1 p

(.Jfol

lArt

( :

.. 1 ...

.... '\

,(. .. _

-.. ~-

-)"

{ ;

;~ ..

\. ~

I 1/

\

. : \,

I

.. '

\.

r I

\ t

~\

I :'

~-----~-----~'~'~-'~~/7~'~~~' 7---~~~~---~~'/

"": I'

I /'

I'~

"'o

o".u

"·

,...

...

I ..

...

/ ,,~ -

.... "

... "

..

,,'

.'-~

I"

I ..

.. '

""'-

-_

'-

...:

. ' .... :

"-

:.'r:::

'---

~

~'-I

-"'~

__ ====

====

====

:=b=

;;;;

;:;;

;;;;

~~==

I

_I

,tf A

IN T

c. N

A--t

J C. E

B

lJIL

,D1

N G

L

AY

-o

ur

...... ....:.--.""""--"--=-:~ ... ~-~ .. .;..' :..- .'"'=" ..... ~: .............. --.. ~- '. ""-_. - --:.;:;'~":""';""- -"-'::::..~~

> ls.. - • a '"1 '..J"

Pl rn i::l. c:c ~

~ ;f.. -....t

. t..J N

~~ , ~ j

/ ~ l-I'

UI

'" Z 88 0 lfl

1./')0 S? ~

e:(s ~~ "i- lJJ ... ~

8 & "" -0 C) U

0 ~ 2:::> oX a: e~ 11'1 ~

ci! ~ ~ o.u n. ti- > .... x

~ ~

w ;l!:d .....J

~ W

~ ~~ ~ u..J '-e::5~ ._-- ~ .....J

cO ~ <t. " l-

i £90L ... ~6·~0'9 ~l

-l-d

--------, : ~nbl.Jp~l~ O..JPAH I L ~ _ id~o~9_-l

1-~-.9

8 ~ ~ 0 J co d

J ~ .~ ~ C5

I -'- ~

I d Q..~

! __ t cM:a " J ~

~.J

. . i I; I . I I • • I I I I I L-J

L~:

------------------~--: 000<;

-...J J IXO~ oo~,

iINSIDE TELESCOPE/

1. GENERAL PREPARATION

* Position telescope

"lock tube

* Shut down telescope

* Clear floor

* Prepare tracks

* Drive elevator/transporter

* Bring carriage under M1

duration manpower

2H 3

2. PREPARATION OF M1 UNIT

* Disconnect all lines to M1 unit

* A~ lifting flo.ffe:llHlt * Adjust and attach to M1 cell

duration manpower

2H 3

DFF-c£LL CoAT/N G

I

/1', I I • \ .

\, I.·' '---- - '

ION TELESCOPE FLOOR/ oP",o N OFF"' - CE.LL C!::>ATI N G

3. REMOVAL OF M1 UNIT

.. Disconnect attachment M1 cell

to telescope

.. Lower M1 unit

.. Slide carriage out of fork

.. Install rigid cover

duration manpower

3H 4

4. TRANSPORT OF M1 UNIT

.. Remove M3 and tower

.. Cover hole

.. Slide carriage on elevator

.. Lower elevator

.. Transport to maintenance building ()

~ -...;:,-

duration manpower

4H 4

END OF FIRST DAY: TOTAL 11 H

I IN MAINTENANCE BUILDING I OPTION oFF' .. CELL CoATIItJ ~

5. PREPARATION OF M1 UNIT

.. Roll in carriage in the preparation

area and align

.. Prepare gantry crane and attach to

cover

.. Install guides on M1 cell

.. Disconnect cover from M1 cell

.. Remove cover and store

duration manpower

1H 3

6. PREPARATION OF M1 MIRROR

.. Disconnect 64 rods of lateral supports

(5 minutes/rod)

.. Disconnect lateral fixed point

duration manpower

'3 H

6000

o

lIN MAINTENANCE BUILDING, oPTIO ,.;

7. PREPARE HANDLING OF M1

.. Bring handling tool attached to

crane

.. lower handling tool and guide into

position

.. Attach the 15 clamps to M1

duration manpower

tH 3

8. HANDLING OF M1

,. lift M1

tr Remove cell

,. Roll in the support trolley

,. lower M 1 on trolley

,. Detach the 15 clamps

... lift handling tool

.. Roll trolley to washing area

duration manpower

OFF- CELL

./

END OF SECOND DAY: HANDLING 6 H + WASHING + PREPARE FOR COATING

///////./////.///

I Ml COATING I

PREPARATION TIME

M1 ALONE M1 IN CEll

1. GENERAL PREPARATION

2. PREPARATION OF M1 UNIT

3. REMOVAL OF M1 UNIT

4. TRANSPORT OF M1 UNIT

5.

6.

7.

8.

9.

TOTAl DAY 1

PREPARATION OF M1 UNIT

PREPARATION OF M1 MIRROR

CELL

HANDLING OF M1

. PREPARATIONS FOR WASHING

AFTER WASHING

PREPARE FOR COATING

TOTAl DAY 2

TOTAl HANDLING TIME

!/.Ad u..~ /ie- "","~iU.((~1!k...... ~ telt2SCof~

2H

2H

3H

4H

11H

1H

3H

2H

6H

2H

8H

3H

4H

11H

1H

4H

4H

2.H

ltH

to 12. H

HANDLJNG TooL ON Ml

------ I •

I I

Q.~t's of hMQ~"'~"Q"~ bu.': (J ,.""

, ," , ~:

'- ' .. __ :' . ~ ~. , .. i " ~-­

. , ., ::--:: :-.

, ,>~:--.:, "; -~ ,~,~, .

''': .

I I II /!

'I II II -I

I

! I I

! I 'I ~ j I,

: I 'I

," "\\'

!

\ I

~\ 1\

\ \

\ 1\, '~

\ \

\

. , \

, \ ' , " . \ , \

, i

\

\ l I

" '\ ':-. \

~, \

--J

1

-

IfALF

M

IRR

N I

ItK

L I

f N

t (Y

OU

fClf[

£L

EN

£ltr

rS)

V o.,

MLS

t!S

sr~e

sS'

ar - u-

::: ~Q.~

I. 24

b.!

lDhA

M

P Itt

AN

SYS

4.4

1\

SEV

39

19

91

11

:15

:41

V

OSH

ST

ItES!

; S

fI,V

:1

ITE

R:1

SIC

!:

(AV

G)

DMX

=.1

.31

38

5.8

SM

=8

.117

611

SMX

=1

.2n

S

MX

8=

t.S

71

IV

=-1

DI5

T::

4S18

X

F =

28

58

IF

=-2

1.8

81

ED

GE - - - - -I::::::~{~} CJ

I::\::

;;}1

!IiI

ii

11.1

1767

1 11

.242

237

1I.

1G

A:t

l3:

11.4

9137

11

.615

93'"

11

.148

58"2

11

.865

853-

".98~

1.1

14

1

.23

9

lMP~

)

M~ b,

SUfP~t2d

~Q.\\o

l ~d

toof

SU

A..

f ci..t:..

.t. 1M/~

" 4 s f/}

o! I ~ ~ -4-

a ....::t---S\ ()

~ -II

.... '" II': X ... ut

IE

" U \101

~ ~ ~ ..J \101

~ VI b;-

= > -... <1 :II!:

~ G-o .. oJ

..J \}

* 1: S . .,) I oS III:

" -:II!: ~ ~

Coating and Coating Equipment

Questionnaire by K. Raybould

II Coah'., CI ~ II off.... fflU4(~ (a/;~~ct! C) f defv"ffl~W /111 par,'y.,'es .'. 1 ,

. ~. &"1,C"itH'~ .r-e,. S,cdllf!!·) tf)}C ,ties - . E ~ tr{,~ dtP1 f f~ 'c(e5 .

- Clt-eM,'cd V~/~ ~ s,4.ra~~~·~ . /

. , /

- £;"'tt''f'1'CJ ~ ~~ c/,Ht,'vtt.e/, .. ,' - $luwf-ctVf 10 S~"f"I'I ? - ff,;w HfItd raJt.'1 /s -/H HU'd - AI-/'-#I;ltdJI.lrJfl5 ~ (JI(~ st:!,,~t,'7//Pl'/"1 - 1?~IJ;'i 1'4- !~'f fY'"6-Ces Df..tl ,z!tIl",:Ht.t..,)

- CI~,,~ he.-i14~ ~ ~o4r.5. ,'~I'~~ ?

Cu 1IV1)l6- (ctnd:) 5AFETT ---I ' Ailrl<lc ACID W?f-sH­~ - A-(~~tz ~ -t re • .. ~

- t/I~'k ~/~~l!e ~ tfow f).sd~ ~ - mu/)l..,jdl-e tv~ o/~s M - 5/1,C:-£TY CLE'/I-#uP./

R/V.5E

DRy I v~

FI ,.1/ IIi. e L ~ A#! A/ 6- (:!ecM-~-;'::: de~b.., <5 «r-(.) ")

- D,s'f,'d..J u/~~-~/y ~"I'~ /

- 5t)!1/~ j S4~ ) r~/~ue - A/~uhv~ 70 }J(Pff V~/ifi-t'l~ I

Ho. " a I cc/'()/ 1V,'ff,. v'4-r r 101.11 Iv~f~ tI~,'~c~~ 1/8Y" ~f- ofJ ~''f c/~ , Idf~~$: 8~c' ,67Y'"~ I'df~H~J

W,/'I"'1 (;.,'c h ~ If,~, I~~/f.y ~ft t- . ..

£' 1. I;; C T ,e /0' L p.'s dttJ.-rr fHe;:&fU/cV

- /t/ G-J ~ aJ tn'" JUr *"' 6/t;w . wltrJWt r .. ... , . WU-tfI1Ye. 14 ~r- /r/S'~-s ?

- tJ/'I,'IItUWI. G-- I r-.s'lK"e. 1~.1 d~aIt~

Presentation by B. Mack

c OJ. S I\OW .fee~I\;)~"-

.. GV.A.o.,·",\ C'tA.-t'/t.L 4:-e~"li\i3Io\u ,. ((e,tLt.C..+ ...... t., 2. Sc.~~(e~OMt+US

-

~·2 M. 'JO "M. ~ 2 ~y. ftMI- 12 - IS s. ... ,I.. fJ.WI~" ," t'v' .. .

·1-.2.. laD,..! ~, TIM'" ?

. ~&JEII - ;Joo- IDe.

, .... ~ •. 8-,-, .,--- 1\ ·

IS- rllil ,.si"LF.

A ~£ .,.11£11£ £A.lIER

Ill'" Eft,.,,, -rlt/£r •

M~s~.

M,ct.l .

• _.11:\-.. __ . . ---- ~

•

Mask

AI-In

let-

FIG 7

: Ty

pes

of ma

'gnetr

on in

stalla

tion

INWER

NAL

JOUN

T

MAGN

ETRO

N

Race

track

1

-po

sitio

n

10.00

j

:/t

Mask

Shad

ox

mKRN

AL IO

UNT

. MA

GNET

RON

//?

)I¥

7/

J....-£

lXJ.OO

-~ S

cale

bar

in m

ill

I ,,,,,,;,,,, ,,11 ",,;~» .. ">,, n""" » ",f~;-,-,-'-,-r-,-;-"" , , ,

•

•

l.:)J)",a"C~'ON. S'PIICE

~(aJ.G\..&..,.v 0' c.~ T,"'t,. 71IIe~N~rr

('} leflt.fc-nv.TV. {. J I»"StcuV.

S liO .£!. I '" { .. ~

N.~ •. i1IlIfAl1rRfJA) .

t M y..,·rt,r ~ SM.

~ liE'S / Nof/R.

MASt( • co".,.,o~ .

...

...

E VAPOR A nON SOURCE

~.-"N'N,-:",~

,/' . -., / .

/' 0 0 . \

f \ /!, . \ t 0 -+~f-- 0 ~ . \ .

~.~

.I \ I

0 0 \ .1 . . . / ., /' '- ' ~-.,..,........-,~

-• :In. 300· ...

! I

.. : .., . . " ~.:". ... ..', -:.' :.' :' .',., .. . ' .

. ,~'.' : .. '::~ .... :,' ... ':.:::~, ... '.":'.' .. " ..... ~:" .. :.' .....•... , ...... ~ ... : .. ~.; .. : ... ~ ...•.. =:~ .. : ..... :: .. :: ...... ~.: ... ""., .',,' ~ .. '<11. ', .• ~. ~., -:' ... '.: ~." '.' •• ... .,:, .. ·~;.:: .. 1··~· .. :> ...... ~.; .. :. : ... ~ ... ~: ... ':~: .. :!~ .••. :~ .... ! .•.•...• : , .. ~.::.

8m MIRROR ALUMINISING TANK USING EVAPORATION

. Figure 2 .. ' ..... "" .. -" ... ~ .... - .. --.- ...

C I

.'

1m f

1.1 Ac;N(TP!ON TWO POSlllONS

B

2m I

1 ______ _

J .. "

Sf:cnON 8-.B

.... .. .. .4 . .." ~ ..

4 .... .. . SECTION A-A

4.2m ALUMINISING TANK WiTH SPUTTERING TEST EQUIPMENT

APP II Figure 6

• ..

EVALUATION OF COATING UNIFORMITY PRODUCED BY SPUTTERING

S.P.Worswick and A.S.Monk ROO

A;pherical surfaced mirror with a radius of curvature of approximately 25')mm and a diameter of 150mm was used for this test. The mirror has a ,;entral hole, with a linear extent of one third the diameter of the mi~ror, which allowed the radial deposition of the sputtered coating as proposed for the 8m mirror.

Th,~ mirror surface was checked, in its uncoated state, using a scatter pl~te interferometer with a hel~um neon laser as the source of il~urnination. The resultant fringe pattern was photographed and anllysed using WISP software. The test was set up twice with the fr~nges running in two directions, at 90 degrees to each other, across th! mirror. The mirror surface is of good quality with localised surface de~iations at the lambda/8 level and RMS deviations of 0.04 lambda (s~e Figure 1).

Teits of two sputtered coatings were undertaken. The first set (tested 30~h May 1990) was on a coating which showed a band of reduced reflectivity at the overlap region where the sputtering source was switched on an~ off. Th·~ interferometer was set up with fringes running both perpendicular and parallel to this band to look for a dtep function or slope in the reflected wavefront which might be associated with'this feature. The uniformity of the fringes limit such an effect to the lambda/8 level and the RMS values from the measurements are again at the 0.04 lambda level (see Figure 2).

Th= second test was of the surface produced by the sputtering run made on the 11th September 1990 when the magnetron was powered off with a ra~p-down voltage. The area of reduced reflectivity was much smaller anj could only just be detected under close inspection. A similar set of fringes to the previous tests were produced, again looking for distortions in the reflected wave front arising from the overlap re1ion in the coating (see Figure 3). As with the previous test no noticeable localised fringe shifts are present and the measured RM3 values are still about 0.04 lambda.

t ____ 5-\b~7

D i\ t i\ Poi 11 S ~1-- t X ~ ------8 /" t 'I \ .1 ~~~

11 7 ... 3 X \ ~ 1 "'-9

, 2/ ~lf~ ~ ~ : ? )~:L "'" .1, ',' ~ ~ ~ ," \ ~ \10

'~ , ' ': ~' .. l' ' *\

~ t t ,"~; ~: ~, ,f ~1 w ~ '~ I ,t I ::+ ~t, +1(

.t V " Y 'I' 1) , ;: ",,~ " r·, 11 \" \ , " \ ~ , ~ I'

( '~ \ , ,

>k " \

\'

, .

d '\

, , , , ,

, , ,., .. I , ,

, , , "

\ , , , , , ,

\ , , '. , ,

, , , \, \

l' ok

Figure 1: Tests of uncoated spherical mirror.

Figure 2: Tests of sputtered aluminium coating. Direction of overlap region marked with arrow.

Figure 3: Tests of sputtered aluminium coating with magnetron ramp-down. Direction of overlap region marked with arrow.

EVALUATION OF COATING UNIFORMITY PRODUCED BY SPUTTERING

S.P.worswick and A.S.Monk RGO

A 3pherical surfaced mirror with a radius of curvature of approximately 250mm and a diameter of 150mm was used for this test. The mirror has a ~entral hole, with a linear extent of one third the diameter of the mi~ror, which allowed the radial deposition of the sputtered coating as proposed for the 8m mirror.

Th,~ mirror surface was checked. in its uncoated state. using a scatter plate interferometer with a hel.ium neon laser as the source of illumination. The resultant fringe pattern was photographed and analysed using WISP software. The test was set up twice with the frLnges running in two directions, at 90 degrees to each other. across th,~ mirror. The mirror surface is of good quality with localised surface de,iations at the lambda/8 level and RMS deviations of 0.04 lambda (s~e Figure 1).

Te3ts of two sputtered coatings were undertaken. The first set (tested 30:h May 1990) was on a coating which showed a band of reduced reflectivity at the overlap region where the sputtering source was switched on an~ off. Th,~ interferometer was set up with fringes running both perpendicular anj parallel to this band to look for a step function or slope in the reflected wavefront which might be associated with'this feature. The uniformity of the fringes limit such an effect to the lambda/8 level ani the RMS values from the measurements are again at the 0.04 lambda le,el (see Figure 2).

Th~ second test was of the surface produced by the sputtering run made on the 11th September 1990 when the magnetron was powered off with a ra~p-down voltage. The area of reduced reflectivity was much smaller anj could only just be detected under close inspection. A similar set of fringes to the previous tests were produced, again looking for di3tortions in the reflected wave front arising from the overlap reJion in the coating (see Figure 3). As with the previous test no noticeable localised fringe shifts are present and the measured RMS values are still about 0.04 lambda.

91

! '~ " ,

* ,'.' \ "

\ ,J \1'

I " ' .. ' ,

Figure 1: Tests of uncoated spherical mirror.

Figure 2: Tests of sputtered aluminium coating. Direction of overlap region marked with arrow.

Figure 3: Tests of sputtered aluminium coating with magnetron ramp-down. Direction of overlap region marked with arrow.

Cleaning Mirrors in situ the Telescopes

Presentation by P. Giordano

D 0

c C

D

D

U 0 C Pi

----"'---.. ._----_ ...

2 .. t1ea.as ~ rl •

• OPTiCAL MAl N,TE N:AM·CE.

~ ":

?~"'a\Hfe QCHcruL

A,," ,'- Jt_b(>? til "-~,J-W.J t~ • :Do",. ~ " (~tsl~ - IM(d.) I

-to w.4tcf'1 cIe.-\\1WS tT~u4"tntftk

. :D..... \1~"~ c.ootef'i~ car t'\. -J rh . ",lnoes

• lNUtt ISCLk r~ ~ "0\",,,,«. _ c'-" .'r (d\l&~ - taend. ft 6Q. -k 01\ ).

~. DU6~ Rlont4-0ri_~":'

_ Sco.ttrl~ m~U'''U\~9

_ l>eWril\~ mch..- ( C~ SnN-f'a'-.)

- OfIi~\~hCS1l ~ d~n'~ ~~ ... t"c;I It. l>'U- .~..,~:

_ 1t\s.\-aI.J ~ ~ \) 1'1 +t,\es~. ~ '4- ""t.

- f1~ c,-",~ {~11 ft LA SlUe.'s .f.JatDpIS - CO, St\cN -rriocfici"J. 1. I'I\OI\~.

, :DOc: "LT-TRE~€50- \\942.-o~

Jb\-e~ l~ June \qq,

In-situ cleanln~ for the VLT

1.1.1 SensltIyity

Past e.xpenence at La Silla shows that the average loss of reDecUvity is of the order of 10% per surlace and per year. For a three-mirrors telescope (e.g. Nasmyth) the total loss per year is estimated to be of the order of 20% (jt is assumed that because of its usual or1entation the secondary mirror Is less affected) i.e. 1.8% per month. Therefore the re.flectMty R.. N months after coaUng. should be

R = R<) 0.982N

where R<) Is the initial reflecUvity after coating. The loss of refiedMty Is equivalent to a reduction of the light collecting area of the telescope. The consequence on the effective cUameter of the telescope 15 shown in the table hereafter. under the assumpUon that dust contamtnaUon is the only conl:Iibutor to signal reduction.

Months after coaUn~ o 3 6 9 12 15 18 21 24 EffecUve D tame ter 8000 7790 7580 7370 7170 6980 6790 6610 6430

A loss of reflectivity of 2~~ after one year also means that even under good seeIng conditions (0.4 arc seconds) where optical quallty should be the limiting factor (and, where best scientific results are e.xpected). the dust contamination reduces the performance by the same amount as optJca.l quallty.

With a monthly cleaning procedure whJcb would compensate for 90% the loss of reflecUvtty due to dust contamtnatlon the evolution of the dfecUve diameter of the telescope would be as follows

Months after tQgUne Q 6 12 H~ 21 3Q 36 42 4a Loss of reDectMty

200b-2896-0) 0 10% 200k 28% 35% 10%- 35%-

12) 0 1% 2% 3% 4% 5% 6% 7% 8% EffecUve Diameter (1) 8000 7580 7170 6790 6430 7580- 7170- 6790- 6430-

(2) 8000 7960 7910 7870 7830 7790 7740 7700 7660

- LOss of reflectivity and effecUve dJameter with :'w1thout in-situ cleaning. recoaUng ls and Without in-sHu cleaning procedure. supposed to take place after 2 years. 0): without cleaning: (2): with cleaning.

The conclusion is that monthly cleaning whIch would compensate for 9()OA> the loss of reflectivity due to dust polluUon would allow to keep the sJgna] throughput above 92% of ~1~~ ',..t~...,l r-I',,,.-.+~,,,,..-"I (f...-r.("t... t"' ........... ~~ ....... ,-f, ".~,L. .-. r,.... .. _ .. _ ~ .. '- r _ _ ,. _~ ___ , , __ ""

SAMPLE

FROM /MA . Techno\o ies

MEASUREMENT S'MTCH

b t:'EC.TOft

~~~r-H--t~- DE1ECTOR [ 0,0]

p" scan scottero m e~ e.r

FlGURE 1 TYPICAL MEASUREMENT HEAD

I I j

I I I

r-(f)

w r-

'-' z H z a: w ~ u C\J 0 U

•• C ((j

U Ul ~

IT: L r-

1 -

L

>­W Y.

L&J r-. cr .J 0..

)­

r­tf) :J ·0 ..

o z: He zo

5! ~ I diU.

t5 I ~ I U· .. o· ......... , ........... .

('oJ N1

,'I -, .

. ;y :-1) .:-4· . :..i - :. '.' -

I -,

.., <.'

" -

-r-rrTTTTTITj-III1-rrl-rT-rrOT'TTTTTiT'-Tn--rrr.--rTTIl-1l . . . . . . . . . ]

r l· ....... . ~ t ......... .

~ r' .......... .

r ~ .......... . I

l-I

L ! r r" L L ... i L.

-, L

. . . . . . . . . ...... '

i

I I

I ..J

I 'tSl

-;(1')

j

~ I

J ! 'Itl

-} T ~ . ~ 1 E

......... -.;tSl a) --- 'N

-- l .-____ 0

-- J --.... / " __ .-.. ,;1

... ...:... nl -..... \II • • . • • . ......... ___ \11 "

.......... , ...... L

... j

./ I

.... - ~:#= I

.., I

j

. IS) ~ ....

i

-'

J i

1 I

-\11

J \

l

l'-U.~LLLLu~U'-LL. LLLhLLdu u. L.LLLL-LuLJ. J~ 0S S7 0;' SE 0E S2 02 51 ~l 5

7-3 * [081 "0£J

----

----

----

----

---

TM

R

}-J S

c a

n :

T

ES

T

SE

NS

ITIV

ITY

mr: ' I

~ :

~r'

. f

(DO

--.

tn

I

I ~

W

~ \ilL'

* I

n t

~t

.... (SJM

If)

nsf

-.

. 8)

u

1----.-

'-:---~

-~-T:

1 1

~ ~

! ~

/ \

.

/ ' .

~

/ \.

/

\.

. .

\. : . / l

I .\

./ ..

\®.

/ .

.\

I .\

·

I .

\ · ,,/

.

\ ~:

--.

0 .

\ :-

-..:

-.;,

-E)

~

./

. \

~

. \

./

. \

/\

" .

\ /

\ ·

-\ /

\ .

~ \

f. \

,. \ , .

\ , '

I.,

. \ , i

.@

.

~-,tt

. "'-

.. -I

\\--~

-:"-®

'.~-

*-.,

~--1--L..-I.

o

.L_!

__ L-!~ __

l-,-

j _

LJ

i il-L

i

.L..L

-l __

4 8

12

1

G

20

2

4

28

3

2

36

* M

ea.su

rem

en

ts

-----.-

~ ...j ~ 40

----

1 2 3 4

I,

-1,-- ,

... I

j ii

~J I,

I :.1

,'-

j,

I 1,

_ 1

._.1

: If

--'4

1 '

.-\

_/

(:;:>

,

\,.~,)) J,

~ I

;'

KE

Y

CL

EA

N

MIR

R •

89

h

EX

POSU

--

---.

AV

ER

V

AL

UE

-'-0

CL

EA

NE

D

HI

----

----

.-.

~-:

t:....

.r,

~ I It':; :;

.,

\'-:'.

~ I'

t I..' 1

'_.

L.f

i{lO

k'i

l'O

k -I

'

TMAfscan ... Ver 1.12 [ESO_SEN2.USN) 11:09:31 10-02-1991 Page 1

COMMENTS: REFERENCE MIRROR MT4: Exposed 89 hours to dust pollution

SOURCE INFORMATION: WaveLength = 670 nm Incident Angle 25.0 degrees

RMS ROUGHNESS BANDWIDTH LIMITS: (0.010, 1.000] 1/tm

MEASUREMENT SUMMARY: =============================~====~=;=============~==============

0.0 50.0 (%) # 0.0 180.0 REFL RMS TIME DATE

===========================~=====================================

1 1. 003E-04 4.887E-05 90.3 7.1 08:51:44 06-24-1991 2 6.335E-05 4.314E-05 91. 7 5.5 08:52:01 06-24-1991 3 1.13SE-04 5.239E-05 91.7 7.5 08:52:10 06-24-1991 4 5.983E-OS 4.97SE-05 91.7 S.4 08:S2:19 06-24-1991 S 1.135E-04 8.144E-OS 91.7 7.4 08:52:28 06-24-1991 6 1. 126E-04 6.736E-OS 91. 7 7.4 08:S2:S2 06-24-1991 7 7.390E-OS 3.874E-OS 91.7 6.0 08:S2:S9 06-24-1991 8 1. 328E-04 4.799E-OS 91. 7 8.3 08:S3:05 06-24-1991 9 4.090E-05 2.46SE-05 91. 7 4.4 08:53:13 06-24-1991

10 5.119E-OS 4'.138E-OS 91.7 5.0 08:53:20 06-24-1991 =================================================================

STATISTICAL SUMMARY: ============================================================================

MINIMUM MAXIMUM **** LINEAR **** AVERAGE STD DEV

** LOGARITHMIC * AVERAGE STD DE

=========================~========================;=========================

0.0, 0.0) 4.090E-OS 1.328E-04 8.619E-OS 3.198E-OS 8.043E-05 0.2

(SO.0,180.0) 2.465E-05 8.144E-05 4.957E-05 1.560E-05 4.739E-05 0.1

REFL{%) 90.3 91.7 91.6 0.4 91. 6 N/A ----------------------------------------------------------------------------RMS(Angstroms) 4.4 8.3 6.4 1.3 6.3 N/A ----------------------------------------------------------------------------I Measurements = 10

PSF

(wlt

h

13.4

rm

s su

rfac

e ro

ughn

ess)

LO

G FL

X/AR

EA

+121~ ----~--~----~---r----~--~----~--~----~--

__

+ 11

+10 +9

'B1m1

==

+8

-+7

+6

J)l r~

"',

mit

" +

5 LX

-J y,J

--------L

-------

--------

--------

--------

. S ~ ..

_",

.

.' : .

---

------

-----:

:---

~ :If

, Ii

'. •

~

------·-.l~~·

. +4

.:

~--------

-"'

--

G";:

-l3

,. 4 1

\ "'

C.\eC

lf\ m

lftO

f' +

3'-

--

-::-

--

--

--

--

-....

. ....

. .'

r I

--

-"

15 !l

x I I

f'"

--

-....:

; -•

I --

__ --

-6'

= 12

. It It

) ,

+2'

I X

-1

00

-80

-60

-40

-2

0

0 20

40

60

80

tfV\

100

. E-3

1

= co

mpo

sIte

/

2 =

s19n

al

psf

/

3 =

scat

ter

psf

. G

) AS

AP Ir

ab

et

8-0C

T-9

1 09

:20

o o

00

o o

----~~--------------------------------------.

1 1 (1l

,...

.N

(1l

~

v (S

l

o (1ll

Zen

W

CDI

CL

ER

NIN

G

TE

CH

NIQ

UE

S:

TE

ST

S

.... ~~

.. ~ ''V

-'"...r

.,..

.._,'''"

''':_ .. _

____

__.

. -~

,,/"/'

0 ~

. ,?~.

,...~'~ _

__ ,-

-..'

. ~~iJ'Y' /.

. "..

..r"

-'_...

...

. • ~

. .J

N en

(Sl

CD

3~~----L

I 4

00

~

, ,,~

, "",

"" .

" .

I .....

"" ~'

'..

' '''

'' .

! ~_

II "

. -,

~

"\ .r

.. ,

",""

/"

/ \..

",,\~

,. "

__ L

I

I 50

0 G

ee

7ee

se

e I

90

(3

HA

VE

LE

NG

TH

(n

m)

----

---

----

-----------------------------

F i9

1

-{--

~JE§

-}

(Q)

<}-

KE

Y

FR

ES

H

AL

....

p~l?

li n

g

a

C0

2-

Sn

ow

.~--..

DU

ST

Y

------

0

28

M~I-

19

91

le~0 [_

bftr

'4A!

mlv

"

----

----

----

----

----

----

----

----

----

--._

----

----

----

----

----

----

-..,

RE

FL

EC

T

IMP

RO

V:

NO

RM

+PO

LY

F

ITS

--}

+1E§

+ (Q

) {>

-----------------------------------------------------------~,

r..

U •

KE

Y

~

v

r ~

C0

2

FL

RK

ES

>-'<t

'

U

I ~ ~~ "A

~Ii\~'

OP

TI-

CL

ER

N

-----

• --

'TJ

,f ~ ..

C0

2

FL

AK

ES

• .A

..

I\~

.~

OP

TI-

CL

EA

N

U. U. WN

L

--_

L I

I J

lIZ

8 M

a ,

. 1 9

9 1

3

00

4~

'"

50

0

6012

1 71

210

aaa

UQ

0--

10

00

W A

VE

L E

NG

T H

(n

m

) '-C

-..J.I!!

--";;-W

-!;t-;--

-. --

---

~