SPSU 15.4.2008

Progress on coatings and grooves

M.Taborelli

-Progress on C based coatings-Progress on SEY instrument-Progress on grooves

SPSU 15.4.2008

Effect of the sputtering gas used during carbon film deposition: Ne and Kr

0.4

0.5

0.6

0.7

0.8

0.9

1

1.1

C run 3, 2hair, 2092-a

bottom,

C run 4, bottom 2h

air

C Ne,bottom, 2hair, 2097-b

rela

tive

yie

ld

500Vdeposited w ith Kr w ith Kr,in SPS linernow

deposited w ith w ith Ne

Progress on coatings

Lowest yield up to now

SPSU 15.4.2008

Complete yield curve (measured at CSIC-Madrid)

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1.60

0 100 200 300 400 500 600 700 800 900

Primary Energy (eV)

SE

Y

After 2 weeks air exposure

dep. with Kr

Dep. with Ne

Progress on coatings

measured at CERN after 2h air after 14 d air

SPSU 15.4.2008

Progress on coatings

Both coatings are quiteCompact and well adhering

C(Kr), in SPS now

C(Ne)

SPSU 15.4.2008

Progress on coatings

The reason of the lower SEY is not understood yet-Implanted gas? some of the Kr deposited coating show Kr in

the spectra (original reason for the Ne trial!) -No difference in the C1s XPS spectra-No difference in the content of O-difference in morphology, xtalline structure……?

0

10000

20000

30000

40000

50000

60000

278280282284286288290292294

binding energy [eV]

Inte

nsi

ty (a

rb. u

n.)

2094-a r4

2097-a

2097-b

C(Ne)

C(Kr)

C1s XPS

SPSU 15.4.2008

Plans for next coatings (….find candidate for next liner)

- reproduce a C(Ne) coating and its SEY

- make rough surface (Cu or Zr) as substrate for low SEY (C) coating

- BC with lower amount of B (B4C has a rather high yield, already measured)

- SiC, TiB2

SPSU 15.4.2008

0.50

0.70

0.90

1.10

1.30

1.50

1.70

1.90

2.10

2.30

0 200 400 600 800 1000 1200 1400 1600 1800 2000

primary electron energy in eV

seco

ndar

y el

ectr

on Y

iled

Cu first

Cu second

Cu fine scan

Cu last

Progress on SEY instrument

First data from new system: unbaked copper

SPSU 15.4.2008

Progress on SEY instrument

Still to be optimized, verified…built:

- Control of focussing (at present some 2 mm spot, but notwell controlled above 1000eV)

-Position (distance) with respect to “optics”-Beam position stability at low Ep and magnetic field screening

-Load lock and transfer to XPS still under construction

-SPS transfer chamber under construction (J.Axensalva and J.Ramillon)

Phase II:-Faster acquisition to avoid high dose...however it seems to be already OK-Implement flood gun for conditioning with e-beam

SPSU 15.4.2008

Grooves made at CERN workshop with cutting tool(J.M.Geisser, S.Atieh)

Progress on grooves

On copper: tool well aligned, small radii on top and bottom, but burrsalong the grooves

On stainless steel 304L:Preliminary trial without perfect alignment of the tool: large radius at the bottom

2mm

SPSU 15.4.2008

Progress on grooves

Grooves in copper

SPSU 15.4.2008

To continue the work:

Progress on grooves

Cost of what has been done until now (short piece on steel and copper): 2000 CHF work + 2000 CHF tool = 4000 CHF

To produce 800 mm x 100 mm (or 400 mm + 400 mm) on steel: 2000 CHF tools + 4000 CHF work =6000 CHF

If we go on the entire amount will be charged: 10000 CHF