12 July 2006Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning 1/25 Update ageing...

12 July 2006 Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning 1/25

Update ageing measurementsat NIKHEF

12 July 2006Niels Tuning, Gras van Apeldoorn, Antonio

Pellegrino

Concentrate on outgassing hypothesis• Long term effect: compare to old measurements• Force outgassing under vacuum• Increase flushing speed

Other studies• Confirm beneficial effect from O2

• Ageing with very small current


Recommendation Ageing Workshop (3 April)

Outgassing: o Check effect after long term (3-4 weeks) flushing o Heat module to 35 – 40 oC

Gas mixture:o Try Ar/CO2/O2 70/27/3 (TRT-like) o Add water (> 5000 ppm)

Processing:o Training procedure under N2 flushing with ~µA currents and with normal/reverse biaso Sputter chambers with Ar/O2 99/1o Burning procedure with reverse voltage (cure, prevent?)

Improve knowledge of phenomenon:o Continue irradiation to see if gain decrease levels offo Large area irradiationo Built new test module with minimal componentso SEM/EDX

o Strawo Clean wire

Checked; need follow up?

This talk

This talk: confirm HDChecked < 2000ppm

Checked to < 300 hrsChecked: link ; pursued in HD

Checked

http://indico.cern.ch/conferenceDisplay.py?confId=1506


Recommendation Ageing Workshop (31 May)

General comment: o compare HD – NIKHEF, agree on quantifying effect

Gas mixture:o Continue Ar/CO2/O2 70/27/3

o vary O2 percentageo Long term > 100 hro Cure old damages?

Processing:o Training procedure under N2 or CO2 flushing with ~µA currents and with normal/reverse biaso Burning procedure with reverse voltage > 200hr

Improve knowledge of phenomenon:o Confirm gas flow dependenceo Verify if maximum ageing is at 2nA/cm o Large area irradiation at GIFF; check for Malter effect

Outgassing: o Continue outgassing tests of glue, lubricant.

This talk

CheckedChecked

This talk: confirm HD


Quantifying the damage

Remember:1 pixel = 1 straw x 1cm = 0.5x1 cm2

Normalize the ratio plot: around the damage ≡ 1

Make rings around source position:


Quantifying the damage

I. HD definition biggest avg damage of a ring

II. Max damage Avg damage of 2 worst pixels

III. Summed damage Add damage of each pixel

Average gain loss Integrated gain loss

Question: which ring has more damage: R1 or R3?


55Fe Comparison NIKHEF – HD

Damage

NIKHEF,70nA,30hr (17)

HD,110nA,95hr

20% 50%

HD

NIKHEF

Agreement reasonable


90Sr Comparison NIKHEF - HD

Damage

NIKHEF,120nA,22hr (16)

HD,70nA,27hr

30% 10%Agreement reasonable

HD

NIKHEF


Small current


1450 V:Does it scale with the accumulated charge?

89 hrs, 1450V

21 hrs, 1450V

4x the irradiation time, ¼ x current: 1.5x more damage:

Damage

140nA, 21hr (10,0)

30nA, 89hr (8,3)

Ratio

I. HD 0.80 0.55 2.3II. Max 0.65 0.42 1.7III. Sum

-11.8 -15.1 1.3

Conclusions: Lower acceleration factor, higher damage


1450 V: Maximum damage depends at 10nA

Conclusions:Max damage around ~ 5-10nA?


Very small current: <2.5 nA

Conditions:Flow: Ar/CO2 20 l/hr1600V, 70/30, 90Sr 22 hrs, 125 nA ~ 10mC166hrs, 2.5 nA ~ 1.5mC

Conclusions: Maximum damage at small currents

22 hrs, 125 nA90Sr(test16)

166 hrs,2.5 nA 90Sr

Current profile


Compare large area irradiation

gas

HD: 9 keV X ray, radius ~50cm, 140 hrs, 50 nA (1520V): 80% damageNI: 2mCu 90Sr, radius ~30cm, 14 hrs, 50 nA (1600V): 10% damageBoth: damage upstream, Both: more damage in the center of the module

rechecked

gas

HD

NIKHEF


Oxygen


Flush with Oxygen,vary gas flow

Conditions:Flow: Ar/CO2/O2 70/27.5/2.5 %2mCu, 90Sr source, 68 hrs

Conclusions: Oxygen ages slower by factor 3 Larger flow, larger ageing

Ar/CO2/O2 70/27.5/2.5, 68hrs, 20 l/hr

Ar/CO2/O2 70/27.5/2.5, 46hrs, 10 l/hr

Ar/CO2 70/30, 22hrs, 20 l/hr

Damage

Ar/CO2 70/30, 22hrs, 20 l/hr

Ar/CO2/O2 70/27.5/2.5 , 68hrs, 20 l/hr

Ar/CO2/O2 70/27.5/2.5, 46hrs, 10 l/hr

Rel Gain

Loss Rel Gain

Loss Rel Gain

Loss

I. HD 0.82 -18% 0.88 -12% 0.97 -3%II. Max 0.70 -30% 0.74 -26% 0.89 -11%III. Sum -8.8% -5.2% -2.4%


Did oxygen flushing prevent ageing?

Test to prevent ageing

Conditions:Flow: Ar/CO2 20 l/hr2mCu, 90Sr source on module surface, 16 hours

Conclusions:Ageing as usual. Irradiation after oxygen flushing does not prevent ageing

No oxygen flushing, irradiated 22 hrs: (test 16)

Flushed with oxygen, irradiated 16 hrs: (test 27)

Damage

no flushing O2 flushing

(irr time: 22hr) (irr time: 16hr)

Rel Gain

Loss Rel Gain

Loss

I. HD 0.82 -18% 0.78 -22%II. Max 0.70 -30% 0.67 -33%III. Sum

-8.8% -12.2%


Outgassing

• Long term• Vacuum• Increased flushing


Long term? Outgassing? 3B (30) - 12/4/2006 – 15hr

3A (3) - 15/4/2006 – 23hr

3A (19) - 23/5/2006 – 22hr

Conditions:Flow: Ar/CO2 70/30 20 l/hr

January: in cleanroomFeb – now: in lab

2mCu, 90Sr source

3B (28) - 21/3/2006 – 21.5hr

3B (17) - 23/2/2006 - 15hr

3B (7) - 18/1/2006 - 15hr


Long term?Outgassing?

3B (28) - 21/3/2006 – 21.5hr

3B (30) - 12/4/2006 – 15hr

3A (3) - 15/4/2006 – 23hr

3A (19) - 23/5/2006 – 22hr

3B (17) - 23/2/2006 - 15hr

3B (7) - 18/1/2006 - 15hr

Conditions:Flow: Ar/CO2 70/30 20 l/hr


2mCu, 90Sr source


Damage vs Time

Conditions:Flow: Ar/CO2 70/30 20 l/hr2mCu, 90Sr source


Flushed for 140 days~65,000 liter gas

Mod

Date Loc I(nA)

Time (hrs)

1 3B 18Jan cleanroom

190 15

2 3B 23Feb

Lab 150 15

3 3B 21Mar

Lab 150 21.5

4 3B 12Apr

Lab 150 15

5 3A 15Apr

Lab 180 23

6 3A 23May

Lab 140 22

normalization?15hr

15hr

careful... Also the ‘tape region’ is integrated here!

Point 4 is a bit strange: • Only 15 hrs of irradiation• More damage


Module improves over time?

• Is it outgassing?? Force outgassing with vacuum Force outgassing with flushing


Put 1m-module 1day, 6days under

vacuumConditions:Flow: Ar/CO2 70/30 2mCu, 90Sr source

Conclusions: Forced outgassing in vacuum helps??

Ageing (22hr) before vacuum treatment

Ageing (19hr) after 6 days vacuum treatment

Damage

Before After 1 day After 6 days After 6days+flushing

RelGain

Loss RelGain

Loss RelGain

Loss RelGain Loss

I. HD 0.87 -13% 0.79 -21% 0.93 -7% 0.98 -2%II. Max 0.72 -28% 0.68 -32% 0.86 -14% 0.95 -5%III. Sum

-6.4%

-12.7%

-3.5% -2.6%

Ageing (19hr) after vacuum treatment

Ageing (18hr) additional 50hrs flushing

Note different scale!


Different F-module: 002Test effect of fast flushing

Conditions:Flow: Ar/CO2 70/30 %2mCu, 90Sr source~20hrsFlushing:

140 l/hr Total 21,000 l of N2

Conclusions: Flushing helps only initially?

Ageing (19hr) before flushing Ageing (21hr) after 21,000 l flushing

Damage

Before After 7,400 liter After 21,000 liter

Rel Gain

Loss Rel Gain

Loss Rel Gain

Loss

I. HD 0.54 -46% 0.68 -32% 0.66 -34%II. Max 0.30 -70% 0.43 -57% 0.41 -59%III. Sum

-20.8%

-16.1%

-11.1%

Ageing (19hr) after 7,400 l flushing


Plans at NIKHEF

Outgassing: o Heat module to 35 – 40 oC

Processing:o Training procedure under N2 or CO2 flushing with ~µA currents and with normal/reverse biaso Sputter chambers with Ar/O2 99/1o Burning procedure with reverse voltage > 200hr

Improve knowledge of phenomenon:o Built new test module with minimal componentso Continue outgassing tests of glue, lubricant.


Conclusions

• Bla


Backup SlidesTOF SIMS wire analysis at NIKHEF


TOF SIMS at Philips

What is TOF SIMS?• Time-of-Flight Secondary Ion Mass Spectroscopy

What can it see?• (Part of) molecules

o positively charged oro negatively charged

• Only the top layer (<1 nm)

Same three samples:1) “Dirty”: Irradiated

sample2) “Clean”: Same wire,

but not irradiated3) “New”: New wire

Analysis gun

Primary ion 15 keV Ga+

Ion current density 2 pA

Mass Resolution M/M= 7000

Raster size 100 * 100 µm2


Conclusions from PhilipsConclusions: By TOF-SIMS it is shown that the surface of the “new” wire is rather clean.

The “clean” wire is slightly contaminated by a nitrogen containing organic compound. Furthermore, the “clean” wire is slightly contaminated by polydimethylsiloxane (Si oil).

The “dirty” wire is strongly contaminated by the N-containing organic compound. The TOFSIMS measurements indicate that the carbon layer must be relatively thick. After cleaning the surface by SE sputtering the amount of C, CN-, Cl-, F-, POx- elements/compounds increases significantly. The “dirty” wire contain a high amount of Na, K and Ca. The detected inorganic/organic elements/compounds might be associated to the kapton XC/Al material.

By surface TOFSIMS it is not possible to detect the exact composition and thickness of the thick carbon layer. XPS (X-ray photon electron spectroscopy) might be more suitable to determine the chemical composition of the carbon layer (information depth is 5 nm).


Backup SlidesSpeculations on the

Mechanism


Cartoon of Mechanism?

Gas flow

Neg.charged, C-containing ion Pos.charged, “healing” ion

Glue?



Gas flow


Glue?

Irradiation breaks molecules



Gas flow


Glue? Partly deposited on the wirePartly prevents deposits



Gas flow


Glue?

High dose cleans the wire


Speculation:

This could explain some observations:• The kidney shape • The flow dependence

Larger flow, larger damage: the red ‘healing’ particles are flushed away fast• The oxygen dependence

The electronegative oxygen transports away the blue ‘evil’• The second source observations

Close by the first source the red ‘healing’ particles hamper the ageing Far (downstream) from the first source the red particles are attracted to the

cathode

But how are these observations explained?• The little damage at the sides

During production, the glue at the sides of the panel hardens/outgasses/dries easier

• The little damage in test modules The glue in the test modules had more time to dry before closing the module

• No damage where dose/current is large The large particle rate cleans the wire; the avalanches sputter the wire surface

12 July 2006Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning 1/25 Update ageing...

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