12 July 2006Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning 1/25 Update ageing measurements at NIKHEF 12 July 2006 Niels 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 O 2 Ageing with very small current

12 July 2006Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning 2/25 Recommendation Ageing Workshop (3 April) Outgassing: o Check effect after long term (3-4 weeks) flushing o Heat module to 35 – 40 o C Gas mixture: o Try Ar/CO 2 /O 2 70/27/3 (TRT-like) o Add water (> 5000 ppm) Processing: o Training procedure under N 2 flushing with ~µA currents and with normal/reverse bias o Sputter chambers with Ar/O 2 99/1 o Burning procedure with reverse voltage (cure, prevent?) Improve knowledge of phenomenon: o Continue irradiation to see if gain decrease levels off o Large area irradiation o Built new test module with minimal components o SEM/EDX o Straw o Clean wire Checked; need follow up? This talk This talk: confirm HD Checked < 2000ppm Checked to < 300 hrs Checked: link ; pursued in HDlink Checked

12 July 2006Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning 3/25 Recommendation Ageing Workshop (31 May) General comment: o compare HD – NIKHEF, agree on quantifying effect Gas mixture: o Continue Ar/CO 2 /O 2 70/27/3 o vary O 2 percentage o Long term > 100 hr o Cure old damages? Processing: o Training procedure under N 2 or CO 2 flushing with ~µA currents and with normal/reverse bias o Burning procedure with reverse voltage > 200hr Improve knowledge of phenomenon: o Confirm gas flow dependence o 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 Checked This talk: confirm HD

12 July 2006Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning 4/25 Quantifying the damage Remember: 1 pixel = 1 straw x 1cm = 0.5x1 cm 2 Normalize the ratio plot:  around the damage ≡ 1 Make rings around source position:

12 July 2006Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning 5/25 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 lossIntegrated gain loss Question: which ring has more damage: R1 or R3?

12 July 2006Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning 6/25 55 Fe Comparison NIKHEF – HD DamageNIKHEF,70nA,30hr (17) HD,110nA,95hr 20%50% HD NIKHEF Agreement reasonable

12 July 2006Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning 7/25 90 Sr Comparison NIKHEF - HD DamageNIKHEF,120nA,22hr (16) HD,70nA,27hr 30%10% Agreement reasonable HD NIKHEF

12 July 2006Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning 8/25 Small current

12 July 2006Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning 9/ 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: Damage140nA, 21hr (10,0) 30nA, 89hr (8,3) Ratio I. HD II. Max III. Sum Conclusions:  Lower acceleration factor, higher damage

12 July 2006Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning 10/ V: Maximum damage depends at 10nA Conclusions:  Max damage around ~ 5-10nA?

12 July 2006Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning 11/25 Very small current: <2.5 nA Conditions:  Flow: Ar/CO 2 20 l/hr  1600V, 70/30, 90 Sr  22 hrs, 125 nA ~ 10mC  166hrs, 2.5 nA ~ 1.5mC Conclusions:  Maximum damage at small currents 22 hrs, 125 nA 90 Sr (test16) 166 hrs, 2.5 nA 90 Sr Current profile

12 July 2006Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning 12/25 Compare large area irradiation gas  HD: 9 keV X ray, radius ~50cm, 140 hrs, 50 nA (1520V): 80% damage  NI: 2mCu 90 Sr, radius ~30cm, 14 hrs, 50 nA (1600V): 10% damage  Both: damage upstream,  Both: more damage in the center of the module rechecked gas HD NIKHEF

12 July 2006Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning 13/25 Oxygen

12 July 2006Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning 14/25 Flush with Oxygen, vary gas flow Conditions:  Flow: Ar/CO 2 /O 2 70/27.5/2.5 %  2mCu, 90 Sr source, 68 hrs Conclusions:  Oxygen ages slower by factor 3  Larger flow, larger ageing Ar/CO 2 /O 2 70/27.5/2.5, 68hrs, 20 l/hr Ar/CO 2 /O 2 70/27.5/2.5, 46hrs, 10 l/hr Ar/CO 2 70/30, 22hrs, 20 l/hr Damage Ar/CO2 70/30, 22hrs, 20 l/hr Ar/CO 2 /O 2 70/27.5/2.5, 68hrs, 20 l/hr Ar/CO 2 /O 2 70/27.5/2.5, 46hrs, 10 l/hr Rel GainLossRel GainLossRel GainLoss I. HD % %0.97-3% II. Max % % % III. Sum-8.8%-5.2%-2.4%

12 July 2006Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning 15/25 Did oxygen flushing prevent ageing? Test to prevent ageing Conditions:  Flow: Ar/CO 2 20 l/hr  2mCu, 90 Sr 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) Damageno flushing O 2 flushing (irr time: 22hr)(irr time: 16hr) Rel GainLossRel GainLoss I. HD % % II. Max % % III. Sum-8.8%-12.2%

12 July 2006Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning 16/25 Outgassing Long term Vacuum Increased flushing

12 July 2006Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning 17/25 Long term? Outgassing? 3B (30) - 12/4/2006 – 15hr 3A (3) - 15/4/2006 – 23hr 3A (19) - 23/5/2006 – 22hr Conditions:  Flow: Ar/CO 2 70/30 20 l/hr  January: in cleanroom  Feb – now: in lab  2mCu, 90 Sr source 3B (28) - 21/3/2006 – 21.5hr 3B (17) - 23/2/ hr 3B (7) - 18/1/ hr

12 July 2006Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning 18/25 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/ hr 3B (7) - 18/1/ hr Conditions:  Flow: Ar/CO 2 70/30 20 l/hr  January: in cleanroom  Feb – now: in lab  2mCu, 90 Sr source

12 July 2006Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning 19/25 Damage vs Time Conditions:  Flow: Ar/CO 2 70/30 20 l/hr  2mCu, 90 Sr source  January: in cleanroom  Feb – now: in lab  Flushed for 140 days  ~65,000 liter gas ModDateLocI(nA)Time (hrs) 13B18Jancleanroom B23FebLab B21MarLab B12AprLab A15AprLab A23MayLab14022 normalization? 15hr careful... Also the ‘tape region’ is integrated here! Point 4 is a bit strange: Only 15 hrs of irradiation More damage

12 July 2006Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning 20/25 Module improves over time? Is it outgassing??  Force outgassing with vacuum  Force outgassing with flushing

12 July 2006Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning 21/25 Put 1m-module 1day, 6days under vacuum Conditions:  Flow: Ar/CO 2 70/30  2mCu, 90 Sr source Conclusions:  Forced outgassing in vacuum helps?? Ageing (22hr) before vacuum treatment Ageing (19hr) after 6 days vacuum treatment DamageBeforeAfter 1 dayAfter 6 daysAfter 6days+flushing RelGainLossRelGainLossRelGainLossRelGainLoss I. HD % %0.93-7%0.98-2% II. Max % % %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!

12 July 2006Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning 22/25 Different F-module: 002 Test effect of fast flushing Conditions:  Flow: Ar/CO 2 70/30 %  2mCu, 90 Sr source~20hrs  Flushing:  140 l/hr  Total 21,000 l of N 2 Conclusions:  Flushing helps only initially? Ageing (19hr) before flushingAgeing (21hr) after 21,000 l flushing DamageBefore After 7,400 literAfter 21,000 liter Rel GainLossRel GainLossRel GainLoss I. HD % % % II. Max % % % III. Sum-20.8%-16.1%-11.1% Ageing (19hr) after 7,400 l flushing

12 July 2006Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning 23/25 Plans at NIKHEF Outgassing: o Heat module to 35 – 40 o C Processing: o Training procedure under N 2 or CO 2 flushing with ~µA currents and with normal/reverse bias o Sputter chambers with Ar/O 2 99/1 o Burning procedure with reverse voltage > 200hr Improve knowledge of phenomenon: o Built new test module with minimal components o Continue outgassing tests of glue, lubricant.

12 July 2006Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning 24/25 Conclusions Bla

12 July 2006Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning 25/25 Backup Slides TOF SIMS wire analysis at NIKHEF

12 July 2006Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning 26/25 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 or o negatively charged Only the top layer (<1 nm) Same three samples: 1)“Dirty”: Irradiated sample 2)“Clean”: Same wire, but not irradiated 3)“New”: New wire Analysis gun Primary ion15 keV Ga + Ion current density2 pA Mass Resolution M/  M= 7000 Raster size100 * 100 µm 2

12 July 2006Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning 27/25 Conclusions from Philips Conclusions: 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).

12 July 2006Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning 28/25 Backup Slides Speculations on the Mechanism

12 July 2006Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning 29/25 Cartoon of Mechanism? Gas flow Neg.charged, C-containing ion Pos.charged, “healing” ion Glue?

12 July 2006Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning 30/25 Cartoon of Mechanism? Gas flow Neg.charged, C-containing ion Pos.charged, “healing” ion Glue? Irradiation breaks molecules

12 July 2006Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning 31/25 Cartoon of Mechanism? Gas flow Neg.charged, C-containing ion Pos.charged, “healing” ion Glue? Partly deposited on the wire Partly prevents deposits

12 July 2006Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning 32/25 Cartoon of Mechanism? Gas flow Neg.charged, C-containing ion Pos.charged, “healing” ion Glue? High dose cleans the wire

12 July 2006Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning 33/25 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