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Update ageing measurements at NIKHEF

Update ageing measurements at NIKHEF. 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 2006

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Update ageing measurements at NIKHEF

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  1. Update ageing measurementsat NIKHEF • 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 12 July 2006 Niels Tuning, Gras van Apeldoorn, Antonio Pellegrino Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning

  2. Recommendation Ageing Workshop (3 April) This talk Checked • Outgassing: • Check effect after long term (3-4 weeks) flushing • Heat module to 35 – 40 oC • Gas mixture: • Try Ar/CO2/O2 70/27/3 (TRT-like) • Add water (> 5000 ppm) • Processing: • Training procedure under N2 flushing with ~µA currents and with normal/reverse bias • Sputter chambers with Ar/O2 99/1 • Burning procedure with reverse voltage (cure, prevent?) • Improve knowledge of phenomenon: • Continue irradiation to see if gain decrease levels off • Large area irradiation • Built new test module with minimal components • SEM/EDX • Straw • Clean wire This talk: confirm HD Checked < 2000ppm Checked; need follow up? Checked to < 300 hrs Checked: link ; pursued in HD Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning

  3. Recommendation Ageing Workshop (31 May) This talk Checked Checked • General comment: • compare HD – NIKHEF, agree on quantifying effect • Gas mixture: • Continue Ar/CO2/O2 70/27/3 • vary O2 percentage • Long term > 100 hr • Cure old damages? • Processing: • Training procedure under N2 or CO2 flushing with ~µA currents and with normal/reverse bias • Burning procedure with reverse voltage > 200hr • Improve knowledge of phenomenon: • Confirm gas flow dependence • Verify if maximum ageing is at 2nA/cm • Large area irradiation at GIFF; check for Malter effect • Outgassing: • Continue outgassing tests of glue, lubricant. This talk: confirm HD Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning

  4. 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: Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning

  5. Quantifying the damage • HD definition • biggest avg damage of a ring • Max damage • Avg damage of 2 worst pixels • Summed damage • Add damage of each pixel Average gain loss Integrated gain loss Question: which ring has more damage: R1 or R3? Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning

  6. 55Fe Comparison NIKHEF – HD Agreement reasonable HD NIKHEF Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning

  7. 90Sr Comparison NIKHEF - HD Agreement reasonable HD NIKHEF Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning

  8. Small current Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning

  9. 1450 V:Does it scale with the accumulated charge? • Conclusions: • Lower acceleration factor, higher damage 21 hrs, 1450V 4x the irradiation time, ¼ x current: 1.5x more damage: 89 hrs, 1450V Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning

  10. 1450 V: Maximum damage depends at 10nA • Conclusions: • Max damage around ~ 5-10nA? Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning

  11. Very small current: <2.5 nA Current profile • Conditions: • Flow: Ar/CO2 20 l/hr • 1600V, 70/30, 90Sr • 22 hrs, 125 nA ~ 10mC • 166hrs, 2.5 nA ~ 1.5mC • Conclusions: • Maximum damage at small currents 22 hrs, 125 nA 90Sr (test16) 166 hrs, 2.5 nA 90Sr Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning

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

  13. Oxygen Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning

  14. Flush with Oxygen,vary gas flow Ar/CO2 70/30, 22hrs, 20 l/hr • 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 Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning

  15. Did oxygen flushing prevent ageing? No oxygen flushing, irradiated 22 hrs: (test 16) • Test to prevent ageing • Conditions: • Flow: Ar/CO2 20 l/hr • 2mCu, 90Sr source on module surface, 16 hours • Conclusions: • Ageing as usual. • Irradiation after oxygen flushing does not prevent ageing Flushed with oxygen, irradiated 16 hrs: (test 27) Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning

  16. Outgassing • Long term • Vacuum • Increased flushing Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning

  17. Long term? Outgassing? 3B (30) - 12/4/2006 – 15hr 3B (7) - 18/1/2006 - 15hr • Conditions: • Flow: Ar/CO2 70/30 20 l/hr • January: in cleanroom • Feb – now: in lab • 2mCu, 90Sr source 3A (3) - 15/4/2006 – 23hr 3B (17) - 23/2/2006 - 15hr 3B (28) - 21/3/2006 – 21.5hr 3A (19) - 23/5/2006 – 22hr Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning

  18. Long term?Outgassing? • Conditions: • Flow: Ar/CO2 70/30 20 l/hr • January: in cleanroom • Feb – now: in lab • 2mCu, 90Sr source 3B (30) - 12/4/2006 – 15hr 3B (7) - 18/1/2006 - 15hr 3B (17) - 23/2/2006 - 15hr 3A (3) - 15/4/2006 – 23hr 3B (28) - 21/3/2006 – 21.5hr 3A (19) - 23/5/2006 – 22hr Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning

  19. Damage vs Time • Conditions: • Flow: Ar/CO2 70/30 20 l/hr • 2mCu, 90Sr source • January: in cleanroom • Feb – now: in lab • Flushed for 140 days • ~65,000 liter gas normalization? 15hr careful... Also the ‘tape region’ is integrated here! 15hr • Point 4 is a bit strange: • Only 15 hrs of irradiation • More damage Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning

  20. Module improves over time? • Is it outgassing?? • Force outgassing with vacuum • Force outgassing with flushing Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning

  21. Ageing (22hr) before vacuum treatment Put 1m-module 1day, 6days under vacuum • Conditions: • Flow: Ar/CO2 70/30 • 2mCu, 90Sr source Conclusions: • Forced outgassing in vacuum helps?? Ageing (19hr) after vacuum treatment Ageing (19hr) after 6 days vacuum treatment Note different scale! Ageing (18hr) additional 50hrs flushing Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning

  22. Different F-module: 002Test effect of fast flushing • Conditions: • Flow: Ar/CO2 70/30 % • 2mCu, 90Sr source~20hrs • Flushing: • 140 l/hr • Total 21,000 l of N2 Conclusions: • Flushing helps only initially? Ageing (19hr) before flushing Ageing (19hr) after 7,400 l flushing Ageing (21hr) after 21,000 l flushing Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning

  23. Plans at NIKHEF • Outgassing: • Heat module to 35 – 40 oC • Processing: • Training procedure under N2 or CO2 flushing with ~µA currents and with normal/reverse bias • Sputter chambers with Ar/O2 99/1 • Burning procedure with reverse voltage > 200hr • Improve knowledge of phenomenon: • Built new test module with minimal components • Continue outgassing tests of glue, lubricant. Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning

  24. Conclusions • Bla Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning

  25. Backup SlidesTOF SIMS wire analysis at NIKHEF Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning

  26. TOF SIMS at Philips • What is TOF SIMS? • Time-of-Flight Secondary Ion Mass Spectroscopy • What can it see? • (Part of) molecules • positively charged or • negatively charged • Only the top layer (<1 nm) • Same three samples: • “Dirty”:Irradiated sample • “Clean”:Same wire, but not irradiated • “New”:New wire Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning

  27. 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). Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning

  28. Backup SlidesSpeculations on the Mechanism Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning

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

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

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

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

  33. 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 Update ageing measurements at NIKHEF - Ageing Workshop - Niels Tuning

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