1 / 33

Update ageing measurements at NIKHEF

Explore outgassing hypothesis effects, compare to old data. Examine long-term impact. Study beneficial effects of O2. Conduct ageing with minimal current. Optimize vacuum conditions for accurate measurements.

trick
Download Presentation

Update ageing measurements at NIKHEF

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  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

More Related