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HBD Conditioning Update 16 Jan 2007

HBD Conditioning Update 16 Jan 2007. Jason, representing just about everybody. HV GUI Version 9. List of loadable tables. Displays date/time. Records all present values/parameters to file. Improved common buttons. Only one En/Dis button per module. % current difference from nominal.

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HBD Conditioning Update 16 Jan 2007

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  1. HBD Conditioning Update 16 Jan 2007 Jason, representing just about everybody

  2. HV GUI Version 9 List of loadable tables. Displays date/time. Records all present values/parameters to file. Improved common buttons Only one En/Dis button per module. % current difference from nominal. The HV GUI has been changing/improving on a daily basis!! Thanks Takao! Plus many other improvements, some you can see and some that you can’t.

  3. 15 Jan 2007 WEST EAST NORTH SOUTH NORTH SOUTH Seemingly good modules gone bad. up to 3600… 2000V dI: 0.30% 5 short ??? 3000V dI: 0.46% 2000V dI: 0.26% up to 3600… trip/short on 09Jan 19:04 short ??? up to 3400… 3000V 4 up to 3600… 3000V up to 3600… trip/short on 12Jan 21:30 short ??? short ??? 3 up to 3600… 3000V MID: did some work, needs more bertan. TOP: (bertan) MID: (bertan) 2 up to 3600… 3000V MID (20MΩ) 2600V up to 3600… 3000V dI: 0.33% up to 3600… HV cover open 1 2600V 3000V TOP (20MΩ) 3000V dI: 0.27% MID (20MΩ) BOT (20MΩ) up to 3600… 3000V 0 2600V

  4. 15 Jan 2007 WEST EAST NORTH SOUTH NORTH SOUTH up to 3600… 2000V dI: 0.30% 5 short ??? 3000V dI: 0.46% 2000V dI: 0.26% up to 3600… trip/short on 09Jan 19:04 short ??? up to 3400… 3000V 4 up to 3600… 3000V Seemingly good modules going bad?? up to 3600… trip/short on 12Jan 21:30 short ??? short ??? 3 up to 3600… 3000V MID: did some work, needs more bertan. TOP: (bertan) MID: (bertan) 2 up to 3600… 3000V MID (20MΩ) 2600V up to 3600… 3000V dI: 0.33% up to 3600… HV cover open 1 2600V 3000V TOP (20MΩ) 3000V dI: 0.27% MID (20MΩ) BOT (20MΩ) up to 3600… 3000V 0 2600V

  5. 15 Jan 2007 WEST EAST NORTH SOUTH NORTH SOUTH up to 3600… 2000V dI: 0.30% 5 short ??? 3000V dI: 0.46% 2000V dI: 0.26% up to 3600… trip/short on 09Jan 19:04 short ??? up to 3400… 3000V 4 up to 3600… 3000V up to 3600… trip/short on 12Jan 21:30 short ??? short ??? 3 up to 3600… 3000V dead-shorted strips, Replaced resistor with 20 MΩ MID: did some work, needs more bertan. TOP: (bertan) MID: (bertan) 2 up to 3600… 3000V MID (20MΩ) 2600V up to 3600… 3000V dI: 0.33% up to 3600… HV cover open 1 2600V 3000V TOP (20MΩ) 3000V dI: 0.27% MID (20MΩ) BOT (20MΩ) up to 3600… 3000V 0 2600V

  6. 15 Jan 2007 WEST EAST NORTH SOUTH NORTH SOUTH up to 3600… 2000V dI: 0.30% 5 short ??? 3000V dI: 0.46% 2000V dI: 0.26% up to 3600… trip/short on 09Jan 19:04 short ??? up to 3400… 3000V 4 up to 3600… 3000V up to 3600… trip/short on 12Jan 21:30 short ??? short ??? 3 up to 3600… 3000V MID: did some work, needs more bertan. TOP: (bertan) MID: (bertan) 2 up to 3600… 3000V MID (20MΩ) 2600V up to 3600… 3000V dI: 0.33% up to 3600… HV cover open 1 2600V 3000V Shows short on LeCroy, but not ID’d with Bertan (yet). TOP (20MΩ) 3000V dI: 0.27% MID (20MΩ) BOT (20MΩ) up to 3600… 3000V 0 2600V

  7. HV conditioning w/ Bertan • 09 Jan morning: • ramp↑ (20V, 50V, 75V) to 100V • tripped. • ramp↑ (in 50V steps) to 350V • nom_I: 8μA …waited… • ~10 min, current dropped to 3μA. • ramp↓ voltage • ramp↑ (25V steps) to 350V. • Held steady drawing 250 nA. • Ramped down, closed HV cover note: log scale! • 09 Jan evening: • ramp↑ with LeCroy • tripped at 2600V (or was this 3200V??) • does anybody know for sure? • now shows short.  • needs to be checked with Bertan (again!).

  8. HV conditioning w/ Bertan • 10 Jan: • ramp↑ ~400V • multiple trips. • drawing ~800nA, • then big trip! • linear curve (20MΩ) • shock therapy at 520: • no response. • installed 20MΩ resistor. Presently sitting at 2600V with LeCroy, no problems (yet!!).

  9. HV conditioning w/ Bertan • 10 Jan: • new method: • ramp↑ • wait for current to drop some amount (few hundred nA) • nudge voltage ↑ to maintain similar current draw. • repeat. • occasional trips. • considered slow, steady progress.

  10. HV conditioning w/ Bertan • 11,12 Jan: • slow progress • 13 Jan: • sudden increase in current overnight • this is a mystery… • 14 Jan: • worse than 13 Jan. • at 300V, 7000 nA: • major current draw! • linear curve (20MΩ) • shock therapy at 520: • no response. • installed 20MΩ resistor. • 11 Jan: • EN0 middle & bottom • linear curve (20MΩ) • shock therapy at 520: • no response. • installed 20MΩ resistor.

  11. HV conditioning w/ Bertan • 13 Jan: • slow progress • 14 Jan: • ramp↑ more aggressively • 495V (164 nA→ 15 nA) • 510V (17 nA→ 515 nA) • ramp↓, ramp↑, ramp↓ • major current draw • not dead-short • ~700 MΩ

  12. “Completely experiential recipe” for conditioning GEMS: • If we stick with conditioning in CF4: • ramp GEM up with Bertan in 20-50 V increments • pause at each new voltage for 1-5 min • at higher voltages take longer pauses • around 300V, pay extra-close attention… • typically between 350-400 V, current might be ~6 μA or more! • wait… • current will drop dramatically! • reduce voltage!! • let GEM “cool off” • measure a new voltage-current curve, your GEM should be (hopefully) cured. •  This is not to be taken too literally as the TRUTH. We don’t know why it works (or if it will work again) but both times we did it this way, we seemed to “fix” the GEM.

  13. CF4 at Stony Brook • 15 Jan: • attached LeCroy to 2R divider chain to gain test box. • filled with CF4. • ramp↑ voltage on a very conditioned stack. • has been running for few weeks at 2680V in ArCO2. • ramp↑ to 3000V, tripped. • ramp↑ to 3600V, saw clear 55Fe spectrum, tripped. • ramp↑ to 500V • noticed slightly high current draw. • increased trip current (1.5% to 3%). • ramp↑ to 3600V: • gain of spectrum was reduced. • signal was difficult to distinguish. • Shut off voltage. • The Point??? • Essentially, the 1st (actually 2nd)spark in CF4 killed us. • Many sparks in nitrogen & ArCO2 were never a problem.

  14. Is CF4 the right conditioning gas?? • In theory, CF4 has 2 problems: • “C” and “F” • If you want to build molecular chains/bonds across a GEM: • Slowly burn CF4! • Carbon becomes solid and attached to anything. • Flourine is the most chemically reactive/electro-negative element. • Sparks in CF4 are much more dangerous than sparks in nitrogen. • Why not CONDITION IN NITROGEN?? • At Stony Brook, we routinely spark GEMs in order to condition them. • All GEMs have high, stable gain afterwards (well-documented). • This is the slide meant to encourage discussion!! ;-)

  15. 15 Jan 2007 SUMMARY WEST EAST NORTH SOUTH NORTH SOUTH up to 3600… 2000V dI: 0.30% 5 short ??? 3000V dI: 0.46% Good modules 2000V dI: 0.26% up to 3600… trip/short on 09Jan 19:04 short ??? up to 3400… 3000V 4 up to 3600… 3000V Seemingly good modules gone bad. up to 3600… trip/short on 12Jan 21:30 short ??? short ??? 3 up to 3600… 3000V Seemingly good modules going bad?? MID: did some work, needs more bertan. TOP: (bertan) MID: (bertan) 2 up to 3600… 3000V MID (20MΩ) dead-shorted strips, Replaced resistor with 20 MΩ 2600V up to 3600… 3000V dI: 0.33% up to 3600… HV cover open 1 2600V 3000V Shows short on LeCroy, but not ID’d with Bertan (yet). TOP (20MΩ) 3000V dI: 0.27% MID (20MΩ) BOT (20MΩ) up to 3600… 3000V 0 2600V

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