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HBD HV Commissioning. Itzhak Tserruya, HBD meeting, February 20, 2006. A few comments. The procedure followed during the last days is working very well. The detailed logs are extremely useful for a real assessment of the data.
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HBD HV Commissioning Itzhak Tserruya, HBD meeting, February 20, 2006
A few comments • The procedure followed during the last days is working very well. • The detailed logs are extremely useful for a real assessment of the data. • We should complete this module by module conditioning as soon as possible. • We need to collect together all information relevant to a given module. • We should take pedestals and perform pulser calibration.
Modules conditioned so far EN0 EN1 EN2 EN3 EN4 EN5 14/2 13/2 16/2 18/2 18/2 18/2 ES0 ES1 ES2 ES3 ES4 ES5 15/2 19/2 19/2 WN0 WN1 WN2 WN3 WN4 WN5 19/2 16/2 14/2 18/2 18/2 WS0 WS1 WS2 WS3 WS4 WS5 15/2 19/2 13/2 18/2 13/2: EN1, WS4 14/2: EN0, WN2 15/2: ES0, WS0 16/2: EN2, WN1 17/2 18/2: EN3, EN4, EN5, WS4, WN3, WN5 19/2: ES1, ES5, WS3,WN0
WN5 (18/2) • No trip in ramping up to 3600 V • 4h at 3600 V: 0 trip • present configuration (TMB): 10 10 10 • Bertan test: Top: 6microamp at 520V --> top total impedance 86.7M Middle and bottom GEMs normal. • looking at the history since the GEM by GEM Bertan tests, WN5 has been very stable, drawing a current of about dI = 0.3% at 3000 V. This current is consistent with the 86.7M total impedance. • At 3600 V the M and B GEMs are at 483.9V. But the top GEM is at 439.7V • I think this is a good module. We need to replace the 10M of the top GEM by an appropriate resistor ( ~11.3M) to restore the normal voltage across the top GEM.
EN4 (18/2) • 3600 V: 3 trips in 25 minutes • 3550 V: 4 trips in 40 minutes • 3500 V: 3 trips in 25 minutes • 3450 V: 3 trips in 50 minutes • present configuration (TMB) 20 10 10. • Bertan test: Top: 18microamp at 520V --> total impedance 28.9MOhm • Midle and Bottom GEMs normal. • A 20MOhm has ben installed in the Top GEM (apparently after the Bertan test?) • Looking at the history since the GEMby GEM Bertan tests, EN4 has been very stable, drawing a current of about dI = -0.6% at 3000 V. With an impedance of 28.9MOhm we would expect dI = -0.8%. • At 3600 V the M and B GEMs are at 483.9V. If we use the impedance of 28.9MOhm, the top GEM is at 558 V !! This could explain the multiple trips. I think we should avoid negative currents. They result in over-voltages on the GEMs
EN4 (18/2) • 3600 V: 3 trips in 25 minutes • 3550 V: 4 trips in 40 minutes • 3500 V: 3 trips in 25 minutes • 3450 V: 3 trips in 50 minutes • present configuration (TMB) 20 10 10. • Bertan test: Top: 18microamp at 520V --> total impedance 28.9MOhm • Midle and Bottom GEMs normal. • A 20MOhm has ben installed in the Top GEM (apparently after the Bertan test?) • Looking at the history since the GEMby GEM Bertan tests, EN4 has been very stable, drawing a current of about dI = -0.6% at 3000 V. With an impedance of 28.9MOhm we would expect dI = -0.8%. • At 3600 V the M and B GEMs are at 483.9V. If we use the impedance of 28.9MOhm, the top GEM is at 558 V !! This could explain the multiple trips. I think we should avoid negative currents. They result in over-voltages on the GEMs
ES1 (12/2) • 3600 V: 1 trip in about 5.5 h (could have been induced by EN4 that draws negative current and was taken to 3550 V a few minutes before the trip) • present configuration (TMB) 10 10 10. • Bertan test: Top: 5 microamp at 520V --> total impedance 104MOhm • Midle and Bottom GEMs normal • Looking at the history since the GEMby GEM Bertan tests, ES1 has not been very stable.