70 likes | 217 Vues
HBD Status. C.Woody For the HBD team in 1008. HBD Meeting February 4, 2009. HV testing. Started flowing CF 4 at 2.5 lpm around mid-day on 1/28 Began first HV testing around mid-day on 1/29 (24 hrs ~ 15 turnovers )
E N D
HBD Status C.Woody For the HBD team in 1008 HBD Meeting February 4, 2009
HV testing • Started flowing CF4 at 2.5 lpm around mid-day on 1/28 • Began first HV testing around mid-day on 1/29 (24 hrs ~ 15 turnovers) - Started by applying 500V module by module to all 3 GEMs simultaneously using CAEN supply and monitoring current. Applied voltage through divider with resistors across GEMs removed ( 500V only if no current draw). If we saw a high current in a given module, we then checked each GEM individually. - All modules in the West were good (< 5nA) - Problem GEMs in the East: • Confirmed short on EN4M as seen at Stony Brook • EN4B - 135 nA @ 500V • EN5B - 19 nA @ 500 V • ES1B - 1000 nA @ 150 V; went to more than 4600 nA depending on voltage • Started conditioning EN4B, EN5B and ES1B - Initially conditioned through divider ( VGEM < Vapplied if substantial current draw) - Later applied voltage directly across GEM to ES1B • Status • EN4B - 134 nA @ 500 V (2/1, 21:00) • EN5B - 10 nA @ 500 V (1/31, 12:00) • ES1B - 950 nA @ 500 V (2/3, 17:30) C.Woody, HBD Group Meeting, 2/4/09
Applying HV to detector Started applying HV to the West detector • Connected representative readout pad to the scope. Monitored noise and looked for any signs of discharge • Raised to 2500V in 500V steps, then to operating voltage in 100V steps Operating voltage = voltage from Tom’s table that gives a gain of 2000 Used corrected voltage, but did not correct for actual P/T ( ~ 2.67) • Started with WS5 with Fe55 source Saw nice spectrum (next slide) • All modules came up nicely without a problem • Held at operating voltage for few minutes and then reduced to 2500V • Lowered voltage to zero during magnet ramps • Raised voltage with magnets on All modules went to operating voltage and held for ~ 30 min with no problem C.Woody, HBD Group Meeting, 2/4/09
Fe55 Spectrum for WS5 3788 V G~2000 C.Woody, HBD Group Meeting, 2/4/09
Noise and other related issues • Relay Boards • Will install linear LV supplies in relay board rack (needs approval by Paul Giannotti) • Modified program so that after a trip, the relay to the LeCroy stays closed and only the discharge relay closes (dumps charge through 10K, stays closed for 10 sec, then opens) • Installed pigtail cables so that relay boards can be re-programmed without removing. Will update program to provide feature that if mesh or GEM channel trips, then the other will trip • RTD readout • Tested single channel Lakeshore and Omega readout units with new shielded cable going from HBD rack to HV feed through on detector. • Grounding shield at detector helped a lot. • Omega was ~ factor of 2 worse than Lakeshore (s up to ~ 3 chs) • Installed single Lakeshore with linear power supplies • Still needs cabling to Rob’s readout • Will install 2 new Lakeshores when they arrive in ~ 2 weeks C.Woody, HBD Group Meeting, 2/4/09
Plan for the week • Raise voltage on East detector today - What to do with ES1 ? • What voltage do we want to leave on the detector for the Shift Crew ? • Implement improvements to HV program • Install linear power supplies in relay rack, connect RTD and measure noise • Continue to develop monitoring software C.Woody, HBD Group Meeting, 2/4/09
Run Schedule thru March C.Woody, HBD Group Meeting, 2/4/09