1. HBD Meeting 4/25/06 SB and BNL Crew

2. 4/25/06 B. Azmoun 2 Installation of HBD into PHENIX Transported HBD from USB under gas (CF4) flow (maintained ~ 1Torr overpressure for ~ 2- 3hrs) Installation was difficult, but went smoothly…Don Lynch suggested the use of temporary lifting handles connected to mounting points during installation of final detector Flash Lamp Positioning HBD into place Also,15%  o Pb converter mounted over ½ area of GEM active area

3. 4/25/06 B. Azmoun 3 HBD Hutch Set up Shop in Space beneath South-side stairs in assembly hall –Ultimately this space is for the Transmission monitor –Some gas flow controls & H2O and O2 monitors & P/T Monitor –2 signal cables + Pulser for PA + Flash lamp Trigger Pad “lucky” #13  Fe55 (2uCi source)  Masked from light Pad # 49  Open to light

4. 4/25/06 B. Azmoun 4 Daily Checks Absolute Gain @ 1 GEM voltage:  V = 495V –Gain consistent w/ USB measurements ~ 9x10 3 Flash Lamp test (PD mode, gain mode) –PD Flash lamp tests also consistent: pulse ~ 520mV in PD mode H2O & O2 –PPM levels seem to be a little higher at PHENIX than at USB…calibration error??? USB PHENIX

5. 4/25/06 B. Azmoun 5 HBD Flash-lamp Event Display (pe signal avalanche through GEMs and map onto hex pads) Pad 13 shadowed by Fe55 2 known dead strips, but there are two others w/ position unknown Sum along strips Sum perp. to strips Known dead strips Known dead strips Possible position of unknown dead strips

6. 4/25/06 B. Azmoun 6 Flash Lamp: Photon Flux Calc’s PD Mode: Entire PC (No Attenuator) –  I = 500mV/50ohm = 0.01C/sec –½ * 0.01 C/sec * 1.2usec = 6nC = 3.75x10 10 pe –3.75x10 10 pe / 0.3 (int. QE) =1.25 x10 11  (entire PC) –1.25 x10 11  (PC) *[1920 (Pad 49)/73317(PC)] = 3.27x10 9  pad #49) 3.27x10 9  pad #49) PC Lifetime…will the flash-lamp harm the PC? –Charge not to exceed 140uC/cm 2 –6nC/(25x25cm 2 ) = 9.6pC/cm 2 –Each test: ~2Hz for ½ hour = 3600 flashes –3600 flashes * 9.6pC/cm 2 = 34.6nC/cm 2 (each test) –# of tests before PC degradation: (140uC/cm 2 )/(34.6nC/cm 2 ) > 4000 tests > 4000 tests Gain Mode: Monitor single pad # 49 (GEM Attenuator) –PA signal (pad #49) = 1920mV @ Gain ~ 250 (  V = 427V) –PA calib.: 2000e-/mV –1920mV * 2000e-/mV = 3.8x10 6 e-’s  3.8x10 6 e-’s / 250 = 1.5x10 4 pe’s –1.5x10 4 pe’s / 0.3 int. QE = 5.12x10 4  (pad #49) Attenuation Factor from 3GEM at Pad #49 –3GEM Attenuator: 5.12x10 4 , No Attenuator: 3.27x10 9  –Attenuation Factor: 3.2x10 9 / 5.12x10 4 = 6.25x10 4 –Attenuation per GEM: (6.25x10 4 ) 1/3 = 39.7 (Probably not this simple) Flash Lamp Pulse (Noise Free)

7. 4/25/06 B. Azmoun 7 Beam Test: Preparation Noise (Baseline ~ 10-20mV p-p) Occasional Oscillating pulses (Corona?) PPM: H2O ~25ppm, O2 ~15ppm (total = 40ppm) Baseline Oscillating Pulses MIP/Fe55/ pe Pulses ~1pe/10ppm

8. 4/25/06 B. Azmoun 8 Beam Test: First look at Signals (Qualitative Results) First Beam this past Saturday (4/22/06) Primary charge –MIP: 7kEv/cm * 3mm / (54eV e-ion pair) * (1.2 rel. rise) = 46.6 e- –Fe55 in CF4: 5.89keV x-ray/(54 eV/e-ion pair) = 109pe (Pad # 13 only) –Photoelectron yield (Cherenkov spectrum + CsI QE ): 36pe-s total  ~15-20 pe per pad max (Pad # 13 masked off) Rate of electrons  15% radiation length MIPS in 100um gap (1.6e-) Fe55 in 100um gap (109e-) Other particles MIPS in 3mm gap (46.6e-) Fe55 in DG (109e-) Other particles MIPS in 100um gap (1.6e-) Cherenkov (1-20max pe/pad) Other particles MIPS in 3mm gap (46.6e-) Cherenkov (1-20max pe/pad) Other particles FB  DG=0.8kV/cm  Loss of pe coll. Efficiency?

9. 4/25/06 B. Azmoun 9 Fe55 Spectrum w/ HBD in IR: Beam Off Peak of spectrum is centered on ~109pe as expected  calibration check for previous measurements (assumed gain was 9.0x10 3 @ Vin= 3700V (  V=495V), DG = 0.8kV/cm )

10. 4/25/06 B. Azmoun 10Outlook Quantitative Beam tests to determine N o (CF4) with HBD in “dead turtle” position – Method of normalizing and subtracting pad 49 spectra from pad 13 spectra Continue to monitor ppm’s  will increase flow rate if needed in order to improve gas purity. Looking ahead: if opportunity permits (during short access), we’ll connect to and check electronics chain, and possibly take data.