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HBD Meeting 4/25/06

HBD Meeting 4/25/06. SB and BNL Crew. Installation of HBD into PHENIX. Transported HBD from USB under gas (CF4) flow (maintained ~ 1Torr overpressure for ~ 2-3hrs)

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HBD Meeting 4/25/06

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  1. HBD Meeting4/25/06 SB and BNL Crew

  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 Positioning HBD into place Flash Lamp Also,15% Co Pb converter mounted over ½ area of GEM active area 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 B. Azmoun

  4. Daily Checks • Absolute Gain @ 1 GEM voltage: DV = 495V • Gain consistent w/ USB measurements ~ 9x103 • 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??? PHENIX USB B. Azmoun

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

  6. Flash Lamp: Photon Flux Calc’s • PD Mode: Entire PC (No Attenuator) • dI = 500mV/50ohm = 0.01C/sec • ½ * 0.01 C/sec * 1.2usec = 6nC = 3.75x1010pe • 3.75x1010pe / 0.3 (int. QE) =1.25 x1011g (entire PC) • 1.25 x1011g (PC) *[1920 (Pad 49)/73317(PC)] = 3.27x109 g (pad #49) • PC Lifetime…will the flash-lamp harm the PC? • Charge not to exceed 140uC/cm2 • 6nC/(25x25cm2) = 9.6pC/cm2 • Each test: ~2Hz for ½ hour = 3600 flashes • 3600 flashes * 9.6pC/cm2 = 34.6nC/cm2 (each test) • # of tests before PC degradation: (140uC/cm2)/(34.6nC/cm2) > 4000 tests • Gain Mode: Monitor single pad # 49 (GEM Attenuator) • PA signal (pad #49) = 1920mV @ Gain ~ 250 (DV = 427V) • PA calib.: 2000e-/mV • 1920mV * 2000e-/mV = 3.8x106 e-’s  3.8x106 e-’s / 250 = 1.5x104pe’s • 1.5x104pe’s / 0.3 int. QE = 5.12x104g (pad #49) • Attenuation Factor from 3GEM at Pad #49 • 3GEM Attenuator: 5.12x104g , No Attenuator: 3.27x109 g • Attenuation Factor: 3.2x109 / 5.12x104 = 6.25x104 • Attenuation per GEM: (6.25x104)1/3 = 39.7 (Probably not this simple) Flash Lamp Pulse (Noise Free) B. Azmoun

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

  8. 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 3mm gap (46.6e-) • Cherenkov (1-20max pe/pad) • Other particles • MIPS in 100um gap (1.6e-) • Cherenkov (1-20max pe/pad) • Other particles 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 FB  DG=0.8kV/cm Loss of pe coll. Efficiency? 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 9.0x103 @ Vin= 3700V (DV=495V), DG = 0.8kV/cm ) B. Azmoun

  10. Outlook • Quantitative Beam tests to determine No (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. B. Azmoun

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