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Prototype Calibration System for Forward Hadron Calorimeter. L. Almeida, M. Baarmand, L. Caraway, M. Hohlmann, T. Qureshi, I. Vodopianov FLORIDA TECH. Electronic pulser for ~100 ns LED pulses w/ single-shot and external trigger capability. 10 m jacketed light fiber. 1->4 light splitter.
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Prototype Calibration System for Forward Hadron Calorimeter L. Almeida, M. Baarmand, L. Caraway, M. Hohlmann, T. Qureshi, I. Vodopianov FLORIDA TECH Electronic pulser for ~100 ns LED pulses w/ single-shot and external trigger capability 10 m jacketed light fiber 1->4 light splitter 1->9 light splitter w/ pulsed LEDs, input for UV laser pulses, and PIN diode light monitoring
HF Calibration Optical Fiber Path Test Beam 2002 Counting Room N2 Laser 200 mJ 337 nm 300 QQ 75m 9 PMT Boxes 9 PMT Boxes 1 4 300 QQ 9m 9 PMT Boxes 9 PMT Boxes Bottom Rack 9 Calib Box 600 QP 18m
Calibration Box -1 x 9 splitter PIN Diode 4mm 4mm 300 QQ ADC LED 1 PIN2 MIXER 50mm 15mm 15mm Polystyrene PIN1 PIN3 LED 2 600 QP 9 Blue Scintilator 8mm 4mm 8mm Pulser To PMT Box
PMT BOX SHIELDING Empty PMT TUBE (CLI) 40cm 600 QP 120 Calibration Tube Light Guide Non-reflective coating 600 QP 5 PMT Light Guide Light Guide
Calibration Light Injector (CLI) Plate 3 Plate 2 Calibration Tube Fiber Ferrule Holographic Diffuser SMA Connector 9cm SMA-SMA connector Jacket Fiber 600 QP SMA Connectors Aspheric Lens 11mm Focal Length Collimation Assembly
1 2 • One-PE Response: • Plot#1 111 or 117 ADC counts • Plot#2 106 ADC counts • Plot#3 104 ADC counts • =>stable laser pulse 3
PMT 154 (315 E22) behavior PMT relative gains for ROBOX 3 measured in Iowa: PMT N 148 149 150 151 152 153 154 155 156 157 158 159 160 161… Gain % 48 74 74 76 76 76 77 78 96 97 98 100 102 104… High output, narrow peak Usual pedestal …
LED Data 1 LED at threshold V 2 LED at 10 V
Comparison of PMT response to laser and LED at similarlight intensity
1 x 4 splitter 75 mm 300m QQ 1000m QQ (Silica) 300m QQ SMA Connectors Fiber to Fiber ratio = (1/0.3)2 11 Average in/out measurement 22
Splitter study PMT 154 “best” 1 4 splitter attenuation: no red fiber light 1 50 43 25 2 49 42 22 3 42 36 22 4 43 37 18 1 2 3 4
100% laser intensity corresponds to 360 GeV electron
100% laser int. corresponds to 933 GeVp for E-PMT 1467 GeVp for H-PMT
Questions • Are fibers in calibration and PMT bundles polished? • How many calibration fibers are used for PMT 154 (315)? What is different in calibration lightpipe for this PMT? • Which PMTs have bad light guides?
Concerns • Insufficient laser intensity (attenuation factor 12 in 150m fiber) place UV laser closer to detector or use blue laser • Build (or buy) low attenuation splitter