1 Prototype Calibration System for Forward Hadron Calorimeter L. Almeida, M. Baarmand, L. Caraway, M. Hohlmann, T. Qureshi, I. Vodopianov FLORIDA TECH 1->9 light splitter w/ pulsed LEDs, input for UV laser pulses, and PIN diode light monitoring 1->4 light splitter Electronic pulser for ~100 ns LED pulses w/ single-shot and external trigger capability 10 m jacketed light fiber
2 N 2 Laser 300 QQ 75m 9 PMT Boxes Calib Box 1 4 Counting Room HF Calibration Optical Fiber Path Test Beam J 337 nm Bottom Rack9 600 QP 18m 300 QQ 9m
3 LED 2 MIXER 50mm 15mm 15mm Polystyrene PIN3 ADC QP 300 QQ Blue Scintilator 8mm 4mm 8mm Calibration Box 1 x 9 splitter To PMT Box PIN Diode 4mm 4mm Pulser PIN1 PIN2 LED 1
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5 Calibration Tube Empty PMT TUBE (CLI) Light Guide Non-reflective coating Light Guide 600 QP PMT BOX SHIELDING 600 QP 40cm Light Guide PMT
6 SMA Connector Fiber 600 QP Jacket SMA Connectors Holographic Diffuser Plate 2Plate 3 SMA-SMA connector Fiber Ferrule Calibration Light Injector (CLI) Calibration Tube 9cm Aspheric Lens 11mm Focal Length Collimation Assembly
7 One-PE Response: Plot#1111 or 117 ADC counts Plot#2106 ADC counts Plot#3104 ADC counts => stable laser pulse 12 3
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9 PMT 154 (315 E22) behavior PMT relative gains for ROBOX 3 measured in Iowa: PMT N … Gain % … High output, narrow peakUsual pedestal …
10 PMT (PE) / (Laser / Laser100%)
11 1 LED at threshold V 2 LED at 10 V LED Data
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13 Comparison of PMT response to laser and LED at similar light intensity
14 2 LED at 10 V (close intensity) Laser 48%
15 ADC C = (ADC-Pedestal) / Gain
16 ADC C
QQ 1000 QQ (Silica) 300 QQ SMA Connectors 1 x 4 splitter 75 mm Fiber to Fiber ratio = (1/0.3) 2 11 Average in/out measurement 22
18 Splitter study PMT 154 “best” 4 splitter attenuation: no red fiber light
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22 100% laser intensity corresponds to 360 GeV electron
23 100% laser int. corresponds to 933 GeV for E-PMT 1467 GeV for H-PMT
24 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?
25 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