Prototype Calibration System for Forward Hadron Calorimeter

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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-gt4 light splitter
1-gt9 light splitter w/ pulsed LEDs, input for UV
laser pulses, and PIN diode light monitoring
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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
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Calib Box
600? QP 18m
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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
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Blue Scintilator 8mm ? 4mm ? 8mm
Pulser
To PMT Box
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PMT BOX
SHIELDING
Empty PMT TUBE (CLI)
40cm
120
600? QP
Calibration Tube
Light Guide Non-reflective coating
600? QP
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PMT
Light Guide
Light Guide
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Calibration Light Injector (CLI)
Plate 2
Plate 3
Calibration Tube
Holographic Diffuser
Fiber Ferrule
SMA Connector
9cm
SMA-SMA connector
Jacket
Fiber 600? QP
SMA Connectors
Aspheric Lens 11mm Focal Length
Collimation Assembly
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2

• One-PE Response
• Plot1 111 or 117 ADC counts
• Plot2 106 ADC counts
• Plot3 104 ADC counts
• gt stable laser pulse

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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
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PMT (PE) / (Laser / Laser100)
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LED Data
1 LED at threshold V
2 LED at 10 V
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Comparison of PMT response to laser and LED at
similar light intensity
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2 LED at 10 V (close intensity) Laser 48
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ADCC (ADC-Pedestal) / Gain
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ADCC
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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
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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
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2
3
4
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100 laser intensity corresponds to 360 GeV
electron
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100 laser int. corresponds to 933 GeV p
for E-PMT 1467 GeV p for H-PMT
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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?

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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