1 prototype calibration system for forward hadron calorimeter l. almeida, m. baarmand, l. caraway,...
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Prototype Calibration System for Forward Hadron Calorimeter
L. Almeida, M. Baarmand, L. Caraway, M. Hohlmann, T. Qureshi, I. VodopianovFLORIDA 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 pulsesw/ single-shot andexternal triggercapability10 m jacketed light fiber
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N2 Laser
300 QQ 75m
9 PMT Boxes
9 PMT Boxes
9 PMT Boxes
9 PMT Boxes
Calib
Box
1 4
Counting Room
HF Calibration Optical Fiber Path Test Beam 2002
200 J 337 nm
Bottom Rack 9
600 QP 18m
300 QQ
9m
3
LED 2
MIXER 50mm 15mm 15mm
PolystyrenePIN3
ADC
9600 QP
300 QQ
Blue Scintilator 8mm 4mm 8mm
Calibration Box 1 x 9 splitter
To PMT Box
PIN Diode 4mm 4mm
Pulser
PIN1PIN2
LED 1
4
5
Calibration Tube
Empty PMT TUBE (CLI)
Light GuideNon-reflective coating
Light Guide
600 QP
PMT BOX
5
120
SHIELDING
600 QP
40cm
Light GuidePMT
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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
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One-PE Response:
Plot#1 111 or 117 ADC counts
Plot#2 106 ADC counts
Plot#3 104 ADC counts
=> stable laser pulse
1 2
3
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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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PM
T (
PE)
/ (L
aser
/ Laser1
00%
)
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1 LED at threshold V
2 LED at 10 V
LED Data
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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
16ADCC
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300QQ 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
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Splitter studyPMT 154 “best”
1 2
3 4
1 4splitter attenuation:
no redfiber
light
1 50 43 252 49 42 223 42 36 224 43 37 18
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100% laser intensity corresponds to
360 GeV electron
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100% laser int.corresponds to
933 GeV forE-PMT
1467 GeV forH-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