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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

2

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

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#1 111 or 117 ADC counts

Plot#2 106 ADC counts

Plot#3 104 ADC counts

=> stable laser pulse

1 2

3

8

9

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 …

10

PM

T (

PE)

/ (L

aser

/ Laser1

00%

)

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

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2 LED at 10 V (close intensity) Laser 48%

15

ADCC = (ADC-Pedestal) / Gain

16ADCC

17

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

19

20

21

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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