Update on the PHENIX Calorimeter Prototypes

Craig Woody BNL

EIC Calorimeter Group MeetingApril 17, 2014

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EMCAL Tilted Plate Configuration

A.Kiselev

Energy Resolution vs Tilt Angle

1mm W + 1mm Fiber

Monte Carlo Simulation (Flat plates - No Accordion)

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Absorber Stack

Stack of 7 tower modules (not yet glued)

Readout has 7x7 optically separated towers

X0 ~ 7 mm RM ~ 2 cm

Readout end of module is potted with white reflecting epoxy. Other end is

covered with 3M ESR reflector

Looking through absorber stack Readout end of absorber stack

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Light Collection Cavities

Seven rows of seven cavities mounted to a frame and readout boards are connected at the back

Many prototypes were tested to determine the placement of the SiPM in order to optimize light collection efficiency and uniformity

Assumed one SiPM per cavity to minimize cost

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Light Collection Efficiency and Uniformity

S. Stoll

SiPM entered on domeAverage efficiency = 4.6%

Max/Min ratio = 2.2

relative efficiency map of a tapered 27x25x50mm printed cavity, 1 SiPM centered on opposing end of the cavity, Hamamatsu 3mm2 SiPMs. readout surface has white painted background

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mean 4.61MAX 6.67min 2.99MAX/min 2.23

relative efficiency map of a tapered 27x25x50mm printed cavity, 1 SiPM ~20deg on the dome of the cavity, Hamamatsu 3mm2 SiPMs. readout surface has white painted background

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mean 4.69MAX 6.25min 3.67MAX/min 1.70

20° from centerAverage efficiency = 4.7%

Max/Min ratio = 1.7

relative efficiency map of a tapered 27x25x50mm printed cavity, 1 SiPM ~45deg on the dome of the cavity, Hamamatsu 3mm2 SiPMs. readout surface has white painted background

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mean 4.23MAX 5.79min 3.09MAX/min 1.87

45° from centerAverage efficiency = 4.2%

Max/Min ratio = 1.6

Area ratio (3x3 mm2 SiPM to 25x27 mm2 cavity) = 1.3%

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LED Calibration System

Splitter fixture for testing uniformity and efficiency of 1x7 splitters

1x7 splitter for distribution of calibration light to light collection cells

LEDPulser

PIN diodefor monitoring LED

1:7 split1:8 splitSiPM

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Final Light Collection Module

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Final Assembly

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Final Assembly

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Fermilab Beam Test

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Fermilab Beam Test

sPHENIXHCAL sPHENIX

EMCAL

Test of combined EMCAL and HCAL prototypes at Fermilab in Feb 2014 (sPHENIX 2/5-2/25, STAR 2/26-3/18)

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Upstream of the Calorimeters

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Measurement of Electrons with PbGl

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LED Pulser Calibration

All channels working and giving reasonable signals

7x7 TowerArray

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MIP Peak 120 GeV protons

Achim F.

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Calibration of Towers with Beam Plates perpendicular to beam (90°) 120 GeV protons

Minimum ionizing peaks correspond to ~ 30 MeV per tower Achim F.

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Measurement of Light Output

Light yield ~ 100 p.e. on PMT

Energy deposit = 29 MeV - total energy deposit from mip traversing perpendicular (12 layers) of one tower of absorber stack

Þ 3.5 p.e./MeV Þ 3500 p.e./GeV

Assume 90% light collectionÞ 3900 p.e./GeV in calorimeter

Light collection efficiency of 4.7% from cavities ~ 180 p.e./GeV with SiPM (assuming PDESiPM QEPMT)

~ 7.5% contribution to energy resolution from photon

statistics

• PMT coupled directly onto one tower module of absorber stack (12 layers)

• Beam (120 GeV p) traverses tower perpendicular to plates (Edep = 29 MeV)

• Light yield measured in three positions across tower module

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Tower Readout with SiPMs

MIPs in single towers

Test with 3 central rows of towers with 2 SiPM readout

2 SiPMs

1 SiPM

x2

Horizontal scan of with MIPs

J.Haggerty

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Transverse Position DependenceUsing hodoscope (8 slats x 5 mm) – 8 GeV electrons

Single Tower 3x3 Tower Sum

Achim F.

~ 5%

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Longitudinal Position Dependence5 different calorimeter positions along fiber direction

120 GeV protons

Achim F.

Dy = 23 mm

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Energy Resolution

90°

10° 20°

Achim F.

Expected Resolution:• Sampling: ~ 15% /√E • Photostatistics: ~ 7.5%/√E • Constant (nonuniformities) ~ 5%

Combined: ~ 17%/√E 5%

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Further Corrections

• Temperature variation• Better gain balance• Other non-uniformities ?

Light output Light collection Absorber stack ???

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HCAL Status and Test Beam Results

E.Kistenev

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Calibration with Cosmic Rays

E.Kistenev

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Raw Data Before Any Corrections

E.Kistenev

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Energy Resolution

Very Preliminary !

E.Kistenev

Monte Carlo Simulation Test Beam Data