Prototype sPHENIX Calorimeters

John Haggerty

Brookhaven National Laboratory

110/24/2013

The sPHENIX Experiment

• Major upgrade to the PHENIX Experiment at RHIC

• Primary purpose is to measure jets in heavy ion collisions• Measure jet energy using calorimetry• Good solid angle coverage (|h|< 1, Df=2p)

• Provide a basis for a future detector at eRHIC • Study nucleon structure and QCD in nuclei over a broad

range of x and Q2 using deep inelastic polarized ep and eA collisions

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Solenoid

MagnetHCAL EMCAL

10/24/2013

410/24/2013

Calorimeter Requirements

• Large solid angle coverage (± 1.1 in h, 2p in f)• Moderate energy resolution

• EMCAL ~ 15%/√E • HCAL ~ 75 %/√E (single particle), ~100 %/√E (jet)

• Compact (for EMCAL small RM, short X0)• Physically small (dense) – occupies minimal space• High segmentation for heavy ion collisions

• Hermetic• Projective (approximately)• Readout works in a magnetic field• Low cost

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EMCAL Tungsten-SciFi Accordion

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Scintillating fibers 1.0 mm

Pure tungsten metal sheets (r ~ 19.3 g/cm3) Thickness: 2x1.0 mm

Epoxy (~ 0.1 mm)

Tapered thickness pure tungsten metal plates with scintillating fiber layer glued in between

X0 = 5.3 mm RM = 15.4 mm

2 W plates/layer 0.6 X0 sampling

~ 10 cm 18 X0

SBIR

EMCAL prototype

• Test of simpler “tilted plate” design

• 1 mm W + 1 mm scintillator

10/24/2013 7

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Towers are formed by Light Collection Cavities

3x3mm SiPM

22 mm

8x8 tower readout board with 2x7 light collection cavities

3D printed light collection cavities

White reflecting epoxy between plates

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Light Yield From Fibers

w/ 2.2cm2 mask on R2059 pmt window

adc channels

0 200 400 600 800 1000

cou

nts

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(189 ch)(6.25E6 e/pC)(0.25pC/ch)/3.19E6 = 93 pe

93 pe/ 0.23 (QE) = ~404 photons

each tower has 5 layers of fibers * 1mm diam * 0.79(mean path) ~ 3.9mm of scintillator

3.9mm * 2MeV / 10mm ~ 0.79 MeV deposited in scintillator

404 photons / 0.79 MeV ~ 511 photons/ MeV in scint

500 g/MeV energy deposit in scintillator

8 % sampling fraction 40 x 103 g/GeV (Edep in calorimeter)

Light Collection Factor (2%) 800 g/GeV

SiPM PDE ~ 0.25 200 p.e./GeV

7%/√E contribution to energy resolution

Light yield from prototype measured with cosmic rays and PMT readout

sPHENIX Hadron Calorimeter

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• Steel plates with scintillating tiles parallel to beam direction• Steel serves as flux return• Steel plates are tapered Sampling fraction changes with depth• Divided into two longitudinal sections

Measure longitudinal center of gravity to correct for longitudinal fluctuations • Plates tilted in opposite directions to avoid channeling

4 inner and 4 outer plates joined together to

form one section

60 cm3.5 labs

30 cm1.5 labs

HCAL Readout

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Scintillating tiles with WLS fibers embedded in groovesFibers read out with SiPMs

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2x11 segments in h ( Dh =0.1)64 segments in f ( Df =0.1) 1408 x 2(inner,outer) = 2816 towers

2x11 scintillator tile shapes

Inner

Outer

Inner readout(~10x10 cm2)

Outer readout

SiPMs + mixers

8 readout fibers per tower

HCAL Scintillator Tiles Manufactured in Russia

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White reflective coating(chemical etching)

WLS fiber embedded in grove in tile (top and bottom)

10/24/2013 13

Light Collection for HCal

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HCAL Tile Measurements at the University of Colorado

Light output and uniformity measurements of scintillating tiles

Top fiber

Light Yield ~ 18 p.e./”mip” (measured with 90Sr)

Bottom fiber

S.Beckman

HCAL prototype

1510/24/2013

Beam Test of the Combined EMCAL/HCAL Prototypes

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Scheduled to take place in the MT6 test beam at Fermilab in Feburary 2014

10/24/2013 17

sPHENIX

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HCAL Prototype Construction at BNL

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Readout Electronics

EMCAL Prototype readout board HCAL Readout Electronics System

Electronic chain test

2010/24/2013

Calorimeter beam test

2110/24/2013

Summary

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• PHENIX is planning a major detector upgrade to replace its existing Central Arm Spectrometer with a new calorimeter system consisting of an electromagnetic and hadronic calorimeter

• These new calorimeters will enable a detailed systematic study of jets produced in heavy ion collisions at RHIC to study the QGP near its transition temperature

• Both calorimeter designs are well under way and prototypes of both calorimeters are currently under construction

• A combined test of both prototype calorimeters is planned to take place at Fermilab in February of next year