Hiroyuki Matsunaga, The 5th ACFA Workshop on Physics and Detector at Linear Collider, July 10–12, 2002

JLC CalorimeterHiroyuki Matsunaga (University of Tsukuba)

For the JLC-CAL Group(KEK, Kobe, Konan, Niigata, Shinshu and Tsukuba)

Outline

Required PerformanceDesign Ideas and Plans- JLC, NLC, TESLA

JLC Calorimeter- Design Concept

- Study on EMCAL/SHmax

- Granularity Optimization

- Photon Detectors

Summary

1

Required PerformanceHiroyuki Matsunaga, The 5th ACFA Workshop on Physics and Detector at Linear Collider, July 10–12, 2002

• At LC energies, high mass particles ( W , Z, t, H?...) are producedin most events

• Most likely they decay into hadronic jets

• Accurate jets energy measurement is needed to reconstruct thehigh mass particles

• Excellent Jet-mass resolution is required→ Di-jet mass resolution better than ΓZ, ΓW (JLC)

σMjj= 2.9 GeV including

natural width of W

Reconstructed W mass for e+e− → W +W − at√

s = 400 GeV(Result of quick simulation)

2

Required PerformanceHiroyuki Matsunaga, The 5th ACFA Workshop on Physics and Detector at Linear Collider, July 10–12, 2002

There are many design parameters to be optimized

2 basic parameters for calorimeter design:

• Energy Resolution and Linearity- Compensation ( e/h = 1) with hardware or software

• Granularity (Segmentation)- Clustering Algorithm- Track-Cluster Association Algorithm- Energy Flow Analysis

Both hardware and simulation studies are needed.

3

Energy Flow ConceptHiroyuki Matsunaga, The 5th ACFA Workshop on Physics and Detector at Linear Collider, July 10–12, 2002

Energy Flow Technique :

• Charged particles in jets more precisely measured in tracker

• Typical multi-jet events:∼ 60 %: charged particles∼ 30 %: photons∼ 10 %: neutral hadrons

• Use tracker for charged particles

• EMCAL for Photon

• HCAL for neutral hadrons

Design optimization for energy flow :

• Dense, highly granular EMCAL and HCAL

• High resolution and efficient tracker

• CAL inside coil

4

Design Ideas and PlansHiroyuki Matsunaga, The 5th ACFA Workshop on Physics and Detector at Linear Collider, July 10–12, 2002

Granularity Very high ReasonableExperiment TESLA, NLC(SD) JLC, NLC (LD)EMCAL Si/W Scint. Tiles/Fiber

Scint. Strip ArrayHCAL “Digital” Calorimeter

Scint. Tiles/Fiber Scint. Tiles/Fiber

Other options:EMCAL : Crystal, Shashlik

Beam direction

Photodetectors

WLS fibers

Calorimeter layout

Photodiodes

Diode electronics

Vacuum

(front view)(top view)Tower structure

Beam direction

Shashlik Calorimeter

5

Si/W CalorimeterHiroyuki Matsunaga, The 5th ACFA Workshop on Physics and Detector at Linear Collider, July 10–12, 2002

• Original idea from SDC

• Used successfully for Lum. monitors at SLD/LEP

• Suited for Energy Flow

• Easily Segmented (5mm – 15mm), ∼ 50M pixels

• Si cost is expensive

Barrel Calorimeter of TESLA

6

“Digital” CalorimeterHiroyuki Matsunaga, The 5th ACFA Workshop on Physics and Detector at Linear Collider, July 10–12, 2002

• “Imaging/Tracking Calorimeter” for Energy Flow measurement

• Cheap, highly-segmented detectors (1cm ×1cm)

• 1 (2?) bit readout

• Number of hit cells → Energy

Same Di-jet for digital-steel(left) and for digital-tungsten(right) HCALhep-ex/0202004 (TESLA)

7

“Digital” Calorimeter (cont.)Hiroyuki Matsunaga, The 5th ACFA Workshop on Physics and Detector at Linear Collider, July 10–12, 2002

• Energy resolution: similar to analog readout

• Active medium candidatesRPCs (Resistive Plate Chambers)GEMs (Gas Electron Multipliers)

• under study- depth- MIP recognition- Algorithm : Software compensation ( π0 recognition)

• No experience. Need verification

8

Tile/Fiber Sampling CalorimeterHiroyuki Matsunaga, The 5th ACFA Workshop on Physics and Detector at Linear Collider, July 10–12, 2002

• Hardware Compensation Possible

• Design Flexibility

• Reasonable cost

• Well-established technology

• Sufficient granularity for EMCAL ?

Scintillator tiles arranged as 5 × 5 segmentation

9

JLC Calorimeter: Design ConceptHiroyuki Matsunaga, The 5th ACFA Workshop on Physics and Detector at Linear Collider, July 10–12, 2002

• Hardware Compensation for excellent hadron energy resolution andlinearity

σEE = 15%√

E+ 1% (e/γ)

σEE = 40%√

E+ 2% (hadron)

• Fine Granularity for precise topological reconstruction

• Whole Calorimeter system inside the solenoid

No software compensationNo extremely-fine granularity

Technology Choice

=⇒ Tile/Fiber Sampling Calorimeter

10

Calorimeter ConfigurationHiroyuki Matsunaga, The 5th ACFA Workshop on Physics and Detector at Linear Collider, July 10–12, 2002

Calorimeter is in the 3 Tesla B-FieldTower StructureCrackless Hermeticity

100 cm

JLC Detector

11

Basic ParametersHiroyuki Matsunaga, The 5th ACFA Workshop on Physics and Detector at Linear Collider, July 10–12, 2002

Barrel Inner Radius 160 cmBarrel Outer Radius 340 cmAngular Coverage (full) |cos θ| < 0.966

(partial) |cos θ| < 0.991SHmax scheme scintillator strip

(1 cm-wide)Option = Si-pad

(1cm × 1cm)Granularity

PreSH/EMCAL transverse 4 cm × 4 cm(24 mrad)

longitudinal 3 sections(6+12+20 layers)

HCAL transverse 12 cm × 12 cm(72 mrad)

longitudinal 4 sections(25+30+35+40 layers)

ThicknessPreSH 4X0

EMCAL 23X0

HCAL 6.5λ0

10 cm

H3H2 H4H1EM2EM1PS

Configuration of Baseline BarrelCalorimeter

12

HCAL beam testsHiroyuki Matsunaga, The 5th ACFA Workshop on Physics and Detector at Linear Collider, July 10–12, 2002

Beam tests done at KEK (1–4 GeV) and at FNAL (10-200 GeV) to prove

• Energy Resolution / Hardware compensation

• Linearity / Dynamic Range

• Tower Boundary Uniformity

• e/π Separation Capability

Beam

Lead Plates(inserted between tile assembly)

FCAL sections

(80 layers)

RCAL superlayers

(20 or 50 layers)

PMT (H1949)

1 2 3 4

6 7 8 9

11 12 13 14

16 17 18 19

21 22 23 24

5

10

15

20

25

1 m

1 m

To PMT

1 mm

WLS fiber(Y11)Cut View

Scintillator (SCSN88)

WLS fiber (Y11)

heat fusing spliceClear fiber

20 cm

20 cm

2 mm

Tile scintillator

PMT (H1949)

Tower ID number

Schematic view of HCAL test module with Tile/Fiber configuration

13

Energy Resolution & LinearityHiroyuki Matsunaga, The 5th ACFA Workshop on Physics and Detector at Linear Collider, July 10–12, 2002

0

10

20

30

40

50σ

/E (%

)E

0.25 0.5 0.75 1.

(GeV )-1/2

e :

stochastic = 46.7 ± 0.6%constant = 0.9 ± 0.9%

π :

= 23.9 ± 0.3%= 0.8 ± 0.3%

-

- σσ

stochastic

constant

σσ

σE

=σ 2

stochastic

E+σ

constant2E

...

...T912 e T912 π

--

...

...T411 e T411 π

--

1/ E

Beam momentum (GeV/c)

Beam momentum (GeV/c)

Mea

sure

d en

ergy

(GeV

)D

evia

tion

from

line

arity

(%)

...

...T912 e T912 π

--

...

...T411 e T411 π

--

Beam momentum (GeV/c)

Dev

iatio

n fro

m li

near

ity (%

)

no-leak sample

(a)

(b)

(c)

• π energy resolution is worse than design due to “fiber-routing”acryl plate→ should be OK but needs verification

• Linearity is good thanks to hardware compensation

14

e/π Separation with PreSH/SHmaxHiroyuki Matsunaga, The 5th ACFA Workshop on Physics and Detector at Linear Collider, July 10–12, 2002

clear fiber(KURARAY, Clear-PSMS, 1.0mmφ)

WLS(KURARAY, Y11, 0.83mmφ)

plastic scintillator(BICRON, BC-408)

Shower-Maximum Detector

Al e

vapo

ratio

n

created by akiraX layer, 200mm

20 strips

MPMT(R5900U)

Y la

yer,

200

mm

2

0 st

rips

connector2 layers, 1

0mm

0.9mmφ

key hole groove

0.8mm

2.85

mm

scintillator strip

200mm

10mm

5mm

Shower MAX detector

preshower (mip)S

prea

d (c

m)

• pion rejection ∼ 1/1400

• efficiency for electron ∼ 98 %

• position resolution 2 ∼3 mmdue to noise/cross-talkneeds improvements

15

Granularity OptimizationHiroyuki Matsunaga, The 5th ACFA Workshop on Physics and Detector at Linear Collider, July 10–12, 2002

Optimization with full simulator based on GEANT3

• Hadron shower clustering algorithm under study2D-JADE, 2/3D-contiguous : not working wellLarger spatial fluctuation in hadron shower development→ Split a cluster in two (or more)

• Cluster-track association algorithm under study

Simulation study is severely behind schedule

16

Longitudinal Shower profileHiroyuki Matsunaga, The 5th ACFA Workshop on Physics and Detector at Linear Collider, July 10–12, 2002

• Longitudinal shower profile and event-by-event fluctuation forhadron shower

– Improve hadron energy resolution– Implementation of hadron shower generator– e/π separation capability

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4 GeV π− (beam test)

17

Longitudinal Shower profile (cont.)Hiroyuki Matsunaga, The 5th ACFA Workshop on Physics and Detector at Linear Collider, July 10–12, 2002

δ(k)i = ph

(k)i − phi at i-th super-layer of k-th event

δ̃(k)i : Orthogonalized δ

(k)i

PH deviation 4 GeV e -

- 40

- 20

0

20

40

- 50 0 50

δ 3

δ 1

- 50 0 50

δ 4

δ 3

- 40

- 20

0

20

40

- 50 0 50

δ∼

3

δ∼

4

- 50 0 50

δ∼

3

δ∼

1

Correlated fluctuation for EM

PH deviation 4 GeV π -

- 40

- 20

0

20

40

- 50 0 50

δ 3

δ 1

- 50 0 50

δ 4

δ 3

- 40

- 20

0

20

40

- 50 0 50

δ∼

3

δ∼

4

- 50 0 50

δ∼

3

δ∼

1

Un-correlated fluctuation for hadrons

Orthogogonalization unsuccessful for hadrons

18

Longitudinal Shower profile (cont.)Hiroyuki Matsunaga, The 5th ACFA Workshop on Physics and Detector at Linear Collider, July 10–12, 2002

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Simulation successfully reproduces samedistribution as real data

19

R & D on EMCAL and SHmaxHiroyuki Matsunaga, The 5th ACFA Workshop on Physics and Detector at Linear Collider, July 10–12, 2002

EMCAL :

• Scint. Tile of 4cm × 4cm × 1mm- 4cm is limited by fiber curvature in the tile

• Scint. Strip of 1cm × 20cm × 2mm- finer granularity- crossed-strip layout like SHmax- needs super multi-channel photo detectors- ghost-rejection capability by full simulation

Staggered fiber layout on every other layer→ Reduce non-uniformity

SHmax :

• Scint. Strip of 1cm × 20cm × 1cm- WLS fiber + multi-channel Photon detector- high-gain APD attached directly at the end of Scint. strip

20

Scint. Tile & StripHiroyuki Matsunaga, The 5th ACFA Workshop on Physics and Detector at Linear Collider, July 10–12, 2002

Scint. Tile with WLS fiber

Scint. Strips with WLS fibers

21

Bench Test: Tile/Fiber moduleHiroyuki Matsunaga, The 5th ACFA Workshop on Physics and Detector at Linear Collider, July 10–12, 2002

Bench Test:

• β rays from RI source

• Multi-Anode PMT

22

Bench Test: Tile/Fiber module (cont.)Hiroyuki Matsunaga, The 5th ACFA Workshop on Physics and Detector at Linear Collider, July 10–12, 2002

ADC distribution Uniformity check (1-dim.)

Npe = 2.2

• Expect a factor of ∼ 1.6 improvement by polishing thefiber end and sputtering Al to it

Uniformity : < 5%< 2% (inside fiber groove)

23

Bench Test: Scint. Strip moduleHiroyuki Matsunaga, The 5th ACFA Workshop on Physics and Detector at Linear Collider, July 10–12, 2002

Setup of bench testβ rays from 90Sr, mapping by X-Y stage Photo-electron yield over a strip

Non-uniformity ∼ 4.8 %Similar to square tiles

24

Plan for Beam Tests: EMCALHiroyuki Matsunaga, The 5th ACFA Workshop on Physics and Detector at Linear Collider, July 10–12, 2002

Aims of the beam test:

• Uniformity

• Ghost rejection capability

• Energy Resolution for electron

• Input for simulation study

• New SHmax scheme

November 2002: π2 beam line at KEK

moving stage

calorimeters

T1 T2C1 C2DC1 DC2

iron wallpseudo-jet generator

(removable)

25

Photon DetectorsHiroyuki Matsunaga, The 5th ACFA Workshop on Physics and Detector at Linear Collider, July 10–12, 2002

Photon detectors used in 3 Tesla Magnetic Field

• Multi-channel(61ch) Hybrid Photo Diodes (HPDs) :- promising (cost-down needed)

• Hybrid Avalanche Photo Diodes (HAPDs) :- difficult to make multi-pixel HAPDs

Vacuum

PhotoCathode

P+N+

N++

PhotoElectron

Photon

Surface Dead Layer

HV

e-h pairse

he

e

e

e

e

ee

hh h

h

h

PIN-silicon photodiode

Schematic view of the HPD structure

0

500

1000

1500

2000

2500

3000

3500

4000

0 2 4 6 8 10 12 14 16High Voltage (kV)

Gai

n

HPD gain as a function of HV∼ 3000 at 14 kV

26

Photon Detectors (cont.)Hiroyuki Matsunaga, The 5th ACFA Workshop on Physics and Detector at Linear Collider, July 10–12, 2002

• For Scintillator-strip EMCAL/SHmax :

– Electron-Bombarded CCD (EBCCD)Ultra-multi-pixel devices, single-photon sensitivityHigher gain is needed.

Gain vs. Photo-cathode voltage for proximity-focused EBCCD

• Si-Photomultipliers (Si-PM’s) : study at Moscow- output signal is proportional to # of pixels fired- sensitive to single photon

27

SummaryHiroyuki Matsunaga, The 5th ACFA Workshop on Physics and Detector at Linear Collider, July 10–12, 2002

JLC Calorimeter :

•Well-established technology: Tile/Fiber scheme

• High Performance: Hermeticity, Resolution, Linearity

• Reasonable Cost: Casting enables further cost reduc-tion

Verification in progress :

• EMCAL/SHmaxBeam tests in 2002,2003

• Granularity optimization, Clustering Algorithmneeds Full Simulation

• Photon Devices

28