The Scintillator ECAL Beam Test at FNAL

K. Kotera, Shinshu-u, 1st October 2009CALICE Scintillator ECAL group;

Kobe University, Kyungpook University, the University of Tsukuba,

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Requirements for ILD Electromagnetic calorimeter

• performance• from a standpoint of particle flow

algorithm for the jet energy resolution• energy resolution• linearity• uniformity• granularity

• Robustness• Low cost• Magnetic field tolerance

5x5~10x10 mm2

(~1%) (~15%)

2

Requirements for ILD Electromagnetic calorimeter

• performance• from a standpoint of particle flow

algorithm for the jet energy resolution• energy resolution• linearity• uniformity• granularity

• Robustness• Low cost• Magnetic field tolerance

Strip scintillator/PPD

Wave length shift fiber

Strip scintillator/PPD

2

Our challengeMPPC

WLS fiber

Kyungpook National University (Korea)

Extrude method→low cost, it can make hole for WLS fiber simultaneously

4 mm

3 m

m

Hamamatsu 1600 pixel 1 x 1 mm PPD

= MPPC in Plastic package

• plastic scintillator 10mm x 45 mm x 3mm

• 1mmΦ WLS fiber

3

First prototype1- 6 GeV e+ beam @ DESY 2007

9 cm

9 c

m26 layer = 18.5 X0

Nice linearity for 1 - 6 GeV

0.2

4

First prototype1- 6 GeV e+ beam @ DESY 2007

9 cm

9 c

m26 layer = 18.5 X0

Nice linearity for 1 - 6 GeV

σ/E

00.2

0.1

0.7 0.70 1/√E(GeV)

4

σstoch ~ 14%, :-)σconst = 2.0% w/high unif.

still larger than 1%,by leakage?

low unif. strips

First prototype

9 cm

9 c

m26 layer = 18.5 X0

Nice linearity for 1 - 6 GeV

Uniform region

σ/E

00.2

0.1

0.7 0.70 1/√E(GeV)σstoch ~ 14%, :-)σconst = 2.0% w/high unif.

still larger than 1%,by leakage?

Beam position

Sensitivity of low unif.

strips

beam

beam

Uniform region

Central region 4

1- 6 GeV e+ beam @ DESY 2007

low unif. strips

First prototype

9 cm

9 c

m26 layer = 18.5 X0

Nice linearity for 1 - 6 GeV

high unif.strips

Uniform region

σ/E

00.2

0.1

0.7 0.70 1/√E(GeV)

Central region

low unif. strips

large σconst by non-unif strips

low unif. strips

Beam position

Sensitivity of low unif.

strips

beam

beam

Uniform region

Central region 4

σstoch ~ 14%, :-)σconst = 2.0% w/high unif.

still larger than 1%,by leakage?

1- 6 GeV e+ beam @ DESY 2007

30 layer21.3 X0

18x4 strips

18 cm

18 c

m

w/ Modified uniformity of response of strips

2160 channel

5

2nd prototype,

2nd prototype, tested at FNAL, Sep 2008 and May 2009

• Study of performance combinedwith AScHCAL and T-Cacher,

• First comprehensive study of performance of ScECAL,

• Linearity of energy response for 1- 32 GeV,

• Energy resolution for 1 - 32 GeV,

• Effect of incident angle of particles,

• Position dependence of response.

• Observation of π0 events - separation 2γ

• Establish LED gain monitoring system

30 layer21.3 X0

18x4 strips

18 cm

18 c

m

w/ Modified uniformity of response of strips

2160 channel

5

pu

rpose

2nd prototype of ScECAL9 MPPCs on a flat cable

In front of AHCAL

Hole to inlet LED light for Gain monitoring

Holding W absorber (3.5 mmT) behind the strip scintillators

6

18 x 4 strips

2nd prototype of ScECAL

Holding W absorber behind the strip scintillators

9 MPPCs on a flat cable

In front of AHCAL

- LED lights are distributed by clear fibers,then fibers distribute the light through notches on them. - MPPC can separate peaks of p.e.

Distance between them gives us absolute gain of MPPC.

- a clear fiber lying along the holes

cover sheet

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MPPC saturation correctionFor each event of each channel, MPPC saturation correction was made.

1 3 6 12 16 25 32 GeV

Electron energy spectra

PMT response

new value of response

≈≈ççPMT response

2 4 6 4 8 10 1214 16 18 20x10 (ADC)

0

4

8

12

14 x102 (ADC)

Fitting result

# of photons from each channel

MPPC

resp

on

se

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Bench test using 400 nm psLaser pulse

Reverse function of fitting result of this function was used to make saturation correction

Output of correction

Input for correction

result of fitting:

Calibration of each strip scintillator channel

- We use muon beam runs made with iron shutter put upstream of exp site.

A typical MIP (muon) event in the online monitor

ADC count distribution of MIP event for a channel.( 1st layer, 46th channel )

x102

Cou

nts

5

10

15

x 10(ADC count)10 12 14 16

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Event selections and spectra

Selection; - Cerenkov, - Layer having maximum (L_Max) energy in ECAL < 20th, - Energy in L_Max > 10 - 150 MIP depending on beam mom., - Energy in L_Max of HCAL < 20MIP, - Energy in last layer of HCAL < 0.4 MIP, - Abs(gravitational center of energy in x(y) axis of ECAL) < 4 cm.

32 G

eV

Effects of cuts After all cuts

Spectra, before any selection cut but Celenkov ^

^

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Each cut variation was investigated to make sure that the cut did not induce a bias.

Sep 2008, linearity

good linearity

Calice Preliminary

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Sep 2008, linearity

good linearity but ...

Calice Preliminary

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Sep 2008, linearity

Deviation from linear< 6%

Candidates to correct residual deviation; - correct with more detail MPPC saturation correction, - investigate some energy leakage (maybe small), - apply temperature correction,

good linearity but ... not enough

Calice Preliminary

Calice Preliminary

only statistic errors

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Sep 2008, energy resolution

constant term 1.41±0.02%

stochastic term 15.15±0.03%

Calice Preliminary

Calice Preliminary

only statistic errors

* only statistic errors

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π0 RunSep.2008,

π- :16,25,32 GeVπ+: 60 GeV(2009)

π ０ peak

- reconstructed mass was well done (Rather small invariant mass than Mπ0 so far ).

Calice Preliminary

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Summary

• ScECAL group of CALICE made 18 cm x 18 cm 2nd prototype, quad surface of 1st prototype.

• Beam test at FNAL Sep.2008, May 2009,

• Sep.2008 data were analyzed;

• good linearity but need more brash up,

• Constant term of resolution was modified → uniformity was modified (2.7%→1.4%)

• π0 is reconstructed ( still small Mπ0 )

• and more detail anelysis is ongoing

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extrude

Plan

• Linearity and resolution,

• do temperature correction,

• do more detail study for MPPC saturation,

• remove the influence of pion contamination,

• estimate any systematic uncertainty.

• brash up π0,

• to study the performance of combination with AScHCAL and Tail Catcher.

• to study the influence of incident angle,

• to study the detailed position dependence.

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