The Scintillator ECAL Beam Test at FNAL K. Kotera, Shinshu-u, 1st October 2009 CALICE Scintillator ECAL group; Kobe University, Kyungpook University, the University of Tsukuba, 1

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 mm 2 (~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 challenge MPPC WLS fiber Kyungpook National University (Korea) Extrude method→low cost, it can make hole for WLS fiber simultaneously 4 mm 3 mm 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 prototype 1- 6 GeV e + DESY cm 26 layer = 18.5 X 0 Nice linearity for GeV 0.2 4

First prototype 1- 6 GeV e + DESY cm 26 layer = 18.5 X 0 Nice linearity for GeV σ/E /√E(GeV) 4 σ stoch ~ 14%, :-) σ const = 2.0% w/high unif. still larger than 1%, by leakage? low unif. strips

First prototype 9 cm 26 layer = 18.5 X 0 Nice linearity for GeV Uniform region σ/E /√E(GeV) σ stoch ~ 14%, :-) σ const = 2.0% w/high unif. still larger than 1%, by leakage? Beam position Sensitivity of low unif. strips beam Uniform region Central region GeV e + DESY 2007 low unif. strips

First prototype 9 cm 26 layer = 18.5 X 0 Nice linearity for GeV high unif.strips Uniform region σ/E /√E(GeV) Central region low unif. strips large σ const by non- unif strips low unif. strips Beam position Sensitivity of low unif. strips beam Uniform region Central region 4 σ stoch ~ 14%, :-) σ const = 2.0% w/high unif. still larger than 1%, by leakage? 1- 6 GeV e + DESY 2007

30 layer 21.3 X 0 18x4 strips 18 cm 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 combined with AScHCAL and T-Cacher, First comprehensive study of performance of ScECAL, Linearity of energy response for GeV, Energy resolution for GeV, Effect of incident angle of particles, Position dependence of response. Observation of π 0 events - separation 2γ Establish LED gain monitoring system 30 layer 21.3 X 0 18x4 strips 18 cm w/ Modified uniformity of response of strips 2160 channel 5 purpose

2nd prototype of ScECAL 9 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 7

MPPC saturation correction For each event of each channel, MPPC saturation correction was made GeV Electron energy spectra PMT response new value of response ō PMT response x10 (ADC) x10 2 (ADC) Fitting result # of photons from each channel MPPC response 8 Bench test using 400 nm ps Laser 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 ) x10 2 Counts x 10(ADC count)

Event selections and spectra Selection; - Cerenkov, - Layer having maximum (L_Max) energy in ECAL < 20th, - Energy in L_Max > 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 GeV Effects of cuts After all cuts Spectra, before any selection cut but Celenkov ^ ^ 10 Each cut variation was investigated to make sure that the cut did not induce a bias.

Sep 2008, linearity good linearity Calice Preliminary 11

Sep 2008, linearity good linearity but... Calice Preliminary 11

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 only statistic errors 11

Sep 2008, energy resolution constant term1.41±0.02% stochastic term15.15±0.03% Calice Preliminary only statistic errors * only statistic errors 13

π 0 Run Sep.2008, π - :16,25,32 GeV π + : 60 GeV(2009) π ０ peak - reconstructed mass was well done (Rather small invariant mass than M π 0 so far ). Calice Preliminary 14

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%) π 0 is reconstructed ( still small M π0 ) and more detail anelysis is ongoing 15 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 π 0, to study the performance of combination with AScHCAL and Tail Catcher. to study the influence of incident angle, to study the detailed position dependence. 16

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