Quick report of a beam test for CsI both-end readout system - PowerPoint PPT Presentation

Nenmatsru (year-end) Quick report of a beam test for CsI both-end readout system 28/12/2017 Tomoo Mari Osaka Univ. Tomoo Mari Nenmatsu 1

Outline • KOTO experiment • Beam test @ELPH • Energy resolution of PMT • Conclusion, Prospects After-party (taken by Shimizu) Tomoo Mari Nenmatsu 2

KOTO experiment, halo neutron B.G. Signal: K L → π 0 ν ¯ ν Background: A beam halo neutron makes hadron shower in a CsI crystal, then another neutron from this shower make another cluster. gamma PMT CsI Signal PMT neutron PMT Background neutron PMT Tomoo Mari Nenmatsu 3

CsI both-end readout system Current readout system PMT Both-end readout system MPPC PMT Timing di ff erence between MPPC and PMT = z position MPPC PMT MPPC PMT Tomoo Mari Nenmatsu 4

Some detail Current readout system CsI PMT reflector Both-end readout system MPPC PMT Quartz plate 4MPPCs + Quartz Reflector Tomoo Mari Nenmatsu 5

Energy resolution of the PMT Energy resolution of the PMT is expected to change, because • Reflector will be replaced with smaller one • (material can also be changed) • MPPCs will cover the upstream surface of CsI To evaluate σ E of the PMT… • 200-800 MeV positron beam data (tested at ELPH) Tomoo Mari Nenmatsu 6

Beam test at ELPH CsI frame CsI Positrons (200-800 MeV) Stacked CsI crystals Cosmic ray data were also acquired while the beam was o ff . Tomoo Mari Nenmatsu 7

Setup ◉ Beam 8 large (50x50x500mm 3 ) CsI crystals 4 small (25x25x500mm 3 ) CsI crystals L0 L1 L2 w/o MPPC w/ MPPC 4 MPPCs for L crystals S1 S0 MPPC none 1 MPPC for S crystals L7 L3 S2 S3 KOTO-reflector Nishimiya-reflector reflector (di ff erent between crystals) (silver, square hall) L6 L5 L4 cosmic rays calibration 800MeV positrons (40mm from the up- stream surface of CsI) beam injection beam-run 200-800 MeV, beam position was the center of the stack Other informations: Beam spot size > 10mm Tomoo Mari Nenmatsu 8

Beam position shift Large crystals: 50mm x 50mm Small crystals: 25mm x 25mm L0 L1 L2 Beam position was deviated 4.5 ~ 6.5 cm S1 S0 from expected position. L7 L3 S2 S3 L6 L5 L4 Tomoo Mari Nenmatsu 9

Calibration (w/o MPPC) 800MeV positron beam was injected at the center of each crystal crystal L0 crystal S0 crystal L0 crystal L0 crystal S0 crystal S0 h[0] h[0] h[8] h[8] Entries Entries 2156 2156 Entries Entries 1942 1942 160 300 Mean Mean 3.734e+04 3.734e+04 Mean Mean 2.797e+04 2.797e+04 Std Dev Std Dev 6988 6988 Std Dev Std Dev 7679 7679 140 2 2 2 2 χ χ / ndf / ndf 3.505 / 6 3.505 / 6 χ χ / ndf / ndf 21.43 / 13 21.43 / 13 250 Prob Prob 0.7432 0.7432 Prob Prob 0.06479 0.06479 120 p0 p0 p0 p0 304.1 304.1 9.9 9.9 149.7 149.7 5.2 5.2 ± ± ± ± p1 p1 p1 p1 4.047e+04 4.047e+04 ± ± 1.344e+02 1.344e+02 3.239e+04 3.239e+04 ± ± 2.395e+02 2.395e+02 200 100 p2 p2 p2 p2 8593 8593 ± ± 1030.8 1030.8 9250 9250 ± ± 916.8 916.8 p3 p3 p3 p3 0.154 0.154 0.026 0.026 0.16 0.16 0.03 0.03 − − ± ± − − ± ± 80 150 60 100 40 50 20 3 3 10 10 × × 0 0 0 10 20 30 40 50 60 70 80 90 100 0 10 20 30 40 50 60 70 80 90 100 Integrated ADC Integrated ADC ◉ Beam • Fitted with asymmetric gaussian Tomoo Mari Nenmatsu 10

Scale factor (w/o MPPC) Geant4 simulation • 800MeV positrons • x=5mm shifted from center line • scale factor := MPV (L) / MPV (S) hs hl 700 Entries 10000 Entries 10000 Small crystal Large crystal Mean 485.6 Mean 633.8 350 Std Dev 61.27 Std Dev 33.55 600 300 500 250 400 200 300 150 200 100 100 50 0 0 0 100 200 300 400 500 600 700 800 0 100 200 300 400 500 600 700 800 deposited E [MeV] Tomoo Mari Nenmatsu 11

Calibration (w/ MPPC) Cosmic rays at 40mm from the upstream surface of CsI crystal L0 crystal S0 h[0] h[0] h[8] h[8] 120 120 Entries Entries 618 618 Entries Entries 734 734 Mean Mean 1109 1109 Mean Mean 2095 2095 Std Dev Std Dev 785.4 785.4 Std Dev Std Dev 519.9 519.9 100 100 2 2 2 2 / ndf / ndf / ndf / ndf χ χ 12.17 / 17 12.17 / 17 χ χ 10.72 / 10 10.72 / 10 Prob Prob 0.3797 0.3797 Prob Prob 0.79 0.79 Width Width 50 50 5.2 5.2 Width Width 124.5 124.5 ± ± 25.5 25.5 ± ± 80 80 MP MP 2032 2032 17.7 17.7 MP MP 1004 1004 11.1 11.1 ± ± ± ± Area Area 4.08e+04 4.08e+04 2.75e+03 2.75e+03 Area Area 5.166e+04 5.166e+04 4.717e+03 4.717e+03 ± ± ± ± GSigma GSigma GSigma GSigma 114.3 114.3 14.4 14.4 131.6 131.6 ± ± 42.4 42.4 ± ± 60 60 Constant Constant 13.86 13.86 4.10 4.10 Constant Constant 20.09 20.09 0.95 0.95 ± ± ± ± Slope Slope Slope Slope 0.01 0.01 0.00 0.00 − − 0.004327 0.004327 ± ± 0.001269 0.001269 − − ± ± 40 40 20 20 0 0 0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 Integrated ADC Integrated ADC ◉ Beam • Fitting function: (landau*gaussian) + pol1 • MPV of landau is used for calibration • Scale factor between large and small crystal = 2.0 Tomoo Mari Nenmatsu 12

Energy resolution of PMT w/ MPPC w/o MPPC h[3] h[0] h[2] h[1] h[2] h[1] h[3] h[0] Entries 16440 Entries Entries Entries 20310 20190 20490 Entries Entries Entries Entries 20100 20490 20700 16110 200MeV 1400 1400 Mean 6.279 Mean 0.5783 Mean Mean Mean 19.19 25.48 12.64 Mean Mean Mean 0.8756 0.2934 1.163 Std Dev 0.9121 Std Dev Std Dev Std Dev 3.729 2.418 4.956 Std Dev Std Dev Std Dev Std Dev 0.04156 0.1087 0.1658 0.2158 400MeV 1200 2 1200 2 2 χ 2 2 2 / ndf / ndf / ndf / ndf 19.05 / 15 χ 2 2 / ndf / ndf / ndf / ndf 23.47 / 18 χ χ χ 30.68 / 25 31.41 / 29 32.36 / 21 χ χ χ 12.28 / 12 37.05 / 25 24.12 / 21 Prob 0.2113 Prob Prob Prob 0.05375 0.3463 0.1997 Prob Prob Prob Prob 0.05709 0.4235 0.2873 0.1731 p0 p0 p0 p0 p0 1172 ± 13.6 p0 p0 p0 1243 13.2 1103 960.5 832.3 ± ± ± 11.7 10.1 8.8 973.4 1121 1411 ± ± ± ± 16.3 11.7 10.1 1000 1000 600MeV p1 6.705 0.009 p1 p1 p1 p1 13.69 27.32 20.65 ± 0.01 0.01 0.01 p1 p1 p1 0.6257 0.3108 1.244 0.939 ± 0.0004 0.0004 0.001 0.001 ± ± ± ± ± ± p2 p2 p2 p2 1.419 ± 0.065 p2 p2 p2 p2 0.086 0.005 2.608 2.715 1.751 ± ± ± 0.155 0.220 0.105 0.05863 0.1108 0.1165 ± ± 0.00294 ± ± 0.0094 0.0072 800 800 p3 0.141 0.010 p3 p3 p3 p3 0.08453 0.09318 0.07025 − ± 0.00805 0.00767 0.00754 p3 p3 p3 − 0.09202 0.06131 0.0962 0.1252 ± 0.00770 0.00759 0.0076 0.0094 − − − ± ± ± − − − ± ± ± 800MeV 600 600 400 400 200 200 0 0 0 5 10 15 20 25 30 35 40 45 50 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 Total Energy [a.u.] 1.2 Blue: w/ MPPC peak = (1, 1) Red: w/o MPPC comparison @200MeV 1 0.8 w/ MPPC is wider than w/o. 0.6 0.4 0.2 0 0 0.2 0.4 0.6 0.8 1 1.2 1.4 Tomoo Mari Nenmatsu 13

Energy resolution of PMT Energy resolution := FWHM / MPV Black / Red E resolution [%] Graph Graph Graph Graph 2 2 / ndf / ndf χ χ 169.3 / 3 169.3 / 3 Black: w/ MPPC 0.2 Prob Prob 1.834e 1.834e − − 36 36 12% 1.12 p0 p0 1.103 1.103 0.002378 0.002378 ± ± Red: w/o MPPC 0.18 1.1 0.16 0.14 1.08 0.12 1.06 0.1 0.08 1.04 0.06 1.02 0.04 200 300 400 500 600 700 800 200 300 400 500 600 700 800 Beam energy [MeV] Beam energy [MeV] Tomoo Mari Nenmatsu 14

Conclusion / Prospects Conclusion • We tested new CsI readout system for the calorimeter upgrade. • I checked how the MPPCs a ff ect energy resolution of PMTs. • Energy resolution got worse (max: 12% @200MeV) Prospects • Analysis of timing resolution of both-end readout system • Analysis of other runs (backward run, rotated run, etc…) • Optical photon simulatoin Tomoo Mari Nenmatsu 15

Back up Tomoo Mari Nenmatsu 16

Setup Tomoo Mari Nenmatsu 17

Asymmetric Gaussian ( x − µ ) 2  � G A ( x ) = N 0 exp − 2( σ 1 x + σ 0 ) 2 4 parameters: N 0 , µ, σ 0 , σ 1 MPV = µ error = δ µ FWHM = µ + ξσ 0 / 2 1 − ξσ 1 / 2 − µ − ξσ 0 / 2 √ ξ ≡ 2 2 ln 2 1 + ξσ 1 / 2 ◆ 2  µ − ξσ 0 / 2 s ✓ ξ � µ + ξσ 0 / 2 ξ 1 − ( ξσ 1 / 2) 2 [( σ 1 δ µ ) 2 + ( δσ 0 ) 2 ] + error = ( δσ 1 ) 2 (1 + ξσ 1 / 2) 2 − 2 (1 − ξσ 1 / 2) 2 Tomoo Mari Nenmatsu 18

Asymmetry of energy deposition X asymmetry Y asymmetry 0.1 0.1 0.09 0.09 0.08 0.08 0.07 0.07 0.06 0.06 0.05 0.05 0.04 0.04 0.03 0.03 0.02 0.02 0.01 0.01 0 0 1 0.5 0 0.5 1 1 0.5 0 0.5 1 − − − − Blue -> (Rotated run) -> Red -> (Backward run) -> Green X asymmetry: S1 - S0 Y asymmetry: S0 - S3 Tomoo Mari Nenmatsu 19