Concept of Hyper Kamiokande (20 times Super K) 48m x 50m x 250m x 2 Total mass ~ 1 Mton Photocathode coverage ~40% of surface ~200,000 PMTs => prohibi

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蜃拙茅
5 years ago
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1 R&D of a Large Format Hybrid Photo-Detector (HPD) for a Next Generation Water Cherenkov Detector Tokyo - HPK joint R&D program H.Aihara University of Tokyo HPK =Hamamatsu Photonics 1 presented at Next Generation of Nucleon Decay and Neutrino Detectors 7-9 April 2005 Aussois, Savoie, France

2 Concept of Hyper Kamiokande (20 times Super K) 48m x 50m x 250m x 2 Total mass ~ 1 Mton Photocathode coverage ~40% of surface ~200,000 PMTs => prohibitive cost (~10,000 PMTs for SK) 2

3 Requirements to a New Photo Sensor Simple structure Suited for mass production : Low cost, Ease of quality control Large sensitive area Single photon sensitivity Advantage in Cherenkov ring reconstruction Wide dynamic range (up to ~300p.e.) Good time resolution (~1ns) Good resolution of neutrino event vertex (Δx cδt) Keep large photocathode and replace dynodes with an avalanche diode =>Hybrid (Avalanche) Photodetector : H(A)PDH 3

4 HPD photon photocathode Principle of HPD Simple structure without dynodes # of parts:1/10 of PMT-SK HV photo electron (p.e.) Bombardment Gain ~4500@20kV Single photon sensitivity large gain at the first stage Bias avalanche diode (AD) cf. PMT-SK dynodes Avalanche Gain ~30 or more Total Gain ~10 5 Total Gain ~10 7 Wide dynamic range(>1000p.e.) determined by AD saturation Good timing resolution(~1ns) cf. PMT-SK: ~2.3ns (mainly TTS) Challenging HV (~20kV) to focus onto a small AD (5mmφ) TTS(Transition Time Spread) Smaller Gain low-noise readout needed 4

5 Bonbardmend Gain (de/dx in Si / 3.6 ev) ~4,500@20kV Avalanche Gain (~30-50) Total Gain ~ 10 5 < 10 7 of SK-PMT 5 5

6 5 inch prototype HPD 5 inch prototype HPD (HY0010) Raw signal 10mV 10ns 6

7 Proof of principle using 5 inch prototype Total Gain ~44,000 Number of events single p.e. two p.e. S/N~21 Q distribution 3mmφ AD ~30pF Bias: 350V HV:-8.5kV Linearity Q [e] Q [e] Peak number T resolution [ns] 1 0 Peak number 7 7

8 Photos of 13inch HPD 33cm 13inch 13inch HPD 13cm 5inch 8

13inch prototype 13inch photocathode (GND) Diameter 13inch 332mm 5inch 128mm Effective area 240mmφ - AD(+HV) AD size 5mmφ 3mmφ AD type Low capacitance (~25pF)

9 13inch prototype 13inch photocathode (GND) Diameter 13inch 332mm 5inch 128mm Effective area 240mmφ - AD(+HV) AD size 5mmφ 3mmφ AD type Low capacitance (~25pF) Low capacitance (~30pF) Bias max 370V 350V HV max +12kV(goal:+20kV) -8.5kV Change from 5inch HV (-8.5kV +12kV) water +HV mode (photocathode=gnd) use in water 9

10 Raw Signal of the HPD HPD preamp DSP HV, Bias: Max(12kV, 370V) Input light: ~30p.e. 1.1ns 6ns Fast signal response Rise time ~ 1.1ns Pulse width ~ 6ns 10mV/div, 2ns/div LHP30 10

11 Avalanche/Bombardment Gain Avalanche Gain Bombardment Gain HV=12kV(fixed), Bias=sweep Bias=50V(fixed), HV=sweep LHP25 current mode Gain (no avalanche effect <40V) ~ Gain Gain Gain rises >3kV (energy loss in an insensitive layer on AD) 11 Total gain ~50,000

12 Signals at preamplifier output HPD preamp DSP HV, Bias: MAX(12kV, 370V) Light input: ~2p.e.(average) 1p.e. 2p.e. 3p.e. Pulse height 1p.e. ~3.2mV Noise RMS~0.5mV LHP25 12

13 Single Photon Sensitivity HPD preamp DSP Number of events 0p.e. 1p.e. 1st peak 2p.e. 3p.e. 2nd peak Pulse height distribution after DSP very clear 1, 2,.. p.e. peaks Gain ~30,000 ENC~3,000 30,000 electrons S/N = 3rd peak Single Photon Sensitivity! Q( pulse height) 13

14 Gain Linearity Peak positions in the Q-histogram Linearity is quite good ~5p.e. Good linearity up to ~150p.e.(preAMP limit) 14

15 Timing Resolution for 1p.e. Timing resolution directly affects to the neutrino vertex reconstruction performance. (Δx ~ cδt) Timing resolution ~0.7ns@1p.e. cf. PMT-SK ~2.3ns@1.p.e. timing (ns) 15

16 Timing Resolution for multi photoelectrons Timing resolution <0.5ns for >2p.e. ~ Meet the requirement (~1ns) 16

17 Gain Uniformity HPD Gain vs. position on the photocathode Light input: 1p.e. r=0 r Light source Gain Uniformity within ~5% 17

18 Timing Uniformity HPD T.O.F (photocathode~ad) vs. position on the photocathode light input: ~30p.e. (timing resolution: r r=0 Light source Timing uniformity ~0.1ns 18

19 Immediate plans New type AD (back illuminating) smaller detector capacitance New Bulb (Max HV: 12kV 20kV) wide effective area & gain increase Readout (mass production, low-noise preamp) ASIC/FPGA implementation HPD preamp (ASIC) sampling, A/D (AMC+FADC) DSP (FPGA) pulse height timing 19

20 Wave form sampling without a fast clock inexpensive low power consumption size 20 Work with KEK 20

21 Summary R&D for a large format hybrid photo detector has started. Initial study shows excellent performance: Single photon sensitivity Wide dynamic range (up to the readout limit) Good time resolution (better than 1ns) Good uniformity (over a large photocathode) Promising 21

iml88-0v C / 8W T Tube EVM - pplication Notes. IC Description The iml88 is a Three Terminal Current Controller (TTCC) for regulating the current flowi

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