Performance evaluation of new photodetectors for Hyper-Kamiokande

Transcription

1 Performance evaluation of new photodetectors for Hyper-Kamiokande Yusuke Suda Y.Nishimura 1, S.Hirota 2, Y.Okajima 3, H.Aihara, M.Yokoyama, M.Shiozawa 4, Y.Hayato 4, S.Nakayama 4, H.Tanaka 4, T.Nakaya 2, A.Taketa 5, Y.Kawai 6, T.Ohmura 6, M.Suzuki 6 Department of Physics, The University of Tokyo(UTokyo), 1 Research Center for Cosmic Neutrino, Institute for Cosmic Ray Research(ICRR), UTokyo, 2 Department of Physics, Kyoto University, 3 Department of Physics, Tokyo Institute of Technology, 4 Kamioka Observatory, ICRR, UTokyo, 5 Earthquake Research Institute, UTokyo, 6 Hamamatsu Photonics K.K. The International Conference on Technology and Instrumentation in Particle Physics 214 Amsterdam, The Netherlands, 2-6 June 214 1

2 Hyper-Kamiokande Next generation Mega-ton water Cherenkov detector Candidate site: Kamioka mine, Japan Volume (fiducial):.99 (.56) Mega-ton Many targets Proton decay search Neutrino physics 25 (fiducial) Super-Kamiokande Leptonic CPV, mass hierarchy, supernova,... 2

3 Hyper-K Photodetector Inner tank: 99, 2-inch photodetectors (5cm) Photo coverage 2% Super-K 4% Outer tank: 25, 8-inch photodetectors (2cm) Requirements for photodetector Inner tank High performance High quantum efficiency photocathode Low cost (if possible) Outer tank (Veto 3

4 R&D of HK photodetector Goal Development of a 2-inch high performance photodetector which can be used in a water Cherenkov detector for a long time Flowchart 2 high-qe box&line PMT High-QE SK PMT 2 QE [%] Super-K PMT QE 4 High-QE R36 35 ZP7 ZP12 ZP ZP ZP21 ZP22 ZP24 ZP25 2 Normal SK PMT 15 8 Hybrid PhotoDetector (HPD) 2 high-qe HPD Normal-QE R36 5 QE~22% well-known Wave Length [nm] QE~3% Test As a first step, we developed 8 HPD and 2 high-qe Super-K PMT We report the status of the test in the tank and the performance of 2 high-qe HPD and 2 high-qe B&L PMT Photodetector test in a 2-ton water tank to confirm the usability of new photodetectors is ongoing 4 2-ton tank

5 Box&Line PMT Super-K PMT (Venetian Blind dynode) e - Box&line PMT (Box&line dynode) e - Various drift path Might miss dynode Line Box Unique drift path Large acceptance Unique drift path Better timing and 1PE resolution Large acceptance Better collection efficiency

6 Hybrid Photo-Detector Metal dynode Avalanche Diode (AD) = APD without photocathode ~26V e - e - e - Amp HPD Advantage ~1kV 1-2kV x ~ 15 5 ~4 ~1,6 5~ ~8kV ΔV ~ -26V Amp. gain first step gain first step gain Avalanche gain Total gain ~ 7 Total&gain&~4x 4 &&& & Amp. gain Simple structure Low cost production possibility Short drift length Fast timing response High first step gain High single photoelectron resolution 5 5mm AD Challenge Difficulty in handling 8kV No experience to use in a water Cherenkov detector

7 Photodetector Test in the Water Tank 2-ton tank 7 8 normal-qe HPD 2 high-qe Super-K PMT

8 Test in the Water Tank Confirm the usability of new photodetectors EGADS tank: the 2-ton scale model of Super-K 24 photodetectors, use the charge and time DAQ with Super-K old electronics Eight 8 normal-qe HPDs, five 2 high-qe Super-K PMTs and 227 Super-K PMTs were installed in 213 summer We measured performance and stability. HV module HPD I-V amp (inverted) 55V/mA 3 output 信 8 normal-qe HPDs 2 high-qe Super-K PMTs Diff. amp CH control signal Control power supply 8 8-inch HPD High-QE R36

9 Performance 1PE timing distribution Number of events / ndf / 927 Scale 67.2 ± 2.58 Mean ± ±.156 low ±.176 up Floor 2.5 ±.1 Scale /Scale up low.9985 ±.16 8 HPD Time [ns] 1PE charge distribution Number of events HPD / ndf / 39 Constant 1834 ±.6 Mean ±.19 Sigma ± Charge [pc] Dark Rate (khz) Dark rate (khz) Dark rate distribution 8 HPD EHD83 213/3/22, Bias=32V 213//12, Bias=33V 213/11/21, Bias=331V Before installation: 2kHz After installation:.4khz 1p.e Threshold (p.e.) Threshold (PE) Number of photodetectors 1 8 HPDs High-QE Super-K PMTs Super-K PMTs No TQ correction only for HPD Time resolution [ns] Number of photodetectors p.e. peak resolution [%] 8 HPD shows better timing&charge resolution and dark rate 9 Number of photosensors Number of photodetectors 4 PMT (Normal QE) PMT (High QE) 35 HPD (8-inch) Dark rate [khz] Dark rate (khz)

10 Calibration and Stability Gain We calibrated all photodetectors in the tank. 6 8 HPD Gain curve EHD74 EHD92 EHD83 EHD78 EHD8 EHD91 EHD Avalanche diode bias voltage (V) Gain ZP15 ZP22 ZP21 ZP12 ZP HV [V] Confirmed the gain was stable for 1month run. We will continue stable data taking. Gain curve 2 high-qe Super-K PMT 8 HPD 2 high-qe Super-K PMT Gain RMS ~ Gain Light yield was decreased RMS ~.1

11 New 2 Prototypes 5mmΦ AD Note 2 high-qe HPD (w/ 5mmΦ AD) Target AD size: 2mmΦ AD 2 high-qe box&line PMT AD used for the evaluation is smaller size, same as 8 HPD 2 HPD w/ 2mmφAD will be later measured with coming new preamplifier.

12 Waveforms Box&line PMT and HPD are faster than Super-K PMT Normalized pulse height inch high-qe HPD(5mm dia. AD) w/ preamp. 2-inch high-qe box&line PMT Super-K PMT Time (ns) 12 prototype HPD B&L PMT SK PMT Rise time (ns) Fall time (ns) Pulse width (ns) HPD w/o preamp. HV: 8kV, AD bias: 26V Rise time: 1.7ns Fall time: 2.7ns HPD itself has very fast response. Preamplifier R&D to get a fast response is ongoing.

13 Timing & Charge 1PE timing distribution 2-inch high-qe HPD (5mm dia. AD) w/ preamp. 2-inch high-qe box&line PMT 2-inch normal-qe Super-K PMT HPD: 1.4ns B&L PMT: 1.1ns SK PMT: 2.1ns PE charge distribution 2-inch high-qe HPD(5mm dia. AD) w/ preamp. 2-inch high-qe box&line PMT 2-inch normal-qe Super-K PMT HPD: 16% B&L PMT: 35% SK PMT: 53% Time (ns) Photoelectron 2 HPD (8 HPD) B&L PMT SK PMT Timing resolution σ (ns) 1.4 (1.1) FWHM (ns) 3.4 (3.3) PE resolution σ/µ 16% (12%) 35% 53% Peak to Valley ratio 3.9 (5.2) HPD calculated timing resolution FWHM:.75ns (2mmφ AD w/o preamp) Both box&line PMT and HPD show better timing and charge resolution than Super-K PMT

14 Multi-PE Distribution 9 2 high-qe HPD 35 Pedestal 2 high-qe Box&line PMT 2 high-qe Super-K PMT Pedestal 1PE 2PE PE PE 15 2PE Charge (pc) Charge (pc) Multi-photoelectron peaks are clearly seen 14

15 Select the Hyper-K photodetector Schedule Here 8 normal-qe HPD Prototype production Performance evaluation Test in the water tank High-QE Super-K PMT 2 high-qe box&line PMT 2 high-qe HPD Development of 2 HPD is still ongoing Preamplifier for large AD size, Low capacitance AD In this summer, 2 high-qe box&line PMT will be installed in the tank 15

16 Summary We have been developing new photodetectors for Hyper-K We evaluated photodetectors in the 2-ton water tank 8 HPDs show good performance Test of 2 high-qe box & line PMT will start this summer Performance of 2 high-qe HPD and 2 high-qe box&line PMT prototype was measured Confirmed better performance than Super-K PMT Details (noise, efficiency, etc) will be also measured soon We will select the best photodetector in

17 5th Hyper-K Open Meeting 4th meeting (Jan. IPMU,Japan Everyone who are interested in Hyper-K can join the meeting Date: July 214 Place: UBC, Vancouver, CANADA 17 Join us!