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Sensitivity of a multi-PMT OM for muon and neutrino detection in KM3NeT. XP53B20C. H. L öhner, KVI Groningen, for the Nikhef / KVI team in KM3NeT A. Mjøs, Master thesis, KVI sep. 2007. Objectives PMT measurements PMT characteristics Detector simulation for ,
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Sensitivity of a multi-PMT OM for muon and neutrino detection in KM3NeT XP53B20C H. Löhner, KVI Groningen, for the Nikhef / KVI team in KM3NeT A. Mjøs, Master thesis, KVI sep. 2007 • Objectives • PMT measurements • PMT characteristics • Detector simulation for , • OM performance H. Löhner, KVI - Sensitivity multi-PMT OM
22 23 21 20 25 24 31 29 28 26 30 27 27 33 35 36 32 37 34 38 Objectives Reduction of sea background: excellent single/multiple hit separation Reduction of atmospheric background: uniform acceptance Sensitivity up-going neutrinos: comparable to ANTARES Sensitivity down-going muons: energy calibration; UHE neutrinos zenith / azimuthal angle acceptance ANTARES: 3 OM with 10” PMT multiPMT: single OM with 38 3” PMT 1140 cm2 with QE = 23% 1560 cm2 with QE = 30 - 45 % H. Löhner, KVI - Sensitivity multi-PMT OM
Measurements fast sampling ADC DAQ 8 GS/s H. Löhner, KVI - Sensitivity multi-PMT OM
Cathode sensitivity Corning blue sensitivity XP53B2 SN100 Skcb = 12.6 µA/lmF SN101 Skcb = 13.5 SN102 Skcb = 15.7 SN103 Skcb = 14.4 SN107 Skcb = 13.8 Mean:14.0±1.0 (7%) XP53B20C SN102 Skcb = 16 µA/lmF SN104 Skcb = 16 SN107 Skcb = 15.7 SN115 Skcb = 15.9 SN116 Skcb = 17.8 16.3±0.8 (5%) mean is higher by: 16% radiant blue sensitivity at 404 nm: 110 mA/W130 mA/W QE: 30%35% a step in the good direction, will continue H. Löhner, KVI - Sensitivity multi-PMT OM
Charge distribution and gain XP53X2 9-stage PMT at reference gain 5 106 P/V 2.8 time-over-threshold (TOT) 1 PE 2 PE XP53B2 10-stage PMT 1 SPE / 1.75 ns P/V 3.9 very good P/V SPE separation possible H. Löhner, KVI - Sensitivity multi-PMT OM
Improved type: XP53B20C XP53B20C#103, HV = 1100 V XP53B20C#106, HV = 1200 V SPE signal at 0.6 pC gain 4 106 dark rate 1.1 kHz at 0.3 SPE P/V=3.6 Pulse [nVs] H. Löhner, KVI - Sensitivity multi-PMT OM
Transit Time Spread at reference gain 5 106 XP53X2 and XP53B2 1/3 of SPE = 1/3 of 0.8 pC 2 ns rise time < 3 ns XP53X2 TTS variation across surface radial position small TTS variation: 2 ns FWHM H. Löhner, KVI - Sensitivity multi-PMT OM
Multi-PMT storey acceptance 22 23 21 20 25 24 31 29 28 26 30 27 27 33 35 36 32 37 34 38 Simulation with Sirène thanks to Eleonora Presani for support with Sirène ANTARES storey acceptance Down Up Corsika generates atmospheric muons, Genhen generates muon-neutrinos proton energy spectrum ~E-2 neutrino spectrum ~E-1.4 “low” E = 1010-1016 eV “high” E = 1015-1017 eV H. Löhner, KVI - Sensitivity multi-PMT OM
Cherenkov vs. Electromagnetic Showers Cherenkov EM shower time interaction - detection 71% 99% time between consecutive photon pairs coincidence requirement within short (20ns) time window H. Löhner, KVI - Sensitivity multi-PMT OM
Cherenkov light from muon tracks Electromagnetic showers (ES) hits per PMT horizontal up down horizontal Atmospheric (upgoing) neutrinos low E = 1010-1016 eV larger number of multiple hits per OM: 2- and 3-fold coincidences 45o 1/3 of photons in upper hemisphere H. Löhner, KVI - Sensitivity multi-PMT OM
Sensitivity of ANTARES vs. multi-PMTfor up-going neutrinos PE response hit response low E = 1010-1016 eV high E = 1015-1017 eV standard QE standard QE multi-PMT arrangement is superior in photo-electron and number-of-hits response H. Löhner, KVI - Sensitivity multi-PMT OM
Atmospheric (downgoing) muons hits per PMT Total ES Cherenkov PE response hit response • Superior detection of signal from atmospheric muons compared to ANTARES standard QE standard QE H. Löhner, KVI - Sensitivity multi-PMT OM
cost efficiency Photonis cost estimate ( nov. 2007 ) 10” PMT: 2.5 € / cm2 3“ PMT: 1.8 € / cm2 (for super-photocathode) cost / (cm2 QE) 10” PMT X3 € / efficient cm2 3” PMT 23 30 40 50 60 H. Löhner, KVI - Sensitivity multi-PMT OM
reliability standard PMT: mass production for PET applications of ca. 10k / year very low failure rate 0.04% innovation through complex arrangement super Quantum Efficiency on-board HV generation (low-voltage supply) simple fast readout (Time over Threshold) low power consumption ( 7W / OM) prototype NIKHEF active base for 10 stage XP53B20 H. Löhner, KVI - Sensitivity multi-PMT OM
Conclusions • Good candidate 3” PMT (XP53B2, 10 stage) • Dark count rate 1kHz • Good timing properties • Improved detection of EM shower photons • Superior detection of down-going atmospheric muons • Super-photocathode sample tubes available: X3 reduced cost / efficient area • reliable OM configuration H. Löhner, KVI - Sensitivity multi-PMT OM