液体xeー用光电子増倍管低温性能...

液体Xe用光電子増倍管低温性能評価,東大素粒子A , 高研B , 早大理工総研C春山富義B, 大谷航A, 小曽根健嗣A, 菊池順C, 道家忠義C三原智A, 森俊則A, 山口敦史C,東京大学素粒子物理国際研究森研究室修士年久松康子,久松康子2004年度低温工学超伝導学会八戸工業大学,Cryogenic performance test of a photomultiplier for the liquid Xe calorimeter,Abstract,About MEG ExperimentPMT for MEG photon detectorWorks on Final Design of PMTPMT test at Univ. of TokyoSummary,久松康子2004年度低温工学超伝導学会八戸工業大学,MEG Experiment,+ e+ ,beyond SMSUSY-GUT promising,MEGA(1999)Br 1.2*10-11,MEGBr 10-14,Approved by Paul Scherrer InstitutUsing intense muon beam PSI1*108/secStart of Physics Run : 2006,52.8 MeV,52.8 MeV,久松康子2004年度低温工学超伝導学会八戸工業大学,Photomultiplier (PMT),Highly sensitive light sensor often used in high energy physics experimentsElectron tube device which converts light into a measurable electric current,Photoelectric effect,photon,Electrode and dynode,photocathode,Measureable electric pulse,久松康子2004年度低温工学超伝導学会八戸工業大学,MEG Liq. Xe detector,Detect scintillation light with 800 Liter liq.Xe and with 830 PMTs,久松康子2004年度低温工学超伝導学会八戸工業大学,PMT,Liq.Xe,PMT 165K (Liq.Xe temp.),久松康子2004年度低温工学超伝導学会八戸工業大学,photocathode,e-,photon,Temperaturesurface resistanceQuantum EfficiencySignal Output,Need to reduce surface resistance of photocathode,PMT 165K under high rate B.G.,First version PMTs output deteriorates under high rate B.G.,Related to the characteristics of photocathode at the low temperature,久松康子2004年度低温工学超伝導学会八戸工業大学,signal output,time,PMT will be exposed to large amount of light produced by high rate background radiation,PMT output needs to be stable under high rate B.G.,PMT,PMT,Development of PMT for MEG Experiment,First Ver.,Second Ver.,Final Ver.,久松康子2004年度低温工学超伝導学会八戸工業大学,Efficient Q.E. 165K (reduction of surface resistance)Stable output under high rate background,How much has Q.E. improved?Will PMT survive the high rate background environment 165K ?,PMT Test Univ. of Tokyo Liq.Xe chamber,Pulse tube refrigerator,Liq.N2,久松康子2004年度低温工学超伝導学会八戸工業大学,Liq. Xe,Liq.N2 cooling pipe,Vacuume,AISIN PR121Compressor : TAC 101JCooling Power : 25W 165K,Cold head temperature monitor : Pt100Platinum Thin Film Resistance,Cold head temperature control :MINCO Thermofoil Heater,65mm,PMT Test Set up Q.E. measurement,55mm,55mm,Observe 5.5MeV alpha eventGain calibration using LED,Gain :106,久松康子2004年度低温工学超伝導学会八戸工業大学,241Am (alpha source),LED,Reference PMT,PMT,How much has Q.E. improved?,46mm,33mm,Q.E. measurement,久松康子2004年度低温工学超伝導学会八戸工業大学,Q.E. ratio,PMT Test Set up Rate dependence test,久松康子2004年度低温工学超伝導学会八戸工業大学,Will PMT survive the high B.G. environment at 165K?,PMT,How to simulate High rate B.G. ?LED,Pulse tube refrigerator,LED,241Am (alpha source),Liq. Xe,PMT,Rate Dependence Test Procedure,241AmLED,PMT,241Am (alpha source),LED,Liq.Xe,alphaObserve 5.5MeV alpha event, 200Hz,LED simulate the high rate backgroundpulse height:40007200 p.e./eventpulse shape: 10nsecrate: 500Hz 10KHz,久松康子2004年度低温工学超伝導学会八戸工業大学,Max. B.G. Level in MEG experiment1.3*107p.e./sec,c.f. First Version PMT,久松康子2004年度低温工学超伝導学会八戸工業大学,time,signal output,20%, 20 min,PMT for MEG final version Rate Dependence Liq. Xe,PMT was tested under various background environment by changing the rate of LED,The output from final version PMT is stable under the high rate background environment,Summary,PMT for MEG experiment has been developed.Able to operate under 165K, Liq.Xe temp.Cryogenic performance of Final Version PMT is tested liq.Xe.PMT has efficient Q.E. even at 165K PMT output at 165K is stable under the high rate background environment.,久松康子2004年度低温工学超伝導学会八戸工業大学,以下予備,PMT for MEG Experiment,Metal Cover SUSAble to withstand pressure up to 0.3MPa,Photocathode : BialkaliSensitive to VUV,Window : Quartz glass,Kovar Glass,Kovar Metal,久松康子2004年度低温工学超伝導学会八戸工業大学,Flow sheet PMT Test Facility,久松康子2004年度低温工学超伝導学会八戸工業大学,PMT Test facility Univ. of Tokyo,Xe tank,Liq.Xe chamber,Purification system,PMT stability, DAQ Procedure,DAQ started after all chamber components become low temperature,Trigger : alpha self triggerDAQ Procedure : Pedestal RunGain Calibrationalpha run,久松康子日本物理学会2004年秋季大会高知大学,muon radiative decayGamma from positron annihilationNeutrons from proton beam, p 0 n 0 , p n ,neutrons from pions CEX reaction (calibration run),55,83,129,MeV, energy spectrum,BG level 2A 106gain (107p.e./sec),Major Background for PMT,52.8 MeV,52.8 MeV,c.f. muegamma event,久松康子2004年度低温工学超伝導学会八戸工業大学,Condition and Procedure,Gain 1*106Trigger: alpha self trigger (veto by LED driver pulse) Procedure,Pedestal Run & Gain calibration using LED Alpha Run LED OFF 20 min