Photomultiplier tube(PMT)has been an essential instrument for low background experiments,and the accuracy of single photoelectron(SPE)calibration will directly affect the energy reconstruction of the detector.The SPE ...Photomultiplier tube(PMT)has been an essential instrument for low background experiments,and the accuracy of single photoelectron(SPE)calibration will directly affect the energy reconstruction of the detector.The SPE spectrum can be acquired from the charge distribution of dark-noise pulses or the low-intensity light signal triggered by LED.However,there are arguments on whether the two methods are consistent.In this paper,the Hamamatsu R5912-20mod PMT and the EMID642KNFL PMT have been tested adopting the two methods with signal waveform recording electronics.As comparison,traditional charge-to-digital conversion system is also used to test SPE spectrum.The results show that they are consistent when the PMTs are working at typical recommended high voltage(HV).展开更多
Background We propose to measure the coherent elastic neutrino-nucleus scattering(CEvNS)using a dual-phase liquid argon time projection chamber(TPC)with 200 kg fiducial mass.The detector is expected to be adjacent to ...Background We propose to measure the coherent elastic neutrino-nucleus scattering(CEvNS)using a dual-phase liquid argon time projection chamber(TPC)with 200 kg fiducial mass.The detector is expected to be adjacent to the JUNOTAO experiment and to be about 35 m from a reactor core with 4.6 GW thermal power at Taishan.The antineutrino flux is approximately 6×10^(12)cm^(−1)s^(−1) at this location,leading to more than 11,000 coherent scattering events per day in the fiducial mass.Motivation The nuclear recoil energies concentrate in the sub-keV region,corresponding to less than ten ionization electrons in the liquid argon.The key question is how to veto and shield the background in the hall where the vertical overburden is about 5 m.w.e.And what is the signal count rate and the background rate.In addition,what physical parameters can be measured what is the sensitivity.Methods We used the Geant4 to simulate the backgrounds from cosmic ray muons and ambient radioactivity decays.And a veto and shielding design is presented.Then a χ^(2) function is constructed and the sensitivity calculate package built to calculate the sensitivity of physical parameters.Results The detection of several ionization electrons can be achieved in the dual-phase TPC due to the large amplification in the gas region.With a feasible detection threshold of four ionization electrons,the signal rate is 955 per day.The detector is designed to be shielded well from cosmogenic backgrounds and ambient radioactivities to reach a 16%background-tosignal ratio in the energy region of interest.With the large CEvNS sample,the expected sensitivity of measuring the weak mixing angle sin^(2)θ_(w),and of limiting the neutrino magnetic moment are discussed.In addition,a synergy between the reactor antineutrino CEvNS experiment and the dark matter experiment is foreseen.展开更多
Introduction Liquid noble gases are widely used as targets in low background search experiments,particularly in direct dark matter search experiments.83mKr is an excellent low-energy internal calibration source for fu...Introduction Liquid noble gases are widely used as targets in low background search experiments,particularly in direct dark matter search experiments.83mKr is an excellent low-energy internal calibration source for future larger liquid noble gas detectors.Purpose To calibrate liquid argon detector with 83mKr in different drift fields and to study the correlation between light yield and drift fields.Method A dual-phase LAr prototype detector was designed to study the 83mKr responses in liquid argon.83mKr atoms are produced through the decay of 83Rb and introduced into the LAr detector through the circulating purification system.Conclusion We report that the light yield reaches 7.26±0.02 pe/keV for 41.5 keV from 83mKr and 7.66±0.01 pe/keV for 511 keV from 22Na,as a comparison.After stopping the fill,the rate decays of 83mKr are with a fitted half-life of 1.83±0.11 h,which is consistent with the reported value of 1.83±0.02 h.The light yield that varies with the drift electric field from 0 to 200 V/cm has also been reported.展开更多
基金The study was supported by China Ministry of Science and Technology under Grant No.2016YFA0400304.
文摘Photomultiplier tube(PMT)has been an essential instrument for low background experiments,and the accuracy of single photoelectron(SPE)calibration will directly affect the energy reconstruction of the detector.The SPE spectrum can be acquired from the charge distribution of dark-noise pulses or the low-intensity light signal triggered by LED.However,there are arguments on whether the two methods are consistent.In this paper,the Hamamatsu R5912-20mod PMT and the EMID642KNFL PMT have been tested adopting the two methods with signal waveform recording electronics.As comparison,traditional charge-to-digital conversion system is also used to test SPE spectrum.The results show that they are consistent when the PMTs are working at typical recommended high voltage(HV).
基金National Key R&D Program of China(2016YFA0400304)National Natural Science Foundation of China(11975244).
文摘Background We propose to measure the coherent elastic neutrino-nucleus scattering(CEvNS)using a dual-phase liquid argon time projection chamber(TPC)with 200 kg fiducial mass.The detector is expected to be adjacent to the JUNOTAO experiment and to be about 35 m from a reactor core with 4.6 GW thermal power at Taishan.The antineutrino flux is approximately 6×10^(12)cm^(−1)s^(−1) at this location,leading to more than 11,000 coherent scattering events per day in the fiducial mass.Motivation The nuclear recoil energies concentrate in the sub-keV region,corresponding to less than ten ionization electrons in the liquid argon.The key question is how to veto and shield the background in the hall where the vertical overburden is about 5 m.w.e.And what is the signal count rate and the background rate.In addition,what physical parameters can be measured what is the sensitivity.Methods We used the Geant4 to simulate the backgrounds from cosmic ray muons and ambient radioactivity decays.And a veto and shielding design is presented.Then a χ^(2) function is constructed and the sensitivity calculate package built to calculate the sensitivity of physical parameters.Results The detection of several ionization electrons can be achieved in the dual-phase TPC due to the large amplification in the gas region.With a feasible detection threshold of four ionization electrons,the signal rate is 955 per day.The detector is designed to be shielded well from cosmogenic backgrounds and ambient radioactivities to reach a 16%background-tosignal ratio in the energy region of interest.With the large CEvNS sample,the expected sensitivity of measuring the weak mixing angle sin^(2)θ_(w),and of limiting the neutrino magnetic moment are discussed.In addition,a synergy between the reactor antineutrino CEvNS experiment and the dark matter experiment is foreseen.
文摘Introduction Liquid noble gases are widely used as targets in low background search experiments,particularly in direct dark matter search experiments.83mKr is an excellent low-energy internal calibration source for future larger liquid noble gas detectors.Purpose To calibrate liquid argon detector with 83mKr in different drift fields and to study the correlation between light yield and drift fields.Method A dual-phase LAr prototype detector was designed to study the 83mKr responses in liquid argon.83mKr atoms are produced through the decay of 83Rb and introduced into the LAr detector through the circulating purification system.Conclusion We report that the light yield reaches 7.26±0.02 pe/keV for 41.5 keV from 83mKr and 7.66±0.01 pe/keV for 511 keV from 22Na,as a comparison.After stopping the fill,the rate decays of 83mKr are with a fitted half-life of 1.83±0.11 h,which is consistent with the reported value of 1.83±0.02 h.The light yield that varies with the drift electric field from 0 to 200 V/cm has also been reported.
