Background Liquid Argon(LAr)is used as a target material in several current and planned experiments related to dark matter direct searching and neutrino detection.Argon provides excellent pulse shape discrimination(PS...Background Liquid Argon(LAr)is used as a target material in several current and planned experiments related to dark matter direct searching and neutrino detection.Argon provides excellent pulse shape discrimination(PSD)capability,which could separate the electron recoil backgrounds from the expected nuclear recoil signals.As the next-generation photosensors,silicon photon multiplier(SiPM)is expected to replace traditional photon multiplier tubes.Purpose The purpose of this paper is to compare the PSD capability of a LAr detector between using SiPMs as photosensors and using PMTs as photosensors.Methods The PSD capability of a LAr detector is determined through the prompt fraction method,which relies on the analysis of output pulses.These pulses are generated using Monte Carlo simulation,incorporating real single photoelectron pulses obtained from a PMT or a SiPM.Results Three kinds of SiPMs and one kind of PMT have been used to compare the PSD capability of a LAr detector.The use of J-60035 SiPM results in a better PSD capability compared to the use of PMT as a photosensor,while using the other two kinds of SiPM deteriorates the PSD capability.Conclusion SiPM is a promising photosensor candidate for a LAr detector.The better energy resolution could help to improve its PSD capability,while the higher probabilities of cross-talk and after-pulse degrade its PSD capability.Notably,after-pulse has a more significant impact compared to cross-talk because after-pulse influences the energy distribution within the time window,while cross-talk primarily affects the energy resolution of the detector.展开更多
Background JUNO(The Jiangmen Underground Neutrino Observatory)is a multipurpose neutrino experiment,and it has very strict requirements for the detector.According to the MC simulation for JUNO experiment requirements,...Background JUNO(The Jiangmen Underground Neutrino Observatory)is a multipurpose neutrino experiment,and it has very strict requirements for the detector.According to the MC simulation for JUNO experiment requirements,the Rn concentration in the water of the veto detector should be less than 0.2Bq/m^(3).In order to measure such low Rn concentration,two kinds of high-sensitivity Rn measurement systems have been developed.Method Based on the water system of JUNO prototype,two kinds of high-sensitivity Rn detectors have been developed,namely the Si-PIN Rn detector and the LS Rn detector.The Si-PIN Rn detector uses a Si-PIN photodiode to detect theαfrom ^(214)Po decay and the LS Rn detector detects the coincident signals ofβfrom ^(214)Bi decay andβfrom ^(214)Po decay.Result The background measurement of Si-PIN Rn detector and LS Rn detector is performed to estimate the sensitivity.The sensitivity of Si-PIN Rn detector is around 9.0mBq/m^(3) and the sensitivity of LS Rn detector is around 64.0Bq/m^(3).Conclusion Both of the Si-PIN Rn detector and the LS Rn detector are working well with the JUNO prototype at present,and both of them can be developed as an online Rn concentration monitoring device for JUNO veto detector.展开更多
Background The Jiangmen Underground Neutrino Observatory(JUNO),a 20-kton multipurpose underground liquid scintillator detector,was proposed with the determination of the neutrino mass hierarchy as a primary physics go...Background The Jiangmen Underground Neutrino Observatory(JUNO),a 20-kton multipurpose underground liquid scintillator detector,was proposed with the determination of the neutrino mass hierarchy as a primary physics goal.To veto the cosmogenic background and shield the central detector from the environmental radioactivity,a multi-veto system,which consists of a water Cherenkov detector and a top tracker detector,is required.In order to keep the water quality good and remove the radon from water,an ultrapure water system,a radon removal system and radon concentration measurement system have been designed.Method The JUNO ultrapure water system was designed on the basis of the water system of the Daya Bay experiment.By installing the degassing membrane devices on the water system of JUNO prototype and Daya Bay experiment which can remove radon from water,the radon removal efficiency has been measured at the conditions of different gas–liquid phase pressures and different gas concentrations in water using the radon measurement system.Result Loading carbon dioxide into the water and increasing the inlet water pressure could help to improve the radon removal efficiency of the degassing membrane devices,and the radon concentration in water can be reduced to∼0.1 Bq/m^(3).Conclusion A reliable ultrapure water production and circulation system has been designed to keep the water quality good and to reduce the radon concentration in water for JUNO water Cherenkov detector.The radon concentration in water can satisfy the requirement of JUNO by using the Liqui-Cel degassing membrane devices.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.12275289,11975257,and 12175247)the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.2023015)the National Key R&D Program of China(Grant No.2016YFA0400304).
文摘Background Liquid Argon(LAr)is used as a target material in several current and planned experiments related to dark matter direct searching and neutrino detection.Argon provides excellent pulse shape discrimination(PSD)capability,which could separate the electron recoil backgrounds from the expected nuclear recoil signals.As the next-generation photosensors,silicon photon multiplier(SiPM)is expected to replace traditional photon multiplier tubes.Purpose The purpose of this paper is to compare the PSD capability of a LAr detector between using SiPMs as photosensors and using PMTs as photosensors.Methods The PSD capability of a LAr detector is determined through the prompt fraction method,which relies on the analysis of output pulses.These pulses are generated using Monte Carlo simulation,incorporating real single photoelectron pulses obtained from a PMT or a SiPM.Results Three kinds of SiPMs and one kind of PMT have been used to compare the PSD capability of a LAr detector.The use of J-60035 SiPM results in a better PSD capability compared to the use of PMT as a photosensor,while using the other two kinds of SiPM deteriorates the PSD capability.Conclusion SiPM is a promising photosensor candidate for a LAr detector.The better energy resolution could help to improve its PSD capability,while the higher probabilities of cross-talk and after-pulse degrade its PSD capability.Notably,after-pulse has a more significant impact compared to cross-talk because after-pulse influences the energy distribution within the time window,while cross-talk primarily affects the energy resolution of the detector.
基金This work is supported by Xie Jialin Foundation of Institute of High Energy Physics(IHEP,Y7546150U2).
文摘Background JUNO(The Jiangmen Underground Neutrino Observatory)is a multipurpose neutrino experiment,and it has very strict requirements for the detector.According to the MC simulation for JUNO experiment requirements,the Rn concentration in the water of the veto detector should be less than 0.2Bq/m^(3).In order to measure such low Rn concentration,two kinds of high-sensitivity Rn measurement systems have been developed.Method Based on the water system of JUNO prototype,two kinds of high-sensitivity Rn detectors have been developed,namely the Si-PIN Rn detector and the LS Rn detector.The Si-PIN Rn detector uses a Si-PIN photodiode to detect theαfrom ^(214)Po decay and the LS Rn detector detects the coincident signals ofβfrom ^(214)Bi decay andβfrom ^(214)Po decay.Result The background measurement of Si-PIN Rn detector and LS Rn detector is performed to estimate the sensitivity.The sensitivity of Si-PIN Rn detector is around 9.0mBq/m^(3) and the sensitivity of LS Rn detector is around 64.0Bq/m^(3).Conclusion Both of the Si-PIN Rn detector and the LS Rn detector are working well with the JUNO prototype at present,and both of them can be developed as an online Rn concentration monitoring device for JUNO veto detector.
基金This work was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA10010300).
文摘Background The Jiangmen Underground Neutrino Observatory(JUNO),a 20-kton multipurpose underground liquid scintillator detector,was proposed with the determination of the neutrino mass hierarchy as a primary physics goal.To veto the cosmogenic background and shield the central detector from the environmental radioactivity,a multi-veto system,which consists of a water Cherenkov detector and a top tracker detector,is required.In order to keep the water quality good and remove the radon from water,an ultrapure water system,a radon removal system and radon concentration measurement system have been designed.Method The JUNO ultrapure water system was designed on the basis of the water system of the Daya Bay experiment.By installing the degassing membrane devices on the water system of JUNO prototype and Daya Bay experiment which can remove radon from water,the radon removal efficiency has been measured at the conditions of different gas–liquid phase pressures and different gas concentrations in water using the radon measurement system.Result Loading carbon dioxide into the water and increasing the inlet water pressure could help to improve the radon removal efficiency of the degassing membrane devices,and the radon concentration in water can be reduced to∼0.1 Bq/m^(3).Conclusion A reliable ultrapure water production and circulation system has been designed to keep the water quality good and to reduce the radon concentration in water for JUNO water Cherenkov detector.The radon concentration in water can satisfy the requirement of JUNO by using the Liqui-Cel degassing membrane devices.
