Purpose The purpose of this work is to study the pulse shape,energy resolution,non-proportionality of energy response for gamma-rays,and time characteristics of CeBr_(3) detector.Method The time and energy responses o...Purpose The purpose of this work is to study the pulse shape,energy resolution,non-proportionality of energy response for gamma-rays,and time characteristics of CeBr_(3) detector.Method The time and energy responses of two CeBr_(3) detectors were characterized by an analog method and a digital method using a set of standardγ-ray sources.The pulse shape,energy resolution and non-proportionality(nPR)of energy response forγ-rays were characterized using the analog method.For the analog method,the high voltage applied to PMTs,parameters of walk and external delay of constant fraction discriminator were optimized.For the digital method,a CEAN 1729A digitizer with sampling frequency of 2 GS/s and resolution of 11 bit,and a digital constant fraction discrimination technique were used to study the time performance of the two CeBr_(3) detectors.Then,the coincidence time resolutions of the CeBr_(3) detectors for the gamma peaks of ^(22)Na and ^(60)Co were measured using the two methods.Results The t_(rise),lifetimeτ,t_(fall) for CeBr_(3)21^(#)and 22^(#)are 11.2 ns,23.8 ns,50.2 ns,and 10.4 ns,26.5 ns,58.6 ns,respectively.The measured non-proportionality of CeBr_(3)21^(#)and 22^(#)are 1.08%and 2.22%,respectively.The time resolutions of the two CeBr_(3) detectors are 244±2 ps and 248±3 ps at the energy peaks of ^(60)Co source,and 336±2 ps and 335±3 ps at 511 keV for the analog and the digital methods.Conclusions The time resolutions obtained by the analog method and the digital method are almost identical.The CeBr_(3) detector is a good option in the applications such as half-life measurements,ToF-PET and high counting rate conditions.Furthermore,it is a goodγ-ray spectrometer owing to the preferable energy resolution and non-internal activity.展开更多
The back-streaming white-neutron beamline(Back-n)of the China Spallation Neutron Source is an essential neutronresearch platform built for the study of nuclear data,neutron physics,and neutron applications.Many types ...The back-streaming white-neutron beamline(Back-n)of the China Spallation Neutron Source is an essential neutronresearch platform built for the study of nuclear data,neutron physics,and neutron applications.Many types of cross-sectional neutron-reaction measurements have been performed at Back-n since early 2018.These measurements have shown that a significant number of gamma rays can be transmitted to the experimental stations of Back-n along with the neutron beam.These gamma rays,commonly referred to as in-beam gamma rays,can induce a non-negligible experimental background in neutron-reaction measurements.Studying the characteristics of in-beam gamma rays is important for understanding the experimental background.However,measuring in-beam gamma rays is challenging because most gamma-ray detectors are sensitive to neutrons;thus,discriminating between neutron-induced signals and those from in-beam gamma rays is difficult.In this study,we propose the use of the black resonance filter method and a CeBr_(3) scintillation detector to measure the characteristics of the in-beam gamma rays of Back-n.Four types of black resonance filters,^(181)Ta,^(59)Co,^(nat)Ag,and^(nat)Cd,were used in this measurement.The time-of-flight(TOF)technique was used to select the detector signals remaining in the absorption region of the TOF spectra,which were mainly induced by in-beam gamma rays.The energy distribution and flux of the in-beam gamma rays of Back-n were determined by analyzing the deposited energy spectra of the CeBr_(3) scintillation detector and using Monte Carlo simulations.Based on the results of this study,the background contributions from in-beam gamma rays in neutron-reaction measurements at Back-n can be reasonably evaluated,which is beneficial for enhancing both the experimental methodology and data analysis.展开更多
基金supported by the National Science Founda-tion of China(Grant No.11575165 and 11775200)
文摘Purpose The purpose of this work is to study the pulse shape,energy resolution,non-proportionality of energy response for gamma-rays,and time characteristics of CeBr_(3) detector.Method The time and energy responses of two CeBr_(3) detectors were characterized by an analog method and a digital method using a set of standardγ-ray sources.The pulse shape,energy resolution and non-proportionality(nPR)of energy response forγ-rays were characterized using the analog method.For the analog method,the high voltage applied to PMTs,parameters of walk and external delay of constant fraction discriminator were optimized.For the digital method,a CEAN 1729A digitizer with sampling frequency of 2 GS/s and resolution of 11 bit,and a digital constant fraction discrimination technique were used to study the time performance of the two CeBr_(3) detectors.Then,the coincidence time resolutions of the CeBr_(3) detectors for the gamma peaks of ^(22)Na and ^(60)Co were measured using the two methods.Results The t_(rise),lifetimeτ,t_(fall) for CeBr_(3)21^(#)and 22^(#)are 11.2 ns,23.8 ns,50.2 ns,and 10.4 ns,26.5 ns,58.6 ns,respectively.The measured non-proportionality of CeBr_(3)21^(#)and 22^(#)are 1.08%and 2.22%,respectively.The time resolutions of the two CeBr_(3) detectors are 244±2 ps and 248±3 ps at the energy peaks of ^(60)Co source,and 336±2 ps and 335±3 ps at 511 keV for the analog and the digital methods.Conclusions The time resolutions obtained by the analog method and the digital method are almost identical.The CeBr_(3) detector is a good option in the applications such as half-life measurements,ToF-PET and high counting rate conditions.Furthermore,it is a goodγ-ray spectrometer owing to the preferable energy resolution and non-internal activity.
基金supported by the Youth Talent Program of China National Nuclear Corporationthe Continuous-Support Basic Scientific Research Project(BJ010261223282)+1 种基金the National Natural Science Foundation of China(No.11790321)the Research and development project of China National Nuclear Corporation。
文摘The back-streaming white-neutron beamline(Back-n)of the China Spallation Neutron Source is an essential neutronresearch platform built for the study of nuclear data,neutron physics,and neutron applications.Many types of cross-sectional neutron-reaction measurements have been performed at Back-n since early 2018.These measurements have shown that a significant number of gamma rays can be transmitted to the experimental stations of Back-n along with the neutron beam.These gamma rays,commonly referred to as in-beam gamma rays,can induce a non-negligible experimental background in neutron-reaction measurements.Studying the characteristics of in-beam gamma rays is important for understanding the experimental background.However,measuring in-beam gamma rays is challenging because most gamma-ray detectors are sensitive to neutrons;thus,discriminating between neutron-induced signals and those from in-beam gamma rays is difficult.In this study,we propose the use of the black resonance filter method and a CeBr_(3) scintillation detector to measure the characteristics of the in-beam gamma rays of Back-n.Four types of black resonance filters,^(181)Ta,^(59)Co,^(nat)Ag,and^(nat)Cd,were used in this measurement.The time-of-flight(TOF)technique was used to select the detector signals remaining in the absorption region of the TOF spectra,which were mainly induced by in-beam gamma rays.The energy distribution and flux of the in-beam gamma rays of Back-n were determined by analyzing the deposited energy spectra of the CeBr_(3) scintillation detector and using Monte Carlo simulations.Based on the results of this study,the background contributions from in-beam gamma rays in neutron-reaction measurements at Back-n can be reasonably evaluated,which is beneficial for enhancing both the experimental methodology and data analysis.
