宇宙射线缪子散射成像领域通常聚焦于提升成像区域的图像质量,对于其他区域的成像点及入射粒子各成分占比,尚缺乏系统的讨论。本文系统研究了海平面宇宙射线对缪子散射成像测量的影响。通过对PoCA(Point of Closest Approach)算法重建...宇宙射线缪子散射成像领域通常聚焦于提升成像区域的图像质量,对于其他区域的成像点及入射粒子各成分占比,尚缺乏系统的讨论。本文系统研究了海平面宇宙射线对缪子散射成像测量的影响。通过对PoCA(Point of Closest Approach)算法重建结果的分析,发现探测器区域内出现的PoCA点聚集并非单纯背景噪声,而是具有特定物理起源的系统性信号,主要源于宇宙射线在探测系统上方材料中相互作用产生的次级粒子,其在探测器中的记录会引发虚假位置信号,进而对散射重建产生显著影响。结合Geant4与CRY(Cosmicray Shower Generator)程序开展蒙特卡洛模拟,定量研究了该效应对覆盖材料种类与面密度的依赖性。在此基础上,进一步利用灵敏区内事例的散射角分布,通过多模板联合拟合方法对海平面宇宙射线粒子成分进行了测定。结果表明,缪子仍占主导地位,电子成分可被约束在百分之几的水平。因此,缪子散射探测系统不仅可用于目标成像,也可为海平面宇宙射线研究与本底扣除提供重要参考。展开更多
We present the results of an experiment conducted to measure cosmic-ray muons and muon-induced fluxes at the China Jinping Underground Laboratory.Utilizing a 28-L 0.5%gadolinium-doped liquid scintillator detector,whic...We present the results of an experiment conducted to measure cosmic-ray muons and muon-induced fluxes at the China Jinping Underground Laboratory.Utilizing a 28-L 0.5%gadolinium-doped liquid scintillator detector,which operated stably for 412 days in a 1-m-thick polyethylene shielding,we reconstructed saturated signal pulses and pulse shape discrimination to facilitate measurements across a range starting from 0.2 MeV.The event rates incorporating the mountain geometry effects for cosmic rays and their induced particles were derived.The experimental results show that the cosmic ray muon flux is(3.64±0.69stat.±0.25syst.)×10−10cm−2s−1,muon-induced electron flux is(5.59±1.06stat.±0.40syst.)×10−10cm−2s−1,and the upper limit of the muon-induced neutron flux was 3.52×10−9cm−2s−1.They indicated that no significant excess was observed at a 90%confidence level,and no muon-induced neutrons above 10 MeVee were detected.展开更多
The precise measurement of the cosmic ray composition is a key objective of ground-based cosmic ray experiments.The primary challenge arises due to the significant uncertainties in high-energy hadronic interaction mod...The precise measurement of the cosmic ray composition is a key objective of ground-based cosmic ray experiments.The primary challenge arises due to the significant uncertainties in high-energy hadronic interaction models.These models not only affect the theoretical description of the propagation and evolution of cosmic rays in the atmosphere,but also directly determine the physical interpretation of experimental observations.As one of the principal secondary particles produced in hadronic cascades,muons retain substantial information from the primary interactions owing to their strong penetrating power and small interaction cross-section with matter.This makes them an effective probe for validating hadronic interaction models.In this study,based on the air shower data acquired by Yangbajing hybrid array,a high-statistics measurement of the muon component in cosmic-rayinduced events was performed.Subsequent systematic comparisons between the experimental observations and predictions of major existing hadronic interaction models revealed overall consistency within the“knee”of the cosmic ray energy spectrum,thereby supporting the basic validity of existing models in this range.Additionally,the results of combined spectral and compositional analyses indicated a transition in cosmic ray mass composition around the“knee,”shifting from light-nuclei dominance to heavy-nuclei dominance.The findings of our study provide important insights into the applicability of hadronic interaction models in the TeV–PeV energy range and offer observational evidence for understanding not only the physical origin of the"knee"in the cosmic ray energy spectrum but also its compositional evolution mechanisms.展开更多
Gsmic rays (CRs) have long puzzled scientists.What kind of drastic physical processes could have produced these highly energetic particles?How come the flux of them drops severely at energies beyond 3peta-electrovolt ...Gsmic rays (CRs) have long puzzled scientists.What kind of drastic physical processes could have produced these highly energetic particles?How come the flux of them drops severely at energies beyond 3peta-electrovolt (PeV,or 1015 eV),forming a knee-like bend?Two papers respectively published on November 16 and November 17 gave the answer.展开更多
We investigate the relationship between the magnitudes of Forbush decreases(FDs)and solar-geomagnetic characteristics using daily-averaged galactic cosmic ray(GCR)data from Inuvick(INVK)and Magadan(MGDN)neutron monito...We investigate the relationship between the magnitudes of Forbush decreases(FDs)and solar-geomagnetic characteristics using daily-averaged galactic cosmic ray(GCR)data from Inuvick(INVK)and Magadan(MGDN)neutron monitor(NM)stations to aid in counting the case of GCR flux intensity modulation.The FDs,obtained with an automated new computer software algorithm from daily-averaged GCR data from the IZMIRAN common website:http://gffzz50888dfc0201490fh0k06qfcqbv506b5n.ffgz.tsg.suse.edu.cn/common,at INVK(224)and MGDN(229)NM stations,from 1998 to 2002,were used in the present work.The associated solar-geomagnetic parameters of the same time range were obtained from the OMNI website.A statistical analytical method was employed to test the link between FD amplitudes and solargeomagnetic variables.We observed negative trends in FD-IMF,FD-SWS,FD-Kp,FD-SSN and FD-SI,while a positive relation was indicated in FD-Dst at both stations.All are statistically significant at a 95%confidence level.The results obtained here imply that solar emission characteristics impact the GCR flux intensity modulation.展开更多
The high-energy cosmic radiation detector(HERD)is a planned experimental instrument at the Chinese Space Station.The silicon charge detector(SCD),a subdetector in HERD,is used to detect cosmic-ray nuclei with a high c...The high-energy cosmic radiation detector(HERD)is a planned experimental instrument at the Chinese Space Station.The silicon charge detector(SCD),a subdetector in HERD,is used to detect cosmic-ray nuclei with a high charge resolution.In this study,we present a compact readout electronic system for the SCD that is designed for the HERD heavy-ion beam test.It comprises front-end readout electronics with 200 input channels as well as data acquisition and data management electronics.The test results showed that the SCD readout system had low noise with a silicon-strip detector connected.The dynamic range could be extended from 200 to 1200 fC,and the cosmic-ray test was performed as expected.展开更多
Intrinsic radiation of materials is one of the major backgrounds for many rare-event search experiments.Thus,the production of pure materials in an underground laboratory is a promising approach for eliminating cosmog...Intrinsic radiation of materials is one of the major backgrounds for many rare-event search experiments.Thus,the production of pure materials in an underground laboratory is a promising approach for eliminating cosmogenic radionuclides.In this paper,we demonstrate a procedure to evaluate the yields of cosmogenic radionuclides in copper and germanium in the second phase of the China Jinping Underground Laboratory.Our results show that for copper and germanium materials,the largest cosmogenic background comes from 3 H and57,58,60Co,and 3 H and 68Ge,respectively,which all have yields on the order of 10-7 kg-1 day-1.The corresponding radioactivities after 90 days pf exposure underground are estimated to be lower than 10-6μBq kg-1.展开更多
高海拔宇宙线观测站(Large High Altitude Air Shower Observatory,LHAASO)是"十二五"批复立项的国家重大科技基础设施,是我国海拔最高的大科学基础设施之一,核心目标是探索高能宇宙线。作为LHAASO的重要组成,地面簇射粒子阵...高海拔宇宙线观测站(Large High Altitude Air Shower Observatory,LHAASO)是"十二五"批复立项的国家重大科技基础设施,是我国海拔最高的大科学基础设施之一,核心目标是探索高能宇宙线。作为LHAASO的重要组成,地面簇射粒子阵列(square KiloMeter detector Array,KM2A)建成探测阵列面积高达1 km^2。不同于大多高能物理实验,KM2A共约6 500路通道,总输入约546 MB·s-1,没有硬件触发功能,因此,需要软件完成触发与数据处理。采用基于标准以太网和TCP/IP协议的数据传输方案,接收包括所有探测器单元同一时间的全部组包数据,利用配置的触发算法对数据包进行在线处理与计算,将具有物理意义的数据提取、打包,组成不同的有物理标签的事例,并按照配置的输出规则将这些事例送出至不同的接收方,实现了实时分布式算法调度与数据处理。软件可以实时触发筛选,降低数据量,减轻传输与存储的负担。软件已在4 410 m海拔实验现场的数据中心投入使用,至今为止一直运行良好。展开更多
基金supported by the National Key Research and Development Program of China(No.2023YFA1607103)the National Natural Science Foundation of China(Nos.11975159 and 11975162).
摘要We present the results of an experiment conducted to measure cosmic-ray muons and muon-induced fluxes at the China Jinping Underground Laboratory.Utilizing a 28-L 0.5%gadolinium-doped liquid scintillator detector,which operated stably for 412 days in a 1-m-thick polyethylene shielding,we reconstructed saturated signal pulses and pulse shape discrimination to facilitate measurements across a range starting from 0.2 MeV.The event rates incorporating the mountain geometry effects for cosmic rays and their induced particles were derived.The experimental results show that the cosmic ray muon flux is(3.64±0.69stat.±0.25syst.)×10−10cm−2s−1,muon-induced electron flux is(5.59±1.06stat.±0.40syst.)×10−10cm−2s−1,and the upper limit of the muon-induced neutron flux was 3.52×10−9cm−2s−1.They indicated that no significant excess was observed at a 90%confidence level,and no muon-induced neutrons above 10 MeVee were detected.
基金supported by the Science and Technology Projects of Xizang Autonomous Region(grant No.00061422)the Central Government Funds for Local Scientific and Technological Development(grant No.XZ202301JD0002G)the Central Government Funds for the Reform and Development of Local Colleges and Universities(No.00061082)。
摘要The precise measurement of the cosmic ray composition is a key objective of ground-based cosmic ray experiments.The primary challenge arises due to the significant uncertainties in high-energy hadronic interaction models.These models not only affect the theoretical description of the propagation and evolution of cosmic rays in the atmosphere,but also directly determine the physical interpretation of experimental observations.As one of the principal secondary particles produced in hadronic cascades,muons retain substantial information from the primary interactions owing to their strong penetrating power and small interaction cross-section with matter.This makes them an effective probe for validating hadronic interaction models.In this study,based on the air shower data acquired by Yangbajing hybrid array,a high-statistics measurement of the muon component in cosmic-rayinduced events was performed.Subsequent systematic comparisons between the experimental observations and predictions of major existing hadronic interaction models revealed overall consistency within the“knee”of the cosmic ray energy spectrum,thereby supporting the basic validity of existing models in this range.Additionally,the results of combined spectral and compositional analyses indicated a transition in cosmic ray mass composition around the“knee,”shifting from light-nuclei dominance to heavy-nuclei dominance.The findings of our study provide important insights into the applicability of hadronic interaction models in the TeV–PeV energy range and offer observational evidence for understanding not only the physical origin of the"knee"in the cosmic ray energy spectrum but also its compositional evolution mechanisms.
摘要Gsmic rays (CRs) have long puzzled scientists.What kind of drastic physical processes could have produced these highly energetic particles?How come the flux of them drops severely at energies beyond 3peta-electrovolt (PeV,or 1015 eV),forming a knee-like bend?Two papers respectively published on November 16 and November 17 gave the answer.
摘要We investigate the relationship between the magnitudes of Forbush decreases(FDs)and solar-geomagnetic characteristics using daily-averaged galactic cosmic ray(GCR)data from Inuvick(INVK)and Magadan(MGDN)neutron monitor(NM)stations to aid in counting the case of GCR flux intensity modulation.The FDs,obtained with an automated new computer software algorithm from daily-averaged GCR data from the IZMIRAN common website:http://gffzz50888dfc0201490fh0k06qfcqbv506b5n.ffgz.tsg.suse.edu.cn/common,at INVK(224)and MGDN(229)NM stations,from 1998 to 2002,were used in the present work.The associated solar-geomagnetic parameters of the same time range were obtained from the OMNI website.A statistical analytical method was employed to test the link between FD amplitudes and solargeomagnetic variables.We observed negative trends in FD-IMF,FD-SWS,FD-Kp,FD-SSN and FD-SI,while a positive relation was indicated in FD-Dst at both stations.All are statistically significant at a 95%confidence level.The results obtained here imply that solar emission characteristics impact the GCR flux intensity modulation.
基金supported by the CNSA program(D050102)National Natural Science Foundation of China(Nos.12061131007,12003038,42365006)Young Scientists Fund of the National Natural Science Foundation of China(No.11903037).
摘要The high-energy cosmic radiation detector(HERD)is a planned experimental instrument at the Chinese Space Station.The silicon charge detector(SCD),a subdetector in HERD,is used to detect cosmic-ray nuclei with a high charge resolution.In this study,we present a compact readout electronic system for the SCD that is designed for the HERD heavy-ion beam test.It comprises front-end readout electronics with 200 input channels as well as data acquisition and data management electronics.The test results showed that the SCD readout system had low noise with a silicon-strip detector connected.The dynamic range could be extended from 200 to 1200 fC,and the cosmic-ray test was performed as expected.
基金supported by the National Natural Science Foundation of China(No.U1865205).
摘要Intrinsic radiation of materials is one of the major backgrounds for many rare-event search experiments.Thus,the production of pure materials in an underground laboratory is a promising approach for eliminating cosmogenic radionuclides.In this paper,we demonstrate a procedure to evaluate the yields of cosmogenic radionuclides in copper and germanium in the second phase of the China Jinping Underground Laboratory.Our results show that for copper and germanium materials,the largest cosmogenic background comes from 3 H and57,58,60Co,and 3 H and 68Ge,respectively,which all have yields on the order of 10-7 kg-1 day-1.The corresponding radioactivities after 90 days pf exposure underground are estimated to be lower than 10-6μBq kg-1.
摘要高海拔宇宙线观测站(Large High Altitude Air Shower Observatory,LHAASO)是"十二五"批复立项的国家重大科技基础设施,是我国海拔最高的大科学基础设施之一,核心目标是探索高能宇宙线。作为LHAASO的重要组成,地面簇射粒子阵列(square KiloMeter detector Array,KM2A)建成探测阵列面积高达1 km^2。不同于大多高能物理实验,KM2A共约6 500路通道,总输入约546 MB·s-1,没有硬件触发功能,因此,需要软件完成触发与数据处理。采用基于标准以太网和TCP/IP协议的数据传输方案,接收包括所有探测器单元同一时间的全部组包数据,利用配置的触发算法对数据包进行在线处理与计算,将具有物理意义的数据提取、打包,组成不同的有物理标签的事例,并按照配置的输出规则将这些事例送出至不同的接收方,实现了实时分布式算法调度与数据处理。软件可以实时触发筛选,降低数据量,减轻传输与存储的负担。软件已在4 410 m海拔实验现场的数据中心投入使用,至今为止一直运行良好。