KM2A(Kilometer-square Array)探测器阵列是LHAASO(Large High Altitude Air Shower Observatory)主体探测器阵列之一,7 000多个探测器和读出电子学在1 km2的实验范围内完全分离并均匀分布排列。在这样大型且分布不集中的高能物理实验中...KM2A(Kilometer-square Array)探测器阵列是LHAASO(Large High Altitude Air Shower Observatory)主体探测器阵列之一,7 000多个探测器和读出电子学在1 km2的实验范围内完全分离并均匀分布排列。在这样大型且分布不集中的高能物理实验中,简洁灵活可靠的电子学远程更新方案具有重要意义。KM2A读出电子学系统采用基于Multi Boot的远程更新方案,此方案实现了无需任何附加电路的远程更新及在线重加载,同时极大程度保证更新可靠性。展开更多
KM2A探测器阵列是高海拔宇宙线观测站(LHAASO)的主体探测器阵列之一,近7000个探测器平均分布在1.3 km 2的实验范围内。针对大面积分布式布局的高能物理实验中读出电子学系统的时间同步和数据传输问题,提出一种可实现高精度时间同步的数...KM2A探测器阵列是高海拔宇宙线观测站(LHAASO)的主体探测器阵列之一,近7000个探测器平均分布在1.3 km 2的实验范围内。针对大面积分布式布局的高能物理实验中读出电子学系统的时间同步和数据传输问题,提出一种可实现高精度时间同步的数据传输方法。借助TCP/IP协议栈和White Rabbit时钟同步技术融合时钟网络与数据网络,TCP/IP协议栈在仅保留PC通信协议的基础上,无需增加额外硬件,即可实现高效可靠的数据传输和高精度时钟同步。测试结果表明,该方法可以实现探测器阵列内LHAASO KM2A读出电子学插件间时间同步精度优于1 ns,同时保证了数据传输的可靠性。展开更多
介绍了大型高海拔空气簇射观测站(Large High Altitude Air Shower Observatory,LHAASO)空气簇射芯探测器阵列(Shower core detector array,SCDA)读出电子学方案的预研设计。系统采用基于电荷积分法的电荷测量方案,读出电子学通过同轴...介绍了大型高海拔空气簇射观测站(Large High Altitude Air Shower Observatory,LHAASO)空气簇射芯探测器阵列(Shower core detector array,SCDA)读出电子学方案的预研设计。系统采用基于电荷积分法的电荷测量方案,读出电子学通过同轴电缆接收光电倍增管输出的电流信号;采用在输入端与电荷积分放大器的虚地点之间接入等效50?电阻的终端阻抗匹配方案,并通过Pspice仿真验证该阻抗匹配的可行性。电路测试结果表明,该电路能满足远距离10 bit大动态范围电荷测量的设计指标要求。展开更多
Using e^(+)e^(−)annihilation data corresponding to an integrated luminosity of 2.93 fb^(−1)taken at the center-of-mass energy√s=3.773 GeV with the BESIII detector,a joint amplitude analysis is performed on the decays...Using e^(+)e^(−)annihilation data corresponding to an integrated luminosity of 2.93 fb^(−1)taken at the center-of-mass energy√s=3.773 GeV with the BESIII detector,a joint amplitude analysis is performed on the decays D^(0)→π^(+)π^(−)π^(+)π^(−)and D^(0)→π^(+)π^(−)π^(0)π^(0)(non-η).The fit fractions of individual components are obtained,and large interferences among the dominant components of the decays D^(0)→a_(1)(1260)π,D^(0)→π(1300)π,D^(0)→ρ(770)ρ(770),and D^(0)→2(ππ)_(S)are observed in both channels.With the obtained amplitude model,the CP-even fractions of D^(0)→π^(+)π^(−)π^(+)π^(−)and D^(0)→π^(+)π^(−)π^(0)π^(0)(non-η)are determined to be(75.2±1.1_(stat).±1.5_(syst.))%and(68.9±1.5_(stat).±2.4_(syst.))%,respectively.The branching fractions of D^(0)→π^(+)π^(−)π^(+)π^(−)and D^(0)→π^(+)π^(−)π^(0)π^(0)(non-η)are measured to be(0.688±0.010_(stat.)±0.010_(syst.))%and(0.951±0.025_(stat.)±0.021_(syst.))%,respectively.The amplitude analysis provides an important model for the binning strategy in measuring the strong phase parameters of D^(0)→4πwhen used to determine the CKM angleγ(ϕ_(3))via the B^(−)→DK^(−)decay.展开更多
文摘KM2A(Kilometer-square Array)探测器阵列是LHAASO(Large High Altitude Air Shower Observatory)主体探测器阵列之一,7 000多个探测器和读出电子学在1 km2的实验范围内完全分离并均匀分布排列。在这样大型且分布不集中的高能物理实验中,简洁灵活可靠的电子学远程更新方案具有重要意义。KM2A读出电子学系统采用基于Multi Boot的远程更新方案,此方案实现了无需任何附加电路的远程更新及在线重加载,同时极大程度保证更新可靠性。
文摘介绍了大型高海拔空气簇射观测站(Large High Altitude Air Shower Observatory,LHAASO)空气簇射芯探测器阵列(Shower core detector array,SCDA)读出电子学方案的预研设计。系统采用基于电荷积分法的电荷测量方案,读出电子学通过同轴电缆接收光电倍增管输出的电流信号;采用在输入端与电荷积分放大器的虚地点之间接入等效50?电阻的终端阻抗匹配方案,并通过Pspice仿真验证该阻抗匹配的可行性。电路测试结果表明,该电路能满足远距离10 bit大动态范围电荷测量的设计指标要求。
基金Supported in part by the National Key R&D Program of China(2020YFA0406300,2020YFA0406400)the National Natural Science Foundation of China(NSFC)(11625523,11635010,11735014,11835012,11935015,11935016,11935018,11961141012,12025502,12035009,12035013,12061131003,12105276,12122509,12192260,12192261,12192262,12192263,12192264,12192265,12221005,12225509,12235017)+15 种基金the Chinese Academy of Sciences(CAS)Large-Scale Scientific Facility Programthe CAS Center for Excellence in Particle Physics(CCEPP)Joint Large-Scale Scientific Facility Funds of the NSFC and CAS(U1732263,U1832103,U1832207,U2032111)CAS Key Research Program of Frontier Sciences(QYZDJ-SSW-SLH003,QYZDJ-SSW-SLH040)100 Talents Program of CASThe Institute of Nuclear and Particle Physics(INPAC)and Shanghai Key Laboratory for Particle Physics and CosmologyEuropean Union's Horizon 2020 research and innovation programme under Marie Sklodowska-Curie grant agreement(894790)German Research Foundation DFG(455635585),Collaborative Research Center CRC 1044,FOR5327,GRK 2149Istituto Nazionale di Fisica Nucleare,ItalyMinistry of Development of Turkey(DPT2006K-120470)National Research Foundation of Korea(NRF-2022R1A2C1092335)National Science and Technology fund of MongoliaNational Science Research and Innovation Fund(NSRF)via the Program Management Unit for Human Resources&Institutional Development,Research and Innovation of Thailand(B16F640076)Polish National Science Centre(2019/35/O/ST2/02907)The Swedish Research CouncilU.S.Department of Energy(DE-FG02-05ER41374)。
文摘Using e^(+)e^(−)annihilation data corresponding to an integrated luminosity of 2.93 fb^(−1)taken at the center-of-mass energy√s=3.773 GeV with the BESIII detector,a joint amplitude analysis is performed on the decays D^(0)→π^(+)π^(−)π^(+)π^(−)and D^(0)→π^(+)π^(−)π^(0)π^(0)(non-η).The fit fractions of individual components are obtained,and large interferences among the dominant components of the decays D^(0)→a_(1)(1260)π,D^(0)→π(1300)π,D^(0)→ρ(770)ρ(770),and D^(0)→2(ππ)_(S)are observed in both channels.With the obtained amplitude model,the CP-even fractions of D^(0)→π^(+)π^(−)π^(+)π^(−)and D^(0)→π^(+)π^(−)π^(0)π^(0)(non-η)are determined to be(75.2±1.1_(stat).±1.5_(syst.))%and(68.9±1.5_(stat).±2.4_(syst.))%,respectively.The branching fractions of D^(0)→π^(+)π^(−)π^(+)π^(−)and D^(0)→π^(+)π^(−)π^(0)π^(0)(non-η)are measured to be(0.688±0.010_(stat.)±0.010_(syst.))%and(0.951±0.025_(stat.)±0.021_(syst.))%,respectively.The amplitude analysis provides an important model for the binning strategy in measuring the strong phase parameters of D^(0)→4πwhen used to determine the CKM angleγ(ϕ_(3))via the B^(−)→DK^(−)decay.
