The building of a large-scale external-target experiment, abbreviated as CEE, in the cooling storage ring at the Heavy Ion Research Facility in Lanzhou has been planned. The CEE is a multi-purpose spectrometer that wi...The building of a large-scale external-target experiment, abbreviated as CEE, in the cooling storage ring at the Heavy Ion Research Facility in Lanzhou has been planned. The CEE is a multi-purpose spectrometer that will be used for various studies on heavy-ion collisions. A multi-wire drift chamber(MWDC) array is the forward tracking detector of the CEE. In this work, GEANT4 simulations were performed for the MWDC forward tracking array with a focus on the track reconstruction algorithm. Combined with the time of flight information,particle identification is achieved. The residue is about 30 μm, while the tracking efficiency is higher than 90%with the current redundancy. In addition, a prototype of the forward tracking system using three MWDCs was assembled and tested using a high-energy proton beam. The firing efficiency of the detector and the reconstruction accuracy of the prototype were derived. The track residue for the protons at about 400 MeV/c is better than 300 μm, meeting the requirements of the CEE. Suggestions for improving the performance of the forward tracking system are given.展开更多
为研究含短贯通导体金属腔体在平面波辐射条件下内部电磁耦合规律,利用电磁数值计算软件CST建立了含短贯通导体金属腔体电磁辐射耦合模型,研究了加载短贯通导体对开孔金属腔体内部屏蔽效能的影响。并基于GHz横电磁波室(gigahertz transv...为研究含短贯通导体金属腔体在平面波辐射条件下内部电磁耦合规律,利用电磁数值计算软件CST建立了含短贯通导体金属腔体电磁辐射耦合模型,研究了加载短贯通导体对开孔金属腔体内部屏蔽效能的影响。并基于GHz横电磁波室(gigahertz transverse electromagnetic cell,GTEM)搭建了含短贯通导体金属腔体电磁耦合实验平台,对数值计算结果进行了实验验证。同时分析了平面波辐射条件下贯通导体长度、贯通导体半径、贯通孔尺寸、电场极化方向等参数对内部电磁耦合的影响规律,揭示了短贯通导体引入电磁干扰的耦合机理。结果表明:当屏蔽效能为40 d B的开孔腔体加载短贯通导体后,腔体内部屏蔽效能明显下降,屏蔽效能最小值达到-15.29 d B;腔体外部裸露贯通导体长度增大3 cm,腔体的屏蔽效能降低约4 d B;腔体内部贯通导体长度主要影响腔体的谐振频点;贯通导体长度不变而内外部分长度变化时,腔体屏蔽效能和谐振频点均发生变化;贯通孔尺寸增大,导致腔体内部屏蔽效能下降;测试点距离贯通导体越远,屏蔽效果越好;贯通导体半径能够影响屏蔽效能和腔体谐振频点;腔体壁厚度每增加0.3 cm,谐振频率增大约8 MHz;平行于贯通导体的电场分量越大,腔体屏蔽效能越差。展开更多
基金supported by the National Basic Research Program of China(973)(No.2015CB856903)the National Science Foundation of China(No.U1332207)
文摘The building of a large-scale external-target experiment, abbreviated as CEE, in the cooling storage ring at the Heavy Ion Research Facility in Lanzhou has been planned. The CEE is a multi-purpose spectrometer that will be used for various studies on heavy-ion collisions. A multi-wire drift chamber(MWDC) array is the forward tracking detector of the CEE. In this work, GEANT4 simulations were performed for the MWDC forward tracking array with a focus on the track reconstruction algorithm. Combined with the time of flight information,particle identification is achieved. The residue is about 30 μm, while the tracking efficiency is higher than 90%with the current redundancy. In addition, a prototype of the forward tracking system using three MWDCs was assembled and tested using a high-energy proton beam. The firing efficiency of the detector and the reconstruction accuracy of the prototype were derived. The track residue for the protons at about 400 MeV/c is better than 300 μm, meeting the requirements of the CEE. Suggestions for improving the performance of the forward tracking system are given.
文摘为研究含短贯通导体金属腔体在平面波辐射条件下内部电磁耦合规律,利用电磁数值计算软件CST建立了含短贯通导体金属腔体电磁辐射耦合模型,研究了加载短贯通导体对开孔金属腔体内部屏蔽效能的影响。并基于GHz横电磁波室(gigahertz transverse electromagnetic cell,GTEM)搭建了含短贯通导体金属腔体电磁耦合实验平台,对数值计算结果进行了实验验证。同时分析了平面波辐射条件下贯通导体长度、贯通导体半径、贯通孔尺寸、电场极化方向等参数对内部电磁耦合的影响规律,揭示了短贯通导体引入电磁干扰的耦合机理。结果表明:当屏蔽效能为40 d B的开孔腔体加载短贯通导体后,腔体内部屏蔽效能明显下降,屏蔽效能最小值达到-15.29 d B;腔体外部裸露贯通导体长度增大3 cm,腔体的屏蔽效能降低约4 d B;腔体内部贯通导体长度主要影响腔体的谐振频点;贯通导体长度不变而内外部分长度变化时,腔体屏蔽效能和谐振频点均发生变化;贯通孔尺寸增大,导致腔体内部屏蔽效能下降;测试点距离贯通导体越远,屏蔽效果越好;贯通导体半径能够影响屏蔽效能和腔体谐振频点;腔体壁厚度每增加0.3 cm,谐振频率增大约8 MHz;平行于贯通导体的电场分量越大,腔体屏蔽效能越差。
