北京谱仪端盖簇射计数器的能量分辨及其模拟研究

利用北京谱仪Ｊ／、Ｄｓ能量下端盖簇射计数器（ＥＳＣ）内的ｅ＋ｅ－末态事例，研究了电子簇射在ＥＳＣ中单个计数管的脉冲幅度分布、击中单元总数分布和各读出层的击中单元数分布、沉积能量分布和总沉积能量的分布；得到能量分辨约为２２％在ＳＯＢＥＲ程序框架的基础上采用双高斯分布描述单计数管脉冲幅度谱，ＥＧＳ４描述电磁簇射，考虑了三维磁场分布，完成了ＥＳＣ蒙特卡罗模拟程序，模拟结果与实验数据符合很好。

Energy resolution and Simulation for the ESC of BES

With data collected by the Beijing Spectmmeter (BES) in the J/, and Ds energy region, a lot of e e - final state evenb are selected in the solid angle region covered by the endcap shower counters (ESC). Some characteristics of the ESC are analysed, such as the spectrnun of pulse height for , a single counter cell, the hit nwnbers in the ESC and in every reading layer of the ESC, the shower energies deposited in the ESC and in every layer of the BSC. The energy resoiudon of the ESC in obtained to be about 22% Based on the odginal frame of SOBER, a Monte Carlo simulation program for the ESC is developed with a dual Gaussian pulse height spectrtun of the single counter cell. The electromagnetic cascades are calculated by the EGS4 package and a three-dimension magnetic field in the BES is included. The simulation results agree with experimented data well.