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1.
李文报道了用宇宙线带电粒子对北京谱仪(BES)桶部簇射计数器多项性能测试的结果,诸如从1到24层的信号电荷量谱;各层计数管的探测效率;信号电荷量在z向(沿丝方向)的均匀性;电荷分配法的z向分辨率;宇宙线径迹重建等.同时还讨论了该计数器工作气体的选择问题.  相似文献   

2.
研究了北京谱仪桶部簇射计数器的性能,对刻度和重建方法作了改进,更好地确定了z向位置坐标,改善了位置分辨率,给出了正确的簇射发展方向.  相似文献   

3.
在北京正负电子对撞机的J/ψ和Ds能区,选择了辐射巴巴事例,并以此来研究北京谱仪的桶部簇射计数器能量响应特性.在消除了由于电子和辐射光子在桶部簇射计数器中沉积能量区域重叠的影响后,正确地得到了桶部簇射计数器在电子和光子动量小于2GeV以下的能量响应,表明在所研究能区,桶部簇射计数器的能量响应线性很好.对桶部簇射计数器微小的非线性进行修正后,重建的π0不变质量谱得到改善.  相似文献   

4.
在甘巴拉山乳胶室中找到了天顶角tgθ>4的多核心簇射,对这类簇射产生的原因进行了讨论,这类事例预示在宇宙实验中可能存在着新现象.  相似文献   

5.
选取辐射Bhabha样本,研究了北京谱仪Ⅱ(BESⅡ)桶部簇射计数器(BSC)对中性径迹的沉积能量和空间位置的测量,定出了实际数据的测量误差.并利用Monte Carlo产生的e+e→γγ事例定出MC数据的能量及位置测量误差.结果已用于BESⅡ运动学拟合,能改善物理分析结果.  相似文献   

6.
本文用Monte Carlo方法研究西藏羊八井空气簇射阵列性能.确定好事例判选标准.簇射中心定位精度达3.4m.原初粒子到达方向角分辨率好于1.1°.原初粒子能量按lgE0=lg(0.45ΣNi)±0.226确定,其中E0(TeV)为初级入射粒子能量,ΣNi为FT探测器上探测到的粒子总数.  相似文献   

7.
描述了北京谱仪端盖簇射计数器的结构及制造工艺.并给出丝张力,暗电流、计数管工作特性等检测结果.  相似文献   

8.
寻找10TeV能区的γ射线暴   总被引:2,自引:0,他引:2  
利用西藏羊八井大气簇射实验数据,开展了对10TeV能区γ暴的全天区搜寻. 分析了4亿个簇射事例,找出在给定的时间间隔和给定的小天区内出现的簇射事例团. 采用等天顶角方法来估计背景. 有少量事例团显示了对背景的超出,但它们的显著性还不够高,尚不足以认定为γ暴. 讨论了羊八井二期阵列实验对寻找10TeVγ暴所具有的高灵敏度.  相似文献   

9.
本文报告了12A GeV α粒子与乳胶作用次级粒子多得数分布以及簇射粒子与重电离粒子之间的关联,得出随着族射粒子数的增加,重电离粒子平均多重数也随着增加.  相似文献   

10.
BES桶部簇射计数器的设计与建造   总被引:2,自引:2,他引:0  
本文描述了北京谱仪(BES)桶部簇射计数器(BSC)的设计与建造.桶部簇射计数器为圆桶形,内径2.5m;外径3.4m;长3.85m,承重铝桶直径为2.5m;厚3cm;长4.23m.由23层铅(每层0.5r.l.)和24层自猝灭流光(SQS)管组成,重40吨,覆盖立体角为4π×80%.  相似文献   

11.
BEPCⅡ上正在进行激光丝系统的研究。基于GEANT4对激光丝系统探测器进行了模拟。首先模拟了康普顿散射信号在探测器材料中电磁簇射的分布,确定了探测器初始尺寸。之后模拟了不同尺寸下探测器的输出,根据模拟结果确定了探测器的最终尺寸,使得探测器在所确定的尺寸有较大的信号输出。还进行了不同康普顿散射位置时探测器的响应模拟,结果表明束流管道的影响是不可忽略的,是探测器响应非线性的主要原因,预计该结果对束流截面测量有重要意义。最后简要介绍了BEPCⅡ几种可能的束流能量时,探测器信号输出和能量泄漏的模拟结果。  相似文献   

12.
In this paper, we studied the development of hadronic shower in an electromagnetic calorimeter of Alpha Magnetic Spectrometer Ⅱ. Two parametrized empirical formulae were proposed to describe the hadronic shower shape in calorimeter. Using 100 GeV proton beam incident on the center of the ECAL, detailed plots of lateral and longitudinal hadronic shower behavior were given and we found the formulae can describe the development of the hadronic shower with the test beam data. The possible application of the parametrized formulae including e±± discrimination and tau jet reconstruction was discussed.  相似文献   

13.
羊八井ARGO实验初期阵列性能   总被引:1,自引:0,他引:1  
中意合作羊八井ARGO实验采用大型RPC阵列探测广延大气簇射事例,本文报告了该探测阵列初期建设进展状况及测试运行的包含16个CLUSTER的局部阵列性能,并探讨由此阵列所采集数据重建后的事例芯位、到达方向与角分辨等.初步测试结果表明RPC阵列可很好地在高海拔、低气压条件下正常运行.  相似文献   

14.
A Bhadra 《Pramana》1999,52(2):133-144
The variation of lateral shower age parameter with zenith angle for different shower size ranges is studied. The observed variation is in agreement with the electron-photon cascade theory and with the other EAS observations. It is found that up to zenith angle 30°, shower ‘age’ is practically independent of zenith angle. So it is difficult to correlate the reported high ‘age’ value of the excess showers from the direction of plausible point sources with zenith angle. The change in the value of shower age with atmospheric depth is studied and is found to be consistent with the prediction of cascade theory and simulation results. From the study of the variation of shower age with shower size for two different zenith angle intervals it is found that the shower age decreases with size but the rate of change of shower age decreases at higher sizes.  相似文献   

15.
An empirical approach is presented for reconstruction of the extensive air shower (EAS) cascade curve according to data of the Cherenkov track detector. The proposed method, unlike conventional ones, is based on experimentally measured parameters and on calculated values which weakly depend on the model of shower development.  相似文献   

16.
Summary We describe a method of analysis for the reconstruction of the arrival direction of a high-energy photon impacting on the top of the atmosphere by using the directions of the particles on the shower front as measured by a ground-based array of tracking chambers uniformly distributed on a square surface; as an example, an array with enclosed surface of (120×120) m2 has been considered. Estimates on the accuracy of reconstruction are given, after application of the method to computer-simulated shower directions as a function of the number of ?smapling? detectors and of their accuracy in the measurement of the ?local? shower direction. Paper presented at the V Cosmic Physics National Conference, S. Miniato, November 27–30, 1990.  相似文献   

17.
A technique for measuring the cascade shower energy in the NEVOD Cherenkov water detector with a spatial lattice of quasi-spherical modules is discussed. The technique allows the number of cascade particles that move near the shower axis to be reconstructed on the basis of analysis of response amplitudes of triggered photomultiplier tubes. The technique of cascade-curve reconstruction was applied to cascade showers generated by near-horizontal high-energy muons extracted by means of the DECOR coordinate-tracking detector arranged around the Cherenkov water detector. The first results of measuring the energy spectrum of cascade showers of 10–1000 GeV are presented.  相似文献   

18.
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。  相似文献   

19.
利用部分子在热密QCD介质中的辐射谱, 研究部分子在热密介质中的演化规律. 研究结果表明, 在相同能量下介质诱导效应使得部分子在介质中的劈裂几率大于部分子在真空中的劈裂几率; 高密度介质中的部分子劈裂几率大于低密度介质中的劈裂几率. 本文研究结果与美国BNL/RHIC相对论重离子碰撞实验中观测到的高横动量强子产额压低现象一致, 揭示了在RHIC能区已经生成高温高密物质.  相似文献   

20.
The electromagnetic calorimeter(ECAL) of the Alpha Magnetic Spectrometer(AMS-02) is one of the key detectors for dark matter searches. It measures the energies of electrons, positrons and photons and seperates them from hadrons. Currently, there are 5 dead cells in the ECAL, which affect the reconstructed energy of 4.2%of total events in the ECAL acceptance. When an electromagnetic shower axis is close to the ECAL border, due to the side leakage, the reconstructed energy is affected as well. In this paper, methods for dead cells and side leakage corrections for the ECAL energy reconstruction are presented. For events with the shower axis crossing dead cells,applying dead cell correction improves the difference in the reconstructed energy from 12% to 1%, while for events near the ECAL border, with side leakage correction it is improved from 4% to 1%.  相似文献   

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