小型宇宙射线探测仪的模拟和测量

Simulation and Measurement of A Small Cosmic Ray Device

介绍了一款小型宇宙射线探测仪。该仪器具有宇宙射线科普演示功能,主要用于实时测量μ子射线并显示计数,以及长时间尺度下(年)稳定地对不同角度的次级宇宙线通量进行监控记录。简要地展示了探测器的硬件构造和探测效率的模拟计算。探测仪单个探测器的探测效率为93.1%,两个探测器符合测量的探测效率为86.6%。根据探测器的计数率以及模拟计算的探测效率,估计了次级宇宙射线垂直地面方向的通量,为J=29±3 m^(-2)sr^(-1)s^(-1)。另外,利用该宇宙射线探测仪,测量了兰州市区的次级宇宙射线的天顶角分布。其结果很好地满足I(θ)=IH+I0 cosαθ经验公式,其中的角度依赖参数α=2.42±0.52。

A small cosmic ray device is introduced in this paper. It has the demonstration function for popularization of science, and can be used mainly to display the μ counts in a real-time measurement, and to monitor the secondary cosmic ray flux at different angles in a very long time scale（years）. We briefly show the hardware of the device and the detecting efficiency calculation by simulation. The detecting efficiency for one detector of the device is 93.1%, and the detecting efficiency is 86.6% for the coincidence measurement of two detectors. Based on the count rate by the detector and the simulated efficiency, the secondary cosmic ray flux perpendicular to the ground surface is measured, which is J = 29 ± 3 m^-2sr^-1s^-1. Moreover, with an application of the device, we measured the angular distribution of the secondary cosmic ray rate in Lanzhou City.The resulting angular distribution agrees well with the empirical formula as I（θ） = IH ＋ I0 cos^αθ, in which the parameter for the angle-dependence is α = 2.42 ± 0.53.