Unified description of angular distributions of target particles in light and heavy ion induced interactions in nuclear emulsions at high energies

Some investigations show that in light ion （LI） induced reactions, such as He, O, Ne, and Ar in nuclear emulsions （Em） at high energies, the angular distributions of the target particles show a wide structure around the polar angle V ≈ 60°. With heavy ions （HI） such as Kr and Au such a wide structure has not been observed. The experimental results on Mg-Em and Si-Em interactions also do not show such a wide structure in the angular distribution of the target particles. Using a multisource ideal gas model we uniformly describe the angular distributions of the target particles produced in LI-Em and HI-Em interactions. The result is not only in agreement with the mean trend, but also with the fluctuations of the experimental data. We conclude that the wide structure observed in LI-Em interactions may be the result of statistical fluctuations.

多功能旋转靶装置研究

针对D-D中子发生器采用静态水冷靶时中子产额不稳定、中子产额持续下降等主要问题,研制了一套多功能紧凑型旋转靶装置。装置采用一体化设计,结构紧凑、尺寸小,具备靶体高速旋转和水冷、靶点可视化监测、靶面温度实时测量、中子产额实时监测等功能。本文介绍了该装置的主体结构、功能设计和性能测试,以及靶结构对中子散射影响的模拟计算。性能测试结果表明,该装置真空度满足加速器运行要求,相比静态水冷靶,束流靶点中心最高温度明显降低,中子产额稳定度明显提高。模拟计算结果显示中子能谱峰展宽范围为0~0.0577 MeV,散射中子占比为10.53%~26.75%。本文还针对模拟计算结果和测量结果中存在的问题进行了分析,提出了改进和优化方案。

基于C语言模拟计算的cdPCR最佳反应通孔数分析

利用C语言能够模拟芯片数字PCR中目的核酸(或目标粒子)进入反应通孔的计算过程,从而可以对干扰粒子对目的核酸分布的影响、检测目的核酸的最佳反应通孔数、目的核酸分布均匀性等问题进行分析与计算。结果表明:(1)无论有无干扰粒子或其存在多少,目标粒子都将具有基本相同的N-Y(入洞总数-出现次数)曲线分布;(2)检测目标粒子的最佳反应通孔数与目标粒子数之比为8∶1或9∶1;(3)当目标粒子数为1000时,最佳反应通孔数为8000或9000,而对应的目标粒子分布均匀性为94.0%或94.6%。基于C语言的统计分析不仅能方便、快捷地完成对任一随机过程的模拟计算,同时能够为数字PCR的芯片设计提供准确的参数依据与理论指导。