基于蒙特卡罗模拟方法的多能X射线二次转换靶研究

Research on Pluripotent X-Ray Quadratic Transformation Based on Monte Carlo Simulation Method

在X荧光分析中,大多数二次转换靶由纯元素组成,每次测量针对待测样品中一种元素的特征谱,而为了对样品中各种元素进行测量,需要多次更换靶材.基于计算粒子输运过程的蒙特卡罗模拟方法实现对多能X射线二次转换靶的研究,该多能二次转换靶的靶材可以由2种及以上元素组成,每种靶材元素都能产生相应的特征X射线,能够实现对2种及以上元素的同时测量.以同时测量大米中的元素Cd和As为例,建立透射靶激发装置模型.模拟实验结果可知,转换靶中元素的面积越大,则对应激发的待测元素特征X射线的计数率越高,相当于通过损失单一元素转换靶对应待测元素的计数率来实现提高多能转换靶对应多种待测元素计数率的最低值.该多能X射线二次转换靶为减少测量的时间和次数且实现多种元素的同时测量提供了参考.

In X-Ray fluorescence analysis,most of the secondary transformation target is composed of pure elements.Each time the measurement aims at the characteristic spectrum of an element of the sample that is going to be tested.In order to measure various elements in the samples,the target material needs to be changed for many times.Based on the MCNP simulation method,the paper studies the pluripotent X-Ray quadratic transformation target.The pluripotent quadratic transformation target material is composed of two or more elements,and each element of target material can produce a corresponding characteristic X-Ray,and can realize the simultaneous measurement of two or more elements.To simultaneously measure the elements Cd and As in the rice,for example,transmission target excitation device model is established.The simulation results show that the area of the elements in the tranformation target is larger,the count rate of the corresponding characteristic X-Ray to be tested and excited is higher.This means that by losing the count rate of the element under test that corresponds to the single element transformation target,the lowest count rate of various elements under test that corresponds to the pluripotent transformation target can be obtained.This paper provides reference for the simultaneous measurement of multi-elements and also for the way to reduce the time and frequency of measurement for the X-Ray quadratic transformation target.