蒙特卡罗模拟技术可以有效提高核辐射探测分析效率、 降低分析成本, 在促进X荧光分析技术发展过程中也发挥了重要作用。 在应用蒙特卡罗模拟能量色散X荧光分析中, 为使蒙特卡罗模拟元素特征X射线注量谱与实验能谱之间的物理差异更小, 提出了一种模拟注量展宽算法。 首先依据离散统计物理理论, 建立了Si-PIN半导体探测器对X射线的响应函数模型, 并利用加权非线性最小二乘法拟合得到各系数, 再对系数进行归一化处理, 得到归一化后的响应函数R(E, E′)。 然后利用R(E, E′)对模拟注量进行展宽转换, 得到脉冲幅度谱(pulse height spectrum, PHS), 使模拟谱更趋近于实验谱, 这样就可以通过蒙特卡罗模拟得到与实测能谱一致性较高的模拟能谱。 研究中最后利用建立的探测器响应函数模型对Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Sn元素K系全能峰拟合χ2r值在1.04～1.18范围内, 对铜合金样品中六种元素特征X射线模拟注量转换结果与实验值一致性较好, 并实现了对多元素混合样品复杂重迭谱的有效模拟和展宽。

In the present study, a kind of broadening algorithm method for simulated spectrum was developed by using the detector response function (DRF), which can be used to reduce the differences between Monte Carlo simulated element characteristic X-ray spectrum and experimental spectrum. First of all, based on in-depth study on previous works of others, we established a kind of detector response function model with strong generality for Si-PIN semiconductor detector. Weighted nonlinear least-square method is used to fit the X-ray spectrum of standard single element, and parameters can be obtained simultaneously. Then these parameters are normalized to get the normalized response function R(E, E′), which will be used to broaden the simulated flux spectrum. Secondly, R(E, E′) is used to broaden and transform the simulated flux spectrum. Then pulse height spectrum (PHS) is obtained to match experiment spectrum. This procedure can obtain the X-ray spectrum conveniently only by using MCNP simulation; moreover, simulated spectrum and experimental spectrum have high consistency. Finally, the simulated spectrum was achieved to match the experimental spectrum. Ten elements (Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As and Sn) K doublet X-ray full energy peak was fitted by the proposed DRF model, and reduced chi-square values for each were in the range of 1.04～1.18. The simulated flux spectrum of a copper alloy sample containing six kinds of elements was transformed and matched the experimental spectrum really well, and the complex overlapped spectrum was resolved.