SNIP法在天然放射性核素γ能谱分析中的应用  

SNIP algorithms applied to analyze γ-ray spectra of natural radioactivity nuclides

作　　者：吴和喜[1,2] 刘庆成[1,2] 杨波[2] 刘玉娟[2] 

机构地区：[1]东华理工大学核资源与环境教育部重点实验室,南昌330013 [2]东华理工大学核工程技术学院,抚州344000

出　　处：《核技术》2010年第7期513-516,共4页Nuclear Techniques

基　　金：国防基础科研(A3420060145);江西省教育厅青年科学基金(GJJ10176);东华理工大学校长基金(DHXK0922)资助

摘　　要：介绍了全谱本底扣除(SNIP)法。研究表明,高次滤波函数或滤波窗口较窄的情况下,SNIP法能有效抑制康普顿散射的影响,并减弱本底峰、散射峰及屏蔽材料的特征X射线等本底因素的影响,但其同时会减少全能峰计数。而采用低次滤波函数或较宽的滤波窗口时,SNIP法不仅不能对本底计数起到有效的抑制作用,反而增加本底计数对全能峰计数的影响。通过实例分析,SNIP法能精确确定边界道;滤波窗口在很宽的变化范围内,SNIP法对天然放射性核素比活度分析精度均较高;在滤波窗口w=47-123时,采用4次滤波函数对天然放射性核素238U、232Th和40K比活度的测量结果总相对误差均小于8.5%。Sensitive nonlinear iterative peak algorithms were discussed and applied to analyze the background of full-energy spectra of the γ-ray in this article. Under high-order filtering or at narrow windows, SNIP algorithms can restrain the influence of Compton scattering greatly and decrease the background effect of backscattering peaks, background peaks and characteristic X-rays from the shielding material, but this reduces full-energy peak counts. On the other hand, the full-energy peak counts become larger than the actual value using low-order filtering or at wide windows. By analyzing the conditions of SNIP algorithms, one can locate the boundary of peaks accurately. High analytical accuracy of specific activity of natural radionuclides can be achieved by SNIP algorithms with the filtering window changing in a large scale. The total relative error for measuring natural radionuclide specific activity of ^23SU, ^232Th and ^40K is less than 8.5% using the fourth-order filtering at the window varying between 47 and 123.

关 键 词：SNIP法 抑制本底 全能谱 

分 类 号：TL84[核科学技术—核技术及应用]