基于离散小波变换的低水平α能谱光滑与评价  

Smoothing and evaluation of low level alpha spectra based on DWT method

作　　者：石睿[1] 庹先国[2,3] 张金钊[1] 李平川[1] 王旭[1] 刘明哲[1,2] 成毅[1] 

机构地区：[1]成都理工大学地学核技术四川省重点实验室,成都610059 [2]成都理工大学地质灾害防治与地质环境保护国家重点实验室,成都610059 [3]西南科技大学核废物与环境安全国防重点学科实验室,绵阳621010

出　　处：《核技术》2013年第12期7-11,共5页Nuclear Techniques

基　　金：国家自然科学基金(41025015;41374130);四川省青年科技创新研究团队(2011JTD0013);国家大学生创新创业项目(201210616005)资助

摘　　要：低水平α能谱测量中,由于α射线的统计涨落和探测器电子学电路的噪声,所得α能谱有严重的谱线噪声。为给精确的α能谱解谱工作做预处理,我们用基于金硅面垒探测器的便携式α能谱仪,在不同真空度下测量239Pu的α能谱,将离散小波变换法应用于α能谱去噪光滑处理,并提出光滑效果评价的新方法。结果表明,与传统多项式最小二乘法相比较,对低水平、高噪声的α能谱去噪,离散小波变换法效果更优。Background： The α particle has a strong ionization but weak penetration ability, and some factors, such as α radioactive source self-absorption, incomplete charge collection, electronic noise and statistical fluctuation, etc. have significant influence on the experimental α spectra synthetically, which can lead to a long tail at low-energy side and serious spectra noise. Purpose： The aim is to reduce the statistical fluctuation and electronics noise in detector, so as to preprocess data for the deconvolution of α spectra. Methods： In this study a portable α spectrometer with a Au-Si surface barrier detector was applied to obtain α spectra of 239Pu under vacuum conditions of -0.01 MPa, -0.02 MPa, -0.03 MPa, -0.04 MPa and -0.05 MPa. A discrete wavelet transform （DWT） method for α spectra smoothing and a new smoothing evaluation method were proposed, and tested on those spectra data for comparative study. Results： The results showed that DWT method had less damage on the peak compared with least squares polynomial smoothing method. The D（r） and ξ values of DWT were greater and x2 values were closer to 1 compared with those of least squares polynomial smoothing method. Conclusion： The DWT method is better than the traditional least squares polynomial smoothing method in smoothing low-level and high noise α spectra.

关 键 词：低水平α能谱 金硅面垒探测器 离散小波变换 光滑效果评价 

分 类 号：TL9[核科学技术]