若能量分辨率不足、对核素的识别能力较差,就需解析仪器谱。本文采用极大似然估计法,对NaI(Tl)探测的仪器谱进行解析。通过对合成谱线的解析,结果表明,该方法可以有效地分解能量差2/3 FHWM重叠峰。将该方法应用到野外γ能谱仪的标定中,在混合模型上的检验结果表明,采用极大似然估计法进行能谱解析,建立含量和净峰面积之间的正比关系,可有效提高野外γ能谱仪对U、Th、K测量精度。
NaI(Tl) detectors,having a good detection efficiency,are used to detect gamma rays in field surveys.But the poor energy resolution hinders their applications,despite the use of traditional methods to resolve the overlapped gamma-ray peaks.In this paper,the maximum likelihood(ML) solution is used to resolve the spectrum.The ML method,which is capable of decomposing the peaks in energy difference of over 2/3 FWHM,is applied to scale NaI(Tl) the spectrometer.The result shows that the net area is in proportion to the content of isotopes and the precision of scaling is better than the stripping ration method.