A Study on the Energy Resolution Correction Method for Measured Spectra of Nuclear Radiations

1987 Fiscal Year Final Research Report Summary

• Project/Area Number: 61460244
• Research Category: Grant-in-Aid for General Scientific Research (B)
• Allocation Type: Single-year Grants
• Research Field: Nuclear engineering
• Research Institution: The University of Tokyo
• Principal Investigator: NAKAZAWA Masaharu Faculty of Engineering, The University of Tokyo, 工学部, 教授 (00010976)
• Co-Investigator(Kenkyū-buntansha): IGUCHI Tetsuo Faculty of Engineering, The University of Tokyo, 工学部, 助手 (60134483)
• Project Period (FY): 1986 – 1987
• Keywords: Resolution correction / Gamma ray spectra / Bayesian theorem / Lognormal distribution / 対数正規分布 / 逆ワイヤシュトラウス変換

Research Abstract

A calculational method to correct and improve the energy resolution of measured gamma ray spectra has been investigated. This method is based on a nonlinear least-squares method using a multi-dimensional lognormal distribution with Bayesian theorem. It can introduce the uncertainties and solve the problems of the vibration and the negative values, which sometimes have been occurred with the ordinary techniques. Resolutions of spectra are made worse in measured systems. This response function in gamma ray spectrometry can be approximated the Gaussian. The initial covariance data as a prior information is estimated using the inverse Weierstrass transformation. This method has been successfully applied to simulate spectra. Through the simulate calculations, these are found that the corrective limitation is strongly related to the uncertainty of measured spectra, and that the applicably limited spectra to separate peaks as the results of resolution correction are composed of peaks of which the intense ration are above the factor of 2 and the distances are closer than the resolution (1 sigma).