DECONVOLUTION OF GAMMA-RAY SPECTRA OBTAINED WITH NAI(Tl) DETECTOR IN A WATER TANK

摘要

Maximum-likelihood fitting by the expectation maximisation deconvolution method is presented to analyse gamma-ray spectra recorded using an NaI(Tl) detector for a water monitoring system. The applicability of the method was tested by deconvolving measured spectra taken using an industry standard 3" × 3" cylindrical NaI(Tl) detector in a model water tank with several calibration sources. The results show significant removal of the Compton continuum counts and efficient transfer of the counts into the corresponding photo-peaks. The peak-to-total count ratio and the number of counts in the photo-peaks in the deconvolved spectra increased approximately 4.67 and 5.29 times, respectively, compared with those of measured spectra taken using an NaI(Tl) scintillation detector in the case of ~(137)Cs.