Determination of Window Analysis and Full Spectrum Analysis Method of Gamma Spectrometry Measurements in Low Level Activity

Analysis of radionuclides at low level activity with the gamma spectroscopy requires high precision. The
common methods used to determine radionuclide concentrations are Window Analysis (WA) and Full Spectrum Analysis (FSA). The purpose of this study was to obtain information in determining methods to be used when performing spectrum analysis because presumably there are differences in the results of the analysis and to ensure they are appropriate for low level radionuclide spectrum analysis. Low level activity radionuclides of 137Cs and 60Co with known activities between 2 Bq up to 6 Bq were used as sample; and 137Cs, 60Co and 152Eu were as standard sources. The sample were counted for short time and long time. The results from comparative studies showed that FSA and WA had 11% to 24% and 1% to 20% of error, respectively. Otherwise there were a correlation between long measurements and short measurements with R2=0.9907 and R2=0.7723, respectively. Based on these data it can be concluded that WA method was more accurate and efficient in time required for counting. On other hand FSA is better in estimating the value of uncertainty. However by the correlation analysis results, the longer counting time would result in no significant difference.