Measurements of sealed radioactive sources by using isothermal microcalorimetry

We have studied to validate the calorimetric method by comparing the 123 I radioactivity measurement results with the national standard. The reason for using 123 I was to determine how much it absorbs radiation decay energy due to γ and electron capture transitions. In addition, due to the characteristic of the calorimeter, stabilization time is required, and we have determined that the half-life time of 123 I is long enough to overcome this problem. We compared two measurement results (calorimeter and ion chamber) and confirmed that the rate of power reduction in the calorimeter was similar to the half-life time of 123 I.