Leveraging gamma and alpha spectrometry optimizes gross alpha measurements for miscellaneous radioactive waste

Determination of alpha emitter concentration is crucial for ensuring safety and compliance in radioactive waste disposal. This study uses gamma and alpha spectrometry to optimize gross alpha measurements for radioactive waste by selecting appropriate calibration curves. The lack of a priori knowledge about the compositions of alpha emitters often results in discrepancies between the gross alpha activities and the summed activities of all alpha emitters when a single mass efficiency curve, such as based on ²⁴¹Am, is applied. We addressed this by revisiting gamma spectrometric data to categorize waste samples into uranium-major and the other groups, applying natural uranium calibration for the former and ²⁴¹Am calibration for the latter. This approach corrected the underestimated gross alpha activities of the uranium-major samples and derived a better correlation between gross alpha activities and alpha activity sums from the alpha spectrometry.