Characterization of PuBe neutron sources by calorimetry and neutron assay

In order to support and refine in-field NDA methods developed for the assay of PuBe sources the heat power of a set of such sources is measured by a heat-flow calorimeter. The Pu isotopic composition of the sources was determined by gamma spectrometry. By combining these two measurements the Pu mass of the sources was determined. In addition, the actual neutron output of the sources was also measured using a calibrated neutron coincidence counter.The measurement campaign resulted in a set of well-characterized PuBe sources, which can be used as secondary standard calibration sources.