A COMPARISON OF THE ISPRA AND HARWELL V.D.C. SYSTEMS FOR THE ASSAY OF 240 Pu BY SPONTANEOUS FISSION NEUTRON MEASUREMENTS

摘要

A comparison is made between the ISPRA and HARWELL variable dead time counter instrumentsnfor the non-destructive assay of 240 Pu. In both instruments the neutron emission of the source is detected and the fraction arising from spontaneous fission is estimated hence giving the 240 Pu content. The construction of the two detector assemblies and their electronic pulse processing systems are compared and found to have a similar performance. Good agreement was found between assay results taken on standard samples of mass ranging between 50 mg and 5 g of total plutonium.