Thermal/Fast Fission Yield Ratio Signature for Neutron Interrogation of Nuclear Materials

Discovery, nuclear properties, synthesis and applications of technetium-101

“…Because of its association with fission-based processes, the 101 Mo/ 101 Tc radionuclidic pair and A = 101 isobar end-member 101 Ru can serve as unique signatures and dialogistic tools 78 , 124 , 125 . For instance, Tohmay et al were able to measure and differentiate fission product yield ratios of short-lived fission products to certify the enrichment of a natural U sample via thermal neutron fission of 235 U and fast neutron fission of 238 U; an Am-Be neutron source was used as a source of neutrons coupled with delayed γ -ray measurements on a HPGe detector for analysing fission products.…”

“…For instance, Tohmay et al were able to measure and differentiate fission product yield ratios of short-lived fission products to certify the enrichment of a natural U sample via thermal neutron fission of 235 U and fast neutron fission of 238 U; an Am-Be neutron source was used as a source of neutrons coupled with delayed γ -ray measurements on a HPGe detector for analysing fission products. Using this method, variations in fissile and fertile compositions (i.e., enrichment and depletion) could be measured, while specific fission product radionuclides including 101 Tc, along with 88 Kr, 91 Sr, 92 Sr, 92 Y, and 105 Ru, were determined to be prominent signatures of enrichment 124 . The authors suggested that a small, portable neutron source, such as the Am-Be source used in the study or one similar, could be implemented for nuclear materials interrogation by applying these techniques.…”