Novel methodology for the quantitative assay of fissile materials using temporal and spectral beta-delayed gamma-ray signatures

作者：Chivers D H; Alfonso K; Goldblum B L^*; Ludewigt B

来源：Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms , 2011, 269(16): 1829-1835.

DOI：10.1016/j.nimb.2011.05.013

• Delayed gamma-rays
• Active interrogation
• Fission reactions

An analytical model for the generation of beta-delayed gamma-ray spectra following thermal-neutron-induced fission of mixed samples of (235)U and (239)PU is presented. Using an energy-dependent figure-of-merit to designate the spectral regions employed in the assay, the unique temporal beta-delayed gamma-ray signatures are utilized to determine the fraction of (239)PU in a mixed U-Pu sample. By evaluating the beta-delayed gamma-ray temporal signatures of both (235)U and (239)PU within a 3 key energy bin, traditional sources of systematic uncertainty in quantitative assay using beta-delayed gamma-ray signals, such as self-attenuation of the sample and energy-dependent 7-ray detection efficiency, are significantly reduced. The effects of the time-dependent Compton-continuum and growth of longer-lived nuclides on the quantitative assessment are explored. This methodology represents a promising extension of the conventional means of analysis for quantitative assay of fissile materials using beta-delayed gamma-ray signatures.

• 出版日期2011-8-15