Measurements of magnetic dipole strength in Pu-239 using nuclear resonance fluorescence

Shizuma, Toshiyuki; Angell, C.*; Hajima, Ryoichi; Ludewigt, B.*; Quiter, B. J.*; Koizumi, Mitsuo 

Nuclear resonance transmission -rays through a Pu-239 target were measured, as a part of a development project of nuclear material non-destructive detection and assay using quasi-monoenergetic laser Compton scattering (LCS) photon beams. The experiment was carried out at Duke University. We used photon beams at energies of 2.14 with energy width of about 4% to irradiate absorber and scattering targets of Pu-239. We measured scattered rays from the scattering target using high-purity Ge detectors. As a result, we found the average integration cross section of 13 eV barn at excitation energies from 2.12 to 2.19 MeV. The sum of the branching ratio from the excited state to the ground and first excited states are 0.4. This enables us to quantify Pu-239 in a assembly with an error of approximately 3% in four-hour measurement with 10 photon/s beams. In this presentation, we will report on the measurement method and the experimental results. We will also talk about the future plan for development of non-destructive assay using mono-energetic LCS -ray beam. (This development was carried out under "the subsidiary for promotion of strengthening nuclear security or the like of MEXT".)