Demonstrating the integral resonance transmission method; Conceptual and experimental studies

Angell, C.; 早川 岳人; 静間 俊行; 羽島 良一; Quiter, B. J.*; Ludewigt, B. L.*; Karwowski, H. J.*; Rich, G.*; Silano, J.*

Proceedings of INMM 56th Annual Meeting (Internet), 9 Pages, 2015/07

Nuclear resonance fluorescence (NRF) is a promising technique for assaying Pu in spent nuclear fuel and for SNM detection applications because of its isotope-specific nature and potential for high sensitivity. To fully utilize the next generation of high-flux -ray sources for NRF applications we developed the integral resonance transmission (IRT) method which integratesover all resonances within the energy width of a quasi-monoenergetic -ray beam allowing the full utilization of the transmission signature. To realize the IRT technique both conceptual studies, exploring the consequences of the loss of resolution, and experimental studies, demonstrating several aspects of the IRT method, were undertaken. The conceptual studies included the development of a performance metric allowing comparison between using the IRT technique and single resonances, a study of the magnitude of resonance overlap, and beam simulations examining performance as a function of beam width. The experimental studies were done at the HIS facility at Duke University, and included an experiment constraining resonance overlap in a NRF transmission measurement through a TMI-2 type canister, demonstration of the IRT technique by a NRF measurement on Ta, and the world's first transmission NRF measurement on Pu. In this talk, we will overview each component of the conceptual and experimental studies for the IRT method.

Validating resonance properties using nuclear resonance fluorescence

Angell, C.; 羽島 良一; 早川 岳人; 静間 俊行; Karwowski, H.*; Silano, J.*

Physical Review C, 90(5), p.054315_1 - 054315_6, 2014/11

AA2014-0567.pdf:0.3MB

https://doi.org/10.1103/PhysRevC.90.054315

Measurement of a resonance's integrated cross section using nuclear resonance fluorescence can be a valuable tool for verifying the properties of the resonance because of the clear and unambiguous physical connection to the spin, lifetime, and ground state branching ratio of the level. We demonstrate this idea by measuring the integrated cross section of the 3.004 MeV level in Al to 4% using the mono-energetic -ray beam at the High Intensity -ray Source. That level was the subject of much debate experimentally in the 1960's, especially its spin, and even now only has a current tentative spin assignment of . The consistency check between this integrated cross section and the known properties of the level indicate that one (or more)of the literature properties is incorrect. Based on the range of extent of each property, a re-assignment of spin to atentative may be warranted, but this would need to be confirmed with other measurements. This result demonstrates the utility of NRF as a way to verify the properties of states in the literature before undertaking more extensive measurements.