Report to NCSP on 2008 DANCE measurements of 233U($$\eta$$,$$\gamma$$)
Uranium-233 plays an important role in the Th-U fuel cycle, with substantial production in the cycle. This cycle has been proposed as an alternative to the U-Pu fuel cycle due to its reduced production of transuranic elements. An accurate measurement of the 233U($$\eta$$,$$\gamma$$) cross section is required by the National Criticality Safety Program (NCSP) to complete the neutron-induced cross section data, where experimental capture cross section data are scarce and were measured decades ago. The most recent capture cross section data available in the literature were measured in 2007 at the n_TOF facility (CERN); in the 60s measurements were performed at Rensselaer Polytechnic Institute (RPI) and at LANL. Finally, as reported by ORNL, a new evaluation with a revised (renormalized) fission cross section is needed on 233U. The challenge for this measurement lies in the difficulty of measuring the capture cross section data in the competing fission background, as the fission cross section is around one order of magnitude larger than the capture cross section for 233U. The accuracy of a capture cross section measurement depends on discrimination between $$\gamma$$’s produced in capture and fission reactions, for which an experimental setup combining capture and fission detectors is needed. For the ($$\eta$$,$$\gamma$$) cross section measurement at LANSCE, this discrimination is achieved by combining the Detector for Advanced Neutron Capture Experiments (DANCE), to measure $$\gamma$$’s from capture reactions, with a Parallel Plate Avalanche Counter (PPAC) to tag the $$\gamma$$’s produced by fission. This method was successfully used to measure 235U and 239Pu capture cross sections. In these measurements, the neutron capture cross section was determined in a large fission background well above 100 keV. As part of the NCSP nuclear data effort, we have looked at past DANCE measurements on 233U($$\eta$$,$$\gamma$$) and evaluated whether existing data is adequate to apply this technique.
- Research Organization:
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA), Nuclear Criticality Safety Program (NCSP)
- DOE Contract Number:
- 89233218CNA000001
- OSTI ID:
- 1638605
- Report Number(s):
- LA-UR-20-25007; TRN: US2201499
- Country of Publication:
- United States
- Language:
- English
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