Measurement of (n,xngamma) Reactions at High Precision

The design of Generation IV nuclear reactors and the research of new fuel cycles require knowledge of cross sections of different nuclear reactions. Our work is focused on the determination of the cross sections of (n,xngamma) reactions occurring in these new reactors. The aim is to measure unknown cross sections and to reduce uncertainty on present data relative to reactions and isotopes present in transmutation or regeneration processes. The current study is relative to measuring 232Th(n,n'gamma) and 235U(n,xngamma) reactions in the fast neutron energy domain (up to 20 MeV). The experiments are performed at GELINA which delivers a pulsed, white neutron beam at IRMM, Belgium. The time characteristics of the beam enable us to measure neutron energies with the time of flight (TOF) technique. The neutron induced reactions (in this case inelastic scattering and (n,2n) reactions) are identified by online prompt gamma spectroscopy with an experimental setup including 4 HPGe detectors. A double layered fission chamber is used to monitor the incident neutron flux. As the precision is a key issue in these measurements, the detectors used in the experiment were studied extensively in order to reduce the uncertainties of the results to a minimum. Simulations and calibration experiments were realized and are presented.

THIRY J.C.;  BORCEA Catalin;  DESSAGNE Philippe;  DROHE Jean Claude;  JERICHA Erwin;  KARAM Habib;  KERVENO Maëlle;  KONING Arjan J.;  NEGRET Alexandru;  PAVLIK Andreas;  PLOMPEN Arjan;  ROUKI Chariklia;  RUDOLF Gerard;  STANOIU Mihai; 

2011-11-15

Organisation for Economic Co-operation and Development (OECD)

JRC61961

http://www.oecd-nea.org/science/docs/2011/index.html,    https://publications.jrc.ec.europa.eu/repository/handle/JRC61961,