Measurement of the 245Cm(n,f) cross section in the resolved resonance region.

The fission cross section of 245Cm was measured at the GELINA neutron facility of the Institute for Reference Materials and Measurements (IRMM) in Geel, Belgium, as a function of the incident neutron energy. The energy of the neutrons is determined applying the time of flight method using a flight path length of about 9 m. A highly enriched 245Cm sample (98.48%) was mounted back-to-back with a 10B sample in the centre of a vacuum chamber together with two surface barrier detectors positioned outside the neutron beam. One detector measured the 10B(n,α)7Li reaction products for the neutron flux determination, while the second one registered the 245Cm(n,f) fragments. A control measurement has been performed replacing the 245Cm sample with a 235U sample in order to check that the well-known 235U(n,f) cross section can be reproduced. In comparison with previous 245Cm fission cross section measurements, our preliminary results show a nice improvement of the energy resolution, in particular below 20 eV where very few data are available. [ABSTRACT FROM AUTHOR]