Abstract
The measurement of the capture cross-section of fissile elements, of utmost importance for the design of innovative nuclear reactors and the management of nuclear waste, faces particular difficulties related to the.-ray background generated in the competing fission reactions. At the CERN neutron time-of-flight facility n_TOF we have combined the Total Absorption Calorimeter (TAC) capture detector with a set of three U-235 loaded MicroMegas (MGAS) fission detectors for measuring simultaneously two reactions: capture and fission.
The results presented here include the determination of the three detection efficiencies involved in the process: epsilon(TAC)(n, f), epsilon(TAC)(n, gamma) and epsilon(MGAS)(n, f). In the test measurement we have succeeded in measuring simultaneously with a high total efficiency the U-235 capture and fission cross-sections, disentangling accurately the two types of reactions.
The work presented here proves that accurate capture cross-section measurements of fissile isotopes are feasible at n_TOF.