Calibrated Fission and Fusion Neutron Fields at the Kyoto University Reactor

Thermal-neutron-driven fast neutron fields using a fission plate and a ⁶LiD converter are briefly reviewed. The characteristics of a large (27-cm-diam × 1.1-cm-thick) fission plate made of highly enriched uranium and a sandwich-type ⁶LiD converter (two 10-cm-square × 1-cm-thick ⁶LiD plates) are presented, both of which have been used at the heavy water thermal neutron facility at the Kyoto University Reactor. The neutron spectra in both fields were calculated by the MCNP Monte Carlo code. The average neutron energy and the neutron spectrum of the ⁶LiD converter were measured and the results agree with the predicted values. Using both fields, we measured the average cross sections for some threshold reactions, 6 with the fission plate and 23 with the ⁶LiD converter. The results are compared with evaluated values and previous measurements.