The new fission converter based epithermal neutron irradiation facility at MIT

A new type of reactor produced epithermal neutron beam based on a sub-critical fission converter and called the FCB, has been constructed at the MIT research reactor (MITR). The use of a fission converter source was originally suggested by Rief. In this approach, a large area thermal neutron beam impinges upon fissionable material, generating a fission neutron spectrum that is moderated and filtered to produce an epithermal neutron beam of high intensity and purity. This paper summarizes the neutronic and engineering aspects and the performance of this facility which was recently, (June 2000), put into operation at the Massachusetts Institute of Technology's research reactor, MITR. (orig.)