Measurements and calculations of neutron spectra from 35 MeV deuterons on thick lithium for the FMIT facility

Neutron yields and energy spectra were measured for 35 MeV deuterons on a thick target of natural lithium. Data were obtained using the time-of-flight technique over an angular range of 0/sup 0/ the 150/sup 0/ and for neutron energies from about 1 to 50 MeV. A simple nuclear model that describes the differential cross sections of neutron production was adjusted to agree with these new thick target data. Different model parameters were obtained when the model was adjusted to agree with previous ORNL thick target data for 40 MeV deuterons. Our experimental data are in good agreement with model predictions based upon the ORNL time-of-flight data but are somewhat lower than predictions based upon the ORNL dosimetry data. Finally the model was used to predict the neutron spectrum at the position of highest flux in the FMIT test cell.