A sensitive neutron spectrometer for the National Ignition Facility

We are developing a sensitive neutron spectrometer for the National Ignition Facility laser at Livermore. The spectrometer will consist of a 1020 channel single-neutron-interaction time-of-flight detector array fielded 23 m from the neutron-producing target. It will use an existing detector array together with upgraded electronics for improved time resolution. Measurements of neutron yield, ion and electron temperatures, and density-radius product are all possible under certain conditions using one-, two-, or three-step reaction processes. The locations of the most important potential sources of scattered neutron backgrounds are determined as the first step in designing collimation to reduce these backgrounds.