A small computer as an on line multi-parameter analyser for a neutron spectrometer

The techniques in current use for the measurement of the neutron energy spectrum above a few kilovolts in the core of a reactor rely on the measurement of the energy of the secondary particles produced as a result of a neutron interaction with a nucleus. The most common reactions are scattering by hydrogen in which the energy of the recoil proton is measured, and the reaction between a neutron and Lithium-6 to produce an alpha particle and a triton which are detected in coincidence. In both these reactions the energy of the reaction products is a linear function of the neutron energy, and it is difficult to cover an energy much greater than a factor of ten in a single measurement with these techniques. This means that at least 4 and often 6 or 7 different measurements are required to cover the energy range from a few keV up to 10 MeV.