Stilbene and NE 213 Characteristics Related to Their Use for Neutron Spectroscopy

The pulse discrimination technique permits scintillators to be used for neutron spectroscopy, in the presence of gamma rays, to investigate a wide variety of problems. The influence of shape and size of stilbene and NE 213 scintillators on their gamma-ray and neutron efficiencies and on the shape correction has been investigated. The neutron efficiency and the shape correction factor enter into the spectrum conversion function which is needed to reduce a recoil-proton energy distribution to a neutron spectrum. Gamma-ray and neutron efficiencies from 0.1 to 24 MeV have been graphed as a function of length. Graphs of the shape correction factor and the spectrum conversion function, up to 24-MeV neutron energy, have been made for various dimensions and similar volumes. These graphs and the summary tables can be used to select the size and shape of a detector to minimize the spread of the correction factor over a given range of neutron energy and to increase the neutron efficiency consistent with conditions of a given experiment or application.