The gamma rays which inevitably accompany a neutron fluence create a well-known requirement for neutron/gamma discrimination before meaningful neutron measurements can be made with scintillators such as NE-213. The intrinsic properties of NE-213 that lead to characteristic pulse-shapes for neutron or gamma induced events have given rise to a wide range of electronic techniques by which this pulse-shape information can be utilised. Reviews of these techniques can be found in standard texts (G.F. Knoll, Radiation Detection and Measurement, second edition, Wiley, 1989) but many require expensive and sophisticated dual-parameter data acquisition systems to achieve good neutron/gamma discrimination at low pulse-heights (neutron energies). Of the techniques which perform well in single-parameter acquisition mode, probably the most commonly used system is the "LINK" system developed at Harwell (G. White, Proc. 2nd Ispra Symp. Nuclear Electronics, Stresa, Italy, May 1975, pp. 447-451). In this work, we shall consider a modification of the "Owens" pulse shape discrimination technique (R.B. Owen, Nucleonics 17(9) (1959) 92) to enable a single parameter data acquisition to be used down to low pulse height.
