Development of a portable scintillation spectrometer with alpha-/beta- and neutron-/gamma- pulse-shape discrimination capabilities

This work presents the design and preliminary tests of a portable scintillation spectrometer dedicated to alpha-/beta- and neutron-/gamma- pulse-shape discrimination (PSD) measurements. The main features of the detector include a specially developed plastic scintillator for enhanced PSD and a digital, real-time pulse processing and analysis acquisition system specifically designed for PSD applications.The performance of the detector is tested in PSD measurement of 222Rn absorbed in the plastic scintillator as well as with a Pu/Be neutron/photon source. Excellent PSD discrimination capabilities have been observed in both alpha-/beta- and neutron-/gamma-measurements. The measurements with 222Rn absorbed in the plastic scintillator demonstrate clear separation between the beta-particles continuum and the alpha- peaks. There is practically no cross-talk between the alpha- and the beta- channels as no alpha-peaks are identified in the beta-channel and very small contribution of the beta- continuum is seen in the alpha channel.