A scintillating plastic fiber tracking detector for neutron and proton imaging and spectroscopy

We report on a prototype detector system designed to perform imaging and sp ectroscopy on 20-250 MeV neutrons. The detection techniques employed can be applied to measurements in a variety of disciplines including solar and at mospheric physics, radiation therapy and nuclear materials monitoring. The detector measures the energy and direction of neutrons by detecting double neutron-proton scatters and recording images of the ionization tracks of th e recoil protons in a densely packed bundle of scintillating plastic fibers stacked in orthogonal layers. The scintillation tracks are detected and im aged by photomultipliers and image intensifier/CCD camera optics. By tracki ng the recoil protons from individual neutrons, the kinematics of the scatt er are determined. This directional information results in a high signal-to -noise measurement. The self-triggering and track imaging features of a pro totype for tracking in two dimensions are demonstrated in calibrations with 14-65 MeV neutrons, 20-67.5 MeV protons, and with cosmic-ray muons. Prelim inary results of phantom imaging measurements using a proton beam are also presented. We discuss several applications for this detector technique and outline future development work. (C) 1999 Elsevier Science B.V. All rights reserved.