Portable wide-angle γ-ray vision systems

The characteristics of two portable γ-ray vision systems, which could be transported by a robot, have been explored and compared. The detector of the first system (CSPMT) consists of an array of 37 CsI(Na) scintillation crystals viewed by a single 5 inch diameter position-sensitive photomultiplier tube (PSPMT), while the second system (CSPD) employs an array of 40 CsI(Tl) scintillation detectors coupled to PIN silicon photodiodes. These devices are designed to operate in the energy range from 50 keV to 1.5 MeV, which encompasses most energies of γ-ray radiation from the radioactive nuclides of interest to the nuclear industry. These systems have good angular resolutions of about 3° FWHM at the central field of view of 10°×10° or better when image reconstruction is employed, and coarser angular resolutions of about 10° FWHM elsewhere within a wide field of view of 50°×50°. The energy resolution of both systems have been tested using individual detector elements, and the imaging performance of proposed full systems have been simulated using a prototype. Our results show that these devices should be good candidates for the next generation portable γ-ray imaging systems