POSITION-SENSITIVE SCINTILLATION DETECTOR FOR HARD X-RAYS

Position-sensitive detectors for hard X-rays (> 10 keV) are of increasing importance in many applications. With the advent of commercially produced PMTs with position-sensitive readout it is possible to construct large area detectors with good position resolution while still having the high detection efficiency of crystal scintillators. Detailed Monte Carlo simulations as well as laboratory tests on a unit with a 42 x 42 mm2 front surface area for such a system have been performed. The PMT had a crossed-wire anode readout and was coupled to different NaI(Tl) scintillator crystals. With a 3 mm thick crystal a position resolution of 1.7 mm FWHM at 122 keV was obtained, while still having an energy resolution of 13%.