Developments in Phosphor Screen Detectors for Proton Radiography and Ultra-Cold Neutrons.

Although the scales of thickness needed for detectors for proton imaging for proton radiography and for detecting Ultra-Cold Neutrons (UCN) are very different these seemingly disparate applications have some requirements in common. Both applications require fast phosphors with low afterglow. Thick large-grain phosphor screens have proven to have advantages over monolithic scintillators for proton imaging. The development of these has led to improved options for UCN detection, particular for the UCNt experiment. Screens have been constructed and tested from granular ZnS(Ag), LYSO(Ce), BGO, YAlO₃. Results from these tests and performance of some of these in proton imaging and UCN detection will be presented.