Directional charged-particle detector with a two-layer ultrathin phosphor foil

Current charged-particle detectors are able to estimate the position and energy of a particle, but not its direction. This study is aimed at developing a detector capable of measuring the direction of a charged particle as well as its position. The detector uses an image intensifier and a lens-coupled CMOS (complementary metal-oxide-semiconductor) camera to capture the scintillation light excited by a charged particle traversing a phosphor assembly. The phosphor assembly is made of two layers of ultrathin phosphor foils separated by an air gap. The performance of the detector is illustrated by simulation, theory and experiment.