Development of a position-sensitive gamma detector based on a scintillating fiber for a 2DACAR study

A position-sensitive gamma detector based on a scintillating fiber is described. At the KEK PF slow-positron facility, an intensity of more than 108 e+/s has already been achieved at the target point of the sample chamber utilizing the PF 2.5 GeV electron linac as its primary beam source, and studies for producing a positron microbeam have been carried out. In parallel with this, we have tried to realize a position-sensitive gamma detector for a positron microbeam. We attempted to use a fiber-optic scintillator for a position-sensitive detector. The glass compositions were alkaline earth, gadolinium, and terbium loaded silicate glasses. The glass was used as the core glass to fabricate bundles of fibers, with each fiber surrounded by cladding glass. Fiber sizes of 6 μm were used, which allowed an image resolution of greater than 20 line pairs per mm. The glass-fiber optic scintillating plate was coupled to an image intensifier. The image-intensifier output image was observed by a CCD camera.