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 10(8) 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 positi on-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 b undles of fibers, with each fiber surrounded by cladding grass. Fiber sizes of 6 mu m were used, which allowed an image resolution of greate r than 20 line pairs per Mn. The glass-fiber optic scintillating plate was coupled to an image intensifier. The image-intensifier output ima ge was observed by a CCD camera.