| 摘要 |
PURPOSE:To facilitate increase in spatial resolution performance of a detector, by properly controlling the effective light receiving area ratio of photomultiplier tubes PMT which are optically coupled to a plurality of scintillators using a photoconducting material to allow the utilization of a desired PMT for detectors of 4-link system. CONSTITUTION:Light guides (A) and (B) such as ultraviolet-transmitting transparent acrylic resin is used as photo transmitting material between PMT-x and PMT-y which are optically coupled to a plurality of scintillators 1-4 as detector. The PMT-x and PMT-y of the guides (A) and (B) are cut slantly so that the effective light receiving area of the PMT-x and PMT-y of the guides A and B can be optically coupled to the scintillators 1 and 2 up to a half thereof. Reflecting agent layers 8 are formed on these cut faces and three sheets are combined to meet d<4a. When d>4a, light guides (C) and (D) are used and as in the case of d<4a, the effective light receiving surface area ratio shall be made equal thereamong. Thus, the desired PMT is utilized for a 4-continuous type detector to facilitate the selection of the PMTs used, thus reducing the unit cost of the detector.
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