| 摘要 |
PURPOSE:To reduce the titled device in size, to fix a distance from a light incident end surface to a photomultiplier tube and to remove the generation of uneven sensitivity by forming plural photomultiplier tubes on a plate-like light condensing body where one longitudinal end surface is used as a light incident end surface and the other longitudinal end surface is used as a projection end surface. CONSTITUTION:In the light condensing body 21, the front end surface opposed to a sheet 3 is used as the incident end surface 21a and the back end surface is used as the projection end surface 21b. The photodetecting surfaces 22a, 24a of the photomultiplier tubes 22-24 are coupled with the projection end surface 21b. Namely, the projection end surface 21b is covered with the photodetecting surfaces 22a-24a at its whole length. The outputs of pre-amplifiers 25-27 amplifying electronic signals outputted from respective photomultiplier tubes 22-24 are inputted to a picture information reading circuit 6 through a correcting circuit 28. The correcting circuit 28 corrects the reduction of sensitivity generated at the joint parts between the photomultiplier tubes 22 and 23, 23 and 24. The outputs outputted from the photomultiplier tubes 22-24 and amplified by the pre- amplifiers 25-27 are added by an adder 30.
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