| 摘要 |
PURPOSE:To reduce the light receiving area of a photomultiplier tube even when a large area scintillator is used while dispensing with a light guide, by focusing light emitted from a scintillator to the photomultiplier tube by a convex lens. CONSTITUTION:The fluorescent substance in a scintillator 1 emits light corresponding to incident radioactive rays and said light is focused by a convex lens 27 having a light pervious film 4 having a thickness of a 1/4 wavelength formed to the convex surface thereof so as to be contacted with a glass window 3. This focused light is received by the light receiving part 6a of the photomultiplier tube 5 opposed to the lens 27 so as to leave a space 22. By this constitution, a scintillation detector requires no light guide and is miniaturized while the light receiving area of the photomultiplier tube can be made small even when a large area scintillator is used. |
