摘要 |
PURPOSE:To contrive a smaller ray source by covering a scintillator section with a relatively thin substance high in the atomic number while a shielding body is provided to shield X rays generated from the substance. CONSTITUTION:gamma-Rays incident from the direction of the arrow are converted into light with a scintillator 1. After amplified with a photoelectron multiplier 2, the light is converted into a transmittable electrical signal with a preamplifier (not illustrated) and a detector is so arranged to be connected to a cable (not illustrated) with a relay box 3. Then, a lead plate 4 with the optimum thickness obtained from the results of experiment is mounted about an outer cylinder 5 covering the scintillator 1 and moreover, the thickness of the outer cylinder 5 is selected to enable the shielding of KX rays from the lead plate 4. This permits drastic reduction in natural counting to achieve a higher detection efficiency with a larger diameter of the scintillator, thus resulting in a smaller ray source. |