| 摘要 |
PURPOSE:To improve the detection efficiency by using a plastic scintillator in structure, which transmits fluorescent light emitted by irradiation with gammarays to a photodetector for converting the light into an electric signal, for a detecting element. CONSTITUTION:The plastic scintillator (PS) is used for the detecting element 1 and the surface around it is treated with a coating material which is different in light refractive index; and a photomultiplier tube 5 is provided at its and part through a light guide 2 and a water-cooled case 4 which protects the element 4 and a circuit part storage case 5 which stores a preamplifier, etc., are provided. Then a ray-source part 22 uses a wide-angle beam system which can irradiates the element 1 with the gamma rays to its overall length and the element 1 is arranged in a direction where the amount of a body to be measured in a vessel varies. |
