| 摘要 |
PURPOSE:To provide a gamma-ray measuring instrument of enhanced measuring accuracy which is less affected by ambient temperature changes, provides reduced noise, is easy to manage and can accurately cope with the change of a subject for measurement. CONSTITUTION:The pulse width and wave height of a pulse generator 18 are both adjustable. Pulse signals from the pulse generator 18 are fed to a light- emitting diode 17 via a temperature compensation circuit 19. The light-emitting diode 17 emits light according to the pulse signals fed thereto. The light emitted from the light-emitting diode 17 impinges on a photomultiplier tube 6, together with a gamma ray and plastic scintillator light. Both optical signals are amplified by an amplifier 10 and the pulses transmitted through a comparator 11 are computed using a computing element 12 and converted into level signals. Both of the optical signals fed to a time constant circuit 20 are attenuated by a CR circuit and a light-emitting diode optical signal and a plastic scintillator signal are separated from each other basing on pulse widths. |
