| 摘要 |
PURPOSE:To stabilize a scintillation counter without using any marker buried type scintillator by using a photoelectric peak present in transmitted gamma rays as a marker. CONSTITUTION:A radiation detector 3 is set where a gamma-ray source 14r faces the scintillator 1 across a steel pipe 12. The position of a photoelectric peak pH in a stably state as to the wave height distribution of a pulse signal detected by the scintillator 1 is regarded as a reference position and discrimination voltages Vu and Vl are set having the same upper and lower widths about the center value as a boundary value Vc; and discriminators having windows Vl-Vc and Vc-Vu are provided to detect passing pulses. In this constitution, the count rate of the photoelectric peak varies invariably with the density of fluid to be measured, but the position of the photoelectric peak pH is fixed, so the control is performed correctly. |
