| 摘要 |
PURPOSE:To separate and measure the beta-rays in food and to facilitate routine measurement by providing a 1st detecting part which detects low-energy beta-rays and a 2nd detecting part and 3rd detecting part which have different absorption layers. CONSTITUTION:The beta-rays of low energy radiated from a sample 24 are detected by the 1st detecting part 26. The beta-rays exclusive of low energy are detected in the 2nd detecting part 30 and the hard cosmic rays are detected in the 3rd detecting part 34. The beta-rays and the cosmic rays exclusive of the low energy rays are eventually and simultaneously made incident to the 1st detector 26 and, therefore, only the electric pulses which are not simultaneously detected by the outputs of the 1st and 2nd detecting parts are taken out and the beta-rays of low energy are measured in a reverse simultaneous counter circuit 40. The measurement of, for example, cesium, is possible in this way. Since the cosmic rays are simultaneously made incident to the 2nd detecting part 30, the reverse simultaneous counting 42 of the outputs of the 2nd and 3rd detecting part is executed and the beta-rays exclusive of low energy are measured. The measurement of, for example, potassium, is possible in this way.
|
