RADIOACTIVITY MEASURING INSTRUMENT FOR RADIOACTIVE WASTE PACKED IN DRUM

摘要

PURPOSE: To accurately measure radioactivity in a drum over a wide range from a low dosage rate to a high dosage rate by optimizing the dead time of a measuring instrument by adjusting the aperture of a collimator arranged in front of a radiation detector and distance between the drum and collimator. ;CONSTITUTION: Drum driving devices 7 and 8 are controlled by a controller 15 so that a drum 1 can be freely moved in its rotating and length directions. By making γ-rays from the drum 1 pass through a collimator 3, only the γ-rays from the sliced section of the drum 1 are measured with a radiation detector and sent to a multichannel analyzer(MCA) 12 after shaping and amplification at a linear amplifier 11. The MCA 12 measures energy spectra from the γ-rays, but requires dead time, namely, processing time for performing A/D conversion. Therefore, a computing element 13 makes evaluation so that the dead time can become the optimum and obtains the optimum γ-ray energy spectra by adjusting the aperture of the collimator 3 and distance between the drum 1 and collimator 3. The element 13 takes the sum of intensities of radiation over the entire cross section and outputs 14.;COPYRIGHT: (C)1993,JPO&Japio