| 摘要 |
PURPOSE:To improve the detecting sensitivity of the title device by providing a multistage collecting section in which filter paper guide plates are hierarchically arranged in multiple stages and a gas leading-out section which is provided below the multistage collecting section and arranging a collecting section pusher, etc., on the multistage collecting section. CONSTITUTION:A collecting section pusher 24 is moved downward by actuating an air cylinder 27 and each filter paper guide plate 12 of a multistage collecting section 11 is moved downward by bending a coil spring 20. After a gas hole 14 is sealed so that no gas can leak out to the surrounding area, a sample gas is made to flow from the gas hole 14 of the pusher 24 to an external suction pump through the hole 14 of each plate 12 of the section 11, long filter paper 29, and hole 14 of a gas leading- out section 22. After the sample gas is collected for a certain period of time, the gas is stopped and the head of the piston rod of the air cylinder 27 is returned to its original position. Then collecting operations are made after moving the filter paper 29 by the distance equal to the diameter of the hole 14 and these collecting and moving operations are repeated. The radioactive iodine collected by the filter paper 29 positioned below the hole 14 is measured with a radioactive detector 31. The filter paper 29 is successively wound around a filter paper take-up section 32.
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