IMPROVEMENT AND TRAIAL MANUFUCTURE ON A PORTABLE APPARATUS FOR CONTINUOUSLY MEASURING Rn-222 EXHALATION FROM GROUND

为了连续测量氡-222从地表呼出的速率，研制了一种装置，该装置由氡收集器、60吨圆柱缓冲罐、三种过滤器和流式电离室组成。测量的电离电流以类比形式连续记录，然后使用事先导出的校准表离线转换为Rn-222浓度。由r -222浓度计算出呼出速率。电离室为圆柱形抽吸冷凝器，内、外圆柱体直径分别为0.05 m和0.2 m，共长0.45 m。外气缸保持在-1080伏特的电位。振动簧片静电计用于测量电离电流。从所进行的基本实验中，得到以下结果：(1)该设备能够连续记录测量数据，为所有实际用途提供足够准确的Rn-222呼出率评估。(2)考虑到地面条件、风和气流速度等因素对集热器内部和外部环境的影响，一旦找到一个合适的公式（目前正在寻找），即使在暴风雨天气下，该装置也能稳定地运行，预计对评估精度的损害将降到最低。

For the purpose of continuously mesuring the rate of Rn-222 exhalation from the ground surface, an apparatus has been developed that consists of a radon collector a 60-litter cylindrical buffer tank, three kinds of filter and an ionization chamber of flow-through type. The measured ionization current is continuously recorded in analogical form, then converted off-line into Rn-222 concentration using a calibration table derived in advance. From the Rn-222 concentration, the exhalation rate is obtained by calculation.The ionization chamber is cylindrical aspiration condenser with inner and outer cylinders meauring respectively 0.05 m and 0.2 m diameter and 0.45 m in common length. The outer cylinder is maintained at a potential of -1080 volts. The vibrating reed electrometer is used to measure the ionization current.From the basic experiments performed, followings were obtained ;(1) The apparatus is capable of continuously recording measured data that provide an evaluation of Rn-222 exhalation rate with sufficient accuracy for all practical purpose.(2) The apparatus operates stably even in stormy weather, and impairment of evaluation accuracy can be expected to be minimized, once a sitable formula-now being sought- is found for taking account of the difference between collector interior and ambient exterior brought by the storm in respect of such factors as the ground conditions, wind and air flow speed.