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

便携式Rn-222地面呼气连续测量仪的改进与试制

基本信息

批准号：
06558075
负责人：
MOCHIZUKI Sadamu
金额：
$ 2.56万
依托单位：
MURORAN INSTITUTE OF TECHNOLOGY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research (B)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-06558075/
关键词：
Radon Exhalation Continuous mesurement

项目摘要

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.

为了连续测量Rn-222从地表呼出的速率，研制了一种由氡气收集器、60升圆柱形缓冲罐、三种过滤器和流通式电离室组成的装置。测量的电离电流以类比形式连续记录，然后使用预先导出的校准表离线转换为 Rn-222 浓度。由Rn-222浓度计算出呼气率。电离室为圆柱形吸气冷凝器，内、外筒直径分别为0.05 m和0.2 m，共同长度为0.45 m。外筒保持在-1080伏的电位。振动簧片静电计用于测量电离电流。从进行的基本实验中，得到以下结果：（1）该装置能够连续记录测量数据，为所有实际目的提供足够准确的Rn-222呼气率评估。（2）即使在暴风雨天气下，该装置也能稳定运行，并且一旦稳定，评估精度的损害预计将降至最低。目前正在寻找的公式是为了考虑风暴带来的集热器内部和环境外部之间在地面条件、风和气流速度等因素方面的差异。