1995 Fiscal Year Final Research Report Summary
IMPROVEMENT AND TRAIAL MANUFUCTURE ON A PORTABLE APPARATUS FOR CONTINUOUSLY MEASURING Rn-222 EXHALATION FROM GROUND
| Project/Area Number |
06558075
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| Research Category |
Grant-in-Aid for Developmental Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Environmental dynamic analysis
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| Research Institution | MURORAN INSTITUTE OF TECHNOLOGY |
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Principal Investigator |
MOCHIZUKI Sadamu MURORAN INSTITUTE OF TECHNOLOGY・DEPARTMENT OF TECHNOLOGY,PROFESSOR, 工学部, 教授 (70084308)
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| Co-Investigator(Kenkyū-buntansha) |
ARIYADA Osamu TAISEISANGYOU Co.Ltd., HEAD OF DIVISION, 部長
TANJI Tatsuo MURORAN INSTITUTE OF TECHNOLOGY・DEPARTMENT OF TECHNOLOGY,ASSISTANT PROFESSOR, 工学部, 助教授 (40002901)
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| Project Period (FY) |
1994 – 1995
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| Keywords | Radon / Exhalation / Continuous mesurement |
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| Research Abstract |
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.
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