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STUDIES ON METHODS AND SYSTEMS FOR MEASURING RADON PROGENIES IN THE ATMOSPHERE
http://hdl.handle.net/10258/1145
http://hdl.handle.net/10258/114584571118-91e5-4dc2-8dbb-3bb361e96f2f
| 名前 / ファイル | ライセンス | アクション |
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otu17 (8.1 MB)
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| アイテムタイプ | 学位論文 / Thesis or Dissertation(1) | |||||||||||||
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| 公開日 | 2012-06-18 | |||||||||||||
| タイトル | ||||||||||||||
| タイトル | STUDIES ON METHODS AND SYSTEMS FOR MEASURING RADON PROGENIES IN THE ATMOSPHERE | |||||||||||||
| 言語 | en | |||||||||||||
| 言語 | ||||||||||||||
| 言語 | eng | |||||||||||||
| 資源タイプ | ||||||||||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_db06 | |||||||||||||
| 資源タイプ | doctoral thesis | |||||||||||||
| アクセス権 | ||||||||||||||
| アクセス権 | open access | |||||||||||||
| アクセス権URI | http://purl.org/coar/access_right/c_abf2 | |||||||||||||
| 著者 |
沖野, 典夫
× 沖野, 典夫
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| 室蘭工業大学研究者データベースへのリンク | ||||||||||||||
| 表示名 | 沖野 典夫（OKINO Michio） | |||||||||||||
| URL | http://rdsoran.muroran-it.ac.jp/html/100000197_ja.html | |||||||||||||
| 抄録 | ||||||||||||||
| 内容記述タイプ | Abstract | |||||||||||||
| 内容記述 | This paper consists of four chapters. In Chap.I，the apparatus for measuring ^<222>Rn concentration in soi1 air is studied.To measure the concentration of ^<222>Rn in soil air，an apparatus has been developed and same four apparatuses were constructed. The apparatus is composed of a hemisphere of double screen meshes of 10 cm in diameter，gold film of 1.0 cm in diameter centered in the hemisphere，and a silicon semiconductor detector placed on the opposite side with 0.2 cm spacing from the gold film，an electronic circuit and a pulse height analyzer for alpha ray spectrometry. Using these apparatuses simultaneously，it is possible to obtain for radon concentrations in soil air at adequate four points under the ground from measured ^<218>PO count rates. From the fundamental experiments for evaluating the working characteristics of the apparatus，it was confirmed that the apparatus is useful to detect and count ^<218>Po in soil air，and possible to use within a long period without change their working characteristics. From the practical use of this apparatus in a soil consisted of river sand，as an estimated value of the diffusion constant of radon in soil air，0.081 (cm^2/sec) at the depth 30cm and 0.092 (cm^2/sec) at 100 Cln were obtained，respectively. In Chap.Ⅱ，the apparatus for continuously measuring ^<222>Rn exhalation from ground is studied. To measure the rate of ^<222>Rn exhalation from the ground surface， an apparatus has been developed. The apparatus is composed of a adon collector，a 60-1 cylindrical buffer tank，three kinds of filter and an onization chamber of flow-through type. To know the working characteristics and the ccuracy of measured values，calibration measurelnents and comparison between values obtained with the present method and with other methods were made by applying two-filter method and by using activated charcoal method, respectively. From the basic experments， the apparatus is capable of continuously recording measured data that provide an evaluation of ^<222>Rn exhalation rate with sufficient accuracy.From the practical use of the apparatus on the different ground conditions，following informations were obtained; a)The apparatus operates stably even in stormy weather. b) From the measurelnents made on the ground inside of a house，the variation trends of exhalation rate were found to be in phase with the variations of telmperature. c) From the measurelnents made on natural ground，the values on one day was considerably different from those at the same time on the other day. The variation of ground condition affected with the weather seems to be main cause to effect the variation of exhalation rates. In Chap. Ⅲ，the apparatus for measuring ^<222>Rn progeny concentration in atlnosphere is studied. To measure the concentration of ^<222>Rn progeny in atmosphere， an apparatus has been developed that consists of a radon rogeny collector，a semiconductor detector and a pulse height analyzer. A membrane filter (TOYO-ROSHI，Ltd. TM-300) was adopted for ^<222>Rn progeny collection. A silicon semiconductor detector (HORIBA，Ltd. 300SB 60L) was adopted for alpha ray detection of ^<222>Rn progenies collected on the filter. Alpha ray spectrometry was adopted for the measurelnents of ^<218>Po and ^<214>Po. As a counting efficiency of this apparatus，a value 0.459 was obtained by calculation. A relative error was estIlnated to be within 20.4 percent. From the observations made on the atmosphere over the ocean，it was confirmed that the apparatus is useful to measure extremely low level concentrations of ^<222>Rn progeny with sufficient accuracy. From the observation made in the atmosphere over the Indian Ocean，followings are obtained;a) On the mid Indian Ocean，radon concentration levels were found to be ranged from 6.6×10^<-4>Bq/m^3 to 7.6×10^<-2>Bq/m^3. b) Clear inverse correlation between radon concentration and electrical conductivity was found in the atmosphere over the mid Indian Ocean. In Chap. IV，the apparatus for measuring the concentration of unattached ^<218>Po in atmosphere is studied. An apparatus has been developed that consists of three kinds of ^<218.Po collector provided with semiconductor detectors in which one of collectors is used for attached ^<218>Po measurement and others are for nattached ^<218>Po，and three pulse height analyzers. A 300 mesh wire screen was adopted for collection of unattached ^<218>Po. A membrane filter (TOYO-ROSHI，Ltd. TM-100) was adopted for collection of attached ^<218>Po. Silicon semiconductor detector (HORIBA，Ltd. 300SB 120L) were used for alpha ray detection. As ollection efficiency of the wire mesh filter and appearing efficiency of ^<218>Po collected on the filter，values 0.72 and 0.686 were adopted in present work，respectively. From some measureluents carried out in a basenlent air，it was confirmed that the apparatus is capable of providing an evaluation of the unattached ^<218>Po concentration and the ratio of unattached ^<218>Po to attached ^<218>Po，simultaneously. | |||||||||||||
| 言語 | ja | |||||||||||||
| 学位授与機関 | ||||||||||||||
| 学位授与機関識別子Scheme | kakenhi | |||||||||||||
| 学位授与機関識別子 | 10103 | |||||||||||||
| 学位授与機関名 | 室蘭工業大学 | |||||||||||||
| 言語 | ja | |||||||||||||
| 学位授与機関名 | Muroran Institute of Technology | |||||||||||||
| 言語 | en | |||||||||||||
| 学位名 | ||||||||||||||
| 学位名 | 博士（工学） | |||||||||||||
| 言語 | ja | |||||||||||||
| 学位の種別 | ||||||||||||||
| 言語 | ja | |||||||||||||
| 値 | 論文博士 | |||||||||||||
| 学位授与番号 | ||||||||||||||
| 学位授与番号 | 乙第17号 | |||||||||||||
| 報告番号 | ||||||||||||||
| 言語 | ja | |||||||||||||
| 値 | 乙第17号 | |||||||||||||
| 学位記番号 | ||||||||||||||
| 言語 | ja | |||||||||||||
| 値 | 博乙第17号 | |||||||||||||
| 研究科・専攻 | ||||||||||||||
| 言語 | ja | |||||||||||||
| 値 | 工学研究科 | |||||||||||||
| 学位授与年月日 | ||||||||||||||
| 学位授与年月日 | 1996-09-30 | |||||||||||||
| 日本十進分類法 | ||||||||||||||
| 主題Scheme | NDC | |||||||||||||
| 主題 | 451 | |||||||||||||
| 著者版フラグ | ||||||||||||||
| 出版タイプ | VoR | |||||||||||||
| 出版タイプResource | http://purl.org/coar/version/c_970fb48d4fbd8a85 | |||||||||||||
| フォーマット | ||||||||||||||
| 内容記述タイプ | Other | |||||||||||||
| 内容記述 | application/pdf | |||||||||||||
