Published 2010 | Version v1
Journal article Metadata-only

Relation between 222Rn concentration in outdoor air and γ-ray dose rate at Oshika Peninsula

Creators

  • 1. Environmental Radioactivity Research Institute of Miyagi, Sendai, Miyagi (Japan)

Description

Gamma-ray dose rate, gamma-ray spectrum and outdoor radon concentration were measured at three sites in the Oshika-Peninsula, Miyagi, Japan. Increase of gamma-ray dose rate by several nGy/h and 222Rn concentration by 60 Bq/m3 were observed, when maritime air mass covered the sites in June 19-20, 2008. In addition, count rates of 214Pb and 214Bi by an NaI(Tl)-detector increased. Meteorological data of wind-direction, wind-speed, temperature, and radiation balance showed that there was an inversion layer by radiation cooling. Considering such circumstances, increases of 222Rn concentration and gamma-ray dose rate can be explained by transport of 222Rn -rich air mass from hills and mountains by offshore wind. Similar phenomena observed at three sites in the Oshika-Peninsula in September 2-4, 2008. In this period, remarkable differences of 222Rn concentration were observed among sites, and the concentration varied from 60 to 213 Bq/m3. The differences might be induced by a different geological condition, spatial distribution of 222Rn, and equilibrium condition between parent and daughter nuclides. (author)

Availability note (English)

Available from https://warp.ndl.go.jp/info:ndljp/pid/12251465/www.pref.miyagi.jp/documents/13512/666959.pdf

Abstract (Japanese)

宮城県牡鹿半島の3地点でガンマ線線量率とスペクトル、及び屋外大気中のラドン(222Rn)濃度を測定した。地点の1つで 2008 年 6 月 19-20 日の海洋性気団の影響下で数 nGy/h のガンマ線線量率上昇と約 60 Bq/m3 のラドン濃度上昇が観測された。風向風速、気温及び放射収支の気象学的データは放射冷却状態を示していた。上記のような状況を考慮すると、ガンマ線線量率とラドン濃度の上昇は、山風によってラドン濃度の高い空気塊が移流してきたためと考えられた。3地点で 2008 年 9 月 2-4 日にも同様な現象が起きたが、その際には地点間で顕著なラドン濃度の違いが認められ、約 60 - 213 Bq/m3 までの範囲で変動した。これらの差は異なった地理的条件、ラドンの空間分布、親核種と娘核種間の放射平衡の程度の違いなどに起因するものと推定された。(著者)

Additional details

Additional titles

Original title (Japanese)
牡鹿半島における大気中ラドン濃度とγ線線量率の関係

Identifiers

URL
https://warp.ndl.go.jp/info:ndljp/pid/12251465/www.pref.miyagi.jp/documents/13512/666959.pdf;

Publishing Information

Journal Title
Miyagiken Genshiryoku Senta Nenpo
Journal Volume
26
Series
雑誌名:宮城県原子力センター年報; Annual Report of Environmental Radioactivity resarch Institute of Miyagi
Journal Page Range
p. 5-12
ISSN
0912-3490

INIS

Country of Publication
Japan
Country of Input or Organization
Japan
INIS RN
53077069
Subject category
S54: ENVIRONMENTAL SCIENCES;
Descriptors DEI
BISMUTH 214; CORRELATIONS; DAUGHTER PRODUCTS; DOSE RATES; IONIZATION CHAMBERS; LEAD 214; METEOROLOGY; NAI DETECTORS; RADIATION MONITORING; RADIATION MONITORS; RADIOACTIVITY; RADON; RADON 222; RAIN WATER
Descriptors DEC
ALPHA DECAY RADIOISOTOPES; BETA DECAY RADIOISOTOPES; BETA-MINUS DECAY RADIOISOTOPES; BISMUTH ISOTOPES; DAYS LIVING RADIOISOTOPES; ELEMENTS; EVEN-EVEN NUCLEI; FLUIDS; GASES; HEAVY NUCLEI; HYDROGEN COMPOUNDS; ISOTOPES; LEAD ISOTOPES; MEASURING INSTRUMENTS; MINUTES LIVING RADIOISOTOPES; MONITORING; MONITORS; NONMETALS; NUCLEI; ODD-ODD NUCLEI; OXYGEN COMPOUNDS; RADIATION DETECTORS; RADIOISOTOPES; RADON ISOTOPES; RARE GASES; SCINTILLATION COUNTERS; SOLID SCINTILLATION DETECTORS; WATER

Optional Information

Notes
15 refs., 8 figs.; This record replaces 53019912