A Measurement of the Exposure Rates by Terrestrial y-rays in Taegu Area

대구지역(大邱地域) 지각(地殼) ${\gamma}$-선(線)의 조사선량율(照射線量率) 측정(測定)

  • Chang, Si-Ho (Department of physics, Kyungpook National University) ;
  • Jeong, Chun-Gyun (Department of physics, Kyungpook National University) ;
  • Kang, Hee-Dong (Department of physics, Kyungpook National University) ;
  • Lee, Mo-Sung (Korea Institute of Nuclear Safety) ;
  • Choi, Mun-Kyu (Wolsung Nuclear Power Unit, Korea Electric Power Corporation) ;
  • Kim, Wi-Soo (Wolsung Nuclear Power Unit, Korea Electric Power Corporation)
  • 장시호 (경북대학교 물리학과) ;
  • 정춘균 (경북대학교 물리학과) ;
  • 강희동 (경북대학교 물리학과) ;
  • 이모성 (한국원자력안전기술원) ;
  • 최문규 (한국전력공사 월성원자력본부) ;
  • 김위수 (한국전력공사 월성원자력본부)
  • Published : 1994.08.30

Abstract

This study concerns about the measurement and the investigation of environmental radiation characteristics which the components and the distribution of exposure rates by terrestrial y-rays in Taegu area. $4^{'}{\phi}{\times}4^{'}$ NaI(T1) scintillation detector with a multichannel analyzer was used in the measurement of y-rays as a part of in-situ spectrometry at twenty eight different locations in this area. The conversion into the exposure rate from the measured ${\gamma}-ray$ spectrum has been carried out leading to a net exposure rate and component ones by $^{40}K,\;^{238}U$ series and $^{232}Th$ series products which are known by the major parts in the terrestrial ${\gamma}-rays$ generally. As a result, the average exposure rate by the terrestrial ${\gamma}-rays$ in Taegu area is $9.4{\mu}R/h$ and the distribution of individual exposure rates shows more or less differences between these locations even after the consideration of diurnal and yearly variations which are always involved in these measurements. The component parts of exposure rates are distributed $^{40}K\;2.9{\sim}4.6{\mu}R/h,\;^{238}U$ series $1.2{\sim}3,\;1{\mu}R/h,\;^{232}Th$ series $2.5{\sim}5.0{\mu}R/h$ over the measured locations.