Dosimetry of $^{222}Rn$ Component in Outdoor Natural Background Radiation

자연 방사선량 중 $^{222}Rn$기여 성분 정량 해석

  • Jun, Jae-Shik (Department of Physics, Chungnam National University) ;
  • Oh, Hi-Peel (Department of Physics, Chungnam National University) ;
  • Chae, Ha-Suk (Department of Physics, Chungnam National University) ;
  • Lee, Byung-Young (Department of Physics, Chungnam National University) ;
  • Kim, Do-Sung (Department of Physics Education, Taegu University)
  • Published : 1989.12.20

Abstract

A study for the assessment of dose given by outdoor radon to respiratory system has been carried out by making use of radon-cups containing CR-39 plastic track detectors. Detection efficiencies were determined by irradiation of the radon-cups in a standard radon chamber of known concentration. Thus determined detection factors of CR-39 plastic track detector in bare, open cup and filtered cup geometry are found to be 0.273, 0.0813 and 0.0371 $trmm^{-2}$/(37$Bqm^{-3}{\cdot}d$), respectively, which are chemically etched in 30% NaOH solution of $70^{\circ}C$ for 220 minutes. The outdoor radon concentrations measured at Taejeon(Chungnam National University) from May 1988 to March 1989 are in the range of 27.4 - 135.8 Bq/$m^3$(0.74 - 3.67pCi/l)by open cup and 16.7 - 143.9 Bq/$m^3$(0.45 - 3.89 pCi/l) by filtered cup, which yield overall annual average value of outdoor radon concentration of $70.8Bq/m^3$(1.91 pCi/l). Corresponding effective dose equivalent rate to respiratory system of ICRP standard man is assessed to be 520 nSv /h.

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