Measurement of ultra-low-level of 137Cs in the fallout using a well-type gamma spectrometry |
Eun-Hee Kwon1,2, Sang-Han Lee1,2, Dong-Hye Heo1, Jong-Man Lee1,2 |
1Korea Research Institute of Standards and Science (KRISS), Daejeon 34113, Rep. of Korea 2University of Science and Technology (UST), Daejeon 34113, Rep. of Korea |
우물형 감마검출기를 이용한 대기 낙진 중 극저준위 137Cs 측정 |
권은희1,2, 이상한1,2, 허동혜1, 이종만1,2 |
1한국표준과학연구원 2과학기술연합대학원대학교 |
Correspondence:
Sang-Han Lee, Tel: 82-42-868-5812, Fax: 82-42-868-5671, Email: s.lee@kriss.re.kr |
Received: 16 April 2019 • Revised: 27 May 2019 • Accepted: 28 May 2019 |
Abstract |
The Korea Institute of Nuclear Safety (KINS) has been monitoring the radioactivity in the atmospheric fallout for a long time. Results show that 137Cs was always below the Minimum Detectable Activity (MDA) except when the Fukushima Nuclear Power Plant accident occurred. The Ionizing Radiation Center at Korea Research Institute of Standards and Science (KRISS) also collected the atmospheric fallouts at the end of each month and measured 137Cs using a well-type HPGe detector (GWL-300-15-s) since 2012. The annual 137Cs depositions ranged from 79 to 225 mBq/m2/year. 137Cs detected in the present atmospheric fallout is considered to be originated from the atmospheric nuclear bomb tests conducted by the USA and the former Soviet Union in the 1950s and early 1960s. The results of this study indicate that the well-type HPGe detector is more suitable for small size environmental samples (i.e., 0.5 - a few grams) and extreme low activity levels compared with the conventional detector (GEM90P4-95). |
Key Words:
Well-type gamma spectrometry, Atmospheric fallout, 137Cs, Fukushima Nuclear Power Plant accident |
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