• 동위원소회보
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• 제21권4호
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• pp.55-65
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• 2006

A passive type radon monitor adopting two silicon PIN detector as radiation detector has been developed, manufactured and test-evaluated. A radiation signal processing circuit has been electronically tested and then the radiation detection characteristics of this instrument has been performance-tested by using reference radon concentration and a reference photon radiation field. As a result, in a electronic performance test, radiation signals from each detector were well observed in each signal processing circuit. The radiation detection sensitivity of this instrument after several test-irradiations to a Cs-137 gamma radiation source and a standard radon concentration appeared to be 1.37 cph/$\mu$Svh-1 and 1.66 pCi/L respectively. The developed radon monitor in this paper could be used conveniently in monitoring of radon concentration in buildings which population utilize in Korea.

• Nuclear Engineering and Technology
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• 제37권4호
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• pp.395-400
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• 2005

An environmental radon monitoring system, comprising a radon-cup, an etching system, and a track counting system, was constructed. The radon cup is a cylindrical chamber with a radius of 2.2 cm and a height of 3.2 cm in combination with a CR-39 detector. Carbon is impregnated in the bodies of the detector chamber to avoid problem of an electrostatic charge. The optimized etching condition for the CR-39 exposed to a radon environment turned out to be a 6 N NaOH solution at 70^{\circ}$ over a 7hour period. The bulk etch rate under the optimized condition was $1.14{\pm}0.03\;{\mu}m\;h^{-1}$. The diameter of the tracks caused by radon and its progeny were found to be in the range of $10\~25\;{\mu}m$ under the optimized condition. The track images were observed with a track counting system, which consisted of an optical microscope, a color charged couple device (CCD) camera, and an image processor. The calibration factor of this system is obtained to be $0.105{\pm}0.006$ tracks $cm^2$ per Bq $m^{-3}$ d.

• Environmental Analysis Health and Toxicology
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• 제24권3호
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• pp.203-211
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• 2009

A lesser degree of research is available with respect to indoor radon characteristics associated with occupants' exposure. The present study evaluated the radon levels in several public-access buildings or underground facilities, and their temporal variation in underground facilities. Radon measurements were conducted in 2005 and 2006, utilizing a continuous radon detector. A solid alpha detector (RAD7) was utilized to measure indoor radon levels. The mean radon concentrations obtained from the building or facilities were in a descending order: platforms of Daegu subway line 2, 2005 (32 $Bq/m^3$), hot-air bathroom (14 $Bq/m^3$), basement of office building (14 $Bq/m^3$), underground parking garage (14 $Bq/m^3$), underground shop (12 $Bq/m^3$), nursery (10 $Bq/m^3$), platforms of Daegu subway line 2, 2006 (9.0 $Bq/m^3$), platforms of Daegu subway line 1, 2006 (8.9 $Bq/m^3$), supermarket (7.9 $Bq/m^3$), hospital (7.3 $Bq/m^3$), and second-floor of office building (5.7 $Bq/m^3$). In general, underground-level facilities exhibited higher radon levels as compared with ground-level facilities. It was suggested that ventilation is an important parameter regarding the indoor levels of a subway. There was a decreasing or increasing trend in hourly-radon levels in a subway, whereas no trend were observed in a basement of office building. In addition, the radon levels in the subway lines 1 and 2 varied according to the platforms. The radon levels in the present study were much lower than those of previous studies. The average annual effective dose (AED) of radiation from indoor radon exposure was estimated to be between 0.043 and 0.242 mSv/yr, depending on facility types. These AEDs were substantially lower than the worldwide average AED (2.4 mSv/yr).

• 한국환경보건학회지
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• 제28권5호
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• pp.71-76
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• 2002

A survey of radon concentrations in both indoor and outdoor atmospheres was carried out using EIRM and Cup Monitor for the period of February 1996 to March 1997. EIRM were used to measure the indoor and outdoor radon concentration at five major cities university. Cup Monitor were also used to measure the indoor radon concentrations at shopping store, office building, apartment, hospital and house in Seoul. The mean indoor and outdoor radon concentrations at the five major cities(Seoul, Daegu, Daejon, Cwangiu and Busan) were 24.1 Bq/m$^3$and 8.62 Bq/m$^3$, respectively. The ratio of indoor to outdoor radon concentrations ranged front 1.7 to 3.9. Inspection of its seasonal distribute pattern indicates the enhancement during winter relative to summer, consistently for both indoor and outdoor air. The results of the survey showed that the concentrations in basements were clearly higher than those in usual living/working places.

• 한국환경보건학회지
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• 제45권6호
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• pp.668-674
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• 2019

Objectives: Modern people spend most of their day indoors. As the health impact of radon becomes an issue, public interest also has been growing. The primary route of potential human exposure to radon is inhalation. Long-term exposure to high levels of radon increases the risk of developing lung cancer. Radon exposure is known to be the second-leading cause of lung cancer, following tobacco smoke. This study measures the indoor radon concentrations in detached houses in area A of Chungcheongbuk-do Province considering the construction year, cracks in the houses, the location of installed detectors, and seasonal effects. Methods: The survey was conducted from September 2017 to April 2018 on 1,872 private households located in selected areas in northern Chungcheongbuk-do Province to figure out the year of building construction and the location of detector installed and identify the factors which affect radon concentrations in the air within the building. Radon was measured using a manual alpha track detector (Raduet, Hungary) with a sampling period of longer than 90 days. Results: Indoor radon concentrations in winter within area A was surveyed to be 168.3±193.3 Bq/㎥. There was more than a 2.3 times difference between buildings built before 1979 and those built after 2010. The concentration reached 195.4±221.9 Bq/㎥ for buildings with fractures and 167.2±192.4 Bq/㎥ for buildings without fractures. It was found that detectors installed in household areas with windows exhibited a lower concentration than those installed in concealed spaces. Conclusion: High concentrations of indoor radon were shown when there was a crack in the house. Also, ventilation seems to significantly affect radon concentrations because when the location of the detector in the installed site was near windows compared to an enclosed area, radon concentration variation increased. Therefore, it is considered that radon concentration is lower in summer because natural ventilation occurs more often than in winter.

• 전자공학회논문지
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• 제53권11호
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• pp.99-106
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• 2016

라돈이 기관지나 폐포에 머무르게 될 때 라돈의 붕괴로 인해 자핵종(알파선, 베타선, 감마선 등)들이 생성되면서 이것들이 방사선을 방출하는데 세포의 염색체에 돌연변이를 일으켜 폐암을 발생할 가능성이 존재한다. 다시 말해 폐암의 원인이 라돈가스 때문이라기보다는 흡수된 일부 라돈의 붕괴로 인해 생기는 부산물이 방사선을 방출하기 때문이라고 할 수 있다. 사람이 연간 노출되는 방사선의 82%가 자연방사선에 의한 것인데 그중 대부분이 라돈이다. 실내의 라돈 농도를 적절하게 제어할 수 있다면 폐암의 발생확률을 30%나 억제할 수 있다고 알려져 있다. 아직까지 실내의 라돈의 농도를 측정하는 데는 외국의 라돈 센서를 사용하고 있는 실정이다. 실내 라돈 방출량에 대한 데이터 구축과 국내에 맞는 실용적인 라돈측정기기를 개발하도록하는 연구가 필요하다. 본 논문에서는 PIN Photodiode를 이용하여 라돈의 농도를 측정하는 라돈 검출기 구현 방법을 제안한다. 실험을 통해서, PIN photodiode의 라돈 센서 모듈로서의 이용 가능성에 대하여 확인하였다.

• Journal of Radiation Protection and Research
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• 제22권4호
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• pp.243-250
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• 1997

공기 중의 라돈 농도를 측정하기 위한 고체비적검출기의 상대교정법을 개발하였으며, 상대 교정된 CN-85를 이용하여 15층 아파트 층 별로 실내 공기 중의 라돈 농도를 측정한 후 피폭 선량을 계산하여 보았다. 측정 결과 아파트 실내 공기 중에서의 라돈 농도는 대체적으로 상층으로 올라갈수록 감소하는 경향이 있었으나, 환기 횟수에 크게 영향을 받음을 알 수 있었다. 측정값의 평균은 $1.50{\pm}0.51pCi/1$ 였으며, 최대값과 최소값은 각각 $2.68{\pm}0.32pCi/l$, $0.69{\pm}0.16pCi/l$였다.

• Journal of Radiation Protection and Research
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• 제16권1호
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• pp.15-24
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• 1991

CR-39 플라스틱 핵비적검출기를 라돈검출기로 내장한 멤브레인 필터컵(일명 : CR-39 라돈컵)을 이용하여 일부 국산건축자재의 라돈방출율을 측정하였다. 표준라듐선원을 이용한 라돈컵의 교정 실험을 수행하여 얻은 CR-39 검출기의 라돈검출인자는 $0.164{\pm}0.005(tracks \;cm^{-2}/Bq\;d\;m^{-3})$였으며 타 연구자들의 발표결과와 잘 일치하였다. 일부 건축자재(모래벽돌, 적벽돌, 화장석판, 콘크리트 덩어리, 건물바닥과 내벽)에 CR-39 라돈컵을 2개월 동안 기밀 부착하여 라돈방출율을 측정한 결과, 라돈방출율은 모래벽돌에서 평균$(75.0{\pm}5.5){\times}10^{-6}(Bq/m^2-s)$, 화강석판에서 $(6.8{\pm}2.9){\times}10^{-6}Bq/m^2-s)$로 10배정도의 차이를 보였으며, 모래벽돌>콘크리트바닥>콘크리트덩어리>건물벽>적벽돌>화강석 판의 순서를 보였다. 본 연구 결과, CR-39 라돈컵에 의해서도 건축자재의 라돈방출율을 효과적으로 측정할 수 있음이 입증하였다.

• 한국환경보건학회지
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• 제30권5호
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• pp.469-480
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• 2004

The radon concentrations were measured to survey distribution of radon concentrations in Seoul subway stations. The radon concentrations in air and water were measured at seventeen subway stations(Mapo, Chungjongno, Sodaemun, Kwanghwamun, Chongno3ga, Ulchiro4ga, Tangdaemun, Sangildong on Line 5;Nowon, Chunggye, Hagye, Kongnung, Taenung, Mokkol, Chunghwa, Sangbong, Myomok on Line 7) using the $RAdtrak^{TM}$ radon gas detector, Pylon AB-5 continuous passive radon detector and liquid scintillation counting method from January to May 1999. The major results obtained from this study were as follows: The long-term mean concentrations of radon were $61.8\;Bq/m^3$ in office, $78.9\;Bq/m^3$ in platform, $38.2\;Bq/m^3$ in concourse and $20.1\;Bq/m^3$ in outdoor, respectively. These levels were less than the action level ($148\;Bq/m^3$) of the U.S. EPA. The highest level of short-term mean concentrations was $116.55\;Bq/m^3$ at Chongno3ga station on the 5th line subway stations, while the lowest mean concentration was $19.55\;Bq/m^3$ at Mokkol station on the 7th line subway stations. The highest concentration of radon in the road water and storing underground water in the subway stations was $234.7\;KBq/m^3\;and\;155.5\;KBq/m^3$ in Sodaemun subway station, respectively. The results suggest that radon concentration in subway stations seems to be affected by ventilation and radon concentratin in underground water in the subway stations.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1998년도 추계학술발표회요약집
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• pp.325-325
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• 1998