• Title, Summary, Keyword: 감마 선량률

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Cross Correlation Analysis of Gamma Exposure Rates and Rainfall, Hours of Saylight, Average Wind Speed in Gangneung Area (강릉 지역 공간 감마선량률과 강수량, 일조시간, 평균풍속 사이 교차 상관성 분석)

  • Cha, Hohwan;Kim, Jaehwa
    • Journal of the Korean Society of Radiology
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    • v.7 no.5
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    • pp.347-352
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    • 2013
  • In this study, we analyze the cross correlation between Gamma exposure rates and Rainfall, Hours of daylight, Average wind speed using cross-correlation coefficient ${\rho}_{DCCA}$ and DCCA cross-correlation coefficient(DCCA ${\rho}$) method. Our data are measured simultaneous in Gangneung regional. First, we find the ${\rho}_{DCCA}$ between Gamma exposure rates and Rainfall is Day(3~7days) 0.57~0.48, Month(30days) 0.39, Season(90days) 0.34, Year(360days) 0.26, between Gamma exposure rates and Hours of daylight is Day -0.20~-0.23, Month -0.22, Season -0.17, Year -0.13, between Gamma exposure rates and Average wind speed is Day -0.10~-0.12, Month -0.11, Season -0.05, Year -0.05. Second, our finding is cross- correlation between Gamma exposure rates and Rainfall, is no cross-correlation between Gamma exposure rates and Hours of daylight, Average wind speed.

A Study of Gamma-ray Irradiation Effects on Commercially Available Single-mode Optical Fiber using Fiber Bragg Grating Sensor Systems (광섬유 브래그 격자 센서를 이용한 국내외 상용 단일모드 광섬유의 감마선 영향 연구)

  • Kim, Jong-Yeol;Lee, Nam-Ho
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.16 no.10
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    • pp.2287-2292
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    • 2012
  • In this study, $Co^{60}$ gamma-ray induced loss on Ge-doped single mode (SM) fiber has been measured. Gamma-ray is irradiated for 4 hours at the dose rate of 0.5 kGy/hr, 2 kGy/hr, 8 kGy/hr. Consequently, gamma-ray induced loss based on radiation effects in Ge-doped SM fiber occur significantly. Furthermore, dose rate effect was observed, that dose rate using the same total dose increased higher, then optical fiber loss increased more. Also annealing effect was observed, that the loss after irradiation, increased higher, then the recovery rate of loss was increased. This results are foreseen to be base data in the future radiation-hardened optical fiber study.

Analysis of the Distributional Effects of Radioactive Materials on External Gamma Exposure (방사성물질의 분포특성에 따른 외부 감마피폭해석)

  • Han, Moon-Hee;Kim, Eun-Han;Suh, Kyung-Suk;Hwang, Won-Tae;Choi, Young-Gil
    • Journal of Radiation Protection and Research
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    • v.23 no.4
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    • pp.211-218
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    • 1998
  • The distributional effects of radioactive materials on external gamma exposure have been analyzed. An approximate method for estimating external gamma dose given from an arbitrary distribution of radioactive material has been developed. The minimum gamma exposure given from a point source is shown at 0.07 MeV if the source to receptor distance is shorter than 10 m. But if the receptor to point source distance is longer than 20 m, gamma exposure rate increases monotonously according to the average gamma energy. For the analysis of the effects of volume source, we estimated the gamma dose given from different size of hemisphere in which radioactive materials are distributed uniformly. When the radius of hemisphere is longer than 40 m, external gamma dose rate increases monotonously. The gamma dose rate given from the radioactive materials deposited on the ground shows the minimum value at 0.07 MeV in any case. The analysis shows that external gamma exposure is strongly dependent on the distribution of radioactive materials in the environment and gamma energy.

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감마선이 Artemia 알의 부화에 미치는 영향

  • 김원록;김진규;이영근;이창주;장화형
    • Proceedings of the Korean Nuclear Society Conference
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    • pp.720-724
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    • 1998
  • 감마선이 Artemia 알의 부화에 미치는 영향을 알아보고자, 10Gy, 100Gy, 3kGy, 6kGy과 9kGy의 선량으로 건조 상태의 알을 조사한 후 부화율과 nauplius기의 출현률을 조사하였다. 1kGy 이하의 방사선 조사군에서는 부화율과 nauplius기의 출현률이 대조군에 비하여 높게 나타났다. 3kGy 방사선조사군의 경우 대조군과 유사한 부화율을 보였으나 nauplius기의 출현률은 감소하였다. 6kGy의 방사선조사군에서는 알들의 부화 지연과 부화율의 감소가 뚜렷하였다. 50%의 부화율을 나타내는 선량은 약 5.5kGy였으며, 9kGy에서는 100% 치사선량을 나타내었다. 본 실험에서 조사한 선량증에서 비교적 낮은 선량의 범위에서는 이온화방사선에 의하여 Artemia 알의 부화시간 단축 및 부화율이 다소 증가하는 결과를 보였다. 따라서 이온화방서선을 이용한 Artemia 알의 부화률을 촉진지킬 수 있는 적정 선량에 대한 연구는 상업적으로도 가치가 있다고 생각되며, 향후 이에 대한 추가적인 연구를 통한 상업적인 활용이 기대된다.

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Time Series Analysis of Gamma exposure rates in Gangneung Area (강릉 지역 공간 감마선량률의 시계열 분석)

  • Cha, Hohwan;Kim, Jaehwa
    • Journal of the Korean Society of Radiology
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    • v.7 no.1
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    • pp.25-30
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    • 2013
  • In this work, we investigate the statistical properties of gamma exposure rates using well-known analysis methods, such as Autocorrelation Function Analysis(ACF), Rescaled Range Analysis(R/S Analysis), and Detrended Fluctuation Analysis(DFA). Especially, DFA is an important method to reliably detect long-range correlations in non-stationary time series. Our data are measured by Gangneung regional radiation monitoring station over the period of 1998 to 2011. First, we find a crossover indicating two different governing regimes in fluctuations of gamma exposure rates. Within a year, they show a strong long-ranged memory while this property vanishes over the range of time period longer than one year. Second, our finding is very securely supported by a variety of analysis tools. Those tools yield many relevant exponents which satisfies the well known relation between them.

Exposure Measurements of Co-60 Gamma rays (Co-60 감마선의 조사선량 측정)

  • Hah, Suck-Ho;Kim, Hyun-Moon
    • Journal of Radiation Protection and Research
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    • v.16 no.2
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    • pp.7-16
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    • 1991
  • Measurement of Co-60 gamma rays has been made for establishment of exposure standard and analyze it's overall uncertainties. Exposure rate determined by the charge mode method using vibrating reed amplifier with cylinderical type cavity chamber. The values of a variety of physical constants and the correction factors are evaluated. The resulting exposure rate is 690.81 R/h at the distance of 1m from the source and the related uncertainties is ${\pm}0.8%$

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The Analysis of Radiation Effects of Single-Mode Optical Fibers Using Fiber Bragg Grating Sensors (광섬유 브래그 격자 센서를 이용한 단일모드 광섬유의 방사선 영향 분석)

  • Kim, Jong-Yeol;Lee, Nam-Ho;Jung, Hyun-Kyu;Kim, Young-woong;Han, Won-Taek
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.732-735
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    • 2013
  • In this study, we are measured gamma-ray induced loss on single-mode (SM) fibers from a total of four different manufactures. The $Co^{60}$ gamma-ray source was used in this test. The gamma-ray is irradiated for 2 hours at the dose rate of 0.6 kGy/hr, 1.2 kGy/hr, 2.4 kGy/hr. In test results, We clearly confirm the dose rate effect in different fiber types and evaluate the radiation sensitivity by the change of the radiation-induced loss.

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Evaluation on the Radiological Shielding Design of a Hot Cell Facility (핫셀시설의 방사선 안전성 평가)

  • 조일제;국동학;구정회;정원명;유길성;이은표;박성원
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.2 no.1
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    • pp.1-11
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    • 2004
  • The hot cell facility for research activities related to the lithium reduction of spent fuel, which is designed to permit safe handling of source materials with radioactivity levels up to 1,385 TBq, is planned to be built. To meet this goal, the facility is designed to keep gamma and neutron radiation lower than the recommended dose-rate in normally occupied areas. The calculations peformed with QAD-CGGP and MCNP-4C are used to evaluate the proposed engineering design concepts that would provide acceptable dose-rates during a normal operation in hot cell facility. The maximum effective gamma dose-rates on the surfaces of the facility at operation area and at service area calculated by QAD-CGGP are estimated to be $2.10{\times}10^{-3}, 2.97{\times}10^{-3} and 1.01{\times}10{-1}$ mSv/h, respectively. And those calculated by MCNP-4C are $1.60{\times}10^{-3}, 2.99{\times}10^{-3} and 7.88{\times}10^{-2}$ mSv/h, respectively, The dose-rates contributed by neutrons are one order of magnitude less than that of gamma sources. Therefore, it is confirmed that the radiological design for hot cell facility satisfies the Korean criterion of 0.01 mSv/h for the operation area and 0.15 mSv/h for the service (maintenance) area.

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Assessment of Gamma-radiation dose Rate in the Ogcheon Lower Phyllite Area, Goesan County, Korea, Using Gamma-ray Spectrometry (감마선분광분석기를 이용한 괴산 옥천하부천매암대 일대의 감마선량 평가)

  • Yun, Uk;Cho, Byong-Wook
    • The Journal of Engineering Geology
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    • v.29 no.4
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    • pp.461-468
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    • 2019
  • Gamma-radiation dose rates were measured at 77 points around the Ogcheon lower phyllite zone (og2) in Goesan County, Korea, using gamma-ray spectrometry. Sample K contents were in the range 1.8-8.8% (average 4.6%), highest in Kgr. The eU contents were 0.2-217.9 ppm (average 16.7 ppm), highest in og2 (median 29.6 ppm). The eTh contents were 11.9-76.5 ppm (average 29.5 ppm) and the average eTh content of Kgr was 45.4 ppm, higher than those of Ogcheon meta-sedimentary rocks (og1, og2, and og3) (26.6-30.6 ppm). Except for some high-uranium sites in og2, 40K is the main radioactive material contributing to the gamma-radiation dose in the study area. Our results indicate that the outdoor effective dose rate of the area is 0.08-1.71 mSv y-1 (average 0.28 mSv y-1), with most areas apart from three points in og2 displaying dose rates <1 mSv y-1, which is the normal natural radiation background level.