• Title, Summary, Keyword: Gamma dose rate

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A Study on the Environmental Radiation of Concrete Apartments and Neighborhood Living Facilities (콘크리트 공동주택과 근린생활 시설의 환경방사선에 관한 연구)

  • Ji, Tae-Jeong;Kwak, Byung-Joon;Min, Byung-In
    • Journal of the Korean Society of Safety
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    • v.24 no.2
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    • pp.100-104
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    • 2009
  • In this study, the space gamma dose rates in the apartments structured with concrete were measured in accordance with construction year. In addition, the environmental radiation rates coming from the subway platforms and the road tunnels were analyzed in the equivalent dose by multiplying the absorbed dose with the radiation weighting factors. The space gamma dose rates measured in apartments were higher than those of outdoor which was $0.08{\sim}0.11uSv/h$ in the natural conditions. Especially, the older construction year is, the higher becomes space gamma dose rate. The average gamma dose rates in the subway platforms were measured. In the case of Busan and Daegu subway, the earlier the opening year is, the higher becomes dose rate. However, the dose rates of Seoul subway Lines were high overall, regardless of opening year. Seoul subway Line 6 showed the highest value of 0.21uSv/h. The gamma dose rate in road tunnels was higher than one of the outdoor and increased with opening year like as apartment. In dose rate comparison of the concrete structures with the outdoor, therefore, the space gamma dose rate of indoor is higher than one of the outdoor and the older structures have a higher dose rate.

A Study on Gamma Dose Rate in Seoul(I) (서울시내 공간 감마선량률 조사(I))

  • Kim, You-Hyun;Kim, Chang-Kyun;Choi, Jong-Hak;Kim, Jeong-Min
    • Journal of radiological science and technology
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    • v.24 no.1
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    • pp.61-65
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    • 2001
  • This study was conducted to find out gamma dose rate in Seoul, from January to December in 2000, and the following results were achieved ; 1. The annual gamma dose rate in Seoul was $17.24{\mu}R/hr$ as average. 2. The annual gamma dose rate in subway of Seoul was $14.96{\mu}R/hr$ as average. 3. The highest annual gamma dose rate was Dong-daemon ku. 4. Annual gamma dose rate in Seoul was higher autumn than winter.

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A CCD Camera Lens Degradation Caused by High Dose-Rate Gamma Irradiation (고 선량율 감마선 조사에 따른 렌즈의 열화)

  • Cho, Jai-Wan;Lee, Joon-Koo;Hur, Seop;Koo, In-Soo;Hong, Seok-Boong
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.7
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    • pp.1450-1455
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    • 2009
  • Assumed that an IPTV camera system is to be used as an ad-hoc sensor for the surveillance and diagnostics of safety-critical equipments installed in the in-containment building of the nuclear power plant, an major problem is the presence of high dose-rate gamma irradiation fields inside the one. In order to uses an IPTV camera in such intense gamma radiation environment of the in-containment building, the radiation-weakened devices including a CCD imaging sensor, FPGA, ASIC and microprocessors are to be properly shielded from high dose-rate gamma radiation using the high-density material, lead or tungsten. But the passive elements such as mirror, lens and window, which are placed in the optical path of the CCD imaging sensor, are exposed to a high dose-rate gamma ray source directly. So, the gamma-ray irradiation characteristics of the passive elements, is needed to test. A CCD camera lens, made of glass material, have been gamma irradiated at the dose rate of 4.2 kGy/h during an hour up to a total dose of 4 kGy. The radiation induced color-center in the glass lens is observed. The degradation performance of the gamma irradiated lens is explained using an color component analysis.

Assessment of the terrestrial gamma radiation dose in Korea

  • Choi, Seok-Won;Yun, Ju-Yong;Kim, Chang-Kyu;Rho, Byung-Hwan;Lee, Jong-Seong
    • Journal of Radiation Protection and Research
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    • v.30 no.4
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    • pp.161-165
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    • 2005
  • The gamma-ray dose rates in air at 233 locations in Korea have been determined. The contribution to the gamma-ray dose rates in air due to the presence of $^{232}Th-series,\;^{238}U-series\;and\;^{40}K$ is as follows: 47.3% $(36\;nGyh^{-1})\;^{232}Th-series$ 14.5% $(11\;nGyh^{-1})\;^{238}U-series$ and 38.2% $(29\;nGyh^{-1})\;^{40}K$. The mean gamma-ray dose rate theoretically derived from $^{232}Th-series,\;^{238}U-series\;and\;^{40}K\;was\;76{\pm}17\;nGyh^{-1}$. This corresponds to an annual effective dose of $410\;{\mu}Sv$ and an annual collective dose of 18900 person-Sv for all provinces under study. The results have been compared with other global radiation dose.

Measurements of X-Ray and Gamma Ray Dosse Rate by the Silicon P-N Junction Diode (Silicon P-N Junction Diode에 대한 X-Ray 및 Gamma-Ray 의 Dose Ratec 측정)

  • 정만영;김덕진
    • 전기의세계
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    • v.13 no.3
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    • pp.13-20
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    • 1964
  • The measurements of X-ray and Gamma-ray Dose Rate have been successfully made by measuring the short circuit current of the Silicon P-N Junction Diode being irradiated. The short circuit current flows when a silicon P-N Junction Diode is irradiated by X-ray of Gammaray radiations due to photovoltaic effect. A brief analysis is given in order to verify the proportionality of a short circuit current to the Dose Rate. Using this method, measurements of X-ray Dose Rate were carried out in the range of 0.05-1600 r/m successfully. The calibration was made by comparing with Victoreen condenser r-meter. Some advantages in this Dose Rate meter over a condenser r-meter were found. One can measure a continous variation of X-ray Dose Rate with this rate meter at the control console of X-ray device.

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Simulation for Dose-Rate Latchup by Transient Radiation Pulse in CMOS Device (CMOS 소자에서 과도방사선펄스에 의한 Dose-Rate Latchup 모의실험)

  • Lee, Hyun-Jin;Lee, Nam-Ho;Hwang, Young-Gwan
    • Proceedings of the IEEK Conference
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    • pp.1185-1186
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    • 2008
  • A nuclear explosion emits a transient radiation pulse like gamma rays. Gamma rays have a high energy and cause unexpected effects in semiconductor devices. These effects are mainly referred to dose-rate latcup and dose-rate upset. By transient radiation pulse in CMOS devices, dose-rate latchup is simulated in this paper.

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Calculation of Neutron and Gamma-Ray Flux-to-Dose-Rate Conversion Factors (중성자(中性子) 및 감마선(線)에 대한 선량율(線量率) 환산인자(換算因子) 계산(計算))

  • Kwon, Seog-Guen;Lee, Soo-Yong;Yook, Chong-Chul
    • Journal of Radiation Protection and Research
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    • v.6 no.1
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    • pp.8-24
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    • 1981
  • This paper presents flux-to-dose-rate conversion factors for neutrons and gamma rays based on the American National Standard Institute(ANSI) N666. These data are used to calculated the dose rate distribution of neutron and gamma ray in radiation fields. Neutron flux-to-dose-rate conversion factors for energies from $2.5{\times}10^{-8}$ to 20 MeV are presented; the corresponding energy range for gamma rays is 0.01 to 15 MeV. Flux-to-dose-rate conversion factors were calculated, under the assumption that radiation energy distribution has nonlinearity in the phantom, have different meaning from those values obtained by monoetiergetic radiation. Especially, these values were determined with the cross section library. The flux-to-dose-rate conversion factors obtained in this work were in a good agreement to the values presented by ANSI. Those data will be a useful for the radiation shielding analysis and the radiation dosimetry in the case of continuous energy distributions.

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Monitoring Performance of Camera under the High Dose-rate Gamma Ray Environment (고선량율 감마선 환경하에서의 카메라 관측성능)

  • Cho, Jai-Wan;Jeong, Kyung-Min
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.61 no.8
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    • pp.1172-1178
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    • 2012
  • In this paper, the gamma ray irradiation test results of the CCD cameras are described. From the low dose-rate (2.11 Gy/h) to the high dose-rate (150 Gy/h) level, which is the same level when the hydrogen explosion was occurred in the 1~3 reactor unit of the Fukushima nuclear power plant, the monitoring performance of the cameras owing to the speckles are evaluated. The numbers of speckles, generated by gamma ray irradiation, in the image of cameras are calculated by image processing technique. And the legibility of the sensor indicator (dosimeter) owing to the numbers of the speckles is presented.

Analysis of Visible Light Communication Module Degraded by High Dose-Rate Gamma Irradiation using Thermal Infrared Image (적외선 열영상을 이용한 가시광 통신모듈의 고선량 감마선조사에 따른 열화 분석)

  • Cho, Jai-Wan;Hong, Seok-Boong;Koo, In-Soo
    • Journal of Institute of Control, Robotics and Systems
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    • v.17 no.12
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    • pp.1203-1209
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    • 2011
  • In this paper, the degradation evaluation method of VLC (Visible Light Communication) wireless module after high dose rate gamma-ray irradiation using the thermal infrared camera is proposed. First, the heating characteristics of the active devices embedded in the VLC wireless module during the condition of normal operation is monitored by thermal infrared camera. By the image processing technique, the trends of the intensity of the heat emitted by the active devices are calculated and stored. The feature of the blob area including the area of the active devices in the thermal infrared image is extracted and stored. The feature used in this paper is the mean value of the gray levels in the blob area. The same VLC module has been gamma irradiated at the dose rate of about 4.0 kGy/h during 72 hours up to a total dose of 288 kGy. And then, the heating characteristics of the active devices embedded in the VLC wireless module after high dose gamma ray irradiation is observed by thermal infrared camera. The high dose gamma-ray induced degradation of the active devices embedded in the VLC module was evaluated by comparing the mean value of the blob area to the one of the same blob area of the VLC module before the gamma ray irradiation.

VLC Wireless Data Transmission of High Luminance LED Irradiated by the High Dose-Rate Gamma-Ray (고 선량 감마선 조사에 따른 고휘도 LED의 가시광 무선 데이터 전송)

  • Cho, Jai-Wan;Choi, Young-Soo;Hong, Seok-Boong
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.5
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    • pp.996-1000
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    • 2010
  • In order to apply VLC (visible light communication) in harsh environment of nuclear power plant in-containment building, the high luminance LEDs, which are key components of the VLC system, have been gamma irradiated at the dose rate of 4 kGy/h during 72 hours up to a total dose of 288 kGy. The radiation induced coloration effect in the high luminance LED bulb made of acryl or plastic material was observed. In the VLC wireless data transmission experiment using the high luminance LEDs irradiated by high dose rate gamma-ray, the radiation induced coloration effect of the high luminance LED bulb extended the communication distance compared to non-irradiated LEDs.