• 전기학회논문지
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• 제58권7호
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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.

• 전기학회논문지
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• 제61권8호
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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.

• 전기학회논문지
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• 제59권5호
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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.

• 제어로봇시스템학회논문지
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• 제17권12호
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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.

• Nuclear Engineering and Technology
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• 제54권9호
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• pp.3398-3402
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• 2022

We fabricated a 15 m long position-sensitive plastic scintillation optical fiber (PSOF) detector consisting of a PSOF, two photomultiplier tubes, four fast amplifiers, and a digitizer. A single PSOF was used as a sensing part to estimate the gamma-ray source position, and ¹³⁷Cs, an uncollimated solid-disk-type radioactive isotope, was used as a gamma-ray emitter. To improve the sensitivity, accuracy, and measurement time of a PSOF detector compared to those of previous studies, the performance of the amplifier was optimized, and the digital signal processing (DSP) was newly designed in this study. Moreover, we could measure very low dose rates of gamma-rays with high sensitivity and accuracy in a very short time using our proposed PSOF detector. The results of this study indicate that it is possible to accurately and quickly locate the position of a very low dose rate gamma-ray source in a wide range of contaminated areas using the proposed position-sensitive PSOF detector.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 춘계학술대회 논문집
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• pp.533-534
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• 2009

• 제어로봇시스템학회논문지
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• 제16권6호
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• pp.586-591
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• 2010

VLC (Visible Light Communication) is a wireless communication method using light that is visible to the human eye. It has a major advantage that it causes no interference to RF-based devices. This makes wireless communication possible in RF hazardous areas such as nuclear facilities. In order to apply VLC communication in harsh environment of nuclear power plant, the high luminance LEDs, which are key components of the VLC communication, have been gamma-ray irradiated at the dose rate of 4kGy/h during 72 hours up to a total dose of 288 kGy. The radiation induced color-center was formed in the LED housing cap made of transparent plastic or acryl material. The beam degradations of high luminance LEDs by high dose-rate gammaray irradiation are analyzed using color CCD image processing technology.

• 식물조직배양학회지
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• 제27권2호
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• pp.143-148
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• 2000

감 돌연변이 획득을 위해 기내배양 신초에 ${\gamma}$-선을 조사하여 변이유기를 위한 적정 선량, ${\gamma}$-선 조사 식물체의 기내 발근 및 생육 특성을 조사한 결과는 다음과 같다. 감 돌연변이 유기를 위한 적정한 조사 선량 (LD$_{50}$)은 서촌조생 품종에서 1 krad와 2 krad사이이었고, 일목계차랑 품종은 1 krad이었다. ${\gamma}$-선을 조사한 신초를 1차,2차, 3차에 걸쳐 계대배양하는 각 기간의 기내 생육상태를 보면 ${\gamma}$-선량이 증가할수록 기내에서 생장한 신초의 길이가 감소하였으며, 신초의 정아가 가장 장애를 많이 받았다. 서촌조생 품종에서 신초의 37.5~58.3% 정도가 발근되었고 발근율은 2 krad 처리에서는 가장 낮았다. ${\gamma}$-선 조사선량이 높아지면 발근율과 뿌리의 발생수가 줄어들었다. 순화한 뒤 6주 동안 생장상에서 생육한 ${\gamma}$-선 조사 개체는 무처리 개체의 묘고가 6.0 cm인데 비해 2krad 처리개체는 평균 묘고는 2.6 cm에 불과하였다. 또한 발생한 가지의 수도 무처리에서는 1.0개인데 비해 2krad에서는 1.8 개로 많았다. 온실 생육시에서 ${\gamma}$-선 처리선량이 높았던 개체는 처리되지 않았거나 낮았던 개체에 비해 묘고가 작고 분지수가 많았으며, 생육상태도 부진하여 생육 중에 33%정도만 생존하고 나머지는 고사하였다.다.

• 센서학회지
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• 제9권4호
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• pp.274-280
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• 2000

본 논문은 감마선 방사선 선량을 측정하기 위하여 상용 반도체를 응용하기 위한 실험적 연구에 대하여 다루었다. 실리콘 포토 다이오드는 값이 싸고 작으며 높은 효율과 견고하여 광검출기로 잘 이용되기 때문에 감마선과 같은 방사선 측정에 효과적으로 이용될 수 있다. 대부분의 PN 포토 다이오드는 이 증가함에 따라 역 방향 전류의 증가하는 특성을 가지고 있다. 그러므로 이 소자들의 공핍층이 역 방향 전류에 영향을 주므로 이 공핍층의 면적이 큰 PIN 포토 다이오드를 선택하였다. 이 연구에서는 방사선량을 검출하고 감마선 선량계를 개발하는데 적용하기 위하여, PIN 다이오드에 대해 몇 가지 실험이 수행되었다. NEC사의 PH 302와 SIEMENS사의 BPW 34와 같은 2가지 종류의 포토 다이오드를 반도체 분석장치를 사용하여 $\gamma$선 방사선원인 Co-60의 저준위 시설에서 시험하였다. 그 결과, 방사선 선량률과 다이오드의 전류 사이에 양호한 선형적 함수 관계가 나타나는 것을 확인할 수 있었다. 따라서, 이들 실리콘 PIN 포토 다이오드들은 $\gamma$선 선량계를 설계하는데 적합하게 이용될 수 있을 것이다.

• 한국환경농학회지
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• 제19권4호
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• pp.324-327
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• 2000

저선량 조사한 대두종자의 초기생육과 대두 유식물체의 후속고선량에 대한 방사선 감수성 변화를 알아보고자 저선량 0, 4, 8, 12, 20 Gy를 조사하여 재배한 대두 유식물체에 ${\gamma}$선 50, 100, 200 Gy를 조사한 후 생육상황을 관찰하였다. 저선량 조사에 의해 대두 신규종자의 발아율 증가효과는 없었으나 작물 생장 증대효과는 있었으며 저선량 8 Gy 조사구가 가장 효과적이었다. 대두유식물체의 고선량 방사선에 의한 생육장해는 사전 저선량조사에 의해 크게 감소되었으며 저선량 조사에 의한 고선량 방사선 저항성 증가는 8 Gy와 20 Gy조사에서 가장 효과적이었다.