• 한국정보통신학회논문지
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• 제20권12호
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• pp.2310-2316
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• 2016

본 논문에서는 격자 공정 중에 KrF 엑시머 UV 레이저 노출시간에 따른 광섬유 브래그 격자의 $Co^{60}$ 감마방사선 영향을 연구하였다. 광섬유 브래그 격자는 게르마늄이 첨가된 일반 광섬유를 이용하였으며, UV KrF 엑시머 레이저 노출시간(30, 60, 90, 120초)을 달리하여 제작하였다. 제작된 광섬유 브래그 격자에 106 Gy/min 선량률로 총 선량 34.3 kGy 감마선을 조사한 후 방사선에 의한 온도감도 계수와 브래그 파장 변화를 분석하였다. 실험결과를 통하여, 격자 공정을 위한 UV 레이저 노출시간이 광섬유 브래그 격자의 방사선 민감도에 큰 영향을 줄 수 있다는 것을 확인하였다. 레이저 노출조건 변화에 따른 방사선에 의한 광섬유 브래그 파장의 변화는 최대 50 % 이상의 차이를 보였다.

• 한국의학물리학회지:의학물리
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• 제27권2호
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• pp.98-104
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• 2016

본 연구는 고선량으로 인한 광자극발광선량계의 방사선 민감도 변화에 관하여 분석하기 위하여 60-Co 감마선에서 상용화된 광자극발광선량계(Landauer, Inc., Glenwood, IL)를 이용하였다. 고선량으로 인한 방사선 민감도 변화를 분석하기 위하여 한번도 사용하지 않은 소자들을 이용하여 상대적 방사선 민감도 변화 경향을 확인하였으며, 7번째까지 3% 정도 증가하다가 그 이후 1 Gy의 조사 횟수에 따라 0.35%씩 감소하는 것을 확인하였다. 그리고 30회까지 조사하였을 때 7% 감소하였다. 고 선량을 받은 소자들의 경우, 15 Gy가 조사된 그룹은 한번도 사용하지 않은 소자들의 방사선 민감도에 비해 6% 감소하였으며, 30 Gy가 조사된 그룹은 12% 감소하였다. 감소되는 경향은 지수함수에 곡선 맞춤 하였다. 고선량을 받은 소자들을 다시 재 사용할 경우 측정에 대한 큰 불확도를 가지고 있으며, 이를 인지 하고 소자에 대한 조사 이력 관리를 하면서 사용해야 할 것이다.

• 방사선산업학회지
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• 제5권3호
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• pp.279-283
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• 2011

This study was compared microbiological safety with gamma-irradiated porcine tendon and skin, as materials for the development of xenografts to regenerate damaged tissues and protect secondary contamination. The porcine tendon and skin were gamma-irradiated after inoculation of bacteria and virus to evaluate irradiation sensitivity of microorganisms. The result showed that the porcine tendon and skin were not different on the sensitivity of microorganisms by gamma irradiation. Bacteria inoculated in the porcine tendon and skin were confirmed that E. coli was the $D_{10}$ values of $0.32{\pm}0.082$ and $0.25{\pm}0.1kGy$ on tendon and skin, and B. subtilis was $4.00{\pm}0.312$ and $3.88{\pm}0.3kGy$ on gamma irradiation, respectively. Moreover, Virus inoculated in the porcine tendon and skin was observed that poliovirus (PV) was $6.26{\pm}0.332$ and $6.88{\pm}0.3kGy$, and porcine parvovirus (PPV) was $1.75{\pm}0.131$ and $1.73{\pm}0.2kGy$ and bovine viral diarrhoea virus (BVDV) was $3.70{\pm}0.212$ and $3.81{\pm}0.2kGy$ on gamma irradiation, respectively. Virus showed higher resistance compared to bacteria on gamma irradiation, but was not detected CPE (cytopathic effect) by virus both tendon and skin at 25 kGy, a standard dose recommended from IAEA for sterilization of medical products. Therefore, These results were considered that gamma irradiation could control effectively bacteria and virus to develop safe porcine xenograft, and apply same irradiation doses to all tissues including tendon and skin of porcine.

• 전기학회논문지
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• 제62권7호
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• pp.963-968
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• 2013

Ionizing Radiation effects on MOS devices provide useful information regarding the behavior of MOS based devices and circuits in the electronic instrumentation parts and instructive data for making the high sensitive sensors. The study presents the results of the analysis on the structural characteristics of MOS capacitor for sensing the ionizing radiation effect. We performed numerical modeling of Ionizing-radiation effect on MOS capacitor and simulation using Matlab program. Also we produced MOS capacitors and obtained useful data through radiation experiment to analyse the characteristic of ionizing radiation effect on MOS capacitor. Increasing the thickness of MOS capacitor's oxide layer enhanced the sensitivity of MOS capacitor under irradiation condition, but the sensitivity of irradiated MOS capacitor is uninfluenced by the area of MOS capacitor. The high frequency capacitance of the MOS capacitor is found to be strongly affected by incident ionizing radiation.

• Nuclear Engineering and Technology
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• 제54권8호
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• pp.2871-2876
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• 2022

The sensitivity of polymer-based capacitive relative humidity (RH) sensors after irradiation with neutrons, electrons and protons was measured. Degradation consists of the decreasing of the upper RH limit that can be measured. At the same time, low RH-level sensitivity is almost stable. After 30 krad of absorption dose, RH cut off is equal to 85% of max value, after 60 krad-40%. Degradation reduces after annealing which indicates high radiation sensitivity of the internal circuit in comparison to RH-sensing polymer film.

• 한국작물학회지
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• 제44권3호
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• pp.296-301
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• 1999

The concerns on the crop damage by ultraviolet (UV) radiations is increasing owing to the decrease of their absorbing stratospheric ozone in the tropospheric. Cultivar differences on early growth of UV radiation among five Korean rice cultivars, four japonica types and one Tongil type (indica-japonica cross hybrid), were studied. Pot-seeded rice plants were grown under four different radiation conditions, i.e., visible radiation only, visible radiation with supplemented with high or low dose of UV-B (280~320 nm in wavelength) and UV-C (less than 280 nm in wavelength). The inhibitory degree on plant height, shoot and root weight and length of leaf blade and leaf sheath were determined at 40 days after seeding. UV-C showed the most severe inhibitory effect on the degree of biomass gain and leaf growth in most cultivars examined, followed by high UV-B and low UV-B. Among the cultivars used, the Kuemobyeo was the most sensitive cultivar and had not repair or showed resistance ability to continued irradiation of UV radiation. However, Janganbyeo and Jaekeon showed different responses that the elongation of leaf blades was promoted on 2nd and 3rd leaves and inhibited on 4th and 5th leaves but this inhibitory degree was reduced on 6 th and 7th leaves. Such tendency on leaf growth means that both cultivars had low sensitivity and most resistant ability to continued irradiation of UV radiation. While Tongil showed different response to enhanced UV radiation, ie., low UV-B promoted leaf growth but the inhibitory was severely increased by continued irradiation of high UV-B and UV-C, which means that Tongil had high threshold of UV radiation for response as an inhibitory light of plant growth. The results of this study indicate that the differences on sensitivity or resistant to the effects of UV radiation were existed among Korean rice cultivars.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.1181-1182
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• 2008

The study presents the results of the analysis on the structural characteristics of MOS capacitor for sensing the ionizing radiation effect. Increasing the thickness of MOS capacitor's oxide layer enhanced the sensitivity of MOS capacitor under irradiation condition, but the sensitivity of irradiated MOS capacitor is uninfluenced by the area of MOS capacitor.

• 한국의학물리학회지:의학물리
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• 제6권1호
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• pp.49-57
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• 1995

반도체검출기는 소형 및 방사선에 고감도특성을 갖고 있으나, 고에너지 광자선 및 전자선등의 조사에 의해 손상을 입어 감도저하를 초래하게 되며 계측시 선량재현성을 기대하기어려워진다. 실험대상은 P-형 실리콘 반도체검출기이며 선량율, 김출방향 및 온도 변화에 따른 선량특성이 조사되었고, 선량재현성을 높이기 위해 18 MeV 고에너지전자선으로 3KGy까지 전처리조사하고 광자선 및 전자선의 전처리조사선량에 대한 감도특성변화를 얻었다. 전처리조사가 작은 0.5KGy인 경우, 저선량율과 고선량율하의 단위선량당 감도는 약 35％의 차이를 보였으며 .3KGy인 경우 약 20％의 차이를 보여 전처리선량이 클 수록 감도차는 작아짐을 알수 있다. 실리콘 반도체검출기의 검출방향성은 임의의 조사각에서 최저치와 최대치의 선량차가 약 13％를 나타내었으며, 검출기의 온도의존성은 4도에서 35도까지 거의 선형성을 보였다.

• Nuclear Engineering and Technology
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• 제31권3호
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• pp.287-293
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• 1999

To assess the effects of gamma-ray (Co-60) on radiation sensitivity and genetic similarity of the basidiospore and mycelium in oyster mushroom, Pleurotus ostreatus, the D$_{10}$ values and RAPD patterns were analysed. Three strains were isolated from basidiospores (PO-Bl, -B2, and - B3 from 2 kGy irradiation group) and five strains from mycelia (PO-Ml, -M2 from 1 key, PO-M3 from 2 kGy, and PO-M4 and -M5 from 2+1 key irradiation group). The D$_{10}$ values of basidiospore and mycelium of P. Preurotus ostreatus were 1,250 Gy and 500 Gy, respectively. The growth rates of the eight strains on the five media were various and the activities of extracellular chitinases of them were generally higher than those of the control. By the gamma-ray radiation, 22-25% of genetic similarities were changed in the basidiospore strains and 23-36% of them in the mycelium strains. From these results, it seems that the basidiospore could be more radio-resistant than the mycelium of P. ostreatus and that the genetic similarity of the mycelium of P ostrentus could be changed easier than that of the basidiospore by the gamma-ray radiation.ion.

• 방사선산업학회지
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• 제6권3호
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• pp.223-229
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• 2012

In this study, we investigated the biological damage and stress responses induced by ion beam (proton beam) irradiation as a basis for the development of protective measures against space radiation. We examined the biological effects of proton beam produced by MC-50 cyclotron at KIRAMS on the cultured cells and mice. The proton beam energy used in this study was 34.9 MeV and the absorption dose rate for cells and mice were $0.509Gy\;sec^{-1}$ and $0.65Gy\;sec^{-1}$, respectively. The cell survival rates measured by plating efficiency showed the different sensitivity and dose-relationship between CHO cells and Balb/3T3 cells. HGPRT gene mutation frequency in Balb/3T3 was $15{\times}10^{-6}Gy^{-1}$, which was similar to the reported value of X-ray. When stress signaling proteins were examined in Balb/3T3 cells, $I{\kappa}B-{\alpha}$ decreased markedly whereas p53, phospho-p53, and Rb increased after proton beam irradiation, which implied that the stress signaling pathways were activated by proton beam irradiation. In addition, cellular senescence was induced in IMR-90 cells. In the experiments with C57BL/6 mouse, the immune cells (white blood cells, lymphocytes) in the peripheral blood were greatly reduced following proton beam irradiation whereas red blood cells and platelets showed relatively little change. These results can be utilized as basic data for studying the biological effects of proton beam using MC-50 cyclotron with respect to proton therapy research as well as space radiation research.