• Journal of the Korean Society of Safety
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• v.19 no.3 s.67
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• pp.26-31
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• 2004

The radiation-induced changes taking place in poly(vinylidene fluoride) (PVDF) exposed to $^{60}Co$ $\gamma-ray$ irradiation were investigated in correlation with the applied doses. Samples were irradiated in air at room temperature by $^{60}Co$ $\gamma-ray$ to doses in the range of 200 to 1000kGy. Various properties of the irradiated PVDF were studied using FTIR, differential scanning calorimetry (DSC), gel fraction and elongation. $^{60}Co\gamma-ray$ irradiation was found to induce changes in chemical, thermal, mechanical and structural properties of PVDF and such changes vary depending on the radiation dose.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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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.

• Journal of the Korean Society of Radiology
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• v.10 no.4
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• pp.223-231
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• 2016

The effects of White Ginseng and Fermented Ginseng on liver damage induced by $^{60}Co$ r-ray irradiation were investigated. To one group of ICR male mice were given in White Ginseng(150 mg/kg/day for 7days, orally) before 5Gy(1.01Gy/min) dose of $^{60}Co$ r-ray irradiation. To another group were given in Fermented Ginseng (150 mg/kg/day for 7days, orally)before 5Gy(1.01Gy/min)dose of $^{60}Co$ r-ray irradiation was investigated. Radiation irradiation group were given with saline(0.1 ml) and 5Gy. Contrast group were given with saline(0.1 ml). The levels of $H_2O_2$, catalase and MDA in liver tissue were measured. In Fermented Ginseng (FG+Rad) group and white Ginseng(WG+Rad) group than irradiation group(Rad), the catalase level were significantly increased, and the catalase levels were appeaWhite at radiation protection. It was significantly decreased to MDA and $H_2O_2$ level to Fermented Ginseng (FG+Rad) group and white Ginseng(WG+Rad) group than irradiation group(Rad). Therefore, Fermented Ginseng and white Ginseng were very excellent protector on radiation of liver in mice.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.782-784
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• 2016

In this study, we studied the gamma-radiation effect of fiber Bragg gratings on the fiber re-coating methods. The fiber Bragg gratings were exposed to gamma-radiation up to a dose of 100 kGy at the dose rate of 104 Gy/min. In our experimental results, we confirmed that the fiber acrylate re-coating process leads to a slightly lower radiation sensitivity of FBGs.

• Progress in Medical Physics
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• v.22 no.1
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• pp.3-11
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• 2011

The purpose of this study was to evaluate feasibility of Vertical Multileaf Collimator for determination of irradiation size using Vertical Multileaf Collimator and lead block to determine 4 different irradiation shape in case of Co-60 gamma-ray and 6 MV X-ray. We chose ion chamber, glass dosimeter and EBT chromic film to compare with Vertical Multileaf Collimator results and lead block results. In case of Co-60 gamma-ray and 6 MV X-ray, the central axis point dose normalized at reference field of lead block with ion chamber results for Vertical Multileaf Collimator were estimated higher than lead block about 5.1%, 4.2%. In case of Co-60 gamma-ray, the central axis point dose normalized at reference field of lead block with glass dosimeter results for Vertical Multileaf Collimator were estimated higher than lead block about 2.2%, 7.8%, 7.2%, 4.0% for reference, circle, triangle, cross field, respectively. In case of 6 MV X-ray, the central axis point dose normalized at reference field of lead block with glass dosimeter results for Vertical Multileaf Collimator were estimated higher than lead block about 6.7%, 6.2%, 3.8%, 6.2% for reference, circle, triangle, cross field, respectively. The results of EBT chromic film, Vertical Multileaf Collimator of penumbra size for all irradiation shape was smaller than lead block of those size that 2.0~3.5 mm for Co-60 gamma-ray, 0.5~1.0 mm for 6 MV X-ray. The results from this study, radiation treatment volume that results in shielding block can be minimized. In addition, during radiation treatment for 2, 3-dimensional radiation therapy using a Vertical Multileaf Collimator of this survey can be used to determine variety of irradiation fields.

• Journal of Korea Society of Industrial Information Systems
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• v.7 no.4
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• pp.37-45
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• 2002

In this study, to measure the density and moisture of compaction, it is designed to use the 2 neutron and 5 gamma-ray detectors. Also, it can be know that Co-60 gamma-ray and Cf-252 neutron source are more useful for this system, because discharge of radiation are better than other sources. They are more profitable to improve their accuracy. Especially, to remove the interference of their reciprocal action between neutron and gamma-ray detectors it is designed shield materials with lead between 2 neutron and 5 gamma-ray detectors each other. It is performed the optimal design to shield under the suggested values completely. Because this system will use portable, so decrease of their weight are so important. For this reason, it can be decrease their weight of 5.2[kg] with shield material between each detectors and it can be think mote easy to carry and use on the industrial Spot.

• Nuclear industry
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• v.5 no.9 s.31
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• pp.47-48
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• 1985

최근 일본은 남서부지방의 과실류 등에 기생하는 것이 확인된 과실파리에 대한 방제법으로 방사선을 이용한 ${\ulcorner}$불임충방사법${\lrcorner}$의 실시를 검토중이라고 한다. 이 방법은 Co-60에 의한 감마선으로 불임화한 숫놈의 성충을 풀어 야생의 암컷과 교미시킴으로서 방제하는 것인데, 우리나라도 소나무의 솔잎혹파리근절이 산림정책의 중요한 과제의 하나인 바, 관심거리가 아닐 수 없다.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2012.05a
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• pp.387-388
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• 2012

• Radiation Oncology Journal
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• v.11 no.2
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• pp.449-454
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• 1993

The skin sparing effect associated with high energy x-ray or gamma ray beams may be reduce or lost under certain conditions of treatment. Current trends in using large fields. Shield carrying trays, compensating filters, and isocentric methods of treatment have posed problems of increased skin dose which sometimes become a limiting factor in giving adquate tumor doses. We used the shallow ion chamber to measure the phantom surface dose and the physical treatment variables for Co-60 gamma ray, 4MV and 10 MV x-ray beam. The dependence of percent surface dose on field sizes, atomic number of the shielding tray materials and its distance from the surface for 4, 10MV x-rays and Co-60 gamma ray is qualitatively similar. The use of 2 mm thick tin filter is recommended for situations where a low atomic number tray is introduced into the beam at distances less than 15 cm from the surface and with the large field sized for 4 MV x-ray beam. In case of Co-60 gamma ray, the lead glass tray is suitable for enhancement of skin sparing. Also, the filter distance should be as large as possible to achieve substantial skin sparing.

• Journal of Radiation Protection and Research
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• v.7 no.1
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• pp.23-33
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• 1982

The characteristic thermoluminescence responses of Teflon thermoluminescent dosimeters to radiations have been studied by the variation of radiation qualities as well as the high dose radiations. The change in the sensitivity of TLDs for different radiation qualities were studied through not only the photon energy dependence but also the change of supralinearity on the photon energy dependence, by exposing $^{60}Co$ gamma rays, the effective X-rays of 44keV, 69keV, 108keV, and thermal neutron of 0.04 eV. The results were as the following: The TL response of $T-CaSO_4$: Dy as a function of absorbed dose was linear up to about 5 Gy, and the response beyond 5Gy was supralinear for $^{60}Co$ gamma rays. The supralinearity of T-LiF-7 became noticeably apparent more than that of $T-CaSO_4$:Dy and also the lower the LET of radiation became the higher the supralinear effects were. No supralinearity appeared for the thermal neutron irradiations equivalent to 10Gy of $^{60}Co$ gamma rays. The relative sensitivities (Rs), which depended on the doses of $^{60}Co$ gamma rays to the TLDs of T-LiF-7 and T-$CaSO_4$:Dy could be, respectively, approximated to the following empirical formula fitted by the least square method: $$R_{LiF}=1.021-0.04581\;logD+0.402(logD)^2-0.405(logD)^3,\;\;5{\times}10^3{\geq}D{\geq}1(Gy)$$ $$R_{CaSO_4}=0.976-0.3241\;logD+0.262(logD)^2-0.298(logD)^3,\;5{\times}10^3{\geq}D{\geq}1(Gy)$$.