• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.12
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• pp.2310-2316
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• 2016

We studied the effect of $Co^{60}$ gamma-radiation on the fiber Bragg gratings (FBGs) by irradiation time of UV Krypton fluoride (KrF) excimer laser among grating processing parameters. The FBGs were fabricated in a different UV laser irradiation time at 30, 60, 90, and 120 seconds using the same commercial Ge-doped silica core fiber (SMF-28e). It was exposed to gamma-radiation up to a high dose of 34.3 kGy at the dose rate of 106 Gy/min, and then it was analyzed radiation effects by measuring the radiation-induced change in the temperature sensitivity coefficient and Bragg wavelength shift. According to the experimental results, We confirmed that the UV laser irradiation period for grating inscription has a highly effect on the radiation sensitivity of the FBGs. The radiation-induced Bragg wavelength shift by the change of laser irradiation conditions showed a difference more than about 50 %.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.11
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• pp.76-83
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• 2006

Space radiation environment for COMS is simulated by NASA AP8/AE8, JPL91 and NRL CREME models, respectively for trapped particle, solar proton and cosmic-ray. The radiation effects on electronic devices in communication payload are also estimated by using simulation results. Dose-depth curve and LET spectrum are calculated for estimating total ionizing dose(TID) effect and single event effect(SEE) respectively. Spherical sector method is applied to dose estimation at each position in the units of communication payload to consider shielding effect of platform and housing. Total ionizing dose at each position varies by 8 times through shielding effect under the same external space radiation environment.

• Journal of the Korean Society of Radiology
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• v.17 no.2
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• pp.267-275
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• 2023

Occupational exposure records are subject of global interest, and analysis of radiation workers in work categories is being conducted. In Rep. of Korea, according to relevant ministries, the MOHW(Ministry of Health and Welfare), the MAFRA(Ministry of Agriculture, Food and Rural Affairs), and the NSSC(Nuclear Safety and Security Commission) collect and analyze records of occupational exposure by dividing them into 11 work categories. However, this classification system lacks consistency with the systems of major countries, including the UNSCEAR(United Nations Scientific Committee on the Effects of Atomic Radiation). The domestic radiation work field classification system does not have clear classification criteria and does not reflect the characteristics of the radiation work field. Through the analysis of the classification system of the UNSCEAR, we suggested the five main categories(nuclear cycle, medical, industrial, others(education/research, military/public) field and several sub-categories according to each radiation work field.

• Journal of radiological science and technology
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• v.6 no.1
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• pp.116-116
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• 1983

• 대한방사선방어학회:학술대회논문집
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• 2010.04a
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• pp.230-231
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• 2010

• the MEAT Journal
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• s.36 summer
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• pp.72-86
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• 2009

Microbial reduction, physicochemical property, and sensory evaluation of irradiated beef patty were investigated. The microbial counts of refrigerated beef patty were reduced to below the number of 3 logs after irradiation at 3 kGy. But no viable microorganism was detected in frozen beef patty irradiated at 3 kGy. Food additives such as nitrite, salt, phosphate and ascorbic acid did not affect on the inactivation of microorganism by irradiation. The irradiation effect on the water holding capacity was not significant, but frozen irradiated beef patty showed higher water holding capacity than refrigerated beef patty. The drip loss of irradiated beef patty did not show significant differences according to irradiation doses. Considering the influence of food additives, the irradiated beef patty mixed with salt and phosphate showed lower drip loss than that without food additives. In refrigerated beef patty, TBARS values were increased with increase of irradiation doses and showed lower values in the beef patty mixed with food additives than that without food additives. The redness of refrigerated beef patty showed highest values at 3 kGy of irradiation and then decreased with increasing irradiation doses, while in the frozen beef patty did not show distinct tendency according to the irradiation doses or food additives. In sensory evaluation. the irradiated beef patty showed unpleasant smell as compared with the non irradiated beef patty, but showed somewhat higher score in smell at the sample contained ascorbic acid regardless of irradiation doses.

• Food Science of Animal Resources
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• v.28 no.4
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• pp.437-444
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• 2008

Microbial reduction, physicochemical property, and sensory evaluation of irradiated beef patty were investigated. The microbial counts of refrigerated beef patty were reduced to below the number of 3 logs after irradiation at 3 kGy. But no viable microorganism was detected in frozen beef patty irradiated at 3 kGy. Food additives such as nitrite, salt, phosphate and ascorbic acid did not affect on the inactivation of microorganism by irradiation. The irradiation effect on the water holding capacity was not significant, but frozen irradiated beef patty showed higher water holding capacity than refrigerated beef patty. The drip loss of irradiated beef patty did not show significant differences according to irradiation doses. Considering the influence of food additives, the irradiated beef patty mixed with salt and phosphate showed lower drip loss than that without food additives. In refrigerated beef patty, TBARS values were increased with increase of irradiation doses and showed lower values in the beer patty mixed with food additives than that without food additives. The redness of refrigerated beef patty showed highest values at 3 kGy of irradiation and then decreased with increasing irradiation doses, while in the frozen beef patty did not show distinct tendency according to the irradiation doses or food additives. In sensory evaluation, the irradiated beef patty showed unpleasant smell as compared with the non irradiated beef patty, but showed some-what higher score in smell at the sample contained ascorbic acid regardless of irradiation doses.

• Korean Journal of Materials Research
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• v.3 no.1
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• pp.65-71
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• 1993

Abstract The effect of final heat treatment and welding on the irradiation growth of Zircaloy-4 was investigated. As a simulation for neurtron irradiation, accelerated proton beam with the energy of 3.5MeV was used up to the proton fluence of 9.8 ${\times}{10^{21}}$p/$m^2$ in the present study. It was found that irradiation growth of the annealed specimen was the highest and that of the ${\beta}$-quenched specimen was the samllest among the present specimens. The magnitude of irradiation growth of the present specimens decreased by welding. The difference in the magnitude of irradiation growth of the present specimens with different final heat treatment and the effect of welding on it were quantitatively analyzed in terms of crystallographic texture by using Kearns number, f, which was calculated from the x-ray diffraction data.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.11
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• pp.84-91
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• 2006

Recently, all the electrical parts for satellite application are required more strong against cosmic rays, because spacecraft's life time and function are depending on the their conditions. Also, a TID effect test was undertaken with units and/or subsystems which are already assembled on the PCB in past time. However, it is very hard to know and analyze that some abnormal states are appeared after launch. Moreover, it is necessary to perform a test of TID effects based on the parts level for preparing preliminary data in cosmic rays. Therefore, this paper presents a test-bed to perform a TID effect test of Metal-Oxide Semiconductor Field Effect Transistor (MOSFET) which is a fundamental element for electronics.

• Journal of Radiation Protection and Research
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• v.12 no.1
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• pp.34-39
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• 1987

Radiation shielding analysis for a 6MeV X-ray facility was carried out. The primary and leakage radiation for the facility can be evaluated based on the methodology in NCRP No. 49 and 51. The present study deals with radiation scattering analysis for the outside and inside door of the facility based on the albedo concept. The calculated dose rates were compared with the results of MORSE-CG code calculation and the measured data, resulting in a good agreement, even though there existed some deviation for the inside door. These results can be utilized to the radiation shielding design of the medical and industrial X and gamma ray facilities, and to the safety evaluation of these facilities.