• Journal of the Korean Society of Radiology
• /
• v.9 no.1
• /
• pp.55-59
• /
• 2015

Research about the proton nuclear reaction is actively achieving on the proton therapy including material development of fusion reactor. The proton induced gamma ray energy(2754, 1386 keV) spectrum of 27Al(p,3p+n)24Na reaction was measured with 100 MeV high energy proton beam. The proton beam in the experiment was derived from 100 MeV proton linear accelerator in the KOMAC. We measured the gamma ray intensity ratio of the decay level from the energy spectrum. The previous results have been compared with the current result. Strength of measured gamma rays will provide very important information though decide high energy gamma radiation detection efficiency.

• Korean Journal of Food Science and Technology
• /
• v.29 no.4
• /
• pp.764-770
• /
• 1997

For the purpose of improving hygienic quality of dried-spirullina and dried-sea tangle powders as raw materials of health food, the comparative effects of ozone treatment and gamma irradiation on the microbial and physicochemical properties were investigated. Gamma irradiation at 7.5 kGy resulted in sterilization of total aerobic bacteria, coliforms and molds below detective levels $(<10^{1}\;CFU/g\;sample)$, while ozone treatment for 8 hr up to 18 ppm could not sufficiently eliminate the microorganisms of the samples. Physicochemical properties including compositions of fatty acid and amino acid, minerals, pH and natural pigments were not changed by gamma irradaition up to 10 kGy, whereas, ozone treatment caused changes in pH, TBA value, natural pigments and fatty acid compositions. Especially, ozone treatment markedly decreased unsaturated fatty acid of the samples.

• Korean Journal of Food Science and Technology
• /
• v.29 no.3
• /
• pp.527-532
• /
• 1997

The comparative effects of gamma irradiation and ozone treatment on the microbial inactivation and fatty acid composition were investigated for improving hygienic quality of aloe and pollen powders. Gamma irradiation at 10 kGy resulted in sterilizing total aerobic bacteria, molds and coliforms below detective levels, while ozone treatment for 8 hours up to 18 ppm did not sufficiently eliminate the microorganisms of aloe and pollen powders. The compositions of fatty acid were not significantly changed by gamma irradiation up to 10 kGy. However, ozone treatment markedly decreased unsaturated fatty acids by approximately $20{\sim}80%$ in contents, whereas it significantly increased saturated fatty acids (p<0.05).

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2015.10a
• /
• pp.1121-1124
• /
• 2015

In this paper, we propose and demonstrate an optimal design of wideband pulsed gamma-ray detectors. Pulsed gamma-ray detectors are designed to operate in a dose rate of $1{\times}10^6{\sim}1{\times}10^8rad(Si)/s$. The input parameter was derived based on the energy ratio of pulse gamma-ray spectrum and the time of the energy. The sensor output current was calculated based on the dose rate control circuit. Using the N-type Epi Wafer, the optimum condition detection sensor was designed based on TCAD. The simulation results show that the optimal Epi layer thickness is 45um when applied voltage 3.3V. The doping concentrations are as follows : N-type is an Arsenic as $1{\times}10^{19}/cm^3$, P-type is a Boron as $1{\times}10^{19}/cm^3$ and Epi layer is Phosphorus as $3.4{\times}10^{12}/cm^3$. Pulse gamma-ray detector diameter is the 1.3mm.

• Korean Journal of Environmental Biology
• /
• v.22 no.3
• /
• pp.472-477
• /
• 2004

To study the radiation related gene expression in mutants of Bacillus lentimorbus WJ5 induced by gamm radiation, the simultaneous gene expression was analyzed by DNA micro array. We constructed DNA chips including two thousand randomly digested genome spots of B. lentimorbus WJ5 and compared its quantitative aspect with seven mutants induced by gamma radiation $(^{60}/Co)$. From the cluster analysis of gene expression pattern, totally 408 genes were expressed and 27 genes were significantly upregulated by the gamma radiation in all mutants. Especially, genes involved in repair (mutL, mutM), energy metabolism (acsA, sdhB, pgk, yhjB, citB), protease (npr), and reduction response to oxidative stress (HMM) were simultaneously upregulated. It seems that the induction of the direct and/or indirect repair related genes in mutants induced by gamma radiation could be remarkably different from the adaptive responses against acute exposure to radiation.

• Korean Journal of Plant Resources
• /
• v.35 no.4
• /
• pp.428-434
• /
• 2022

Glycyrrhizae Radix is an herbal medicine vulnerable to fungi. So there are regulations on mycotoxins. Therefore, in this study, the affect of various drying methods and additional gamma irradiation (10 kGy) was studied to suppress the microbial generation of Glycyrrhizae Radix. As a result of detecting and comparing microorganisms using the dry film method for samples prepared by each of natural, hot air, freezing, microwave drying and gamma irradiation, the affect of reducing microorganisms by microwave drying and gamma irradiation was confirmed. There was no statistically significant change in the content of the active compounds between the treatment groups.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.52 no.2
• /
• pp.173-181
• /
• 2015

We developed a wireless gamma-ray probe based on radiation photon counting method to diagnose and detect remaining lesions after surgery, and its effectiveness was evaluated using calibration sources and a phantom. The probe was designed and miniaturized using a semi-conductor-based radiation sensor, and a Bluetooth remote communication module was used to implement the wireless diagnosis and detection system. Moreover, a remote monitoring system was implemented to monitor affected areas during diagnosis and surgery. To assess the effectiveness of the developed probe in this study, calibration sources $^{57}Co$, $^{133}Ba$, $^{22}Na$ and $^{137}Cs$ and a chicken breast phantom were used. Furthermore, the probe's detection response to gamma ray was confirmed through evaluation. Its clinical applicability was verified by assessing the response linearity and detection direction according to gamma-ray intensity, as well as the detection efficiency according to the depth of the gamma source in the phantom.

• Journal of Radiation Protection and Research
• /
• v.34 no.4
• /
• pp.170-175
• /
• 2009

For the emergency radiation monitoring using gamma spectrometry, we should sufficiently survey the background spectra as environmental samples with systematic nuclide identification method. In this study, we obtained the gamma ray energy spectrum using a HPGe gamma spectrometry system from an air sample. And we identified nuclide of the gamma ray energy peaks in the spectrum using two methods -1) Half life calculation and 2) survey for cascade coincidence summing peaks using nuclear data. As the results, we produced the nuclide identification results for the air sample.

• The Korean Journal of Malacology
• /
• v.27 no.3
• /
• pp.247-252
• /
• 2011

The effect of ${\gamma}$-ray irradiation on the color of nucleus and cultured pearls was investigated. After ($^{60}Co$) ${\gamma}$-ray irradiation on the pearl nucleus, its color was altered from brownish to blackish brown or gray depending on irradiation dose. It was clearly found that the all samples are composed of aragonite. ESR spectra were based on the measurement of the paramagnetic species $CO_2$-radicals by the interaction with the ${\gamma}$-ray irradiation in $Mn^{2+}$ containing $CaCO_3$. In this study, we investigated optimal detection method of ${\gamma}$-ray irradiation to establish destructive or non-destructive test for pearl nucleus.

• Korean Journal of Food Science and Technology
• /
• v.32 no.4
• /
• pp.822-827
• /
• 2000

Gamma irradiation was applied to reduce shrimp allergy. Shrimp heat-stable protein(HSP) and shrimp protein extract were gamma-irradiated at 1, 3, 5, 7 or 10 kGy in an aqueous state (1.0 mg/mL). The changes in allergenic and antigenic properties of protein extract and HSP resulted from gamma irradiation were monitored by ELISA with mouse mAb or human patients sera and immunoblotting. Conformational changes in irradiated HSP were measured by both GPC-HPLC and SDS-PAGE. The binding ability of shrimp allergic patients IgE to irradiated protein extract or irradiated heat-stable protein was dose-dependently reduced. When measured by gel permeation chromatography and sandwich ELISA, the amount of intact heat-stable protein in the irradiated solution was reduced by gamma irradiation depending upon the applied dose. SDS-PAGE showed that the main band disappeared and new bands appeared in a higher molecular weight zone. The results provide a new possibility to use irradiation process for reducing the allergenicity of shrimp.