• Journal of Sensor Science and Technology
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• v.9 no.4
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• pp.274-280
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• 2000

This paper deals with an experimental study to apply commercial semiconductors to measure radiation dose rate for gamma ray. Since the low cost, small size, high efficiency and ruggedness of silicon photodiodes make them attractive photodetectors, they coulde be effectively used in measuring any radiation such as gamma ray. Most PN photodiodes show that the reverse current increases when the light is increased. Therefore the depletion region of them have influence on the reverse current, so we choose silicon PIN photodiodes with large depletion region. In order to detect radiation dose rate and then, to apply in developing any gamma ray dosimeter, some examinations and experiments were performed to PIN photodiodes in this work. Two kinds of PIN photodiodes, such as NEC's PH302 and SIEMENS's BPW34, were tested in a Co-60 gamma irradiation facility with a semiconductor parameter analyzer. As a result, we found that such PIN photodiodes present good linearity in diode current characteristics with dose rate. Therefore silicon PIN photodiodes could be suitably used in designing gamma ray dosimeters.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.4
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• pp.193-200
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• 2014

In this paper, the prototype of one-channel gamma-ray spectroscope for automatic radiopharmaceutical systhesis system was designed and characterized. The prototype employed CZT (CdZnTe) spear detector for gamma-ray detection and employed analog-type signal processing method. A radioactive sample Co-60 was used for measuring performance of the gamma-ray spectroscope and energy spectrum is gained with bandwidth of 1173keV. The analog board is made up of SF (shaping filter) and PHA (peak and hold amplifier) for shaping CZT output signal appropriately and ADC (analog to digital converter) and FPGA (field programmable gate array) for drawing gamma-ray spectrum by counting the digitalized gamma-ray signal data.

• Journal of the Korean Society of Radiology
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• v.13 no.5
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• pp.819-824
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• 2019

In this study, we proposed a method for identifying isotopes generated from high-energy proton $^{nat}Pb$(p,xn) nuclear reactions through the difference of gamma rays generated through nuclear reactions using different proton energies. The experiment was performed by using a high energy proton generated from a 100 MeV proton linear accelerator of the Korea Atomic Energy Research Institute. Gamma rays generated by various nuclides generated through proton nuclear reactions were measured using a gamma-ray spectroscopy system composed of HPGe detectors. Gamma-ray standard sources were used for accurate energy calibration and efficiency measurements of HPGe gamma-ray detectors. For the proposed method, 100 and 60 MeV proton energy beams were used for the same natural lead samples. This method was found to be very effective in identifying nuclides produced by comparing gamma rays generated from the same sample with each other. The results of this study are expected to be very effective in obtaining other proton nuclear reaction results in the future.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.5
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• pp.777-781
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• 2001

The effects of gamma-irradiation on the nutritional components of some Korean soybean-based fermentation foods were studied. Doenjang (soybean paste), kochujang (red pepper paste) and chungkukjang were prepared, irradiated at 0, 5, 10 and 20 kGy, and their compositions of free amino acid, free fatty acid and organic acid were determined. Compositions of free amino acid and free fatty acid in gamma irradiated sample were stable compared to non-irradiated control. Content of citric acid and succinic acid increased, while that of malic acid decreased in the gamma irradiated chungkookjang, but there were no significant changes in organic acid composition in organic and kochujang.

• Polymer(Korea)
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• v.34 no.5
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• pp.454-458
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• 2010

In this study, the microstructural changes in orthopaedic-grade ultra high molecular weight polyethylene (UHMWPE) were compartively investigated for six different gamma-irradiation methods. Compared with un-irradiation (UGI), conventional gamma-irradiation in air room temperature (AR) induced statistically significant increases of relative crystallinity and percent crosslinking in UHMWPE. Vacuum environment (VR) during gamma-irradiation significantly increased the percent crosslinking in UHMWPE. Vacuum extreme low temperature (V77) during gamma-irradiation induced no significant changes in both relative crystallinity and percent crosslinking of UHMWPE but the percent crosslinking of UHMWPE in VR and V77 was significantly larger than that in AR. Post-irradiation stabilization process significantly increased the relative crystallinity of UHMWPE in V77, and it also significantly increased the percent crosslinking of UHMWPE in AR and V77.

• Nuclear Engineering and Technology
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• v.2 no.4
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• pp.273-278
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• 1970

The Contents of uranium and thorium in radioactive ores produced in Korea were determined by gamma-ray spectrometry utilizing Ge (Li) diode detector. Both methods, namely, gamma-ray spectrometries of activated samples and non-activated samples, were tested and compared for their accuracies and rapidness in determination of contents. Also the useful-ness of application of Ge(Li) diode detector to the determination of uranium and thorium contents in ores was discussed in detail.

• Nuclear Engineering and Technology
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• v.7 no.3
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• pp.223-226
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• 1975

The relative detection efficiency of ${\gamma}$-ray full-energy Peaks was obtained by a pair-point method using the $^{56}$ Co source whose ${\gamma}$-ray relative emission rates were well measured. Three Ge(Li) detectors with active volumes of 43.8cc, 32.6cc, and 6cc were calibrated over the ${\gamma}$-ray energy energy range 800-5, 500keV.

• Korean Journal of Food Science and Technology
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• v.2 no.1
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• pp.81-87
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• 1970

Effects of varying gamma-irradiation doses and polyethylene package on the quality and chemical components of Jonathan apples were investigated. The results obtained are as follows: 1. The doses of 50 to 100 krad were effective in the control of fruit rot and physiological disorders. 2. Gamma-irradiation to Jonathan apples rather accelerated shrivelling at the early stage of storage period. 3. Combined treatments of radiation and polyethylene package enabled to control the shrivelling of apples. 4. The rate of freight loss was lower in the irradiated and/or packing lots than control 5. Gamma-irradiation and polyethylene package did not appear to influence on the sugar content of apples.

• Journal of Food Hygiene and Safety
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• v.15 no.3
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• pp.256-261
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• 2000

Effect of gamma irradiation on quality properties of half·cooked noodle was studied. The noodle were treated with lactic acid(0.1%, w/w), heat(10 min in boiling water) or their combination after cooking for 3 min, and irradiated at 0, 5 and 10 kGy. The noodle were stored at 25。C for 5 weeks and microbial population, Aw, pH, and texture profiles were examined. Fungi were completely eliminated by gamma-irradiation with 5 or 10 kGy does. Number of aerobic bacteria were also decreased by 2 and 4 log cycles with dose of 5 and 10 kGy, respectively. The D10 values of aerobic bacteria were 2.34∼2.95 kGy. Growth of the aerobic bacteria that survived even at 10 kGy of irradiation were significantly inhibited during storage. Acidification of half-cooked noodle was suppressed by gamma irradiation but A${_w}$ were not affected. Stickiness was decreased at the beginning of storage by gamma irradiation but was restored after 3 weeks. The results indicated that the gamma irradiation would be useful to improve quality and storage stability of half-cooked noodle.

• Journal of the Korean Society of Radiology
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• v.12 no.2
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• pp.133-138
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• 2018

The measurement of gamma-ray spectrum of $^{nat}W(p,xn)$ reaction with natural tungsten were performed by using a high energy proton generated from a 100-MeV proton linear accelerator of the Korea Multi-purpose Accelerator Complex (KOMAC). Gamma rays generated by various nuclides generated through the nuclide were measured using a gamma-ray spectroscopy system composed of HPGe detector. A gamma-ray standard source was used for energy calibration and efficiency measurement of the detector. Analysis of the gamma rays observed in the measured spectra showed that the radionuclides produced were $^{167}Re$, $^{178}Re$, $^{179}Re$, $^{180}Re$, $^{181}Re$, $^{182}Re$, $^{184}Re$, $^{172}Ta$, $^{174}Ta$, $^{178}Ta$, $^{182}Ta$, $^{184}Ta$, $^{175}W$, $^{176}W$, $^{177}W$ and $^{179}W$. Nuclides were generated. The results of this study will be applied to nuclear fusion, astrophysics, and nuclear medicine applications in the future.