• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.780-781
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• 2016

The stereo radiation detection system detects gamma ray source and measures the two dimensional distribution image based on the detection result. Then the system is implemented to measure the distance to the radiation source from the system in 3D space using stereo vision algorithm. In this paper, we reduced the time for a gamma-ray scan space detection through image processing algorithms. In addition, it combines radiation and visible light images. Then we conducted a study for improving the distribution of gamma-ray detection efficiency through the stereo calibration using a 3D visualization. As a result, we obtain an improved detection time by more than 30% and have acquired a visible image with a 3D monitor.

• Food Industry And Nutrition
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• v.10 no.2
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• pp.26-31
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• 2005

천연물 유래 기능성 물질 탐색의 일환으로 녹차 추출물의 산업적 적용을 용이하게 하기 위하여 감마선 조사를 병용하여 추출물의 색도 및 라디칼 소거능을 확인하고, 이 추출 파우더를 돈육 패티에 적용하여 항산화, 색도 및 관능검사를 통해 기호도를 조사하였다. 생리활성을 가지는 녹차 잎 추출물의 라디칼 소거능은 $68.2\%$를 나타냈으며, 20 kGy로 조사했을 경우 비조사구와 큰 차이를 나타내지 않았다. 또한, 감마선조사에 의한 색도의 변화는 감마선 조사 후 $L^{\ast}-value$는 증가했고, $a^{\ast}$- 및 $b^{\ast}-value$는 감소하는 것으로 확인되었다. 또한, 녹차 잎 추출 파우더를 돈육 패티에 적용해본 결과 비첨가구에 비해 라디칼 소거능 및 지질 산화를 지연시키며, 조사된 녹차 잎 추출 파우더를 첨가한 돈육패티가 비첨가구 혹은 비조사된 녹차 잎 첨가구에 비해 저장 기간에 따라$L^{\ast}-value$가 높게 나타났다. 또한, 모든 처리구에서 관능적으로도 큰 차이를 보이지 않았다 그러므로 천연물 유래 녹차 추출물 파우더는 돈육 패티의 기능성 첨가제로서 우수하며, 감마선 조사는 녹차 잎 추출 파우더의 산업적 적용을 용이하게 하는 방법 중의 하나라고 사료된다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.961-963
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• 2015

In this study, we studied the effect of $Co^{60}$ gamma-radiation on the fiber Bragg gratings written by femtosecond UV laser in single mode optical fibers. The fiber Bragg gratings were exposed to gamma-radiation up to a dose of about 31.6 kGy at the dose rate of 106 Gy/min. According to the experimental data and analysis results, we confirmed Bragg gratings written by femtosecond laser have the excellent radiation-hardened characteristics for high radiation environments.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.835-836
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• 2014

In this paper, we have designed the collimator of different sizes structure for the development of stereo radiation detector. And we conducted a study of the optimal structure of collimator using the results of the Gamma-ray irradiation test associated with the change of the incident angle. According to the results of the performance analysis, and showed the results of the optimal incident angle 2. Results of the paper are used as basic data for designing the structure of the detector efficiency for radiation detection.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.06a
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• pp.407-417
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• 2004

This study is to verify radiation detection method by using $\alpha$-spectroscopy and ${\gamma}$-spectroscopy for concretes and components which will be generated during the decommissioning of the uranium conversion plant. Components and inside walls of the building were contaminated with natural uranium materials. Some parts of the stainless steel pipes and concretes of the walls were sampled and analyzed their alpha and gamma activities respectively. Alpha and gamma activities are well matched each other in the range of high activity region to 0.01 Bq/g and gamma activities are over estimated comparing alpha activities corresponded in below 0.005 Bq/g region for the natural uranium of AUC sample. The $^{238}U$ originated from natural products of conversion process could be distinguished by measuring $^{214}Pb$ or $^{214}Bi$ and $^{234}Th$ or $^{234m}Pa$. Uranium contaminations mainly are in the wall surface of the plant. Decontamination process of generating wastes which can be reached tp background level gamma activities measured by gamma spectroscopy can also be used to conservative assessment data.

• Journal of Radiation Protection and Research
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• v.38 no.2
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• pp.119-123
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• 2013

A simple laboratory-made radioactive source to check the integrity of a gamma spectrometry system with HPGe detector was developed. The check source consists of radium-riched soil which was ground in size of less than 0.154mm and contained in air tight cylinderical vial, and provides photons with 12 distinct energies. The spectra of the check source were measured once a month during one year, analyzed the charactreictics of their peaks. When the gamma spectrometry system was in normal state, the areas and FWHMs of the gamma rays with more than 3% gamma emission rate in radium and its decay products was constant within standard deviation 2% and 3%, respectively, except 77 keV peak. And it was found that this check source can play a sufficient role to check the integrity of a gamma spectrometry system using 10 peaks in the range of 77 to 2202 keV.

• Progress in Medical Physics
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• v.25 no.3
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• pp.151-156
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• 2014

The purpose of this study was to confirm the feasibility of imaging of therapy region from the boron neutron capture therapy (BNCT) using the measurement of the prompt gamma ray depending on the neutron flux. Through the Monte Carlo simulation, we performed the verification of physical phenomena from the BNCT; (1) the effects of neutron according to the existence of boron uptake region (BUR), (2) the internal and external measurement of prompt gamma ray dose, (3) the energy spectrum by the prompt gamma ray. All simulation results were deducted using the Monte Carlo n-particle extended (MCNPX, Ver.2.6.0, Los Alamos National Laboratory, Los Alamos, NM, USA) simulation tool. The virtual water phantom, thermal neutron source, and BURs were simulated using the MCNPX. The energy of the thermal neutron source was defined as below 1 eV with 2,000,000 n/sec flux. The prompt gamma ray was measured with the direction of beam path in the water phantom. The detector material was defined as the lutetium-yttrium oxyorthosilicate (Lu0,6Y1,4Si0,5:Ce; LYSO) scintillator with lead shielding for the collimation. The BUR's height was 5 cm with the 28 frames (bin: 0.18 cm) for the dose calculation. The neutron flux was decreased dramatically at the shallow region of BUR. In addition, the dose of prompt gamma ray was confirmed at the 9 cm depth from water surface, which is the start point of the BUR. In the energy spectrum, the prompt gamma ray peak of the 478 keV was appeared clearly with full width at half maximum (FWHM) of the 41 keV (energy resolution: 8.5%). In conclusion, the therapy region can be monitored by the gamma camera and single photon emission computed tomography (SPECT) using the measurement of the prompt gamma ray during the BNCT.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.6
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• pp.768-773
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• 2006

Effect of gamma irradiation on the microbiological and physicochemical characteristics of vacuum-packaged sugar-treated corns was examined to improve taste and shelf-life during storage at room or low temperature. When the vacuum-packaged sugar-treated corns were stored at $25^{\circ}C$ for 7 months, total counts and yeast and molds in the control increased approximately 2.4 and 3.5 log CFU/g, respectively but complete inactivation was observed for irradiated corns at 3 and 5 kGy. Similar results were observed at $15^{\circ}C\;and\;4^{\circ}C$ storage. There were no significant differences in hardness between irradiated sugar-treated waxy corns and control group before storage, but the hardness in control significantly increased during the storage, compared to those of irradiated corns. Also, changes in sugar content were not significant between the irradiated sugar-treated waxy corns and control during storage. Sensory evaluation for steamed-waxy corns showed that total sensory scores were higher in irradiated corns than in control, which were increased with irradiation doses. It was considered that maintaining good quality and increasing shelf-life of irradiated vacuum-packaged sugar treated corns could be possible at $15^{\circ}C$ storage for long-term period.

• Analytical Science and Technology
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• v.16 no.5
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• pp.1041-1051
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• 2003

Neutron induced prompt gamma activation analysis (PGAA) offers a nondestructive, sensitive and relatively rapid method for the determination of trace and major elements and is proven to be convenient for online analysis of minerals, metals, coal, cement, petrochemical, coating, paper as well as many other materials and products. The technique has found many uses in medicine, industry, research, security and the detection of contraband items. This report reviews the present status and future trends of the PGAA techniques. Requirements for the system are neutron source, high resolution HPGe detectors with a high-voltage power supply, an amplifier, analog-to-digital converter, and a multichannel analyzer for the detection and measurement of prompt ${\gamma}$-ray emit form the neutron capture elements. Introducing a ${\gamma}$-${\gamma}$ coincidence system also improves the quality of the ${\gamma}$-ray spectrum by suppressing the background created from the Compton scattering of high energy prompt ${\gamma}$-rays. A PGAA system using a $^{252}Cf$ neutron source is currently under construction for the on-line measurement of several elements in aqueous samples at KAERI. The system can be applied for the detection of chemical weapons and explosives as well as various narcotics.

• Journal of Radiation Protection and Research
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• v.39 no.2
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• pp.81-88
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• 2014

Recently, a new imaging method, gamma vertex imaging (GVI), was proposed for the verification of in-vivo proton dose distribution. In GVI, the vertices of prompt gammas generated by proton induced nuclear interaction were determined by tracking the Compton-recoiled electrons. The GVI system is composed of a beryllium electron converter for converting gamma to electron, two double-sided silicon strip detectors (DSSDs) for the electron tracking, and a scintillation detector for the energy determination of the electron. In the present study, the modules of a charge sensitive preamplifier (CSP) and a shaping amplifier for the analog signal processing of DSSD were developed and the performances were evaluated by comparing the energy resolutions with those of the commercial products. Based on the results, it was confirmed that the energy resolution of the developed CSP module was a little lower than that of the CR-113 (Cremat, Inc., MA), and the resolution of the shaping amplifier was similar to that of the CR-200 (Cremat, Inc., MA). The value of $V_{rms}$ representing the magnitude of noise of the developed system was estimated as 6.48 keV and it was confirmed that the trajectory of the electron can be measured by the developed system considering the minimum energy deposition ( > ~51 keV) of Compton-recoiled electron in 145-${\mu}m$-thick DSSD.