• Journal of Radiation Protection and Research
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• v.24 no.1
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• pp.1-7
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• 1999

Using the TBP slovent extraction method, a simple and precise method for determining uranium isotopes in the environment samples was developed. The soil sample was decomposed with $HNO_3$ and HF. Uranium isotopes were extracted with 15% TBP in $CCl_4$ from aqueous phase to organic phase, and Th fraction was removed with 8M HCl. Uranium fraction was purified in back extraction step with 1M HCl. Optimized electrode position conditions of uranium Isotopes were set using a new electrode position solution including a DTPA chelating agent. The new method of uranium isotopes determination was validated with a result of application to IAEA Reference Soils.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.235-235
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• 2011

진단용 또는 의료용 동위원소들은 안정한 표적물질에 높은 에너지의 양성자가 조사 될 때 핵반응에 의해서 생성된다. 양성자를 충분한 에너지로 가속하기 위해서 이용되는 사이클로트론의 주요 부분은 (1) 진공시스템, (2) 자석시스템, (3) RF 시스템, (4) 외부 이온원, (5) 수직 축 방향빔의 수평방향 전환 시스템, (6) 빔 인출 장치, 그리고 빔전송과 표적장치로 구성된다. 인출된 빔은 표적까지 손실 없이 전송 될 수 있도록 빔 라인에 설치된 광학적 요소에 의해 집속되어 전송된다. 방사성동위원소의 생산량은 양성자 빔의 특성과 표적 물질의 종류에 따라 결정된다. 즉, 표적 물질에 조사하는 입자의 종류, 적절한 핵반응 선택, 최소량의 불순핵종과 원하는 방사핵종의 최대수율을 얻을 수 있는 최적 에너지 범위결정, 표적 물질의 냉각능력과 입자전류의 세기 등을 고려 하여야 한다. 동위원소 생산에 있어서 예측되는 수율은 입자전류와 비례하며, 에너지에 대한 핵반응 단면적 즉, 여기함수를 적분하여 아래와 같이 얻을 수 있다. 주 생성핵종의 생산 효율을 최대로 높이고 불순 핵종의 생성량을 최소로 감소시키기 위해서는 정확한 여기 함수 자료를 바탕으로 최적 입자를 결정하여야 한다. 또한 이론적인 생산 수율은 입자 전류에 정비례하지만, 입자 전류가 클경우 생산수율은 이론적인 수율보다 적다. 입자빔의 불균일성, 표적의 방사선 피폭에 의한 손상, 높은 입자전류에 의해 발생하는 열로 인하여 생성 핵종이 증발하여 생산 수율이 감소된다. 본 발표에서 방사핵종 C-11과 Tc-99m을 개발하기 위한 최적 조건에 관한 연구결과를 보고하고자 한다.

• Journal of Radiation Protection and Research
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• v.35 no.3
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• pp.117-123
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• 2010

Plutonium is by far the most important of the transuranic elements which have been released into the environment due to radio-toxicity and long term radiation effects on humans. And Pu isotope ratio ($^{240}Pu/^{239}Pu$) is of great interest because this ratio is used as a fingerprint for different sources. Mass spectrometry has been used as an useful atom counting technique with several advantages over decay counting techniques for the determination of Pu isotopes. It enables a determination of Pu isotope ratio in the environmental samples with a low detection limit and a short determination time. An ICP-MS is the representative mass spectrometry for Pu determination. In this study, the precision of $^{240}Pu/^{239}Pu$ isotope ratio was improved by using 4 multiple ion counters of MC-ICP-MS. The detection limit of $^{239}Pu$ and $^{240}Pu$ were $0.10\;fg\;ml^{-1}$ ($0.24\;{\mu}Bq\;ml^{-1}$), $0.12\;fg\;ml^{-1}$ ($0.97\;{\mu}Bq\;ml^{-1}$), respectively. The relative standard deviation of $^{240}Pu/^{239}Pu$ isotope ratio was less than 1 % in trace level. The various reference materials (seawater, soil and sediment) were analyzed to verify this method and their analytical results were in good agreement with the certified (or recommended value) value.

• Journal of Radiation Industry
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• v.5 no.1
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• pp.87-93
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• 2011

A laboratory experiment using a radioisotope was performed to analyze the characteristics of transport and diffusion of a pollutant released from industrial plants. A wave hydraulic model based on the similarity theory was constructed and used to reappear the tidal wave in the laboratory. Two-dimensional numerical models were used to reproduce the results of a wave hydraulic model. The measured and calculated concentrations were compared with the same conditions. As a result of the comparative study, the time of maximum concentration showed slight difference between them, but the values of maximum concentration were relatively well agreed.

• Journal of Radiation Industry
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• v.4 no.1
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• pp.79-83
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• 2010

The pollutants in subsurface soil are advected by groundwater flow and transported by the hydrodynamic dispersion. In this study, laboratory-scale experiments by using a radioisotope were conducted to evaluate the characteristics of the transport and dispersion of pollutants in the soil. The hydraulic model of the laboratory-scale was manufactured based upon its geometric similarity. Tc-99m having a short half-life was used with a tracer and it was injected instantaneously into the soil. Tc-99m milked from a $^{99}Mo/^{99m}Tc$ portable generator fabricated for medical purposes had 0.141 MeV of gamma radiation. The experiments are performed by the different conditions like the variations of groundwater velocity and the results are analyzed by the measured CPS of Tc-99m.

• Journal of Radiation Industry
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• v.6 no.1
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• pp.41-47
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• 2012

A field tracer experiment using a radioisotope was conducted to analyze the transport and dispersion characteristics of pollutants in the coastal area near a Wolsung. A rod float including GPS was released to track the paths of radioisotope. NaI detector was installed to measure the released radioisotope from the boat, and measurements were performed with the real time. The measured tracer data by a field experiment can be used as the basic data for understanding the transport characteristics of pollutants and verifying numerical models near the offshore.

• Radioisotope journal
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• v.21 no.4
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• pp.46-54
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• 2006

Biocompatible and biodegradable hydrogels based on carboxymethyl cellulose(CMC) and polyethyleneglycol(PEG) were prepared far physical barriers for preventing surgical adhesions. These interpolymeric hydrogels were synthesized by a gamma irradiation crosslinking technique. The 1Scmxl.Scm of cecal serosa and adjacent abdominal wail were abraded with bane burr until tbe serosal surface was disrupted and hemorrhagic but not perforated. and the serosa of tbe cecum was sutured to the abdominal wall in 5mm apart from the injured sire. The denuded cecum was covered with either CMC/PEG hydrogels or solution from CMC/PEG hydrogel. Control rat serosa was not covered. Two weeks later. the rats were sacrificed and adhesion was scored on a 0-5 scale. No treatment showed the significantly higher incidence of adhesions than either CMC/BEC hydrogels or solution from CMC/PEG hydrogel. In conclusion, these studies demonstrate that CMC/BEG hydrogels have a function of prevention of intra abdominal adhesion in a rat model.

• Journal of the Korean Society for Nondestructive Testing
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• v.22 no.5
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• pp.474-482
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• 2002

One dimensional Radiometric scanning system was fabricated and tested as a filmless radiographic inspection system, which could be applied to the evaluation of the corrosion and deposits in the pipeline. This system is composed of the single radioactive source of the collimated focusing beam, and single scintillation detector of BGO, and the mechanical scanning system to transport and align the source and detector, and the operating software to automatically control the mechanical scan system. The performance of the system was simulated using GEANT4 software. This system is applied to one specimen having an artificial falw(flat bottom hole) in the pipe and the other specimen with thickness variation. For the inspection by using the radioactive source in the pipeline, it is possible to evaluate the corrosion and deposits in real time and without film.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2006.04a
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• pp.107-110
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• 2006

국가 환경방사선/능 자동감시망과 원전주변의 환경방사선/능 감시를 통해서 연속적으로 측정 기록된 대량의 환경방사선/능 정보들이 효과적으로 활용되고 있지 않는 상황에서 환경방사선/능 정보에 내재되어 있는 공간정보 속성들을 정량적으로 해석하고 시공간적으로 예측할 필요성이 있다. 지구통계기법을 활용하면 환경방사선 감시설비가 비록 설치되어 있지 않은 지점일지라도 환경방사선/능 정보에 대한 예측이 가능하므로 향후 추가적인 감시기의 설치와 시료분석에 소요되는 시간과 비용을 절감할 수 있다. 본 연구에서는 고리, 월성, 영광, 울진 원자력발전소와 대전 한국원자력연구소 등 국내 원자력이용시설 주변 토양중의 환경방사능 분포를 감마동위원소인 $^{137}Cs$과 $^{40}K$을 중심으로 파악하였다.

• Journal of the Korean Society of Radiology
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• v.15 no.6
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• pp.789-794
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• 2021

Brachytherapy is a treatment in which radioactive isotopes are placed inside the body to intensively irradiate the tumor with radiation. Because brachytherapy uses a radioisotope source with a high dose rate, it is very important to know the exact location and dose of the source. However, in clinical practice, it is evaluated inaccurately with the naked eye through rulers and autoradiographs. Therefore, in this study, a dosimeter that can be used for brachytherapy was developed using a lead(II) iodide (PbI₂) material, and the applicability was evaluated by analyzing the reproducibility, linearity, and PID items. As a result of reproducibility evaluation, the RSD value was 1.41%, satisfying the evaluation criteria of 1.5%. As a result of the linearity evaluation, the R² value was 0.9993, which satisfies the evaluation criterion of 0.9990. As a result of PID evaluation, it showed only a difference of 0.06 cm compared with the theoretical value of the inverse square law of distance at the 50% dose reduction point. The dosimeter manufactured in this experiment shows results that satisfy the standard in all evaluations, so it is judged that the possibility of applying the dosimeter in the radiation brachytherapy area is sufficient.