• 한국콘텐츠학회논문지
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• 제16권7호
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• pp.681-688
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• 2016

본 논문은 IEC 61267에서 제시하는 RQA3, 5, 7, 9의 선질 조건과 임상검사 조건을 조합한 선질들을 사용하여 공간분해능과 선예도를 평가하고 선질들의 스펙트럼을 분석하고자 하였다. 실험방법으로 첫째, 부가필터와 SID에 따른 공간해상력 평가에 사용된 영상은 IEC 62220-1 에 제시된 edge method을 이용하여, 영상을 획득하였으며 Matlab 프로그램을 사용하여 영상에 대한 해상력 평가는 MTF 측정값 10%(0.1)에서, 선예도 평가는 MTF 측정값 50%(0.5)에서 평가하였다. 둘째, MCNPX 시뮬레이션을 이용하여 선질들의 입자플루언스율과 에너지대별 스펙트럼 분석을 하였다. 실험결과 부가필터 사용과 SID에 따른 영상품질평가에서는 RQA3 선질 조합조건에서 공간분해능과 선예도는 부가필터 미사용과 SID 100 cm에서 높게 나타났다. RQA5 선질 조합조건에서 공간분해능과 선예도는 부가필터를 사용하고 SID 100 cm에서 높게 나타났다. RQA7 선질 조합조건에서 공간분해능은 부가필터 미사용과 SID 150 cm에서 높게 나타났다. 선예도는 부가필터를 사용하고 SID 150 cm에서 높게 나타났다. RQA9 선질 조합조건에서는 공간분해능과 선예도는 부가필터 사용하고 SID 180 cm에서 높게 나타났다. 선질들의 스펙트럼 분석은 X선관의 재현성에 따른 오차, 검출기의 보정에 따른 오차 등 실험에서 발생하는 필연적인 오차를 줄여 가장 이상적인 조건을 제공하는 MCNPX 시뮬레이션을 통해 스펙트럼을 분석하였다. 결론적으로 다양한 선질들에 대한 공간분해능과 선예도 결과를 제시함으로써 임상에서 사용 중인 검출기의 평가에 있어 선질조건과 검사실 환경에 맞는 정량적인 평가방법을 제시할 수 있는 기초자료로 제공하고자 한다.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2010년도 학술논문요약집
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• pp.375-376
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• 2010

• 대한방사선방어학회:학술대회논문집
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• 대한방사선방어학회 2011년도 추계 학술발표회 및 심포지엄
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• pp.342-343
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• 2011

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2011년도 춘계학술논문요약집
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• pp.93-94
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• 2011

• 품질경영학회지
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• 제43권3호
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• pp.239-252
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• 2015

Purpose: Lead has been widely used in radiation shielding for its low price and high workability. Recently in several europe countries, use of lead was banned for environmental issues. Also lead can cause health problems like alergies. Alternative materials for lead are highly required. The purpose of this study was to propose lead free radiation shielding material. Methods: Research of radiation shielding in Korea is not easy for certain limits such as radiation materials, experimental facilities and places. The collected data through the research were simulated using MCNPX. The simulation tools used for this study were utilized Monte Carlo method. Results: we suggest new design of lead free radiation shielding material using MCNPX code comparing shielding performance of new composite materials to lead. Conclusion: This newly introduced nano-scale composite of metal and polymer makes new chance for highly lightened radiation protective garments with endurable shielding performance.

• Nuclear Engineering and Technology
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• 제52권5호
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• pp.1002-1007
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• 2020

The purpose of the current study was to evaluate a spectrum formulation set employed to modify the neutron spectrum of D-D fusion neutrons in a IS plasma focus device using GEANT4, MCNPX2.6, and FLUKA codes. The set consists of a moderator, reflector, collimator and filters of fast neutron and gamma radiation, which placed on the path of 2.45 MeV neutron energy. The treated neutrons eliminate cancerous tissue with minimal damage to other healthy tissue in a method called neutron therapy. The system optimized for a total neutron yield of 10⁹ (n/s). The numerical results indicate that the GEANT4 code for the cubic geometry in the Beam Shaping Assembly 3 (BSA3) is the best choice for the energy of epithermal neutrons.

• Nuclear Engineering and Technology
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• 제53권7호
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• pp.2133-2150
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• 2021

In this work, Esfahan light water subcritical reactor (ELWSCR) is analysed using experimental and theoretical diagnostic methods. Important neutronic parameters of the system such as prompt neutron lifetime, delayed neutron fraction, prompt neutron decay constant, negative reactivity of the core, fuel and moderator temperature coefficient of reactivity, and overall and local void coefficient of reactivity are estimated. Also, neutron flux distribution, reflector saving, water level effect, and lattice pitch of the core including operating point of the facility are studied in details. Theoretical results are calculated by MCNPX and measurements are performed utilizing zero power reactor noise method. Detailed descriptions of the results are explained in the text.

• Nuclear Engineering and Technology
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• 제51권1호
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• pp.269-274
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• 2019

$^{64}Cu$ is a favorable radionuclide in nuclear medicine applications because of its unique characteristics such as three types of decay (electron capture, ${\beta}^-$ and ${\beta}^+$) and 12.7 h half-life. Production of $^{64}Cu$ by irradiation $^{nat}Cu$ and $^{nat}CuNPs$ in Tehran Research Reactor was investigated. The characteristics of copper nanoparticles were investigated with SEM, TEM and XRD analysis. The cross section of $^{63}Cu(n,{\gamma})^{64}Cu$ reaction was done with TALYS-1.8 code. The activity value of $^{64}Cu$ was calculated with theoretical approach and MCNPX-2.6 code. The results were compared with related experimental results which showed good adaptations between them.

• Journal of Astronomy and Space Sciences
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• 제41권1호
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• pp.17-23
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• 2024

The safety of electronic components used in aerospace systems against cosmic rays is one of the most important requirements in their design and construction (especially satellites). In this work, by calculating the dose caused by proton beams in geostationary Earth orbit (GEO) orbit using the MCNPX Monte Carlo code and the MULLASSIS code, the effect of different structures in the protection of cosmic rays has been evaluated. A multi-layer radiation shield composed of aluminum, water and polyethylene was designed and its performance was compared with shielding made of aluminum alone. The results show that the absorbed dose by the simulated protective layers has increased by 35.3% and 44.1% for two-layer (aluminum, polyethylene) and three-layer (aluminum, water, polyethylene) protection respectively, and it is effective in the protection of electronic components. In addition to that, by replacing the multi-layer shield instead of the conventional aluminum shield, the mass reduction percentage will be 38.88 and 39.69, respectively, for the two-layer and three-layer shield compared to the aluminum shield.

• 대한방사선방어학회:학술대회논문집
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• 대한방사선방어학회 2009년도 추계 학술발표
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• pp.204-205
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• 2009