• Nuclear Engineering and Technology
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• 제53권11호
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• pp.3759-3763
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• 2021

In this study, 3" × 3" NaI(Tl) detector, which is widely used in gamma spectroscopy, was modeled with FLUKA code, and calculations required to determine the detector's energy resolution were reported. Photon beams with isotropic distribution with 59, 81, 302, 356, 511, 662, 835, 1173, 1275, and 1332 keV energy were used as radiation sources. The photon pulse height distribution of the NaI(Tl) without influence of its energy resolution obtained with FLUKA code has been converted into a real NaI(Tl) response function, using the necessary conversion process. The photon pulse height distribution simulated in the conversion process was analyzed using the ROOT data analysis framework. The statistical errors of the simulated data were found in the range of 0.2-1.1%. When the results, obtained with FLUKA and ROOT, are compared with the literature data, it is seen that the results are in good agreement with them. Thus, the applicability of this procedure has been demonstrated for the other energy values mentioned.

• 대한방사선방어학회:학술대회논문집
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• 대한방사선방어학회 2009년도 추계 학술발표
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• pp.230-231
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• 2009

• Nuclear Engineering and Technology
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• 제54권5호
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• pp.1769-1780
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• 2022

A new method of dose calculation algorithm, called GPU-accelerated Monte Carlo and collapsed cone Convolution (GMCC) was developed to improve the calculation speed of BNCT treatment planning system. The GPU-accelerated Monte Carlo routine in GMCC is used to simulate the neutron transport over whole energy range and the Collapsed Cone Convolution method is to calculate the gamma dose. Other dose components due to alpha particles and protons, are calculated using the calculated neutron flux and reaction data. The mathematical principle and the algorithm architecture are introduced. The accuracy and performance of the GMCC were verified by comparing with the FLUKA results. A water phantom and a head CT voxel model were simulated. The neutron flux and the absorbed dose obtained by the GMCC were consistent well with the FLUKA results. In the case of head CT voxel model, the mean absolute percentage error for the neutron flux and the absorbed dose were 3.98% and 3.91%, respectively. The calculation speed of the absorbed dose by the GMCC was 56 times faster than the FLUKA code. It was verified that the GMCC could be a good candidate tool instead of the Monte Carlo method in the BNCT dose calculations.

• 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.

• 한국방사선학회논문지
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• 제16권4호
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• pp.381-386
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• 2022

비파괴검사(NDT; Non-Destruction Test)는 제품의 기능을 손상시키거나 물리적으로 파괴시키지 않고 내부의 결함을 검사하는 방법이다. 이러한 방사선투과검사는 고에너지의 방사선을 사용하기 때문에 방사선작업종사자들의 방사선피폭을 방지하는 것은 매우 중요하다. 이에 본 연구는 PbI₂에 Gd₂O₂S:Tb를 결합하여 기존 PbI₂보다 방사선 검출성능을 더욱 향상시켜 방사선투과검사에서 선원누출 등의 사고를 즉각적으로 감지할 수 있는 새로운 구조의 방사선 센서를 제시하였다. 평가는 FLUKA 전산 모사를 통하여 감마선원에서 Gd₂O₂S:Tb 결합 전후의 변환 효율을 분석하였다. Gd₂O₂S:Tb가 결합된 PbI₂는 방사선 검출성능이 1.22배에서 3.22배까지 더 높은 것으로 나타났다. 이러한 결과로부터 본 연구에서 제시된 센서는 방사선투과검사 선원 감지용 방사선 센서로 적용 가능할 것으로 분석되었다.

• 한국방사선학회논문지
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• 제11권7호
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• pp.547-553
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• 2017

현재 의료분야에서는 방사선 차폐체로서 납(Pb)이 널리 쓰이고 있다. 하지만 납은 무게가 매우 무거워 납치마 등의 방호복은 장시간 착용이 어려우며, 인체에 치명적인 납 중독의 위험이 상시 가지고 있다는 문제점을 가지고 있다. 이러한 문제점을 해결하고자 납을 대체 할 수 있는 물질에 대한 많은 연구가 진행되고 있다. 현재 납의 대체물질로써 대표적인 바륨(Ba)과 요오드(I) 등은 우수한 차폐능을 가지고 있지만, 30keV 근처의 에너지 영역에서 특성 X선을 방출하는 특성을 가지고 있다. 환자나 방사선 종사자의 경우 차폐체를 인체에 접촉하고 있는 경우가 많으므로 차폐체에서 발생되는 특성 X선이 인체에 직접 조사되어 방사선 피폭을 증가시킬 위험이 매우 높다. 본 연구에서는 바륨(Ba)과 요오드(I)등에서 발생되는 특성 X선을 제거하기에 적절한 이중구조 차폐체를 방사선 수송코드 중 하나인 FLUKA 수송코드를 개발하여 선행연구로서 진행된 MCNPX 시뮬레이션과 비교 분석하여 이중구조 차폐체의 차폐율에 대한 신뢰성을 검증하고자 하였다. MCNPX와 FLUKA를 이용하여 황산바륨($BaSO_4$)과 산화비스무스($Bi_2O_3$)로 이루어진 다양한 두께조합의 이중구조 차폐체를 설계하였으며, IEC61331-1에 제시된 모식도를 기하학적으로 동일하게 시뮬레이션 상에 구현하였다. 또한, 120 kVp의 연속 X선 스펙트럼에 대한 차폐체의 투과스펙트럼과 흡수선량을 납과 비교 평가하였다. 평가결과, $0.3mm-BaSO_4/0.3mm-Bi_2O_3$ 와 $0.1mm-BaSO_4/0.5mm-Bi_2O_3$ 구조에서는 33 keV와 37 keV의 특성 X선을 모두 흡수하였으며, 90 keV 이상의 고에너지 X선에 대해서도 납과 거의 유사한 차폐효율을 보였다. 또한, FLUKA의 수송코드는 33 keV 이하에서는 cut-off 가 발생하여 저에너지 X선 광자에 대한 전산모사에 제약이 있지만, 40 keV 이상의 고에너지 영역에서 MCNPX와의 상대오차가 6 % 이내로 신뢰성이 매우 우수하다는 것을 확인할 수 있었다.

• Bulletin of the Korean Chemical Society
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• 제20권5호
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• pp.556-558
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• 1999

Lead-selective PVC membrane electrodes based on newly synthesized bis(crown ether)s containing 18-crown-6 moiety was prepared using standard PVC membrane composition. In order to monitor lead in environmental samples by lead sensor, especially good selectivity over alkali and alkaline earth metals has to be obtained. Thus, responses of the PVC membrane prepared with new bis(crown ether)s and Fluka ionophore V (crown ether) base to various cations include lead, alkali and alkaline earth metal ions were investigated for their use as a lead sensor. The polymeric liquid membrane based on trans-1 8-crown-6 ether exhibits the best overall potentiometric performances as a lead-selective electrode in terms of a wide linear dynamic range (between 10-6 and 10-2 M, Pb2+), excellent detection limit (less than 10-6 M) and good durability within limited error. The preferences of lead over other cations, such as Ag+, Hg2+, Na+, Ca2+ and even K+ in the aforementioned electrode are much better than the Fluka ionophore V system.

• 한국방사선학회논문지
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• 제11권6호
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• pp.437-442
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• 2017

꿈의 암치료기라고 불리는 중입자 치료는 환자의 암세포에 입사하여 암세포만을 사멸하고 사라지는데 이때 중성자 및 감마선이 발생되어 치료실 내 영상장비, 그 밖의 전자장비에 영향을 미치게 된다. 중입자 치료시설을 구축하기 위해서는 약 2,000억 원 가량의 예산이 필요하며 구축기간도 5년 이상 소요된다. 따라서 구축 전 몬테카를로 시뮬레이션을 이용하여 치료실 내 선량 분포에 대해 관찰하여 적절한 대비를 하는 것이 중요하다. 본 연구에서는 몬테카를로 시뮬레이션 툴인 FLUKA를 이용하여 중입자 치료 시 치료실 내 선량분포에 대해 알아보았으며 1분 치료 시 치료실 내에는 약 0.1 mSv에서 2 pSv 정도의 영향이 있을 것으로 파악되었다.

• Nuclear Engineering and Technology
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• 제52권10호
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• pp.2410-2414
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• 2020

Heavy ions have a high potential for destroying deep tumors that carry the highest dose at the peak of Bragg. The peak caused by a single-energy carbon beam is too narrow, which requires special measures for improvement. Here, carbon-12 (¹²C) ion with different energies has been used as a source for calculating the dose distribution in the water phantom, soft tissue and bone by the code of Monte Carlobased FLUKA code. By increasing the energy of the initial beam, the amount of absorbed dose at Bragg peak in all three targets decreased, but the trend for this reduction was less severe in bone. While the maximum absorbed dose per bone-mass unit in energy of 200 MeV/u was about 30% less than the maximum absorbed dose per unit mass of water or soft tissue, it was merely 2.4% less than soft tissue in 400 MeV/u. The simulation result showed a good agreement with experimental data at GSI Darmstadt facility of biophysics group by 0.15 cm average accuracy in Bragg peak positioning. From 200 to 400 MeV/u incident energy, the Bragg peak location increased about 18 cm in soft tissue. Correspondingly, the bone and soft tissue revealed a reduction dose ratio by 2.9 and 1.9. Induced neutrons did not contribute more than 1.8% to the total energy deposited in the water phantom. Also during ¹²C ion bombardment, secondary fragments showed 76% and 24% of primary 200 and 400 MeV/u, respectively, were present at the Bragg-peak position. The combined treatment of carbon ions with neutron or electron beams may be more effective in local dose delivery and also treating malignant tumors.

• Nuclear Engineering and Technology
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• 제52권9호
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• pp.2078-2084
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• 2020

Magnesium oxide (MgO) and Zinc oxide (ZnO) nanoparticles (NPs) have been successfully synthesized by solid-solid reaction method. The structural properties of ZnO and MgO NPs were studied using X-ray diffraction (XRD) and scanning electron microscopy (SEM). XRD results indicated a formation of pure MgO and ZnO NPs. The mean diameter values of the agglomerated particles were around to be 70 and 50 nm for MgO and ZnO NPs, respectively using SEM analysis. Further, a wide-range of nuclear radiation shielding investigation for gamma-ray and fast neutrons have been studied for Magnesium oxide (MgO) and Zinc oxide (ZnO) samples. FLUKA and Microshield codes have been employed for the determination of mass attenuation coefficients (μ_m) and transmission factors (TF) of Magnesium oxide (MgO) and Zinc oxide (ZnO) samples. The calculated values for mass attenuation coefficients (μ_m) were utilized to determine other vital shielding properties against gamma-ray radiation. Moreover, the results showed that Zinc oxide (ZnO) nanoparticles with the lowest diameter value as 50 nm had a satisfactory capacity in nuclear radiation shielding.