Study on Radiation Production in the Charge Stripping Section of the RISP Linear Accelerator

오주희,Leila Mokhtari Oranj,이희석,고승국 한국물리학회 2015 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.66 No.3

The linear accelerator of the Rare Isotope Science Project (RISP) accelerates 200 MeV/nucleon238U ions in a multi-charge states. Many kinds of radiations are generated while the primarybeam is transported along the beam line. The stripping process using thin carbon foil leads tocomplicated radiation environments at the 90-degree bending section. The charge distribution of238U ions after the carbon charge stripper was calculated by using the LISE++ program. Theestimates of the radiation environments were carried out by using the well-proved Monte Carlocodes PHITS and FLUKA. The tracks of 238U ions in various charge states were identified usingthe magnetic field subroutine of the PHITS code. The dose distribution caused by U beam lossesfor those tracks was obtained over the accelerator tunnel. A modified calculation was applied fortracking the multi-charged U beams because the fundamental idea of PHITS and FLUKA was totransport fully-ionized ion beam. In this study, the beam loss pattern after a stripping sectionwas observed, and the radiation production by heavy ions was studied. Finally, the performanceof the PHITS and the FLUKA codes was validated for estimating the radiation production at thestripping section by applying a modified method.

FLUKA 코드를 이용한 Critical Assembly(KUCA)의 중성자 선속 Benchmarking Study

이희석,Leila Mokhtari Oranj,이태연 대한방사선방어학회 2013 대한방사선방어학회 학술발표회 논문요약집 Vol.2013 No.11

몬테카를로 시뮬레이션을 이용한 중입자 치료실의 선량분포 추정

송용근(Yongkeun Song),허승욱(Seunguk Heo),조규석(Gyuseok Cho),최상현(Sanghyun Choi),한무재(Moojae Han),박지군(Jikoon Park) 한국방사선학회 2017 한국방사선학회 논문지 Vol.11 No.6

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 치료실내 선량분포에 대해 알아보았으며 1분 치료 시 치료실 내에는 약 0.1 mSv에서 2 pSv 정도의 영향이 있을 것으로 파악되었다. Heavy ion therapy has a high cure rate for cancer cell. So many countries are introducing heavy ion therapy facility. When treating a cancer using heavy ion therapy, neutrons and gamma rays are generated and affect electronic equipment. A budget of about KRW 200 billion is needed to build a heavy ion therapy facility, and it takes more than five years to build it. Therefore it is important to observe the dose distribution in the treatment room using the monte carlo simulation before construction. In this study, we used the FLUKA of monte carlo simulation to investigate the dose distribution in the heavy ion treatment room.

장기선량 재구성을 위한 Monte-Carlo Simulation FLUKA의 유효성 검증

허재,김상돈 대한방사선방어학회 2018 대한방사선방어학회 학술발표회 논문요약집 Vol.2018 No.04

Measurement of Neutron Production Double-differential Cross-sections on Carbon Bombarded with 430 MeV/Nucleon Carbon Ions

Itashiki, Yutaro,Imahayashi, Youichi,Shigyo, Nobuhiro,Uozumi, Yusuke,Satoh, Daiki,Kajimoto, Tsuyoshi,Sanami, Toshiya,Koba, Yusuke,Matsufuji, Naruhiro The Korean Association for Radiation Protection 2016 방사선방어학회지 Vol.41 No.4

Background: Carbon ion therapy has achieved satisfactory results. However, patients have a risk to get a secondary cancer. In order to estimate the risk, it is essential to understand particle transportation and nuclear reactions in the patient's body. The particle transport Monte Carlo simulation code is a useful tool to understand them. Since the code validation for heavy ion incident reactions is not enough, the experimental data of the elementary reaction processes are needed. Materials and Methods: We measured neutron production double-differential cross-sections (DDXs) on a carbon bombarded with 430 MeV/nucleon carbon beam at PH2 beam line of HIMAC facility in NIRS. Neutrons produced in the target were measured with NE213 liquid organic scintillators located at six angles of 15, 30, 45, 60, 75, and $90^{\circ}$. Results and Discussion: Neutron production double-differential cross-sections for carbon bombarded with 430 MeV/nucleon carbon ions were measured by the time-of-flight method with NE213 liquid organic scintillators at six angles of 15, 30, 45, 60, 75, and $90^{\circ}$. The cross sections were obtained from 1 MeV to several hundred MeV. The experimental data were compared with calculated results obtained by Monte Carlo simulation codes PHITS, Geant4, and FLUKA. Conclusion: PHITS was able to reproduce neutron production for elementary processes of carbon-carbon reaction precisely the best of three codes.

몬테카를로 시뮬레이션을 통한 중하전입자의 콘크리트 방사화 비교평가

배상일(Sang-Il Bae),조용인(Yong-In Cho),김정훈(Jung-Hoon Kim) 대한방사선과학회(구 대한방사선기술학회) 2021 방사선기술과학 Vol.44 No.4

A heavy particle accelerator is a device that accelerates particles using high energy and is used in various fields such as medical and industrial fields as well as research. However, secondary neutrons and particle fragments are generated by the high-energy particle beam, and among them, the neutrons do not have an electric charge and directly interact with the nucleus to cause radiation of the material. Quantitative evaluation of the radioactive material produced in this way is necessary, but there are many difficulties in actual measurement during or after operation. Therefore, this study compared and evaluated the generated radioactive material in the concrete shield for protons and carbon ions of specific energy by using the simulation code FLUKA. For the evaluation of each energy of proton beam and carbon ion, the reliability of the source term was secured within 2% of the relative error with the data of the NASA Space Radiation Laboratory(NSRL), which is an internationally standardized data. In the evaluation, carbon ions exhibited higher neutron flux than protons. Afterwards, in the evaluation of radioactive materials under actual operating conditions for disposal, a large amount of short-lived beta-decay nuclides occurred immediately after the operation was terminated, and in the case of protons with a high beam speed, more radioactive products were generated than carbon ions. At this time, radionuclides of 44Sc, 3H and 22Na were observed at a high rate. In addition, as the cooling time elapsed, the ratio of long-lived nuclides increased. For nonparticulate radionuclides, 3H, 22Na, and for particulate radionuclides, 44Ti, 55Fe, 60Co, 152Eu, and 154Eu nuclides showed a high ratio. In this study, it is judged that it is possible to use the particle accelerator as basic data for facility maintenance, repair and dismantling through the prediction of radioactive materials in concrete according to the cooling time after operation and termination of operation.

A Study on the Evaluation of Radiation Safety in Opened-Ceiling-Facilities for Radiography Testing

허성회(Sung-Hoe Heo),박원석(Won-Seok Park),허승욱(Seung-Uk Heo),민병인(Byung-In Min) 한국방사선학회 2022 한국방사선학회 논문지 Vol.16 No.6

산업체에서 용접구조물을 파괴 없이 품질을 검증하는 방사선투과검사는 압도적으로 많이 이용되지만, 방사선을 이용함에 따라 많은 안전사항이 요구된다. 방사선투과검사 작업종사자는 검사부재의 이동유무에 따라 감마선조사기인 운반용기에 내장된 Iridium-192 방사선원을 사용시설 내 혹은 사용시설 외의 장소에서 이동시켜 작업을 수행 한다. 일반적인 사용시설은 두꺼운 콘크리트로 외부와 방사선을 전면 차단한 시설이지만, 검사부재의 취급이 용이하지 않은 등의 사유로 천장이 개방된 사용시설이 있다. 일반적인 사용시설은 외부가 모두 차단되어 이론적인 선량 평가 방법을 통하여 건설하여도 무방하지만, 천장이 개방된 경우 스카이샤인효과로 인하여 단순 이론적인 계산 방법으로 방사선 안전성을 평가하는 것은 적합하지 않다. 따라서 본 연구에서는 실제 현장에서 해당 시설의 방사선 안전성을 이온챔버형 방사선측정기와 누적선량계형인 OSLD를 통하여 평가하고, 실제 평가 환경을 몬테카를로 시뮬레이션 코드인 플루카를 이용하여 모델링 및 평가를 하였다. 해당 시설에서 조사방향에 따라 시설 경계의 방사선량은 규제기관에서 정하는 기준을 만족하기 어려웠고, 추가의 방법을 통하여 방사선 안전성을 확보할 수 있었다. 또한, Iridium-192 선원을 이용한 시뮬레이션 결과가 실제 측정값과 유효한 결과임을 확인할 수 있었다. Radiography-Testing that verify the quality of welding structures without destruction are overwhelmingly used in industries, but many safety precautions are required as radiation is used. The workers for Radiography-Testing perform the inspection by moving the Iridium-192 radiation source embedded in the transport container of the gamma-ray irradiator within or outside the facility. The general facility is completely blocked about radiation from the outside with thick concrete, but if it is difficult for worker to handle object of inspection, facilities ceiling can be opened. A general facility may be constructed using a theoretical dose evaluation method because all exterior facilities are blocked, but if the ceiling is open, it is not appropriate to evaluate radiation safety with a simple theoretical calculation method due to the skyshine effect. Therefore, in this study, the radiation safety of the facility was evaluated in the actual field through an ion chamber survey-meter and an accumulated dose-meter called as OSLD, and the actual evaluation environment was modeled and evaluated using the Monte Carlo simulation code as FLUKA. According to the direction of the irradiation, the radiation dose at the facility boundary was difficult to meet the standards set by the regulatory authority, and radiation safety could be secured through additional methods. In addition, it was confirmed that the simulation results using the Iridium-192 source were valid evaluation with the actual measured results.

FLUKA 전산 모사를 통한 감마선원 조건에서의 요오드화납(Ⅱ)과 Gd2O2S:Tb가 결합된 센서의 적용가능성 연구

양승우,박윤희,박지군,허예지 한국방사선학회 2022 한국방사선학회 논문지 Vol.16 No.4

Non-Destruction Test (NDT) is a method to check internal defects without destroying the product. Among them, radiographic testing (RT) uses high-energy radiation, so it is very important to prevent radiation exposure of workers. Therefore, in this study, in this study, a radiation sensor structure that improves radiation detection performance compared to the existing PbI2 and can immediately detect accidents in RT was presented. For evaluation, the conversion efficiency was analyzed in the gamma ray source through FLUKA simulation. PbI2 with overlapping Gd2O2S:Tb presented in this study showed a higher radiation sensitivity from 1.22 to 3.22 times than that of non-overlapping PbI2. This indicates that the presented sensor is suitable for use as a radiation sensor for source detection in RT. 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.

A Comparison Study of the Ridge Filter Parameter by Using FLUKA and GEANT4 Simulation Codes

Yongkeun Song,Jaeik Shin,Sungho Cho,Seunghoon Yoo,Ilsung Cho,Eunho Kim,Wongyun Jung,Sanghyoun Choi,오경민 한국물리학회 2015 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.67 No.1

We investigated the parameter optimization of the ridge filter’s thickness for carbon-ion therapy by using a Monte Carlo simulation. For this study, a ridge filter was designed for the spreadout Bragg peak (SOBP) by considering the relative biological effectiveness (RBE). The thickness, height, and width of the ridge filter were designed by using the FLUKA and the GEANT4 codes, and we analyzed and compared the results of the physical dose distributions for the FLUKA and the GEANT4 codes. The results showed that the minimum width of the groove for the ridge filter should be at least 0.5 cm for an appropriate biological dose. The SOBP sections were 8 cm, 9 cm, and 10 cm, respectively, when the heights were 3.5 cm, 4.0 cm, and 4.5 cm. The height of the ridge filter was designed to be associated with the SOBP width. Also, the results for the FLUKA and the GEANT4 codes showed that the average value of the difference was 3% and that the maximum error was 5%; however, the trends were similar. Therefore, the height and the width of the groove for the ridge filter are important parameters for deciding the length and the plateau of the SOBP.

Determination of energy resolution for a NaI(Tl) detector modeled with FLUKA code

Demir, Nilgun,Kuluozturk, Zehra Nur Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.11

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.