• Title/Summary/Keyword: Proton accelerator

Search Result 122, Processing Time 0.027 seconds

A Study of Radiation Exposure in Proton Therapy Facility (양성자치료기 가속기 시설에서의 작업종사자의 방사선 피폭 연구)

  • Lee, Sang-Hoon;Shin, Dong-Ho;Yoon, Myong-Geun;Shin, Jung-Wook;Rah, Jeong-Eun;Kwak, Jung-Won;Park, Sung-Yong;Shin, Kyung-Hwan;Lee, Doo-Hyun;Ahn, Sung-Hwan;Kim, Dae-Yong;Cho, Kwan-Ho;Lee, Se-Byeong
    • Progress in Medical Physics
    • /
    • v.20 no.1
    • /
    • pp.37-42
    • /
    • 2009
  • Proton therapy facility, which is recently installed at National Cancer Center in Korea, generally produces a large amount of radiation near cyclotron due to the secondary particles and radioisotopes caused by collision between proton and nearby materials during the acceleration. Although the level of radiation by radioisotope decreases in length of time, radiation exposure problem still exists since workers are easily exposed by a low level of radiation for a long time due to their job assignment for maintenance or repair of the proton facility. In this paper, the working environment near cyclotron, where the highest radiation exposure is expected, was studied by measuring the degree of radiation and its duration for an appropriate level of protective action guide. To do this, we measured the radiation change in the graphite based energy degrader, the efficiency of transmitted beam and relative activation degree of the transmission beam line. The results showed that while the level of radiation exposure around cyclotron and beam line during the operation is much higher than the other radiation therapy facilities, the radiation exposure rate per year is under the limit recommended by the law showing 1~3 mSv/year.

  • PDF

Shielding Calculations of Accelerator Facility for Medical Isotope Production using MCNPX Code (MCNPX 코드를 이용한 의료용 방사성동위원소 생산을 위한 가속기 시설의 방사선차폐 및 선량 계산)

  • Seo Kyu-Seok;Kim Chan-Hyeong
    • Progress in Medical Physics
    • /
    • v.15 no.4
    • /
    • pp.210-214
    • /
    • 2004
  • Since production of radioactive isotope for using PET, a lot of neutrons were produced. The produced neutrons were mainly shielded by concrete facility. Secondary photons are generated and emitted from the concrete shielding wall of the PET cyclotron since the proton-generated neutrons are thermalized and absorbed in the concrete wall and emit secondary radiations, i.e., photons. This study calculated neutron dose and photon dose at outside of the accelerator facility using MCNPX code. As results of the calculation, total dose were calculated less than limited dose by law.

  • PDF

Current status of research on radionuclides used in nuclear mediccine (중성자선 실험 및 발암연구의 현황과 미래)

  • Kim, Hui-Seon
    • Radioisotope journal
    • /
    • v.21 no.3
    • /
    • pp.46-60
    • /
    • 2006
  • In recent years the progress of nuclear medicine advanced dramatically in imaging and targeted radionuclide therapy is able to open op exciting perspectives as standard diagnostic and therapeutic modalities, complementing conventional modalities. Positron emission tomography/computed tomography (PET/CT) technology with FDG has been developed clinically in less than 10 years as a routine standard in oncological imaging, including a number of other fluorinated radiopharmaceuticals being evaluated for their ability to complement FDG. However, the limitation of FDG-PET such as non-specific uptake and its short half-life is not compatible with the time necessary for optimal tumour targeting. Therefore, a development of innovative positron-emitting radionuclides with half-lives longer than 10 h is needed. For therapeutic applications, the injection of higher activities is required to reach efficient adsorbed doses in radioresistant solid tumours, while limiting the irradiation of vital organs. In this application, the longer half-life of radiolsotopes are more fit well for radionuclide therapy. To achieve this, researches have to be carried in a largor spectrum of radionuclides for diagnosis and therapy. In the context of rapidly growing nuclear medicine and strong demanding innovative radionuclides, a high-energy (100 MeV), high-intensity (-mA) accelerator with proton (PEFF at KAFRI). will be operating in 2011. The priorities of PEFP will include supporting the nuclear medicine research community by providing those radionuclides with current limited availability by means of a high-energy, high-intensity accelerator.

  • PDF

Numerical Simulations of Subcritical Reactor Kinetics in Thermal Hydraulic Transient Phases

  • J. Yoo;Park, W. S.
    • Proceedings of the Korean Nuclear Society Conference
    • /
    • 1998.05a
    • /
    • pp.149-154
    • /
    • 1998
  • A subcritical reactor driven by a linear proton accelerator has been considered as a nuclear waste incinerator at Korea Atomic Energy Research Institute(KAERI). Since the multiplication factor of a subcritical reactor is less than unity, to compensate exponentially decreasing fission neutrons from spallation reactions are essentially required for operating the reactor in its steady state. furthermore, the profile of accelerator beam currents is very important in controlling a subcritical reactor, because the reactor power varies in accordance of the profile of external neutrons. We have developed a code system to find numerical solutions of reactor kinetics equations, which are the simplest dynamic model for controlling reactors. In a due course of our previous numerical study of point kinetics equations for critical reactors, however, we learned that the same code system can be used in studying dynamic behavior of the subcritical reactor. Our major motivation of this paper is to investigate responses of subcritical reactors for small changes in thermal hydraulic parameters. Building a thermal hydraulic model for the subcritical reactor dynamics, we performed numerical simulations for dynamic responses of the reactor based on point kinetics equations with a source term. Linearizing a set of coupled differential equations for reactor responses, we focus our research interest on dynamic responses of the reactor to variations of the thermal hydraulic parameters in transient phases.

  • PDF

A Study on Design of Transport Container for Radio-activated Targets (방사화 표적물질 운반용기 설계 연구)

  • Hey Min Park;Tae Young Kim;Hae Young Kim;Yang Soo Song;Un Jang Lee;Won-Je Cho;Myeong Hwan Jeong
    • Journal of Radiation Industry
    • /
    • v.17 no.2
    • /
    • pp.191-197
    • /
    • 2023
  • Abstract KOMAC(Korea Multi-Purpose Accelerator Complex, KAERI) has been operating a 100 MeV proton accelerator and is going to produce 68Ga isotope which is useful for diagnosis of cancer. So, it is necessary to develop a transport container for radio-activated targets. In this study, we carry out shielding analysis and structural analysis for the radio-activated target transport container using simulation programs. According to the Type A standard, the transport container includes an inner container and an overpack container. The main material of inner container is lead, and the shape is cylindrical with diameter of 152mm, height of 142mm and weight about 29 kg. It is planned to verify the possibility of field application through production of the transport container prototype in the future.

Conceptional design of an adjustable moderator for BNCT based on a neutron source of 2.8 MeV proton bombarding with Li target

  • Yinan Zhu;Zuokang Lin;Haiyan Yu;Xiaohan Yu;Zhimin Dai
    • Nuclear Engineering and Technology
    • /
    • v.56 no.5
    • /
    • pp.1813-1821
    • /
    • 2024
  • Beam shaping assembly (BSA) is a vital component in Boron Neutron Capture Therapy (BNCT) for obtaining epithermal neutron beams. Several feasible designs of BSA for accelerator-based BNCT (AB-BNCT) neutron source are carried out based on neutrons by bombarding a natural lithium target with 10 mA, 2.8 MeV proton beams. The calculation results demonstrate that a thickness of 45 cm is appropriate for general moderators referring to the therapeutic parameter of Advanced Depth (AD). A series of optimizations are performed and two results are confirmed: One is that employing the configuration of MgF2 and FLUENTAL combined by 1:1 could improve the therapeutic rate (TR) of tumors at a depth of middle region, and the other one is that the TR of superficial tumors can be increased by adding a 5 cm thick boron-11 secondary moderator at the end of general moderators. As a result, an innovative conception of an adjustable moderator is recommended to BNCT. Compared to the MgF2 moderator with a fixed thickness of 45 cm, the TR value can be improved by a maximum of 47.7 % by using the adjustable moderator. Furthermore, the configuration of adjustable moderator has been designed with regulation method for treating tumors of different depths.

A Study on the Measurement of the Relative Nuclear Reaction Cross-Section of the natW(p,xn)176Re Reaction using 100 MeV Proton (100 MeV 양성자를 이용한 natW(p,xn)176Re 핵반응의 상대 핵반응단면적 측정에 대한 연구)

  • Lee, Samyol
    • Journal of the Korean Society of Radiology
    • /
    • v.15 no.2
    • /
    • pp.257-263
    • /
    • 2021
  • This study derives the relative cross-section for the natW(p,xn)176Re nuclear reaction by measuring the gamma rays generated from the nuclear reaction with natural tungsten using a 100 MeV linear accelerator of the Korea Multi-purpose Accelerator Complex in the Korea Atomic Energy Research Institute. In general, research on isotopes with a short half-life always shows a tendency that the intensity of radioactivity decreases rapidly within a short period of time, making it very difficult to measure itself. In particular, 176Re is one of the relatively short radionuclides with a half-life of 5.3 minutes. In this study, 109.08 keV gamma rays generated from the 176Re isotope having such a short half-life were measured using a high-purity Ge detector(HPGe detector). The obtained relative measurements were the results in the 8 to 14 MeV proton energy domain published by Richard G. in 1967, and the TENDL-2019 value, which was the result of A. J. Koning in 2019, which evaluated the nuclear reaction cross-section by calculation based on this comparative analysis was performed. The results of this study are expected to be usefully applied to the design of nuclear fusion reactor which is known as future energy sources, elements ratio for the nuclear synthesis of astrophysics.

A Comparative Study of Branching Ratio of 167Yb Radioactive Isotope from Gamma-ray Spectrum Produced by 169Tm(p,3n)167Yb Reaction with 100-MeV Proton Beam (100-MeV 양성자 빔을 이용하여 169Tm(p,3n)167Yb 반응에 의해 생성된 167Yb 방사성동위원소에서 방출되는 감마선 스펙트럼 비교 연구)

  • Sam-Yol, Lee
    • Journal of the Korean Society of Radiology
    • /
    • v.16 no.7
    • /
    • pp.953-960
    • /
    • 2022
  • The measurement of branching ratio of 167Yb radioactive isotopes from gamma-ray spectrum of 169Tm(p,3n)167Yb reaction were performed by using a 100-MeV proton linear accelerator of the Korea Multi-purpose Accelerator Complex (KOMAC). The 167Yb isotope has a half-life of 17.5 minutes and decays to 169Tm. The gamma rays generated from the 167Yb isotope were measured using an HPGe detector gamma ray spectroscopy system. The energy calibration of the detector and the efficiency measurement of the detector were determined using a standard source. The gamma rays of known main energy (62.9, 106.2, 113.3, 143.5 and 176.3 keV) were measured. On the other hand, information about the intensity of the generated gamma rays is very inaccurate. Therefore, in this study, the decay strength of the main gamma rays was accurately measured. Overall, it was different from the previously known results, and in particular, it was found that the intensity of the main decay gamma ray, such as the 113.3 and 106.2 keV gamma ray, was overestimated, and it was found that the gamma ray, such as 62.9, 116.7 and 143.5 keV was underestimated. The present results are considered to be important information in the fields of nuclear fusion, astrophysics and nuclear physics in the future.

The optimization study of core power control based on meta-heuristic algorithm for China initiative accelerator driven subcritical system

  • Jin-Yang Li;Jun-Liang Du;Long Gu;You-Peng Zhang;Cong Lin;Yong-Quan Wang;Xing-Chen Zhou;Huan Lin
    • Nuclear Engineering and Technology
    • /
    • v.55 no.2
    • /
    • pp.452-459
    • /
    • 2023
  • The core power control is an important issue for the study of dynamic characteristics in China initiative accelerator driven subcritical system (CiADS), which has direct impact on the control strategy and safety analysis process. The CiADS is an experimental facility that is only controlled by the proton beam intensity without considering the control rods in the current engineering design stage. In order to get the optimized operation scheme with the stable and reliable features, the variation of beam intensity using the continuous and periodic control approaches has been adopted, and the change of collimator and the adjusting of duty ratio have been proposed in the power control process. Considering the neutronics and the thermal-hydraulics characteristics in CiADS, the physical model for the core power control has been established by means of the point reactor kinetics method and the lumped parameter method. Moreover, the multi-inputs single-output (MISO) logical structure for the power control process has been constructed using proportional integral derivative (PID) controller, and the meta-heuristic algorithm has been employed to obtain the global optimized parameters for the stable running mode without producing large perturbations. Finally, the verification and validation of the control method have been tested based on the reference scenarios in considering the disturbances of spallation neutron source and inlet temperature respectively, where all the numerical results reveal that the optimization method has satisfactory performance in the CiADS core power control scenarios.

Development of Chemical Separation Process for Thallium-201 Radioisotope with Lead Standard Material (납 표준물질을 이용한 방사성동위원소 Thallium-201의 화학적 분리공정 개발)

  • JunYoung Lee;TaeHyun Kim;JeongHoon Park
    • Journal of Radiation Industry
    • /
    • v.17 no.4
    • /
    • pp.543-549
    • /
    • 2023
  • Thallium-201 (201Tl) is a medical radioisotope which emits gamma rays when it decays and used in myocardial perfusion scans in single-photon emission tomography due to its similar properties to potassium. Currently, the Korea Institute of Radiological & Medical Sciences is the only institution producing 201Tl in Korea, and optimization of 201Tl production research is necessary to meet supply compared to domestic demand. To this end, technical analysis of plating target production and chemical separation methods essential for 201Tl production research is conducted. It deals with the process of generating and separating 201Tl radioisotope and target production, It can be generated through a nuclear reaction such as natHg(p,xn)201Tl, 201Hg(p,n)201Tl, natPb(p,xn)201Bi → 201Pb → 201Tl, 205Tl(p,5n)201Pb → 201Tl, and considering impure nuclide generated simultaneously with the use of proton beam energy of 35 MeV or less, it is intended to be produced using the 203Tl(p,3n)201Pb→201Tl nuclear reaction. In particular, the chemical separation of Tl is a very important element, and the chemical separation methods that can separate it is broadly divided into four types, including solid phase extraction, liquid-liquid, electrochemical, and ion exchange membrane separation. Some chemical separations require additional separation steps, such as methods using selective adsorption. Therefore, this technical report describes four chemical separation methods and seeks to separate high-purity 201Tl using a method without additional separation steps