Korea Institute Of Radiological & Medical Sciences Research Articles

Experimental Transverse Beam Emittance Measurement Using Solenoid Magnet Strength Variation in AB-BNCT

Boron neutron capture therapy (BNCT) is a more efficient cancer treatment method compared to direct radiation therapy using charged particles such as protons or carbon beams. Particularly, accelerator-based BNCT (AB-BNCT) is attracting attention due to easy construction in a hospital. The Korea Institute of Radiological & Medical Sciences (KIRAMS) has constructed an injection system for an electrostatic AB-BNCT accelerator and commissioned 30 keV H− and 5 keV D− ion beam facilities. The beam characteristic parameters and Twiss parameters should be confirmed experimentally, and various methods have to be applied for the related measurements. In this study, the linear matrix formalism is used as a technique to measure the beam characteristic and Twiss parameters by varying the magnetic field strength of a solenoid in the beam line. To confirm the validity of this method, a multi-particle tracking code was executed. The simulation results confirm that the proposed method is effective for extracting Twiss parameters. After verification via the multi-particle tracking code, the method was applied to perform experimental measurements. Notably, the method accurately obtains the transverse beam emittance within reasonable uncertainty levels. Thus, our results show that the proposed method is a convenient technique for extracting the Twiss parameters indirectly. The results of the Twiss parameter measurement can potentially be more precise if other aspects, such as the quadrupole magnetic field strength, are incorporated.

Measurements of cross sections for the 209Bi(n, 4n) reaction by using high energy neutrons with continuous energy spectra

We measured 209 Bi(n, 4n) cross sections at neutron energies E n = 29.8 ± 1.8 MeV and E n = 34.8 ± 1.8 MeV. Bismuth oxide samples were irradiated with the neutrons produced by impinging 30, 35 and 40 MeV proton beams on a 1.05 cm thick beryllium target, where the proton beams were from the MC-50 Cyclotron of Korea Institute of Radiological Medical Sciences (KIRAMS). The neutron flux for each proton beam energy E p , Φ E p ( E n ), has a broad spectrum with respect to E n . By taking the difference in the neutron fluxes, the difference spectra, Φ 40 ( E n ) −Φ 35 ( E n ) and Φ 35 ( E n ) −Φ 30 ( E n ), are obatined and found to be peaked at E n = 29.8 and 34.8 MeV, respectively, with a width of about 3.6 MeV. By making use of this observation and employing the TENDL-2009 library we could extract the 209 Bi(n, 4n) 206 Bi cross sections at the aforementioned neutron energies.

Development of a robotic patient positioning system with a wide beam-angle range for fixed-beam particle therapy

This paper describes a robotic patient positioning system (PPS) for a fixed-beam heavy-ion therapy system. In order to extend the limited irradiation angle range of the fixed beam, we developed a 6-degree-of-freedom (6-DOF) serial-link robotic arm and used it as the robotic PPS for the fixed-beam heavy-ion therapy system. This research aims to develop a robotic PPS for use in the Korea Heavy Ion Medical Accelerator (KHIMA) system, which is under development at the Korea Institute of Radiological & Medical Sciences (KIRAMS). In particular, we select constraints and criteria that will be used for designing and evaluating the robotic PPS through full consultation with KIRAMS. In accordance with the constraints and criteria, we develop a 6-DOF serial-link robotic arm that consists of six revolute joints for the robotic PPS, where the robotic arm covers the upper body of a patient as a treatment area and achieves a 15 ° roll and pitch angle in the treatment area without any collision. Various preliminary experiments confirm that the robotic PPS can meet all criteria for extension of the limited irradiation angle range in the treatment area and has a positioning repeatability of 0.275 mm.

Neutron spectra produced by 30, 35 and 40 MeV proton beams at KIRAMS MC-50 cyclotron with a thick beryllium target

Neutrons over a wide range of energies are produced by bombarding a 1.05cm thick beryllium target with protons of different energies delivered by the MC-50 Cyclotron of the Korea Institute of Radiological Medical Sciences (KIRAMS). The neutron flux Φ(En) versus neutron energy En, produced by protons of 30, 35, and 40MeV energies, was obtained by using the GEANT4 code with a data-based hadronic model. For the experimental validation of the simulated neutron spectra, a number of pure aluminum and iron oxide samples were irradiated with the neutrons produced by 30, 35, and 40MeV protons at 20 μA beam current. The gamma-ray activities of 24Na and 56Mn produced, respectively, through 27Al(n,α)24Na and 56Fe(n,p)56Mn reactions were measured by a HPGe detector. The neutron flux Φ(En) at each neutron energy from the simulation was multiplied with the evaluated cross-sections σ(En) of the respective nuclear reaction, and the summation ∑Φ(En)σ(En) was calculated over the neutron spectrum for each proton energy of 30, 35, and 40MeV. The measured gamma-ray activities of 24Na and 56Mn were found in good agreement with the activities estimated by using the summed values of ∑Φ(En)σ(En) along with other parameters in a neutron activation method.

Real‐Time Imaging Reveals Glioblastoma Suppression Effects of Curcumin in Mouse Brains

Centers for Neuro-Medicine, Neuroscience and Theragnosis, Korea Institute of Science and Technology (KIST), Seoul 136-791, Republic of Korea. *E-mail: yskim@bio.kist.re.kr Biological Chemistry Program, Korea University of Science and Technology (UST), Daejeon 305-350, Republic of Korea Department of Biochemistry and Biomedical Sciences, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea Department of Life Sciences, Korea University, Seoul 136-701, Republic of Korea kYonsei University Wonju College of Medicine, Gangwon-do 220-701, Republic of Korea Molecular Imaging Research Center, Korea Institute of Radiological &Medical Sciences (KIRAMS), Seoul 139-706, Republic of Korea Received October 30, 2014, Accepted January 14, 2015, Published online April 27, 2015

Evaluation of the latent radiation dose from the activated radionuclides in a cyclotron vault

The production of short-lived radioisotopes for the synthesis of radiopharmaceuticals typically takes advantage of a cyclotron that accelerates a proton beam up to a few tens of MeV. The number of cyclotrons has been continuously increasing since the first operation of the MC-50 for the production of radiopharmaceuticals at the Korea Institute of Radiological & Medical Sciences (KIRAMS) in 1986, and currently 35 cyclotrons are under operation throughout the nation. As the number of operating cyclotrons has increased, concerns about radiation safety for the persons who are working at the facilities and dwelling in the vicinity of the facilities are becoming important issues. Radiation that could emit a time-dependent dose was shown to exist in a cyclotron vault after its shutdown. The calculation of the latent radiation dose rate was performed by using the MCNPX and the FISPACT. The calculated results for the activated long-lived radioisotopes in the concrete wall and the structural components of the cyclotron facility were compared with the measured data that were obtained by using gamma-ray spectroscopy with a HPGe detector.

Transverse beam emittance measurement using quadrupole variation at KIRAMS-430

In order to produce a 430 MeV/u carbon ion (12C6+) beam for medical therapy, the Korea Institute of Radiological & Medical Sciences (KIRAMS) has carried out the development of a superconducting isochronous cyclotron, the KIRAMS-430. At the extraction of the cyclotron, an Energy Selection System (ESS) is located to modulate the fixed beam energy and to drive the ion beam through High Energy Beam Transport (HEBT) into the treatment room. The beam emittance at the ion beamline is to be measured to provide information on designing a beam with high quality. The well-known quadrupole variation method was used to determine the feasibility of measuring the transverse beam emittance. The beam size measured at the beam profile monitor (BPM) is to be utilized and the transformation of beam by transfer matrix is to be applied being taken under various transport condition of varying quadrupole magnetic strength. Two different methods where beam optics are based on the linear matrix formalism and particle tracking with a 3-D magnetic field distribution obtained by using OPERA3D TOSCA, are applied to transport the beam. The fittings for the transformation parameters are used to estimate the transverse emittance and the twiss parameters at the entrance of the quadrupole in the ESS. Including several systematic studies, we conclude that within the uncertainty the estimated emittances are consistent with the ones calculated by using Monte Carlo simulations.

Comparative study of MC-50 and ANITA neutron beams by using 55 nm SRAM

Single event upset (SEU) is mainly caused by neutrons in the terrestrial environment. In addition, SEU effects become more and more problematic as technology scales. It is, therefore, important to understand the SEU behaviors of semiconductor devices under neutron reactions. ANITA (atmospheric-like neutrons from thick target) in TSL (The Svedberg Laboratory), Sweden, resembles the neutron energy and flux spectrum to neutrons at the terrestrial level and are typically used to estimate the soft error rate (SER). On the other hand, the neutron energy and flux spectrum from the MC-50 cyclotron at KIRAMS (Korea Institute of Radiological & Medical Sciences) differs greatly from the atmospheric environment. The main objective of this work is finding the efficacy of the neutron beam at KIRAMS for a SEU analysis by using a comparative analysis; 55 nm SRAM is used to determine SEU difference under the beams at two different locations. Since MCU (multi-cell upset) is the dominant effect in emerging technologies with smaller critical charges, the MCU cross sections from the two different beam tests are compared.

Magnet Design of the Superconducting Cyclotron for Carbon Therapy

Korea Institute of Radiological & Medical Sciences (KIRAMS) has started the development of a superconducting cyclotron for carbon therapy. The goal of the development is to produce a 430 MeV/u carbon beam for medical use. The magnet system is composed of one set of NbTi superconducting coils and four spiral sectors with a return yoke. The hill angular widths, hill gaps, and spiral angles with radius have been designed for the isochronous magnetic field. The spiral sector shape and the beam characteristics of the designed magnetic field have been presented.

Time-of-flight system for a CTOF prototype counter with fine-mesh and standard photomultipliers

The upgrade of Continuous Electron Beam Accelerator Facility (CEBAF) is undergo since 2010. The updated CEBAF Large Acceptance Spectrometer (CLAS12) detector is being developed for the JLab upgrade program up to 12 GeV. One of the important component of CLAS12 will be the central time-of-flight system (CTOF). The CTOF will provide detection and identification of charged particles emitted at central angles from 40° to 130°. The design goal is to achieve a time-of-flight resolution σTOF = 50 ps. This study evaluated the timing properties of the CTOF prototype counter. The performance of the upgraded prototype 3 × 3.2 × 66 cm3 scintillation bar of BC-408, coupled to fine-mesh R5924-70 and R7761-70 Hamamatsu photomultipliers via acrylic light guides, has been measured by using two different methods: cosmic rays at Kyungpook National University (KNU), and proton beams at the MC-50 cyclotron of the Korea Institute of Radiological & Medical Sciences (KIRAMS). The gain and the timing resolution of fine-mesh PMs were compared with a conventional Hamamatsu R2083 PM. In the cosmic-ray test, the TOF resolutions were measured to be σFM-PM = 79 ± 0.75stat ± 4syst ps and σR2083 = 73 ± 1.3stat ± 4syst ps for fine-mesh and ordinary photomultipliers, respectively. With proton beams, these values were σFM-PM = 39.1 ± 0.55 ps and σR2083 = 35.0 ± 0.54 ps at count rate 0.15 MHz. These remained constant at higher count rates up to 1.5 MHz. The average ratio of the fine-mesh to the ordinary PM resolutions was 1.123 ± 0.02.

Proton Beam Energy Determination Using a Device for Range Measurement of an Accelerated High Energy Ion Beam

Various nominal proton beam energies from 20 to 45 MeV in 5 MeV steps were determined by measuring each range using a homemade range measurement device for accelerated high energy ion beams that were produced by the MC-50 cyclotron at the Korea Institute of Radiological & Medical Sciences (KIRAMS). First, we carried out the range measurements for incident protons with three dierent stopping materials, aluminum, carbon (graphite), and Lexan (polycarbonate), with densities of 2.7, 1.8, and 1.2 g/cm 3 , respectively, which were employed in order to measure dierent ranges for various proton beam energies. Also, we conducted the MCNPX simulation under conditions identical to those of the above experimental environment. Finally, we determined the proton beam energy by applying the measured experimental ranges to the simulated results, and we compared them with well-known data like SRIM 2008 and ICRU Report 49. From the results, the newly-determined proton energies and the nominal ones were found to be in good agreement, within statistical error. In this work, the results for the proton energies determined applying MCNPX simulations show that the developed device for ion beam range measurements is very useful for determining the energy because of its accuracy, rapidity and convenience.

Development of a Beam Buncher for the KIRAMS-30 Cyclotron

A beam buncher transforms the DC beam generated by an ion source into a pulsed beam. The period of a bunched beam is matched to the RF frequency of a particle accelerator. In this way, a beam buncher increases the beam efficiency of a particle accelerator with an external ion source. The Korea Institute of Radiological & Medical Sciences (KIRAMS) developed a 13 MeV cyclotron (KIRAMS-13) and a 30 MeV cyclotron (KIRAMS-30). The KIRAMS-30 uses an external ion source, and its injection system uses a beam buncher to increase the beam efficiency. We developed a beam buncher for the KIRAMS-30 at the Advanced Radiation Technology Institute (ARTI). The injection system of the KIRAMS-30 is composed of a solenoid-quadrupole-quadrupole (SQQ) unit and a beam buncher. In this paper, we represent an optimized design and experimental results for the beam buncher for the KIRAMS-30.

Design Study of a K22 Prototype Superconducting Cyclotron Magnet

Korea Institute of Radiological & Medical Sciences (KIRAMS) has been developing a superconducting cyclotron since 2007. This paper is concentrated on the design of the superconducting magnet system. The superconducting magnet for a cyclotron consists of an iron yoke and a superconducting coil system. This paper presents the designed spiral sector for beam stability and the design results of the superconducting coil system. Additional test results of the superconducting coils are described.

과학기술위성 3호 대용량 메모리에 대한 오류복구 코드 및 SEU 시험 결과 분석

과학기술위성 3호 대용량 메모리를 SEU로부터 보호하기 위해서 4비트 심볼을 이용하는 RS(10,8) 코드를 개발 하였다. 따라서 32비트 데이터에 대해서 8비트의 페리티를 추가 하였으며 1 심볼에 대해서 에러를 복구할 수 있다. 또한 우리별 3호의 결과를 이용하여 예상되는 SEU 발생률과 스크럽 주기를 계산하였다. 이 결과를 바탕으로 한국원자력 의학원에 있는 Cyclotron 양성자 가속기를 이용하여 SEU 시험을 수행 하였다. RS(10,8) Code by 4-bit symbol was developed to protect the mass memory of STSAT-3 from SEU in orbit. Therefore, one symbol can be corrected for 32-bit data with 8-bit parity configuration. Moreover, scrubbing period and SEU occurrence rate was calculated based on the KITSAT-3 result. A prediction of SEU rates was performed based on the ground experiment results with a proton accelerator in the KIRAMS(Korea Institute of Radiological Medical Sciences).

Central Region Design of the K120 Superconducting Cyclotron

Central Region Design of the K120 Superconducting Cyclotron Dong Hyun An, Joonsun Kang, In Su Jung and Yu-Seok Kim Laboratory of Accelerator Development, Korea Institute of Radiological & Medical Sciences, Seoul 139-706 (Received 4 September 2008) The K120 superconducting cyclotron, which is able to accelerate ions with a range of charge-tomass ratio between 0.13 and 0.5 from 2.0 to 30 MeV/amu is now under design at Korea Institute of Radiological & Medical Sciences(KIRAMS). If the whole range of ions is to be accelerated with only one spiral in ector and central region, the initial energy, electric potential of the spiral in ector and the dee voltage with respect to the injected ions have been determined. The magnetic eld at the center of the cyclotron is about 3.1 Tesla and the operating RF frequency is in the range between 24 and 48 MHz with harmonic numbers of 2 and 4. This paper presents the design parameters of the spiral in ector and the central region of the K120 superconducting cyclotron and the results of the carbon ion beam simulations. PACS numbers: 29.20.Hm, 29.27.-a, 29.27.Ac

Development of Liquid Scintillator System for Proton Flux Monitoring

We developed a Liquid SCintillator (LSC) system for proton beam flux monitoring. A circulation system for a liquid scintillator is designed to the radiation damage to the LSC during proton beam irradiation. In this system, the LSC is made as thin as possible to minimize the energy loss because we want to use this detector as a trigger system for other detectors. The proton beam flux was measured using different beam currents at the MC-50 cyclotron at KIRAMS (Korea Institute of Radiological & Medical Sciences), and the results were compared. We can monitor the proton beam flux up to 10 proton/sec accurately by using a counting method with an ATMEGA128 embedded process equipped with a network system. Also, this system can be used to provide the trigger system for other detectors during the beam test.

The Implementation of Testing Board forSingle Event Upsets

One of the major problem encountered in nuclear plants and satellites design isEMI (Electro-Magnetic Interference) and EMC (Electro-Magnetic Compatibility).Here, our focus is to implement the test board for checking SEU (Single EventUpsets); the effects of protons on the electronic system. The SEU results from thelevel change of stored information due to photon radiation and temperature in thespace environment. The impact of SEU on PLD (Programmable Logic Devices)technology is most apparent in ROM/SRAM/DRAM devices wherein the state ofstorage cell can be upset. In this paper, a simple and powerful test techniques issuggested, and the results are presented for the analysis and future reference. In ourexperiment, the proton radiation facilitv (having the energy of 50 MeV with a beamcurrent of 60 uA of cyclotron) available at KIRAMS (Korea Institute of RadiologicalMedical Sciences) has been applied on a commercially available SRAM manufacturedby Hynix Semiconductor Company.