• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.70.1-70.1
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• 2015

The facility for RAON superconducting heavy-ion accelerator at a beam power of up to 400 kW will be produced rare isotopes with two electron cyclotron resonance (ECR) ion sources. Highly charged ions generated by the ECR ion source will be injected to a superconducting LINAC to accelerate them up to 200 MeV/u. During the acceleration of the heavy ions, a good vacuum system is required to avoid beam loss due to interaction with residual gases. Therefore ultra-high vacuum (UHV) is required to (i) limit beam losses, (ii) keep the radiation induced within safe levels, and (iii) prevent contamination of superconducting cavities by residual gas. In this work, a RAON vacuum design for all the accelerator system will be presented along with Monte Carlo simulation of vacuum levels in order to validate the vacuum hardware configuration, which is needed to meet the baseline requirements.

• Progress in Superconductivity and Cryogenics
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• v.18 no.4
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• pp.40-43
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• 2016

Beam trajectory is needed to be controlled in heavy ion accelerator system. Quadruple magnets are widely used in heavy ion accelerator for focusing the transporting particles. A quadruple triplet system which consists of three consecutive quadrupoles, Q1, Q2 and Q3, is used to control beam trajectory at a focused position. Q1 and Q3 have symmetry with respect to Q2. The beam trajectory in magnet system is affected by higher order fields existed in real fields. For quadrupoles, the representation simulation of beam trajectory was carried out to study the beam trajectory and to estimate an effect of higher order field in triplet system. SCALA program was used to simulate the beam trajectory in $Opera^{TM}$. SCALA can analyze a large number of beam trajectories at the same time by adjusting the size of finite element of the emitter. With $Opera^{TM}$ and $Matlab^{TM}$ programs, the position of focused beam spot in quadruple triplet system can be increased or decreased using evolution strategy (ES) method, therefore the length of triplet system can be controlled. Finally, the quadruple triplet system with the appropriate length and expected beam spot range was suggested in this paper.

• Progress in Medical Physics
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• v.28 no.2
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• pp.67-75
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• 2017

Prior to the introduction of a medical apparatus based on heavy-ion medical accelerator in Korea, a study is needed on quality control in clinical operation for the safe and appropriate usage of the instrument. Data relevant for the study were obtained via information sharing sessions and visits by the Particle Therapy Co-Operative Group (PTCOG) and other related academic associations. Furthermore, investigative analysis of the European and Japanese performance evaluation guidelines for heavy ion, as well as research on relevant literature, were conducted. In addition, instrumental standards were analyzed through an investigation of the current usage status of the heavy-ion medical accelerator, and further analysis was conducted on the evaluation methods for the performance, safety, and significance of the instrument. Based on these analyses, regular quality control procedures for heavy-ion medical accelerators in hospitals and other institutes were extrapolated. It is hoped that the results of this study will facilitate hospitals that have introduced heavy-ion medical accelerators, or are considering the implementation of the instrument, in their understanding of the fundamental standards and capabilities of the treatment system, as well as in establishing and carrying out quality control procedures for clinical operations such that it will contribute to the safety of patients and the efficiency of medical practitioners.

• Vacuum Magazine
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• v.4 no.1
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• pp.4-11
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• 2017

The Rare Isotope Science Project (RISP) has been launched for developing a superconducting heavy-ion linear accelerator, which produces various rare isotopes for low energy nuclear science and applied sciences. This superconducting linac is designed to achieve a very high beam current (200Mev/u with 400 kW beam power) of heavy ions including Uranium. For the high current accelerator, the requirement of ultra high-vacuum level is considered as one of the of important factors. Vacuum calculations have been carried out to verify the vacuum system design satisfied the requirements. In this paper, an overview of RISP and vacuum calculation methods for several interesting sections of the superconducting linear accelerator.

• Journal of Astronomy and Space Sciences
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• v.29 no.3
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• pp.315-320
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• 2012

We developed a mass-memory chip by staking 1 Gbit double data rate 2 (DDR2) synchronous dynamic random access memory (SDRAM) memory core up to 4 Gbit storage for future satellite missions which require large storage for data collected during the mission execution. To investigate the resistance of the chip to the space radiation environment, we have performed heavy-ion-driven single event experiments using Heavy Ion Medical Accelerator in Chiba medium energy beam line. The radiation characteristics are presented for the DDR2 SDRAM (K4T1G164QE) fabricated in 56 nm technology. The statistical analyses and comparisons of the characteristics of chips fabricated with previous technologies are presented. The cross-section values for various single event categories were derived up to ~80 $MeVcm^2/mg$. Our comparison of the DDR2 SDRAM, which was fabricated in 56 nm technology node, with previous technologies, implies that the increased degree of integration causes the memory chip to become vulnerable to single-event functional interrupt, but resistant to single-event latch-up.

• Progress in Superconductivity and Cryogenics
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• v.18 no.4
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• pp.35-39
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• 2016

In recent years, high-temperature superconductor (HTS) Quadruple Triplets are being developed for heavy ion accelerators, because the HTS magnets are suitable to withstand radiation and high heat loads in the hot cell of accelerators. Generally, an iron yoke, which costs a mass of material, was employed to enhance the magnetic field when a quadrupole magnet was designed. The type of the magnet is called iron-dominated magnet, because the total magnetic field was mainly induced by the iron. However, in the HTS superconductor iron-dominated magnets, the coil-induced field also can have a certain proportion. Therefore, the air-core HTS quadrupole magnets can be considered instead of the iron-core HTS quadrupole magnet to be employed to save the iron material. This study presents the design of an air-core HTS quadruple triplet which consists three by air-core HTS quadruple magnet and compare the design result with that of an iron-core HTS quadruple triplet. First, the characteristics of an air-core HTS quadrupole magnet were analyzed to select the magnet system for the magnetic field uniformity impairment. Then, the field uniformity was improved(< 0.1%) exactly using evolution strategy (ES) method for each iron-core HTS quadrupole magnet and the air-core HTS quadruple triplet was established. Finally, the designed air-core triplet was compared with the iron-core HTS quadruple triplet, and the results of beam trajectories were presented with both the HTS quadruple triplet systems to show that the air-core triplet can be employed instead of the iron-core HTS triplet. The design of the air-core quadruple triplet was suggested for a heavy ion accelerator.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.544-549
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• 1997

Injector of high voltage or linear ion accelerator is intended to generate, extract and form beam of certain species with required parameters at the entrance of accelerating structure or, for low energy case, directly in the processing chamber (end station). Injector is the main part defining the ion accelerator performance and reliability. Its power supply and control system (PSCS) features are conditioned by placing the injector equipment at high voltage potential and by complexity of the plasma-beam load. The injector's PSCS should provide: - Transmission of electric power onto high voltage (h/v) terminal; - Obtaining of required output characteristics for injector equipment operation; - Transmission of the operational data and start/stop signals from h/v terminal to control cabinet; - Rremote control of injector; - Withstanding the high voltage breakdowns and X-ray radiation; - Compatibility with other equipment. The paper is concerned with analysis of injectors' PSCS structure and description of the system developed for 50 keV, 20 mA heavy ion injector.

• Progress in Superconductivity and Cryogenics
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• v.18 no.2
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• pp.21-24
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• 2016

In recent years, the iron-dominated high-temperature superconductor (HTS) quadrupole magnets are being developed for heavy ion accelerators. Field analyses for iron-dominated quadrupole magnets were based on the normal-conducting (NC) quadrupole magnet early in the development for accelerators. Some conclusions are still in use today. However, the magnetic field of iron-dominated HTS quadrupole magnets cannot fully follow these conclusions. This study established an HTS quadrupole magnet model and an NC quadrupole magnet model, respectively. The harmonic characteristics of two magnets were analyzed and compared. According to the comparison, the conventional iron-dominated quadrupole magnets can be designed for maximum field gradient; the HTS quadrupole magnet, however, should be considered with varying field gradient. Finally, the HTS quadrupole magnet was designed for the changing field gradient. The field quality of the design was improved comparing with the result of the previous study. The new design for the HTS quadrupole magnet has been suggested.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.3-5
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• 2002

This paper describes research activities at National Institute of Radiological Sciences (NIRS), Japan in development of radiological apparatus, which cover 4-dimensinal (4D) CT, next-generation PET and several progresses in heavy-ion irradiation system at HIMAC (Heavy Ion Medical Accelerator in Chiba).

• Progress in Superconductivity and Cryogenics
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• v.17 no.3
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• pp.23-27
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• 2015

Quadruple magnet is an essential component for the accelerator, and the field uniformity in the good field region reflects the quality of quadruple magnet. In this paper, the total magnetic field B was separated into the coil-induced magnetic field $B_s$ and the iron-induced magnetic field $B_c$ to explain why the total magnetic field B has some inhomogeneity. Using Fourier analysis, harmonic components of $B_s$, $B_c$ and B have been analyzed at good field region, respectively. The harmonics of multipole magnet and Fourier analysis are helpful to show the uniformity of magnetic field. Several geometries of yoke and coils were defined to analyze the effect on field uniformity of an HTS quadruple magnet. By the analysis, it was found that the sixth harmonics which is the main factor of field inhomogeneity can be reduced to zero. It means that the sixth harmonics of the magnetic field B can be removed by adjusting the geometry of the magnet pole and the position of coils. We expect that this result can effectively improve the uniformity of an HTS quadruple magnet.