Yu-Seok Kim

Electrical Insulation Characteristics of PPLP as a HTS DC Cable Dielectric and GFRP as Insulating Material for Terminations

A high-temperature superconducting (HTS) DC cable system has attracted a great deal of interest from the view point of low loss, dense structure and large capacity compared to HTS AC cable system. It has a HTS cable and a termination. A HTS DC cable system consists of a conductor, cooling system and electrical insulation. To realize the HTS DC cable system, it is important to study not only high current capacity and low loss of conductor but also optimum electrical insulation at cryogenic temperature. The electrical insulation technology of HTS DC cable and termination must be solved for the long life, reliability and compact of cable. In this paper, we will discuss mainly on the electrical insulation characteristics and the insulation design of 220 kV class HTS DC cable. Voltage-time (V-t) characteristics of laminated polypropylene paper (PPLP) in LN2 were studied. Furthermore, the surface flashover characteristics of glass fiber reinforced plastic (GFRP) for termination insulators under DC and lightning impulse voltage were studied.

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.

Simulation Study on Duoplasmatron With Optimization of Ion Beam Extraction System

The ion beam extraction system for various ion sources must be designed and evaluated using optimized parameters such as the gap distance between electrodes, applied voltage, and beam properties, using several different programs. SIMION, a 3-D simulation program, can transport various particles at once, and it is useful for simulating beam trajectories from the ion source and the beam line. PBGUNS can be used to calculate the effect of the gap between the plasma electrode and the extraction electrode on the ion beam properties. We propose combining the SIMION and PBGUNS results to compensate for problems in the calculation for the plasma. The calculation result from PBGUNS is utilized to perform ion beam extraction, which is close to the plasma model in SIMION, which can be used to easily simulate beam trajectories and model electrodes. We proposed a simulation method using SIMION to develop a model using plasma information from the PBGUNS result.

Emittance Measurement for Beamline Extension at the PET Cyclotron

Particle-induced X-ray emission is used for determining the elemental composition of materials. This method uses low-energy protons (of several MeV), which can be obtained from high-energy (of tens MeV) accelerators. Instead of manufacturing an accelerator for generating the MeV protons, the use of a PET cyclotron has been suggested for designing the beamline for multipurpose applications, especially for the PIXE experiment, which has a dedicated high-energy (of tens MeV) accelerator. The beam properties of the cyclotron were determined at this experimental facility by using an external beamline before transferring the ion beam to the experimental chamber. We measured the beam profile and calculated the emittance using the pepper-pot method. The beam profile was measured as the beam current using a wire scanner, and the emittance was measured as the beam distribution at the beam dump using a radiochromic film. We analyzed the measurement results and are planning to use the results obtained in the simulations of external beamline and aligned beamline components. We will consider energy degradation after computing the beamline simulation. The experimental study focused on measuring the emittance from the cyclotron, and the results of this study are presented in this paper.