Yujong Kim

Energy measurement of 50 MeV proton beam with a NaI(Tl) scintillator

Abstract Energy measurement of 50 MeV proton beam produced on the AVF MC-50 Cyclotron was conducted using a detector telescope with a NaI(Tl) scintillator as an E counter. Protons of various energies, elastically and inelastically scattered from the 12 C target nucleus were measured at four different angles of 35°, 40°, 50° and 55°. We applied the chi-square method to determine the beam energy, which showed a well defined minimum chi-square corresponding to a beam energy of 49.6 ± 2.3 MeV at the 68% confidence level. Also the light output response of NaI(Tl) to proton energies between 31 and 44 MeV is linear within 0.5 MeV and is in good accord with the recent result of Romero et al. [Nucl. Instr. and Meth. A 301 (1991) 241].

Beam Parameter Optimization for UEM Facility with Photo-Emission S-band RF Gun

Ultrafast Electron Microscopy (UEM) can provide snapshot images of a dynamic process in samples with an ultrafast time resolution, which is shorter than picosecond. The Future Accelerator R&D Team at KAERI has been preparing a UEM facility with a photo-emission S-band (= 2856 MHz) RF gun by collaborating with GIST and KRISS. To achieve a higher spatial resolution as well as a higher time resolution, the transverse beam emittance, beam divergence, and energy spread should be smaller, and the bunch length should be shorter. Beam dynamics simulations with ASTRA code are used to optimize those beam parameters in the RF gun. In this paper, we describe ASTRA optimizations of the S-band RF gun to achieve high spatial-temporal resolutions for the UEM facility.

Development of EPICS Control System for ODA Magnet Power Supplies and GigE CCD Camera

The Radiation Equipment Research Division of the Korea Atomic Energy Research Institute has been operating a 10 MeV RF electron linear accelerator, which is used for electron beam irradiation. The beam power and energy of the RF electron linear accelerator are 10 kW and 10 MeV. The accelerator is composed of an electron gun, an S-band (= 2856 MHz) accelerating structure, a klystron, electromagnetic solenoids, a scanning electromagnet, an RF driver, a modulator, and a chiller. The linac components have deteriorated due to a long operation time of 9 years. In this paper, we described Experimental Physics and Industrial Control System (EPICS) to control ODA magnet power supplies for solenoids and steering magnets of the 10 MeV electron beam irradiation accelerator. INTRODUCTION The Korea Atomic Energy Research Institute has used a 10 MeV RF electron linac [1-2] for electron beam irradiation service. The accelerator was fabricated from Russian about 10 years ago. Therefore, the overall system is corroded and difficult for user services due to the use of Russian. Thus, our purpose is upgrade and convert the linac to Korea designed linac. The accelerator is used for irradiation treatment by electron beam radiation such as deformation ecology / environment, disinfection / sterilization, radiation treatment of foodstuffs, sterilization of organic fertilizer, and wood / sterilization. The accelerator specifications are summarized in table 1. The linac has a beam energy of 10 MeV, operation frequency of 2856 MHz (Sband), and a variable energy range of 5 MeV and 10 MeV. Table 2 summarizes the specifications of the klystron. In the linear RF electron accelerator, the klystron produces a high RF power from the RF drivers low RF power. The peak power of the klystron is 6 MW, the average power is 25 kW, and the beam duty is 0.4%. The vacuum system of the RF linac is operated at about 1 10-6 Torr and cooling has been supplied through the chiller. Currently, the accelerator control is operated using a Windows XP system. The communication system has difficulty maintaining the linac, which has a complicated configuration with a double jumper wire. In this paper, we describe how to implement control through EPICS and clear the old version of the window operating system. Table 1: RF Linac Specifications Parameter Value Unit Particle Electron Operation Mode Pulse RF Frequency 2856 ± 5 MHz Repetition Rate 10 300 Hz RF Power 6 MW