Kang, H.-S.

Paper	Title	Page
WEPLS131	Programmable Power Supply for Distribution Magnet for 20-MeV PEFP Proton Linac	2682
	S.-H. Jeong, J. Choi, H.-S. Kang, D.E. Kim, K.-H. Park PAL, Pohang, Kyungbuk
	The distribution magnet is powered by bipolar switching-mode converter that is employed IGBT module and has controlled by a DSP (Digital Signal Process). This power supply is operated at 350A, 5 Hz programmable stair output for beam distribution to 5 beamlines of 20-MeV PEFP proton linac. Various applications for the different power supply are made simple by software. This paper describes the design and test results of the power supply.
THOAFI02	Ion Instability Observed in PLS Revolver In-vacuum Undulator	2771
	H.-S. Kang, J. Choi, M. Kim, T.-Y. Koo, T.-Y. Lee, P.C.D. Park PAL, Pohang, Kyungbuk
	Revolver In-Vacuum X-ray Undulator which was designed and fabricated at Spring-8 is under commissioning at PLS. This planar undulator whose permanent magnet array structure is a revolving type with 90-degree step provides 4 different undulator wavelengths of 10, 15, 20, and 24 mm. The minimum gap of the undulator is as small as 5 mm. It was observed that the trailing part of a long bunch train was scraped due to ion instability when the undulator gap was closed below 6 mm. At that time the vacuum pressure in the undulator, which is estimated to be about one order of magnitude lower than that of the undulator gap, increased from 1.4 x 10-10 (gap 20 mm) to 7.9 x 10-10 Torr (gap 6 mm) at the stored beam current of 100 mA. This high vacuum pressure causes fast beam-ion instability: trailing part of a long bunch train oscillates vertically. It was also confirmed that adjusting the orbit along the undulator has improved the situation to some extent. The ion instability measured with a pico-second streak camera and a one-turn BPM as well as the result of orbit adjustment and chromaticity control will be described in this paper.
	Transparencies
THPCH121	Development of Machine Interlock System HMI for PLS	3086
	B.R. Park, J. Choi, H.-S. Kang, J.-W. Lee, J.C. Yoon PAL, Pohang, Kyungbuk
	The Machine Interlock System (MIS) for the Pohang Light Source (PLS) is used for the monitoring and control of machine devices and equipments for operation and maintenance, and protects machine devices and equipments by interlock chain program at fault status. The MIS consists of one central system unit and seven remote local system units, and is implemented mainly using GE-FANUC's Programmable Logic Controller (PLC). Using information and data in the MIS, a human-machine interface (HMI) for the MIS is developed for the operator and system manager to efficiently control and monitor the MIS and also to log various event, trip, fault data automatically. Wonder's FactorySuite is used for the HMI development software. The HMI is developed under PC environments, which communicates with the MIS through RS-485 serial link.