Author: Joo, Y.D.
Paper Title Page
MOPEA048 Operation Status of RF System for the PLS-II Storage Ring 187
  • M.-H. Chun, J.Y. Huang, Y.D. Joo, H.-G. Kim, S.H. Nam, C.D. Park, H.J. Park, I.S. Park, Y.U. Sohn, I.H. Yu
    PAL, Pohang, Kyungbuk, Republic of Korea
  Funding: Supported by the Korea Ministry of Science and Technology
The RF system of the Pohang Light Source-II (PLS-II) storage ring is operating at the 3.0GeV/200mA with two superconducting RF (SRF) cavities. Each RF station is composed with a 300kW klystron with power supply unit, transmission components, a digital LLRF and a SRF cavity. And a cryogenic system of 700W capacities is supplied the LHe and LN2 to three cryomodules of SRF cavities. The second SRF cavity is installed during at the beginning in 2013 and the third one will be installed during summer shutdown in 2014 for stable 400mA operation with all 20 insertion devices. Also the third high power RF station with a 300kW klystron, power supply unit and WR1800 waveguide components will be prepared in 2013. The third LLRF system is already installed, but improved stabilities of amplitude, phase and tuner control. This paper describes the present operation status and improve plan of the RF system for the PLS-II storage ring.
WEPWO041 Beam Commissioning Superconducting RF Cavities for PLS-II Upgrade 2390
  • Y.U. Sohn, M.-H. Chun, J.Y. Huang, Y.D. Joo, S.H. Nam, C.D. Park, H.J. Park, I.S. Park, I.H. Yu
    PAL, Pohang, Kyungbuk, Republic of Korea
  Two superconducting RF cavities were commissioned with electron beam at PLS-II, which is upgraded machine from PLS with 3 GeV, 20 insertion devices, and now on user service. These srf cavities have been prepared during last 3 years. Each cavity was tested with higher than 2 MV rf voltage and 125 kW standing wave power at CW mode after installation at storage ring. PLS-II is on user operation with 200 mA beam current now, and on the way of beam current improvement upto 400mA, by synchrotron conditioning for beam chamber and in-vacuum udulators. Upto 200 mA beam current no beam instability from the higher order modes is observed. With top-up mode operation, the errors of amplitude of rf field and phase are recorded as 0.3% and 0.3 degree peak to peak, respectively during one day. Successful PLS-II upgrade with hardware and its designed performance will be declared at the end of 1st half user run in 2013.  
WEPFI044 High Power Test of New SLED System with Biplanar 3-dB Power Divider and Dual Side-wall Coupling Irises for PAL XFEL 2803
  • Y.D. Joo, H. Heo, W.H. Hwang, H.-S. Lee, K.M. Oh, Y.J. Park
    PAL, Pohang, Kyungbuk, Republic of Korea
  The new type of the Stanford Linear Accelerator Energy Doubler (SLED) system for the PAL (Pohang Accelerator Laboratory) XFEL (X-ray Free Electron Laser) is developed to be operated with an RF input power of 80 MW and a pulse width of 4 μs. To prevent the RF breakdown such a high power operation, a biplanar 3-dB power divider and dual side-wall coupling irises structure are used in the new SELD system. It is shown that the field gradient and surface current is reduced from that of the original SLED system using the the finite-difference time-domain (FDTD) simulation. The high power test result of the new SLED system in the PAL XFEL test facility will be presented.  
WEPFI045 PAL-XFEL Accelerating Structures 2806
  • H.-S. Lee, H. Heo, J.Y. Huang, W.H. Hwang, S.D. Jang, Y.D. Joo, H.-S. Kang, I.S. Ko, S.S. Park, Y.J. Park
    PAL, Pohang, Kyungbuk, Republic of Korea
  • I.S. Ko
    POSTECH, Pohang, Kyungbuk, Republic of Korea
  • H. Matsumoto
    KEK, Ibaraki, Japan
  • S.J. Noh, K.M. Oh
    Vitzrotech Co., Ltd., Ansan City, Kyunggi-Do, Republic of Korea
  We need 172 accelerating structures for the PAL-XFEL 10 GeV main linac. It takes long time for these structures to be delivered. So we are trying to find suppliers of the accelerating structures. First, we made an order of 40 accelerating structures to Mitsubishi Heavy Industry (MHI), which have Quasi-type couplers to reduce the quadruple and sextuple components of the electric field in the coupling cavity. And Research Instruments (RI) has fabricated a 3m long race type accelerating structure for PAL-XFEL. Also, Vitzrotech which is a domestic company and IHEP in China are under developing accelerating structures for PAL-XFEL respectively. We will describe the current status of accelerating structures and high power test results of the newly developed structures in this paper.