Author Index: A   B   C   D   E   F   G   H   I   J   K   L   M   N   O   P   Q   R   S   T   U   V   W   X   Y   Z

Choi, J.

Paper Title Page
MOPP045 Preliminary RF Test in PLS 2.5GeV Linac for PAL-XFEL 150
 
  • W.H. Hwang, J. Choi, Y.J. Han, J.Y. Huang, H.-G. Kim, W.W. Lee
    PAL, Pohang, Kyungbuk
  
 

Funding: Work supported by MOST and POSCO.

In PALXFEL [1], the specification of the beam energy spread and rf phase is tighter than PLS Linac. We examined the rf performance in the present PLS 2.5GeV Linac. The beam energy is changed by cooling temperature, air condition, and modulator high voltage jitter. The main factor to change the beam energy is the rf phase drift by environmental conditions. We measured rf phase drift according to the variation of environmental condition and cooling temperature. We reduced the beam energy drift and the rf phase drift in long-term by improvement of cooling and air conditioning control system. Also, rf phase compensation system is needed for stable beam quality. This paper describes the microwave system for the PALXFEL the rf phase measurement and phase compensation system.

[1] Pohang Accelerator Laboratory, POSTECH Pohang 790-784, Korea

  
   
MOPP046 Beam Transport Line Design for Emittance Adjustment PLS X-FEL 153
 
  • M. Kim, Y.S. Bae, J. Choi, H.-S. Kang, T.-Y. Lee
    PAL, Pohang, Kyungbuk
  
 

PLS W-FEL (1.2 GeV) and X-FEL (3.7 GeV) are designed to have large angle about 30 degree and 20 degree totally because of geometric restriction. This results in severe emittance growth. So PLS FEL BTL Design is focused to adjust emittance growth. This paper talks simulation results of emittance growth and another beam dynamic parameters.

  
   
THPP021 Issue of Energy Spread and Transverse Coherency of PAL-XFEL 499
 
  • H.-S. Kang, J. Choi, T.-Y. Lee
    PAL, Pohang, Kyungbuk
  
 

Funding: The Ministry of Science and Technology, Korea

PAL-XFEL has been designed to generate 0.3-nm SASE radiation with 3.7-GeV electron beam and 4-mm gap in-vacuum undulator. The requirement of energy spread in undulator is tighter than LCLS and EU-FEL. Laser beam heating to reduce the micro-bunching instability inevitably induces an increase of energy spread during the bunching process in bunch compressor. Two factors are contradictory, which should be compromised. Transverse higher modes have comparatively large growth rates which results in poor transverse coherency. Growth rates of transverse modes are calculated with different beam conditions.

  
   
THPP024 Study of PAL-XFEL Wake Field Effects with the Genesis Code 502
 
  • T.-Y. Lee, J. Choi, H.-S. Kang
    PAL, Pohang, Kyungbuk
  
 

PAL-XFEL is the newly announced SASE FEL project that is going to achieve 0.3 nm wavelength radiation with 3.7 GeV electron beam. To overcome the relatively low energy of 3.7 GeV, short period and small gap in-vacuum undulator will be adopted. Wake field effects of this in-vacuum undulator on the SASE process is studied in this paper.