• J.Y. Ryu, E.-S. Kim, H.D. Kim, H.K. Park
  KNU, Deagu
• J.G. Hwang
  Kyungpook National University, Daegu
• C. Kim
  PAL, Pohang, Kyungbuk

The synchrotron-radiation interferometer was employed for the beam size measurement of electron beam circulating in the storage ring at 2.5 GeV Pohang Light Source. We measured the beam sizes in both vertical and horizontal directions as function of stored beam current. In this presentation, we will discuss the interferometer system, analysis method for the measurement and the measured results. We also compared the measured beam sizes with predicted values from the lattice parameters in the ring.

• T. Miyajima
  KEK, Ibaraki
• J.G. Hwang
  Kyungpook National University, Daegu
• E.-S. Kim
  KNU, Deagu

Start-to-end (S2E) simulation from electron gun to beam dump is required to estimate light source performance and beam loss, which are essential parts in synchrotron light source based on Energy Recovery Linacs (ERL). Since the beam energy is widely varied from eV to GeV order in the ERL, the S2E simulation have to include many effects, e.g., space charge (SC) effect, coherent synchrotron radiation (CSR), cathode model, wake function, ions and beam break up. In order to carry out the S2E simulation, the preparation of it using General Particle Tracer (GPT), which is a particle tracking code including SC routine, has been started for compact ERL (cERL) beamline. The cERL is a test accelerator to establish accelerator technologies for GeV-class synchrotron light source based on ERL, and consists of an injector with photo cathode DC gun, a merger section, SRF cavities for acceleration and energy recovery, return loops, and a beam dump. In this presentation, the result of the S2E simulation from gun to the middle of return loop with SC and CSR effects, and the results of bench marking for each part in cERL, e.g. injector, merger, SRF cavities and return loop section, are shown.

• J.G. Hwang, S.W. Jang, E.-S. Kim
  Kyungpook National University, Daegu

Pohang Light Source-Ⅱ (PLS-Ⅱ) is an upgrade project of the existing 2.5 GeV PLS. The circumference, beam current and energy of PLS-Ⅱ storage ring are 281.82 m, 400 mA and 3 GeV, respectively. The upgrade project has many issues on beam dynamics. We investigated lattice optimization such as lattice corrections, dynamic aperture, selection of optimized tune & emittance and effects of insertion devices. MAD, SAD and Elegant have been used to the lattice optimization. We investigated the effects of machine errors and 20 IDs to the dynamic aperture. PLS-Ⅱ lattice include twenty insertion devices and their effects on the beam dynamics are investigated. We also investigate possibility to reduce the emittance by increasing horizontal betatron tune and adjusting the dispersion by using of MAD, SAD and Elegant and also examined the required strengths of sextupoles for the various emittances.