Author: Andersson, Å.
Paper Title Page
MOPEA056 Measuring and Improving the Momentum Acceptance and Horizontal Acceptance at MAX III 205
  • A. Hansson, Å. Andersson, J. Breunlin, G. Skripka, E.J. Wallén
    MAX-lab, Lund, Sweden
  Lifetime measurements for varying horizontal scraper positions performed at different RF frequencies suggested a horizontal aperture restriction in the MAX III synchrotron light source. A combination of local orbit distortions and horizontal scraper measurements pinpointed the location of the horizontal aperture restriction to the center of the main cavity straight section. The aperture restriction was determined to be located 10.4 ± 0.3 mm from the beam center. The precise result was achieved by measurements and calculations of the Touschek lifetime as a function of the main cavity voltage. Realignment of the main cavity increased the average lattice momentum acceptance from 0.0116 ± 0.0003 to 0.0158 ± 0.0003 and the horizontal acceptance from 26 ± 2 × 10-6 m to larger than 44 ± 2 × 10-6 m. The increase in momentum acceptance increased the lifetime in MAX III by a factor of two.  
MOPEA057 Studies of the Electron Beam Lifetime at MAX III 208
  • A. Hansson, Å. Andersson, J. Breunlin, G. Skripka, E.J. Wallén
    MAX-lab, Lund, Sweden
  MAX III is a 700 MeV 3rd generation synchrotron light source located at the MAX IV Laboratory in Sweden. The lifetime in the storage ring is lower than originally envisaged. From vertical scraper measurements the lifetime contributions at 300 mA stored current have been determined. The lifetime is mainly limited by the Touschek lifetime, which is lower than its design value, whereas the vacuum lifetime is close to the expected value. The low Touschek lifetime is explained by a lower than design emittance ratio and momentum acceptance in the storage ring.  
MOPWA041 The New SLS Beam Size Monitor, First Results 759
  • Á. Saá Hernández, N. Milas, M. Rohrer, V. Schlott, A. Streun
    PSI, Villigen PSI, Switzerland
  • Å. Andersson, J. Breunlin
    MAX-lab, Lund, Sweden
  Funding: This research has received funding from the European Commission under the FP7-INFRASTRUCTURES-2010-1/INFRA-2010-2.2.11 project TIARA (CNI-PP). Grant agreement no. 261905.
An extremely small vertical beam size of 3.6 μm, corresponding to a vertical emittance of 0.9 pm, only about five times bigger than the quantum limit, has been achieved at the storage ring of the Swiss Light Source (SLS). The measurement was performed by means of a beam size monitor based on the imaging of the vertically polarized synchrotron radiation in the visible and UV spectral ranges. However, the resolution limit of the monitor was reached during the last measurement campaign and prevented further emittance minimization. In the context of the work package “SLS Vertical Emittance Tuning” of the TIARA collaboration, a new improved monitor was built. It provides larger magnification, an increase of resolution and enables two complementary methods of measurement: imaging and interferometry. In this paper we present the design, installation, commissioning, performance studies and first results obtained with the new monitor.
TUPWA038 Equilibrium Bunch Density Distribution with Passive Harmonic Cavities in the MAX IV 3 GeV Storage Ring 1790
  • P.F. Tavares, Å. Andersson, A. Hansson
    MAX-lab, Lund, Sweden
  The MAX IV storage rings will use third harmonic cavities operated passively to lengthen the bunches and alleviate collective instabilities. These cavities are an essential ingredient in the MAX IV design concept and are required for achieving the final design goals in terms of stored current, beam emittance and beam lifetime. This paper reports on fully self-consistent calculations of the longitudinal bunch density distribution in the MAX IV 3 GeV storage ring, which indicate that up to a factor 5 increase in RMS bunch length is achievable with a purely passive system.