Author: Corbett, W.J.
Paper Title Page
MOPO043 Applications of Lasers to Accelerator Physics at SSRL 580
 
  • D.L. Robinson
    Cal Poly, San Luis Obispo, California, USA
  • W.J. Corbett
    SLAC, Menlo Park, California, USA
 
  Recent advances in accelerator physics and SR research have generated the need for high-power lasers in the SPEAR3 accelerator complex. On the injector side, two lasers are being used to test different photocathode materials and to provide photo-assisted emission from the standard dispenser cathode RF gun. For the storage ring, both a TiSa oscillator and a fiber laser locked to the RF master oscillator have been used to characterize short-pulse electron bunches in cross-correlation experiments. These lasers are also used in SR experiments for pump-probe characterization of materials. In this paper we review the laser-based systems, preliminary results and outlook for the future.  
 
MOPO044 Bunch Length Measurements in Low-Alpha Mode at SPEAR3 with First Time-Resolved Pump/Probe Experiments* 583
 
  • J.S. Wittenberg, A. Lindenberg, A. Miller
    Stanford University, Stanford, California, USA
  • W.J. Corbett, L. Wang
    SLAC, Menlo Park, California, USA
 
  Funding: Work sponsored by U.S. Department of Energy Contract DE-AC03-76SF00515, Office of Basic Energy Sciences and SLAC Laboratory Directed Research Development funds (LDRD)
The SPEAR3 synchrotron light source can be operated in low-alpha mode to generate x-ray pulse durations of order 1ps, well below streak camera resolution limits yet accessible by laser/sr cross-correlation measurements. Initial CC tests performed with a 50fs TiSa laser, frequency doubling BBO, photodiode and lock-in amplifier resolved bunch lengths down to about 6ps rms with 85uA single-bunch current. By reconfiguring the experimental setup to utilize a fiber laser, sum frequency generation and single photon counter it is now possible to measure profiles in the 1ps rms range with only 5uA single-bunch current. In this paper we report on the most recent measurements, simulations, modeling efforts and prospects for further improvement.
 
 
MOPS090 Observation of Beam Ion Instability in SPEAR3 814
 
  • L. Wang, Y. Cai, W.J. Corbett, T.O. Raubenheimer, J.A. Safranek, J.F. Schmerge, J.J. Sebek
    SLAC, Menlo Park, California, USA
  • D. Teytelman
    Dimtel, San Jose, USA
 
  Weak vertical coupled bunch instability with oscillation amplitude at μm level has been observed in SPEAR3. The instability becomes stronger when there is a vacuum pressure rise by partially turning off vacuum pumps and it becomes weaker when the vertical beam emittance is increased by turning off the skew quadrupole magnets. These confirmed that the instability was driven by ions in the vacuum. The threshold of the beam ion instability when running with a single bunch train is just under 200 mA. This paper presents the comprehensive observations of the beam ion instability in SPEAR3. The effects of vacuum pressure, beam current, beam filling pattern, chromaticity, beam emittance and bunch-by-bunch feedback are investigated in great detail.pattern, chromaticity, beam emittance and bunch-by-bunch feedback are investigated in great detail.