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Zholents, A.

Paper Title Page
MOZAAB01 Generation of Subpicosecond X-ray Pulses in Storage Rings 69
  • A. Zholents
    LBNL, Berkeley, California
  Funding: This work was supported by DoE under contract No: DE-AC02-05CH11231

Subpicosecond x-ray pulses are now routinely obtained at the ALS, BESSY and SLS light sources using laser e-beam slicing technique. Other x-ray pulse shortening techniques were also proposed and are now under consideration for ALS, APS, DIAMOND and PETRA light sources. In this talk I review current results and discuss R&D plans and activity.

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TUPMN114 Simulation of the Microbunching Instability in Beam Delivery Systems for Free Electron Lasers 1179
  • I. V. Pogorelov, J. Qiang, R. D. Ryne, M. Venturini, A. Zholents
    LBNL, Berkeley, California
  • R. L. Warnock
    SLAC, Menlo Park, California
  In this paper, we examine the growth of the microbunching instability in the chain of linac sections and bunch compressor chicanes used in the electron beam delivery system of a free electron laser. We compare the results of two sets of simulations, one conducted using a direct Vlasov solver, the other using a particle-in-cell code Impact-Z with the number of simulation macroparticles ranging up to 100 million. The comparison is focused on the values of uncorrelated (slice) energy spread at different points in the lattice. In particular, we discuss the interplay between physical and numerical noise in particle-based simulations, and assess the agreement between the simulation results and theoretical predictions.  
TUPMN116 Numerical Study of Coulomb Scattering Effects on Electron Beam from a Nano-tip 1185
  • J. Qiang, J. N. Corlett, S. M. Lidia, H. A. Padmore, W. Wan, A. Zholents, M. S. Zolotorev
    LBNL, Berkeley, California
  • A. Adelmann
    PSI, Villigen
  Funding: This work was supported by the U. S. Department of Energy under Contract no. DE-AC02-05CH11231.

Nano-tips with high acceleration gradient around the emission surface have been proposed to generate high brightness beams. However, due to the small size of the tip, the charge density near the tip is very high even for a small number of electrons. The Coulomb scattering near the tip can significantly degrade the beam quality and cause extra emittance growth and energy spread. In the paper, we present a numerical study of these effects using a direct relativistic N-body model. We found that emittance growth and energy spread, due to Coulomb scattering, can be significantly enhanced with respect to mean-field space-charge calculations in different parameter regimes.

TUPMN109 A High Repetition Rate VUV-Soft X-Ray FEL Concept 1167
  • J. N. Corlett, J. M. Byrd, W. M. Fawley, M. Gullans, D. Li, S. M. Lidia, H. A. Padmore, G. Penn, I. V. Pogorelov, J. Qiang, D. Robin, F. Sannibale, J. W. Staples, C. Steier, M. Venturini, S. P. Virostek, W. Wan, R. P. Wells, R. B. Wilcox, J. S. Wurtele, A. Zholents
    LBNL, Berkeley, California
  Funding: This work was supported by the Director, Office of Science, High Energy Physics, U. S. Department of Energy under Contract No. DE-AC02-05CH11231.

The FEL process increases radiation flux by several orders of magnitude above existing incoherent sources, and offers the additional enhancements attainable by optical manipulations of the electron beam: control of the temporal duration and bandwidth of the coherent output, and wavelength; utilization of harmonics to attain shorter wavelengths; and precise synchronization of the x-ray pulse with laser systems. We describe an FEL facility concept based on a high repetition rate RF photocathode gun, that would allow simultaneous operation of multiple independent FELs, each producing high average brightness, tunable over the soft x-ray-VUV range, and each with individual performance characteristics determined by the configuration of the FEL SASE, enhanced-SASE (ESASE), seeded, self-seeded, harmonic generation, and other configurations making use of optical manipulations of the electron beam may be employed, providing a wide range of photon beam properties to meet varied user demands. FELs would be tailored to specific experimental needs, including production of ultrafast pulses even into the attosecond domain, and high temporal coherence (i.e. high resolving power) beams.