Author: Zolotorev, M.S.
Paper Title Page
TUOCN6
Emittance Exchange and Bunch Compression  
 
  • A. Zholents
    ANL, Argonne, USA
  • M.S. Zolotorev
    LBNL, Berkeley, California, USA
 
  Funding: This work was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Transverse to longitudinal emittance exchange was proposed in* as a tool for matching of the electron beam phase space to requirements of a possible application. Here we propose a new purpose, namely, use of two consequential emittance exchanges and the focusing telescope for a bunch compression that can be done without the energy chirp in the electron bunch. It allows to move bunch compressor to the end of the linac and thus to reduce the electron peak current in the linac and relax collective effects. It is also possible to have a split action compression when the first part is done inside the low energy part of the linac and the second and final part is done after the linac. We also demonstrate how proposed bunch compressor can be used for frequency up conversion of the energy modulation provided by laser interacting with the electron beam and thus can prepare a significantly higher frequency seed for seeded free-electron lasers. Same approach can be used for a frequency down conversion that can be useful for a generation of a THz radiation. Finally we note that the proposed bunch compression is practically free from destructive effects of coherent synchrotron radiation.
* M. Cornacchia, P. Emma, Phys. Rev. Spec. Topics – Acc. and Beams, 5, 084001(2002).
 
slides icon Slides TUOCN6 [5.347 MB]  
 
THP200 Photoinjector Beam Dynamics for a Next Generation X-Ray FEL 2495
 
  • C. F. Papadopoulos, J.N. Corlett, D. Filippetto, G. Penn, J. Qiang, F. Sannibale, J.W. Staples, M. Venturini, R.P. Wells, M.S. Zolotorev
    LBNL, Berkeley, California, USA
 
  Funding: This work was supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231.
In this paper, we will present the status of the beam dynamics simulations for a Next Generation Light Source (NGLS) injector, based on a high repetition rate (1 MHz), high brightness design. A multi-stage beam compression scheme is proposed, based on the concepts of velocity bunching and emittance compensation. For the optimization of the design parameters we use a genetic algorithm approach, and we focus on a mode providing charges of 300 pC, with normalized transverse emittance less than 0.6 microns, suitable to operate a next generation light source based on an X-ray FEL. In addition, we discuss the effects of bunch compression and linearity of the transverse and longitudinal phase space of the beam.
 
 
WEP222 Low Energy Beam Diagnostic for APEX, the LBNL VHF Photo-injector 1903
 
  • D. Filippetto, J.M. Byrd, M.J. Chin, C.W. Cork, S. De Santis, L.R. Doolittle, J. Feng, W.E. Norum, C. F. Papadopoulos, G.J. Portmann, D.G. Quintas, F. Sannibale, M.E. Stuart, R.P. Wells, M.S. Zolotorev
    LBNL, Berkeley, California, USA
 
  Funding: This work was supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231
A high-repetition rate (MHz-class), high-brightness electron beam photo-gun is under construction at Lawrence Berkeley National Laboratory in the framework of the Advanced Photo-injector EXperiment (APEX). The injector gun is based on a normal conducting 187 MHz RF cavity operating in CW mode. In its first operational phase it will deliver short bunches (~ 1 to tens of picoseconds) with energy of 750keV, and bunch charges ranging from 1pC to 1nC. Different high efficiency cathode materials will be tested, and the beam quality will be studied as a function of parameters as charge, initial bunch length and transverse size, focusing strength. Both the laser and electron beam diagnostics have been designed to assure the needed flexibility. In particular a high-resolution electron diagnostic section after the photo-gun provides the necessary dynamical range for scanned beam parameters: energy and energy spread, charge and current, transverse and longitudinal phase spaces, slice properties. The photo-gun electron beam diagnostic layout is presented, and the hardware choices, resolution and achievable dynamical ranges are also discussed.
 
 
THP180 Studies of a Linac Driver for a High Repetition Rate X-ray FEL 2450
 
  • M. Venturini, J.N. Corlett, L.R. Doolittle, D. Filippetto, C. F. Papadopoulos, G. Penn, D. Prosnitz, J. Qiang, M.W. Reinsch, R.D. Ryne, F. Sannibale, J.W. Staples, R.P. Wells, J.S. Wurtele, M.S. Zolotorev
    LBNL, Berkeley, California, USA
  • A. Zholents
    ANL, Argonne, USA
 
  Funding: Work carried out under Department of Energy contract No. DE-AC02-0SCK11231
We report on on-going studies of a superconducting CW linac driver intended to support a high repetition rate FEL operating in the soft x-rays spectrum. We present a point-design for a 1.8 GeV machine tuned for 300~pC bunches and delivering low-emittance, low-energy spread beams as needed for the SASE and seeded beamlines.