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Title: UCLA Neptune Facility for Advanced Accelerator Studies

Abstract

The Neptune Laboratory at UCLA is being used for exploring concepts useful for advanced accelerators. This facility hosts a TW-class CO2 laser system and a high-brightness photoinjector producing a 14 MeV electron beam. The goal for the laboratory is to carry out experiments on high-gradient acceleration of externally injected electrons in both laser-driven relativistic plasma waves and EM laser field in vacuum. Experiments on plasma beat-wave acceleration using a prebunched electron beam, a high-energy gain 10-{mu}m inverse free electron laser accelerator, longitudinal electron beam shaping and laser based light-sources are planned.

Authors:
; ; ;  [1]; ;  [2]
  1. Neptune Laboratory, Department of Electrical Engineering, University of California at Los Angeles, 405 Hilgard avenue, Los Angeles, CA 90095 (United States)
  2. Neptune Laboratory, Department of Physics, University of California at Los Angeles, 405 Hilgard avenue, Los Angeles, CA 90095 (United States)
Publication Date:
OSTI Identifier:
20655268
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 737; Journal Issue: 1; Conference: 11. advanced accelerator concepts workshop, Stony Brook, NY (United States), 21-26 Jun 2004; Other Information: DOI: 10.1063/1.1842606; (c) 2004 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; ACCELERATION; ACCELERATORS; BRIGHTNESS; CARBON DIOXIDE LASERS; ELECTRON BEAM INJECTION; ELECTRON BEAMS; FREE ELECTRON LASERS; LASER RADIATION; LIGHT SOURCES; MEV RANGE 10-100; PARTICLES; PLASMA WAVES; RELATIVISTIC PLASMA; UCLA

Citation Formats

Tochitsky, Sergei Ya., Clayton, Christopher E., Marsh, Kenneth A., Joshi, Chandrashekhar, Rosenzweig, James B., and Pellegrini, Claudio. UCLA Neptune Facility for Advanced Accelerator Studies. United States: N. p., 2004. Web. doi:10.1063/1.1842606.
Tochitsky, Sergei Ya., Clayton, Christopher E., Marsh, Kenneth A., Joshi, Chandrashekhar, Rosenzweig, James B., & Pellegrini, Claudio. UCLA Neptune Facility for Advanced Accelerator Studies. United States. doi:10.1063/1.1842606.
Tochitsky, Sergei Ya., Clayton, Christopher E., Marsh, Kenneth A., Joshi, Chandrashekhar, Rosenzweig, James B., and Pellegrini, Claudio. 2004. "UCLA Neptune Facility for Advanced Accelerator Studies". United States. doi:10.1063/1.1842606.
@article{osti_20655268,
title = {UCLA Neptune Facility for Advanced Accelerator Studies},
author = {Tochitsky, Sergei Ya. and Clayton, Christopher E. and Marsh, Kenneth A. and Joshi, Chandrashekhar and Rosenzweig, James B. and Pellegrini, Claudio},
abstractNote = {The Neptune Laboratory at UCLA is being used for exploring concepts useful for advanced accelerators. This facility hosts a TW-class CO2 laser system and a high-brightness photoinjector producing a 14 MeV electron beam. The goal for the laboratory is to carry out experiments on high-gradient acceleration of externally injected electrons in both laser-driven relativistic plasma waves and EM laser field in vacuum. Experiments on plasma beat-wave acceleration using a prebunched electron beam, a high-energy gain 10-{mu}m inverse free electron laser accelerator, longitudinal electron beam shaping and laser based light-sources are planned.},
doi = {10.1063/1.1842606},
journal = {AIP Conference Proceedings},
number = 1,
volume = 737,
place = {United States},
year = 2004,
month =
}
  • The planned plasma lens experiment at the UCLA Neptune Laboratory is described. In the experiment, electron beams with an energy of 16 MeV, a charge of 4 nC, and a pulse duration of 30 ps [full-width at half-maximum (FWHM)] are designed to be produced from the 1.625-cell photoinjector radio-frequency gun (f = 2.856 GHz) and PWT linac in the Neptune. The generated beams are passed through a thin underdense argon plasma with a density of low 10{sup 12} cm{sup {minus}3} range and a thickness of a few centimeters. For this experiment, a LaB{sub 6}-based discharge plasma source was developed andmore » tested. In this paper, the overview of the planned plasma lens experiment and the test results of the plasma source for various conditions are presented. In addition, computer simulations with a 2{1/2} dimensional particle-in-cell code (MAGIC) were performed and the simulation results are shown.« less
  • A ramped electron bunch (i.e. one having a current density which rises linearly from the head to the tail and then drops sharply to zero) has been predicted to be an ideal drive beam for the plasma wake field accelerator due to the large transformer ratio it is capable of generating. A scheme was recently proposed for the creation of a relativistic electron bunch that approximates a ramped current profile [England, et al., AIP Conf. Proc. 647, p.884 (2002)], using a dogleg or dispersionless translating section as a bunch compressor. An experiment is underway at the Neptune laboratory using thismore » scheme to create such a beam. The diagnostic being developed for measuring the temporal profile of the beam is an X-Band transverse deflecting mode cavity.« less
  • A proof of principle experiment is underway at the UCLA Neptune laboratory to test the concept of generating linearly ramped relativistic electron bunches (rising in density from head to tail followed by a sharp cutoff) by using a sextupole-corrected dogleg section as a bunch compressor. Bunches with this structure have been predicted to be ideal for use as a plasma wake-field drive beam. The diagnostic being developed to measure the time profile of the beam is an X-Band (9.6 GHz) deflecting cavity. The recently completed cavity is a 9-cell standing wave structure operating in a TM110-like mode, designed to measuremore » the temporal structure of the 2 to 10 ps, 14 MeV electron bunches generated by the Neptune S-band photoinjector and plane-wave transformer (PWT) accelerator beamline, with 50 fs resolution. We discuss the experimental plan for the ramped bunch experiment and present preliminary data related to the tuning and operation of the deflecting cavity.« less
  • A plasma source was developed at UCLA for planned underdense plasma lens experiments, where the plasma density is less than the electron beam density. The argon plasma, produced by a discharge between a LaB{sub 6} cathode at 1330 deg. C and a tantalum anode, is confined by a solenoidal magnetic field and flows transversely across the electron beam path. Extensive test of the plasma source is under way for various conditions before it is assembled with the UCLA photocathode-based electron linac. In particular, different longitudinal (with respect to the electron beam) plasma profiles and effective plasma lengths can be obtainedmore » by adjusting the moveable sliding door between the plasma source and the transverse beamline. Test results of the plasma source are presented.« less
  • Seeded high-gain FELs, which can generate very powerful radiation pulses in a relatively compact undulator and simultaneously modulate the electron beam longitudinally at the seed wavelength, are important tools for advanced accelerator development. A single-pass 0.5-9 THz FEL amplifier-buncher driven by a regular photoinjector is being built at the UCLA Neptune Laboratory. FEL interactions at 340 {mu}m (1 THz) are considered for the first experiment, since time-resolved measurements of longitudinal current distribution of the bunched beam using the RF deflecting cavity are possible. A design of a 0.2-2.0 {mu}m FEL using the same undulators is presented. In this case themore » FEL is driven by a high-peak current beam from the laser-plasma accelerator tunable in the 100-300 MeV range.« less