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Title: Betatron Radiation from a Beam Driven Plasma Source

Betatron Radiation from a Beam Driven Plasma Source Photons produced by the betatron oscillation of electrons in a beam-driven plasma wake provide a uniquely intense and high-energy source of hard X-rays and gamma rays. This betatron radiation is interesting not only for its high intensity and spectral characteristics, but also because it can be used as a diagnostic for beam matching into the plasma, which is critical for maximizing the energy extraction efficiency of a plasma accelerator stage. At SLAC, gamma ray detection devices have been installed at the dump area of the FACET beamline where the betatron radiation from the plasma source used in the E200 plasma wakefield acceleration experiment may be observed. The ultra-dense, high-energy beam at FACET (2 x 10{sup 10} electrons, 20 x 20 {micro}m{sup 2} spot, 20-100 {micro}m length, 20 GeV energy) when sent into a plasma source with a nominal density of {approx} 1 x 10{sup 17} cm{sup -3} will generate synchrotron-like spectra with critical energies well into the tens of MeV. The intensity of the radiation can be increased by introducing a radial offset to the centroid of the witness bunch, which may be achieved at FACET through the use of a transverse deflecting RF cavity. The E200 gamma ray detector more » has two main components: a 30 x 35 cm{sup 2} phosphorescent screen for observing the transverse extent of the radiation, and a sampling electromagnetic calorimeter outfitted with photodiodes for measuring the on-axis spectrum. To estimate the spectrum, the observed intensity patterns across the calorimeter are fit with a Gaussian-integrated synchrotron spectrum and compared to simulations. Results and observations from the first FACET user run (April-June 2012) are presented. « less
Authors: ; ;
Publication Date:
OSTI Identifier:OSTI ID: 1048646
Report Number(s):SLAC-PUB-15215
TRN: US1204238
DOE Contract Number:AC02-76SF00515
Resource Type:Conference
Resource Relation:Conference: Presented at 15th Advanced Accelerator Concepts Workshop (AAC 2012), Austin, Texas, 10-15 Jun 2012
Research Org:SLAC National Accelerator Laboratory (SLAC)
Sponsoring Org:US DOE Office of Science (DOE SC)
Country of Publication:United States
Language:English
Subject: 43 PARTICLE ACCELERATORS; ACCELERATION; ACCELERATORS; BETATRON OSCILLATIONS; BETATRONS; CALORIMETERS; DETECTION; EFFICIENCY; ELECTRONS; PHOTODIODES; PHOTONS; PLASMA; PLASMA GUNS; RADIATIONS; SAMPLING; SCREENS; SPECTRA; STANFORD LINEAR ACCELERATOR CENTER; SYNCHROTRONS Accelerators,ACCPHY