Betatron radiation from a beam driven plasma source
- SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (United States)
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 Multiplication-Sign 10{sup 10} electrons, 20 Multiplication-Sign 20{mu}m{sup 2} spot, 20 - 100{mu}m length, 20GeV energy) when sent into a plasma source with a nominal density of {approx} 1 Multiplication-Sign 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 has two main components: a 30 Multiplication-Sign 35cm{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.
- OSTI ID:
- 22075913
- Journal Information:
- AIP Conference Proceedings, Vol. 1507, Issue 1; Conference: 15. advanced accelerator concepts workshop, Austin, TX (United States), 10-15 Jun 2012; Other Information: (c) 2012 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ACCELERATION
BEAM BUNCHING
BETATRON OSCILLATIONS
BETATRONS
CALORIMETRY
GAMMA DETECTION
GAMMA RADIATION
HARD X RADIATION
PARTICLE BEAMS
PHOSPHORESCENCE
PHOTODIODES
PLASMA
PLASMA DENSITY
PLASMA DIAGNOSTICS
PLASMA GUNS
RF SYSTEMS
STANFORD LINEAR ACCELERATOR CENTER
SYNCHROTRONS
WAKEFIELD ACCELERATORS
X-RAY DETECTION