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abstract:
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In an inverse-Compton scattering source, in which a relativistic electron beam collides
with a high-power laser pulse, the x-ray flux produced is proportional to the brightness of the
two beams and the size of their overlap region in three-dimensional space. In vacuum, this
overlap is limited by the diffraction of the two beams, but the diffraction limit can be overcome
by confining both beams in a plasma guiding channel. A dense, bunched electron beam injected
into an underdense plasma will self-guide via ``blowout,'' in which the beam head creates a
focusing ion channel through which the body of the beam is guided; this same channel can also
guides a counterpropagating laser beam. Constraints include the need for long laser wavelength
(1 to 10 μm) and high beam densities. We present a possible configuration for a gamma-ray
source using 180° Compton scattering in a uniform plasma, including 2D simulation results.
Estimated photon yields are up to a factor of 5 larger than in vacuum scattering, with production
of nearly 1010 photons per nanocoulomb of electron beam charge.
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