  All-optical Compton sources combine laser wakefield accelerators and intense
scattering pulses to generate ultrashort bursts of backscattered radiation. The
scattering pulse plays the role of a short-period undulator in which
relativistic electrons oscillate and emit x-ray radiation. To date, most of the
working laser-plasma accelerators operate preferably at energies of a few
hundreds of MeV and the Compton sources developed so far produce radiation in
the range from hundreds of keV to a few MeV. However, for such applications as
medical imaging and tomography the relevant energy range is 10-100 keV. In this
article, we discuss different scattering geometries for the generation of
X-rays in this range. Through numerical simulations, we study the influence of
electron beam parameters on the backscattered photons. We find that the
spectral bandwidth remains constant for beams of the same emittance regardless
of the scattering geometry. A shallow interaction angle of 30 degrees or less
seems particularly promising for imaging applications given parameters of
existing laser-plasma accelerators. Finally, we discuss the influence of the
radiation properties for potential applications in medical imaging and
non-destructive testing.
