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abstract:
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An Inverse Compton Scattering (ICS) experiment,
which will investigate nonlinear properties of scattering
utilizing a terawatt CO2 laser system with various
polarizations, is ongoing at the UCLA Neptune
Laboratory. When the normalized amplitude of the
incident laser's vector potential ao is larger than unity the
scattering occurs in the nonlinear region; therefore, higher
harmonics are also produced. ICS can be used, e.g., for a
polarized positron source by striking a thin target (such as
tungsten) with the polarized X-rays. As such, it is critical
to demonstrate the production of polarized scattered
photons and to investigate the ICS process as it enters the
nonlinear regime. We present the description of the
experimental set up and equipment utilized, including
diagnostics for electron and photon beam detection. We
present the current status of the experiment.
electron beam focusing and recollimating systems consist
of 5 equal strength and length PMQs each, set up as a
modified FF-DD-F triplet.
The high power CO2 laser is focused by an off-axis
parabolic mirror with a 12.7 cm diameter and 17 cm focal
length. Since the divergence of the scattered photons is
quite large (-I/, where 28) it is necessary to place the
detector (soft X-ray camera and/or micro-channel plate)
very close to the IP. This requires bending the electron
beam immediately after the recollimating PMQ system, in
a very short bending radius. To this end, we have designed
and built a permanent magnet dipole (PMD) with a -60
mm bending radius for this purpose.
Table 1: Electron and Laser Beam Parameters
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