  ARES (Accelerator Research Experiment at SINBAD) is a linear accelerator at
the SINBAD (Short INnovative Bunches and Accelerators at DESY) facility at
DESY. ARES was designed to combine reproducible beams from conventional
RF-based accelerator technology with novel but still experimental acceleration
techniques. It aims to produce high brightness ultra-short electron bunches in
the range of sub fs to few fs, at a beam energy of 100-150 MeV, suitable for
injection into novel acceleration experiments like Dielectric Laser
Acceleration (DLA) and Laser driven Plasma Acceleration (LPA). This paper
reports the conceptual design and simulations of a final focus system for
injecting into a LPA experiment at ARES, including permanent magnetic
quadrupoles (PMQ), sufficient longitudinal space for collinear laser and
electron transport, space for required diagnostics and a LPA setup.
Space-charge effects play a significant role and are included. Simulation
results on the focusing of the ARES electron bunches into and their transport
through the laser-driven plasma are presented. The effects of several errors
have been simulated and are reported.
