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Optics Design for FACET

FACET is a proposed facility at SLAC National Accelerator Laboratory. It will provide high energy, tightly focused and compressed electron and positron bunches for beam driven plasma wakefield acceleration research and other experiments. FACET will be built in the SLAC linac sector 20, where it will be separated from the LCLS located immediately downstream and will take advantage of the upstream 2 km linac for up to 23 GeV beam acceleration. FACET will also include an upgrade to linac sector 10, where a new e+ compressor chicane will be installed. The sector 20 will contain a new optics consisting of two chicanes for e+ and ebunch length compression, a final focus and an experimental line with a dump. The e+ and e- chicanes will allow the transport of e+ and ebunches together, their compression and proper positioning of e+ witness bunch behind the e- drive bunch at the plasma Interaction Point. The new optics will mostly use the existing SLAC magnets to minimize the project cost. Details of the FACET optics design and results of particle tracking simulations are presented.