FEL performance and tolerance studies of the EuPRAXIA@SPARC_LAB beamline AQUA

The AQUA beamline of the EuPRAXIA@SPARC_LAB facility is a SASE free-electron laser designed to operate in the water window, in the 3-4 nm wavelength range. The electron beam driving this source is accelerated up to about 1-1.2 GeV by an X-band normal conducting linear accelerator, followed by a plasma wakefield acceleration stage. The main radiator consists of an array of ten APPLE-X permanent magnet undulator modules, each 2 m long and with a period length of 18 mm. Tolerance analyses against resistive wall wakefields and injection misalignments at undulator entrance are performed, and the related effects on the laser yield performance are evaluated and discussed.