LINAC-Based Synchrotron Radiation Facility with Femtosecond Soft X-ray Pulses

In this paper we perform design consideration of a femtosecond linac-based synchrotron radiation facility. Proposed technique is based on the generation of energy chirped short electron bunches that would subsequently spontaneously radiate frequency chirped soft X-ray pulses in an undulator. These pulses are then spectrally dispersed using grazing incident grating. The spectrum is propagated through exit slit (spectral window) which lters the pulses of femtosecond duration. The shortest temporal structures (about 10 fs) are limited by the energy chirp and longitudinal emittance of the electron bunch, number of undulator periods, and resolution of monochromator. In this paper we analyze potential of the TESLA Test Facility (TTF) at DESY for construction of such a femtosecond X-ray facility. TTF linac would be able to deliver up 500-700 MeV electron beam, prepared with properties to allow generation of fs soft X-ray pulse (with electron pulse duration 0.16 ps FWHM, energy chirp 1 %). The electron beam qualities required for fs facility operation (longitudinal emittance 10 keV-mm, normalized transverse emittance 2 mm-mrad, charge 0.1 nC) can be met with laser-driven rf-gun. After the exit of the undulator (number of periods N w ' 250) the spontaneous undulator radiation enters the angular lter, which select power radiated in the central cone. After lter the frequency chirped soft X-ray pulse enters the monochromator with resolution