Photon pulse filtering and modulation based on the extreme temporal compression and correlated energy spread of the electron bunches in the SLAC Linac Coherent Light Source (LCLS)

The LCLS photon pulses are expected to attain unprecedented levels of brightness and brevity in the 300-400 eV range. Nominally, the photon pulse length will be dominated by the electron bunch length, while the performance of conventional X-ray reflecting and band-shaping optics will be limited by: 1) peak power damage, and 2) transform-limited monochromatization. In this paper we describe how: 1) the correlated energy spread in the electron bunch can be used to selectably compress the LCLS photon pulses to below their nominal length; 2) gas optics can be used to mitigate peak damage problems; 3) the LCLS pulse structure can, in principle, accommodate schemes based on “disposable” optics; and 4) pulse lengthening schemes can be used to extend the attainable degree of monochromatization