In this talk, I will present a method for generating femtosecond duration x-ray pulses using a single-pass free-electron laser (FEL). This method uses an energy-chirped electron beam passing through an undulator to produce a frequency-chirped x-ray pulse through self-amplified spontaneous emission (SASE). Since the frequency is correlated to the longitudinal position within the pulse, a monochromator may be used to select the bandwidth, and therefore, the duration of the radiation pulse. The short-pulse radiation may be seeded into a second undulator, and amplified to saturation. In addition to short-pulse generation, this scheme has the ability to control shot-to-shot fluctuations in the central wavelength due to electron beam energy jitter. Calculations of the radiation characteristics produced by the chirped-beam two-stage SASE FEL are presented, and the performance of the chirped-beam two-stage option for the Linac Coherent Light Source (LCLS) is considered.


Talk Slides:



(Coffee & Cookies before the seminar starting 10:00 am)