Fluctuation of femtosecond X-ray pulses generated by a laser-Compton scheme

A short-pulse X-ray-generation experiment was performed by Compton scattering through interaction between a 3-ps electron beam and 100-fs laser photons in a 90° scattering configuration. The observed X-ray intensity was typically 3×104 photons/pulse and roughly matched the theoretically expected intensity. The X-ray energy and pulse duration were estimated theoretically to be 2.3 keV and 280 fs from the observed electron- and laser-beam parameters. The fluctuation of the X-ray output was measured as 25% (rms) during a 30-min operation. The fluctuation was expressed as a function of the fluctuation of the timing between the electron and laser beams. The measured fluctuation of the X-rays was approximately consistent with that caused by the fluctuation of the timing between the beams.