COMPARISON OF HARD X-RAY SELF-SEEDING WITH SASE AFTER A MONOCHROMATOR AT LCLS ∗

Self-seeding using hard x-rays was demonstrated at LCLS in January 2012 and produced a factor of 4050 bandwidth reduction from normal SASE operation. For many hard x-ray users, the photon intensity after a monochromator is an important performance parameter, whether or not the beam is seeded or SASE. In this paper, we report results from a study of self-seeding performance using the Si (111) K- monochromator with a full bandwidth of 1.2 eV at 8.2 keV. These include a direct comparison of the average intensity of the monochromatized seeded beam with that of a monochromatized fully tuned-up SASE beam, in both cases using 150 pC bunch charge.