Exploring the wavefront of hard X-ray free-electron laser radiation.
The high photon flux and femtosecond pulse duration of hard X-ray free-electron lasers have spurred a large variety of novel and fascinating experiments in physical, chemical and biological sciences. Many of these experiments depend fundamentally on a clean, well-defined wavefront. Here we explore the wavefront properties of hard X-ray free-electron laser radiation by means of a grating interferometer, from which we obtain shot-to-shot wavefront information with an excellent angular sensitivity on the order of ten nanoradian. The wavefront distortions introduced by optical elements are observed in-situ and under operational conditions. The source-point position and fluctuations are measured with unprecedented accuracy in longitudinal and lateral direction, both during nominal operation and as the X-ray free-electron laser is driven into saturation.
Paul Scherrer Institut, 5232 Villigen PSI, Switzerland. simon.rutishauser@psi.ch
Simon
S
Rutishauser
Liubov
L
Samoylova
Jacek
J
Krzywinski
Oliver
O
Bunk
Jan
J
Grünert
Harald
H
Sinn
Marco
M
Cammarata
David M
DM
Fritz
Christian
C
David