Open AccessCharacterization of windows and filters for coherent X‐ray beamlines
Author(s) -
Suzuki Yoshio,
Momose Atsushi,
Sugiyama Hiroshi
Publication year - 1998
Publication title -
journal of synchrotron radiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 99
ISSN - 1600-5775
DOI - 10.1107/s0909049597020165
Subject(s) - optics , beryllium , physics , distortion (music) , coherence (philosophical gambling strategy) , x ray optics , beam (structure) , scattering , x ray , materials science , amplifier , optoelectronics , nuclear physics , cmos , quantum mechanics
Beryllium windows and graphite heat absorbers used in coherent X‐ray beamlines must be optically flat. If the optical path through the window varies by more than λ/4, the X‐ray wave front will be distorted after passing through the window, and the divergence of the X‐ray beam may be increased. This reduces the beam coherence. Beryllium, graphite and Kapton films have been tested using ultra‐small‐angle X‐ray scattering. Wave‐front distortion was also directly observed by means of phase‐contrast X‐ray microradiography. The measured increase of angular divergence is about 4 µrad. The wave‐front distortion is larger than 2π (optical path difference of λ). These are serious problems for utilizing coherent X‐ray beams.