Open AccessUsing refractive optics to broaden the focus of an X‐ray mirror
Author(s) -
Laundy David,
Sawhney Kawal,
Dhamgaye Vishal
Publication year - 2017
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/s1600577517006038
Subject(s) - optics , x ray optics , beamline , synchrotron radiation , focal length , physics , diffraction , beam (structure) , centroid , synchrotron , physical optics , x ray , computer science , lens (geology) , artificial intelligence
X‐ray mirrors are widely used at synchrotron radiation sources for focusing X‐rays into focal spots of size less than 1 µm. The ability of the beamline optics to change the size of this spot over a range up to tens of micrometres can be an advantage for many experiments such as X‐ray microprobe and X‐ray diffraction from micrometre‐scale crystals. It is a requirement that the beam size change should be reproducible and it is often essential that the change should be rapid, for example taking less than 1 s, in order to allow high data collection rates at modern X‐ray sources. In order to provide a controlled broadening of the focused spot of an X‐ray mirror, a series of refractive optical elements have been fabricated and installed immediately before the mirror. By translation, a new refractive element is moved into the X‐ray beam allowing a variation in the size of the focal spot in the focusing direction. Measurements using a set of prefabricated refractive structures with a test mirror showed that the focused beam size could be varied from less than 1 µm to over 10 µm for X‐rays in the energy range 10–20 keV. As the optics is in‐line with the X‐ray beam, there is no effect on the centroid position of the focus. Accurate positioning of the refractive optics ensures reproducibility in the focused beam profile and no additional re‐alignment of the optics is required.