Premium
Measurement of the spatial coherence of synchrotron beams using the Talbot effect
Author(s) -
Kluender Rafael,
Masiello Fabio,
van Vaerenbergh Pierre,
Härtwig Jürgen
Publication year - 2009
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200881619
Subject(s) - talbot effect , optics , synchrotron radiation , coherence (philosophical gambling strategy) , synchrotron , physics , coherence length , spatial coherence , diffraction , coherence time , image resolution , beam (structure) , laser , superconductivity , quantum mechanics
We present an application of the Talbot effect [Talbot et al., Philos. Mag . 11 , 196 (1836)] to measure the spatial coherence of a synchrotron beam, as well as the influence of optical elements on it. One advantage of using this effect is that regions of the beams down to 50 µm × 50 µm are still analysable (in our case). This spatial resolution allows analysing the local coherence degradation caused by small regions in the investigated optical element, like windows or Bragg diffraction crystals with defects. A second advantage is the independence of the results on the detector point spread function. This method is used by the Optics and the X‐ray Imaging Group at the ESRF in the hard X‐ray domain at 20.5 keV. Although already presented by Cloetens et al., J. Synchrotron Radiat . 11 , 476 (2004), this technique was mainly used to analyse the spatial beam coherence itself. In order to measure the coherence degradation due to non‐perfect optical elements, we improved the data analysis which was very deficient when applied to diffractive samples. These improvements have led to accurate and reliable results and have allowed to extend the application field of that method towards diffracting crystals.