Abstract
A general theoretical approach based on the results of statistical optics is used for the analysis of the transverse coherence properties of third generation hard x-ray synchrotron sources and x-ray free-electron lasers (XFEL). Correlation properties of the wavefields are calculated at different distances from an equivalent Gaussian Schell-model source. This model is used to describe coherence properties of the 5 m undulator source at the synchrotron storage ring PETRA III. In the case of XFEL sources the decomposition of the statistical fields into a sum of independently propagating transverse modes is used for the analysis of the coherence properties of these new sources. A detailed calculation is performed for the parameters of the SASE1 undulator at the European XFEL. It is demonstrated that only a few modes contribute significantly to the total radiation field of that source.
Highlights
With the construction of 3-rd generation, hard x-ray synchrotron sources (ESRF, APS and SPring8) with small source sizes and long distances from source to sample (Fig. 1 (a)), new experiments that exploit the high coherence properties of these x-ray beams have become feasible
Using the previously introduced values of the degree of the transverse coherence ζ ( 35) and the parameters obtained for an equivalent Gaussian Schell-model (GSM) source we find that ζ = 0.63 for that source
We have demonstrated how a general theoretical approach based on the results of statistical optics can be applied to give a sufficient description of the correlation properties of the fields generated by 3-rd generation synchrotron sources and FELs
Summary
With the construction of 3-rd generation, hard x-ray synchrotron sources (ESRF, APS and SPring8) with small source sizes and long distances from source to sample (Fig. 1 (a)), new experiments that exploit the high coherence properties of these x-ray beams have become feasible. [30, 31]), or a detailed modeling of the SASE process by performing calculations of nonlinear electromagnetic equations at different conditions of operation (linear regime, saturation, etc.) [26] Another possible approach is based on the results of statistical optics [32, 33], when the statistics of the radiation wavefield is analyzed with the very general assumptions about the origin of the radiators [34, 35, 36]. With this approach we will substitute a real synchrotron source by an equivalent source with a certain source size and, what is especially important, a finite degree of coherence that will produce wavefields with the same statistical properties as a radiation field from a real source With these general assumptions we will use the results of statistical optics to calculate the statistical properties of beams emerging from a new source, PETRA III, at different distances from the source. In the Appendix we compare results obtained in this paper with the theoretical approach developed in Ref. [31] for calculation of coherence properties of radiation emerging from the undulator sources
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
