Small‐angle scattering of polychromatic X‐rays: effects of bandwidth, spectral shape and high harmonics. (16th February 2018)

• Record Type: Journal Article
• Authors: Chen, Sen; Luo, Sheng-Nian
• Is Part Of: Journal of synchrotron radiation. Volume 25:Part 2(2018)
• Page Start: 496
• Page End: 504
• Publication Date: 2018-02-16
• Subjects: SAXS -- polychromatic -- size distribution -- undulator light source; Synchrotron radiation -- Periodicals; Free electron lasers -- Periodicals; 539.73505
• DOI: 10.1107/S1600577517018355
• Languages: English
• ISSNs: 0909-0495

Abstract

Abstract : The effects of bandwidth, spectral shape and high harmonics for undulator sources on SAXS measurements are evaluated quantitatively. Monodisperse and polydisperse systems are explored. Abstract : Polychromatic X‐ray sources can be useful for photon‐starved small‐angle X‐ray scattering given their high spectral fluxes. Their bandwidths, however, are 10–100 times larger than those using monochromators. To explore the feasibility, ideal scattering curves of homogeneous spherical particles for polychromatic X‐rays are calculated and analyzed using the Guinier approach, maximum entropy and regularization methods. Monodisperse and polydisperse systems are explored. The influence of bandwidth and asymmetric spectra shape are explored via Gaussian and half‐Gaussian spectra. Synchrotron undulator spectra represented by two undulator sources of the Advanced Photon Source are examined as an example, as regards the influence of asymmetric harmonic shape, fundamental harmonic bandwidth and high harmonics. The effects of bandwidth, spectral shape and high harmonics on particle size determination are evaluated quantitatively.