Synchrotron Radiation Sources

Hulbert, Steven L.; Williams, Gwyn

doi:10.1016/b978-012617560-8/50002-5

Cited by 4 publications

(1 citation statement)

References 16 publications

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“…Intuitively, in this situation one would apply methods from wave optics in order to solve the image formation problem. At variance, in the literature an estimation of the source size for the case of diffraction-limited radiation from a bending magnet based on geometrical optics is often discussed (Green, 1976;Krinsky et al, 1983;Hulbert & Weber, 1992;Hulbert & Williams, 1998b;Williams, 2006). A situation where one deals with a similar problem is in the calculation of a laser beam focus through a lens, when severe aberrations are present.…”

Section: Bending Magnetsmentioning

confidence: 99%

Brightness of synchrotron radiation from undulators and bending magnets

Geloni

Kocharyan

Saldin

2015

J Synchrotron Radiat

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The maximum of the Wigner distribution (WD) of synchrotron radiation (SR) fields is considered as a possible definition of SR source brightness. Such a figure of merit was originally introduced in the SR community by Kim [(1986),Nucl. Instrum. Methods Phys. Res. A,246, 71–76]. The brightness defined in this way is always positive and, in the geometrical optics limit, can be interpreted as the maximum density of photon flux in phase space. For undulator and bending magnet radiation from a single electron, the WD function can be explicitly calculated. In the case of an electron beam with a finite emittance the brightness is given by the maximum of the convolution of a single electron WD function and the probability distribution of the electrons in phase space. In the particular case when both electron beam size and electron beam divergence dominate over the diffraction size and the diffraction angle, one can use a geometrical optics approach. However, there are intermediate regimes when only the electron beam size or the electron beam divergence dominate. In these asymptotic cases the geometrical optics approach is still applicable, and the brightness definition used here yields back once more to the maximum photon flux density in phase space. In these intermediate regimes a significant numerical disagreement is found between exact calculations and the approximation for undulator brightness currently used in the literature. The WD formalism is extended to a satisfactory theory for the brightness of a bending magnet. It is found that in the intermediate regimes the usually accepted approximation for bending magnet brightness turns out to be inconsistent even parametrically.

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Section: Bending Magnetsmentioning

confidence: 99%