Wiggler Systems as Sources of Electromagnetic Radiation

Spencer, J.E.; Winick, H.

doi:10.1007/978-1-4615-7998-4_21

Cited by 11 publications

(3 citation statements)

References 27 publications

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“…This¯ux can be obtained on the brightest undulator beamlines at third-generation synchrotron sources. The¯ux depends critically on the resonant energies of the undulator cavity, which produces a series of relatively sharp maxima as a function of energy (Spencer & Winick, 1980), and the undulator gap can usually be tuned to obtain the maximum of a ®xed harmonic over a limited energy range. In order to illustrate the application and utility of RADDOSE, in the calculations presented below we have used the same incident¯ux for each X-ray energy.…”

Section: Figurementioning

confidence: 99%

X-ray absorption by macromolecular crystals: the effects of wavelength and crystal composition on absorbed dose

2004

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Radiation damage restricts the useful lifetime for macromolecular crystals in the X-ray beam, even at cryotemperatures. With the development of structural genomics pipelines, it will be essential to incorporate projected crystal lifetime information into the automated data collection software routines. As a ®rst step towards this goal, a computer program, RADDOSE, is presented which is designed for use by crystallographers in optimizing the amount of data that can be obtained from a particular cryo-cooled crystal at synchrotron beamlines. The program uses the composition of the crystal and buffer constituents, as well as the beam energy,¯ux and dimensions, to compute the absorption coef®cients and hence the theoretical time taken to reach an absorbed dose of 2 Â 10 7 Gy, the so-called`Henderson limit'. At this dose, the intensity of the diffraction pattern is predicted to be halved. A`diffraction±dose ef®ciency' quantity is introduced, for the convenient comparison of absorbed dose per diffracted photon for different crystals. Four example cases are considered, and the implications for anomalous data collection are discussed in the light of the results from RADDOSE.

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Section: Figurementioning

confidence: 99%

X-ray absorption by macromolecular crystals: the effects of wavelength and crystal composition on absorbed dose

2004

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“…The SR continuum spectral coverage makes it possible to excite core-holes in any atom of the periodic table, either selectively using monochromatized SR or nonselectively using broadband SR. Because of the small cross sections for PSID from most surfaces, intensity as high as that of the SR source is a necessity. New higher-intensity wiggler, 121 undulator,122,123 or free-electron laser 124 beams may increase the PSD sensitivity for the study of rare (low-concentration) surface sites. The ultraclean-vacuum environment of storage-ring SR sources is an essential feature for any optical study of surfaces, including PSD, in spectral ranges characterized by a scarcity or absence of transparent materials for windows.…”

Section: Methodsmentioning

confidence: 99%

Photon-Stimulated Desorption

Rehn

Rosenberg

1992

Synchrotron Radiation Research

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“…This would not be the case near the IR unless the basic ring configuration were changed.^ A more de tailed discussion of such questions is given In Ref. 6.…”

Section: Descriptionmentioning

confidence: 99%