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Methodology for the characterisation of characteristic spectral profiles, applied to chromium K β
Author(s) -
Smale L. F.,
Chantler C. T.,
Kimpton J. A.
Publication year - 2015
Publication title -
x‐ray spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.447
H-Index - 45
eISSN - 1097-4539
pISSN - 0049-8246
DOI - 10.1002/xrs.2579
Subject(s) - robustness (evolution) , chromium , computational physics , interferometry , calibration , spectral line , wavelength , radiant intensity , radiation , energy (signal processing) , analytical chemistry (journal) , optics , physics , atomic physics , chemistry , quantum mechanics , biochemistry , chromatography , gene , organic chemistry
The investigation of tests of quantum electrodynamics in the X‐ray regime down to 2–20 parts per million (ppm) amplifies the need for improved characterisation of asymmetric reference sources and energies in this regime. While several transition metal characteristic energies have been defined, most are not referenced to accurate profiles or robust links to the metre via X‐ray optical interferometry. Lower intensity K β transitions have relatively poor accuracy – we ask how to determine K β transitions to an accuracy approaching those of K α transitions. Instrumental broadening normally encountered in X‐ray experiments shifts the features of profiles used for calibration, such as peak energy, by a significant amount many times the quoted accuracies. We present a study of a methodology used recently to determine energies and profiles experimentally down to 4.5 and 2.7 ppm for Ti and V K β . In this study, we investigate the robustness of the methodology for a difficult data set and demonstrate that the approaches to and characterisation of the chromium K β spectral profile are consistent with accurate measurements in the literature down to 24 ppm. The peak energy of the chromium K β spectral profile is found to be 5946.68(14) eV prior to instrumental broadening. Characterisation of the spectral profile of the radiation, including the instrumental broadening, allows us to obtain an accurate and notably transferable standard. Significantly, we present a widely applicable methodology for achieving and using this standard. This approach has been used down to an accuracy of 2–5 ppm.