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An X‐ray spectrometer with an energy resolution of 54 meV
Author(s) -
Hofmann W.,
Kalus J.,
Schmelzer U.
Publication year - 1992
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889891012876
Subject(s) - monochromator , spectrometer , monochromatic color , silicon , bragg's law , optics , analyser , x ray , resolution (logic) , monocrystalline silicon , wavelength , crystal (programming language) , atomic physics , single crystal , physics , diffraction , nuclear magnetic resonance , optoelectronics , artificial intelligence , computer science , programming language
The performance of a high‐energy‐resolution X‐ray spectrometer using the characteristic 7.47815 keV Kα 1 emission line of Ni is described. Monochromatization of this line is achieved by Bragg reflection on a focusing perfect single‐crystal of silicon in near‐backscattering geometry ( Θ B = 89.61°). With the 533 reflection, a reasonable matching between the lattice parameter d and the X‐ray wavelength λ was achieved ( λ = 2 d sin Θ B ≃ 2 d ). Tuning the X‐ray energy is performed by changing the temperature, which changes the lattice spacing d of the silicon crystal. The energy resolution of the monochromator alone was 38 meV. The energy resolution of the whole instrument, measured with an analyser equal in construction to the monochromator, was 54 meV, in good agreement with a calculated value. The intensity of the monochromatic X‐rays was 4.5 × 10 6 quanta s −1 , concentrated on a spot with a full width at half‐maximum of 2.7 mm, if a 10 kW X‐ray generator ( U = 50 keV, I = 200 mA) is used. Again, this value is in good accordance with calculations using published data for X‐ray emission. The effective spot size of the electron beam was 1 × 1 mm. It is shown that, in principle, an intensity increase of a further order of magnitude is possible by heating the silicon crystal to 570 K.