ISSN:
1600-5767
Source:
Crystallography Journals Online : IUCR Backfile Archive 1948-2001
Topics:
Geosciences
,
Physics
Notes:
The performance of a high-energy-resolution X-ray spectrometer using the characteristic 7.47815 keV Kα1 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 (ΘB = 89.61°). With the 533 reflection, a reasonable matching between the lattice parameter d and the X-ray wavelength λ was achieved (λ = 2d sin ΘB ∼ 2d). 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 × 106 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.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1107/S0021889891012876
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