Design optimisation of a high-temperature X-ray diffractometer for in-situ determination of lattice mismatch and residual stress -: the Hotbird

The current paper extends the pioneer diffractometer optimisation studies of the sixties to a general type of source including narrow wavelength distribution sources, the so-called monochromatic sources. The performance requirements for a double-crystal X-ray diffractometer are formulated and expressions for the full width at half maximum and the intensity of the Bragg peak are deduced. For fixed values of the resolution, the influence on the count rate of several parameters - divergencies of collimators and mosaic spreads of monochromator and sample - are studied. Results are applied to a particular diffractometer, the Hotbird.