Measurements of transmitted diffraction profiles on Bragg angles at π/2

Transmitted diffraction profiles of a thin Ge 620 crystal at Bragg angles around and including π/2 were obtained for different crystal temperatures using Co Kα1 radiation. A grooved crystal monochromator operating at Bragg angles near 89.5°, providing a highly monochromatic beam in the forward direction, is described. Rocking curves widths of 30 arcmin and energy resolution ΔE/E=1.66×10−5 were measured. Great sensitivity with crystal temperature and incident wavelength were observed. An intensity enhancement at the normal incidence position due to multiple diffraction occurrence was detected.