MEASUREMENTS OF TRANSMITTED DIFFRACTION PROFILES ON BRAGG ANGLES AT PI/2

Transmitted diffraction profiles of a thin Ge 620 crystal at Bragg angles around and including pi/2 were obtained for different crystal temperatures using Co K-alpha-1 radiation. A grooved crystal monochromator operating at Bragg angles near 89.5-degrees, providing a highly monochromatic beam in the forward direction, is described. Rocking curves widths of 30 arcmin and energy resolution DELTA-E/E = 1.66 x 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.