Ay. Nikulin et al., 3-DIMENSIONAL DIFFRACTION PHENOMENON AT A 90-DEGREES BRAGG REFLECTION, Physica status solidi. a, Applied research, 169(1), 1998, pp. 3-8
The experimental observation of a three-dimensional diffraction phenom
enon at a 90 degrees Bragg reflection is reported and discussed. A ref
ined experimental technique for the direct observation and accurate me
asurement of scattered intensity profiles in the vicinity of a 90 degr
ees Bragg reflection was proposed and implemented. The detector arrang
ement allowed the scintillator detection of back-reflected beams via f
luorescence scattering from an in-beam copper plate. A small hole in t
he plate allowed free passage of the incident beam. This detector syst
em has allowed a very high ratio, up to five orders of magnitude, of f
luorescence back-reflection peak to the incident beam air scattering b
ackground. Three-dimensional tracking of the reciprocal lattice point
of the Si(800) Bragg reflection around the 90 degrees Bragg position w
as studied over a range of tilt angles in a plane perpendicular to the
diffraction plane.