Flat Graded X-ray Optics

Flat graded multilayers are artificial optical components with a 1-dimensional lattice deposited on a substrate.
These optical devices monochromize the incoming beam while leaving the divergence unchanged, i. e. they generate a divergent monochromatic beam. To obtain high efficiency, the d-spacing of the lattice has to be changed from the front end to the rear end of the multilayer. A plane figure is required for this type of mirror. The device has a single focal point. Either the X-ray source or the detector (or detector slit) may be placed at the optics focal distance, for primary or secondary side applications, respectively.


Generation of a monochromatic 1-dimensional divergent beam

Spectral lines

Cr, Co, Cu, Ga, Mo, Ag
(can be used for different wavelengths)

Mean Reflectivity

R > 70%

Monochromacy

1+Kα2

Mirror length

L = 20 mm ... 80 mm
(on customers' request)

X-ray source geometry

line focus preferred

Capture angle

φ=0.20° (L = 20 mm) ...
φ=0.50° (L = 80 mm)
for Cu Kα

Application

monochromator
(primary or secondary)
in Bragg-Brentano geometry





Beam path and main parameters of a flat graded multilayer




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