A COMPACT DOUBLE-CRYSTAL MONOCHROMATOR WITH A BROAD ENERGY-RANGE

A compact double-crystal monochromator has been designed for producing energies between 0.3 and 12 keV with a resolution between 1 and 2 eV. This range is to be achieved by a choice of carbon-free synthetic-layer microstructures and different crystal pairs mounted on four-position turrets. This allows energy overlap between crystal pairs. The first turret is fixed in position but rotates to select an X-ray energy from the spectrum produced by the source. The second turret rotates and translates to redirect the selected radiation parallel to its incident direction with a fixed lateral displacement. To increase the angular range, the two main beam directions are between the rotation axes and parallel to the incident and exiting beams. With this geometry, the footprints of the X-ray beams travel over the entire crystal surfaces. The resulting angular range is between 23-degrees and 80-degrees, considering an incident beam width of 10 mm, a spacing of 40 mm between parallel beams, and a translation of about 160 mm. Thus, the present solution is well adapted for synchrotron radiation stations, particularly when inserting a,new beam line between existing ones.