The versatility of collimated plane grating monochromators

In the last few years monochromator development at the German synchrotron radiation facility BESSY II improved conventional monochromator designs, especially the SX700 design, considerably. It was possible to convert the high brilliance of undulator radiation at third generation synchrotron sources very successfully into outstanding monochromator performance in terms of high energy resolution, photon flux and focus size. New mechanical designs and precise control of the angular settings of optical elements resulted in very high monochromator stability and allowed even for an absolute energy calibration of monochromators. This report reviews the design principles of collimated plane grating monochromators and presents results obtained within the first two years of BESSY II operation.