In the last few years monochromator development at the German synchrotron r
adiation facility BESSY II improved conventional monochromator designs, esp
ecially 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 hi
gh energy resolution, photon flux and focus size. New mechanical designs an
d precise control of the angular settings of optical elements resulted in v
ery high monochromator stability and allowed even for an absolute energy ca
libration of monochromators. This report reviews the design principles of c
ollimated plane grating monochromators and presents results obtained within
the first two years of BESSY II operation. (C) 2001 Elsevier Science B.V.
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