The BESSY constant length Rowland circle monochromator

The BESSY constant length Rowland circle monochromator (CL-RCM) was designe d for high resolution spectroscopy in the soft x-ray region. The principle is based on a spherical grating/plane mirror assembly, which is moved betwe en the fixed entrance and exit slits for photon energy scan. By this means, the Rowland conditions are fulfilled over an energy range of 270-590 eV, y ielding excellent resolution. Fast beamline optimization and, most importan t, the efficient use of beamlime in routine user operation is considerably enhanced by the newly implemented on-the-fly measuring mode, as demonstrate d by the first results obtained on the beamline. (C) 1999 Elsevier Science B.V. Ail rights reserved.