Monochromator design for the HADAS reflectometer in Julich

A reflectometer with polarization analysis is being built on the basis of t he HADAS spectrometer in the neutron guide hall at the research reactor FRJ -2 (DIDO) in Julich. For obtaining the optimal flux at the sample position, the performances of several monochromator designs have been calculated, e. g. focusing mirrors, mosaic monochromator crystals and bent perfect crystal monochromators. Under the given geometrical limitations a double monochrom ator with bent perfect Si crystals and vertical focusing has the best perfo rmance. (C) 2000 Elsevier Science B.V. All rights reserved.