On the use of a multilayer monochromator in neutron reflectometry

In neutron reflectometry experiments, the intensity reflected from the samp le under investigation is determined as a function of the wave-vector trans fer. One way of doing this is to start with a monochromatic beam and perfor m the so-called theta/2 theta scans. The monochromatic beam can be produced by Bragg reflection from a single crystal, or from a multilayer system. In this paper, we experimentally investigate the performance of a multilayer monochromator. We demonstrate that the large-wavelength contamination, intr insically present, may lead to large errors in the obtained reflectivity at large values of the wave-vector transfer. (C) 2000 Elsevier Science B.V. A ll rights reserved.