A DOUBLE MULTILAYER MONOCHROMATOR AT AN ESRF UNDULATOR FOR MICROBEAM EXPERIMENTS

A water-cooled double W/Si-multilayer monochromator has been operated at an ESRF low-beta undulator beam. For a fixed distance of the two mu ltilayers the first-order Bragg reflection was at similar to 8 keV. Th e peak power density of the beam at the exit of the multilayers was si milar to 1 W mm(-2) and the Aux density of the first order after a 10 mu m collimator was 4 x 10(5) photons s(-1) mu m(-2) mA(-1). The perfo rmance of the beam in microbeam diffraction has been tested on a 20 mu m W wire. The observed pseudo-laue pattern is discussed with respect to the multilayer spectrum.