Development of wide band neutron monochromator consisting of a stack of multilayers

A wide band neutron monochromator consisting of a stack of four multilayers an two Si wafers has been developed. One multilayer has 201 Ni/Ti layers. The layer thickness is gradually changed in order to extend the neutron ref lection wavelength range similar to a supermirror. Multilayers were fabrica ted by the vacuum evaporation methods on each side of a Si substrate of 225 mu m in thickness. Neutron reflectivity was measured by the theta-2 theta reflectometer using cold neutrons. The neutron reflection wavelength was br oadened to 19-40 nm by this stack from 26-40 nm of one multilayer.