Multilayer neutron monochromator using double reflection for cold neutrons

A multilayer neutron monochromator using double reflection is developed for monochromatizing and polarizing cold neutrons. It utilizes a successive double Bragg reflection by two multilayer neutron mirrors arranged at a designed angle. The multilayer mirror has a layer spacing distribution like a supermirror with a narrow band width deposited on a silicon substrate. A number of pairs of the two mirrors are assembled in a Soller type to cover the width of the incident neutron beam. This double-reflection multilayer monochromator functions as a monochromator, polarizer with magnetic mirrors, collimator and bender of a neutron beam at the same time. The double reflection brings us a low contamination of undesirable neutrons with low reflectivity. The properties of the double-reflection multilayer monochromator are discussed numerically and experimentally. (author)