Development of Wide Band Neutron Monochromator Consisting of a Stack of Multilayers

Abstract

A wide band neutron monochromator consisting of a stack of four multilayers on 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 reflection wavelength range similar to a supermirror. Multilayers were fabricated by the vacuum evaporation methods on each side of a Si substrate of 225 μm in thickness. Neutron reflectivity was measured by the θ-2θ reflectometer using cold neutrons. The neutron reflection wavelength was broadened to 19–40 nm by this stack from 26–40 nm of one multilayer.

KEYWORDS:

• monochromators
• multilayer
• stack
• slow neutrons
• supermirrors
• nickel
• titanium
• neutron reflectivity