Graded d-spacing multilayer telescope for high-energy x-ray astronomy

Abstract

A high energy telescope design is presented which combines grazing incidence geometry with Bragg reflection in a graded d-spacing multilayer coating to obtain significant sensitivity up to --6O keV. The concept utilizes total reflection and first order Bragg reflection in a graded d-spacing multilayer structure in a way that higher energies are reflected from the deepest layers in the stack. The specific design presented in this paper is based on Ni/C and Mo/C structures with dspacings ranging from 25A to 100 A. X-ray reflectivity data obtained with Cu Kc1 (8. 05 keV) are presented from the first graded d-spacing structures of this kind.