W/SiC x-ray multilayers optimized for use above 100 keV.
We have developed a new depth-graded multilayer system comprising W and SiC layers, suitable for use as hard x-ray reflective coatings operating in the energy range 100-200 keV. Grazing-incidence x-ray reflectance at E = 8 keV was used to characterize the interface widths, as well as the temporal and thermal stability in both periodic and depth-graded W/SiC structures, whereas synchrotron radiation was used to measure the hard x-ray reflectance of a depth-graded multilayer designed specifically for use in the range E approximately 150-170 keV. We have modeled the hard x-ray reflectance using newly derived optical constants, which we determined from reflectance versus incidence angle measurements also made using synchrotron radiation, in the range E = 120-180 keV. We describe our experimental investigation in detail compare the new W/SiC multilayers with both W/Si and W/B4C films that have been studied previously, and discuss the significance of these results with regard to the eventual development of a hard x-ray nuclear line telescope.
Columbia Astrophysics Laboratory, 550 West 120 Street, New York, New York 10027, USA. windt@astro.columbia.edu
David L
DL
Windt
Soizik
S
Donguy
Charles J
CJ
Hailey
Jason
J
Koglin
Veijo
V
Honkimaki
Eric
E
Ziegler
Finn E
FE
Christensen
Hubert
H
Chen
Fiona A
FA
Harrison
William W
WW
Craig