Hard x-ray characterization of a HEFT single-reflection prototype

Christensen, Finn E.; Craig, William W.; Hailey, Charles J.;
Jimenez-Garate, Mario A.; Windt, David L.; Harrison, Fiona A.; Mao,
Peter H.; Ziegler, Eric; Honkimaki, Veijo; Sanchez del Rio, Manuel;
Freund, Andreas K.; Ohler, M.; 

AA(Danish Space Research Institute) AB(Columbia Univ.) AF(California
Institute of Technology) AH(European Synchrotron Radiation Facility) 
AL(Institute of Microtechnology)

Publication: Proc. SPIE Vol. 4012, p. 626-638, X-Ray Optics, Instruments, 
and Missions III, Joachim E. Truemper; Bernd Aschenbach; Eds.

Publication Date: 07/2000

Abstract:

We have measured the hard X-ray reflectivity and imaging performance
from depth graded W/Si multilayer coated mirror segments
mounted in a single reflection cylindrical prototype for the hard X-ray
telescopes to be flown on the High Energy Focusing
Telescope (HEFT) balloon mission. Data have been obtained in the energy
range from 18 - 170 keV at the European Synchrotron
Radiation Facility and at the Danish Space Research Institute at 8 keV.
The modeling of the reflectivity data demonstrate that the
multilayer structure can be well described by the intended power law
distribution of the bilayer thicknesses optimized for the
telescope performance and we find that all the data is consistent with
an interfacial width of 4.5 angstroms. We have also
demonstrated that the required 5% uniformity of the coatings is obtained
over the mirror surface and we have shown that it is
feasible to use similar W/Si coatings for much higher energies than the
nominal energy range of HEFT leading the way for
designing Gamma-ray telescopes for future astronomical applications.
Finally we have demonstrate 35 arcsecond Half Power
Diameter imaging performance of the one bounce prototype throughout the
energy range of the HEFT telescopes.

©2000 SPIE--The International Society for Optical Engineering.