Grazing-Incidence-Designs For Wide-Field X-Ray Imaging Applications
The classical Wolter type I grazing–incidence x–ray telescope consists of a paraboloidal primary mirror and a confocal hyperboloidal secondary mirror. This design exhibits stigmatic imaging on–axis but suffers from coma, astigmatism, field curvature, and higher–order aberrations such as oblique spherical aberration. Wolter–Schwarzschild designs have been developed that strictly satisfy the Abbe sine condition and thus exhibit no spherical aberration or coma. However, for wide–field applications such as the solar x–ray imager (SXI), there is little merit in a design with stigmatic imaging on–axis. Instead, one needs to optimize some area–weighted–average measure of resolution over the desired operational field of view. This has traditionally been accomplished by mere despacing of the focal plane of the classical Wolter type I telescope. Here we present and evaluate in detail a family of grazing–incidence x–ray telescope designs whose wide–field performance is much improved over that of an optimally despaced Wolter type I and even somewhat improved over that of an optimally despaced Wolter-Schwarzschild design. © 2001 Optical Society of America.
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Harvey, James E.; Krywonos, Andrey; and Thompson, Patrick L., "Grazing-Incidence-Designs For Wide-Field X-Ray Imaging Applications" (2001). Scopus Export 2000s. 426.