Diffraction Effects in Grazing Incidence X-Ray Telescopes

Article type: Research Article

Authors: Harvey, James E.

Affiliations: Center for Research in Electro-optics and Lasers (CREOL), University of Central Florida, 12424 Research Parkway, Orlando, Florida 32826

Abstract: There is increasing interest worldwide in the use of tightly nested grazing incidence imaging mirrors for high-throughput x-ray telescopes. Diffraction effects of x-ray optical systems are often (justifiably) ignored due to the small wavelength of the x-ray radiation. However, the extremely large obscuration ratio inherent to grazing incidence optical systems produces profound degradation of the diffraction image over that produced by a moderately obscured aperture of the same diameter. Although many of the intended applications are moderate-resolution spectroscopic instruments, there is always a desire for high-resolution imaging as well. In this paper we show that diffraction effects can dominate other potential error sources at the low-energy (long-wavelength) end of the intended operating spectral range of some existing or planned x-ray telescopes. Parametric performance predictions are presented and compared with x-ray astronomy performance goals.

DOI: 10.3233/XST-1991-3106

Journal: Journal of X-Ray Science and Technology, vol. 3, no. 1, pp. 68-76, 1991