A study of the performance of the Athena X-ray Telescope through ray-tracing using McXtrace

This thesis presents the results of ray-tracing simulations of the mirror assembly of the Athena X-ray telescope. It describes SPORT, the Silicon Pore Optics Ray-tracing Tool, and McXtrace, the Monte Carlo X-ray Tracer, simulation tools that were both adapted as part of the thesis to fit its scientific purposes. It then presents two studies, in which a number of different variants of Athena’s optics are simulated. Variations of the optics consist of different combinations of
mirror curvature and SPO wedging, and both point sources and extended sources are simulated. Each study assesses a different performance metric: effective area in the first, angular resolution in the second.

The thesis finds that all polynomial variants meet the on-axis effective area requirement of 1.4 m2 at 1 keV and 0.25 m2 at 6 keV. The absolute angular resolutions of the variants have not been determined because geometric effects of non-specular scatter were not included in the simulations. However, a ranking of variants based on angular resolution was found, and is assumed to be true even with the inclusion of blurring due to non-specular scatter.

Of the polynomial variants, the secondary polynomial, wedging 0/2 variant was shown to be superior under a majority of source conditions. Under most source conditions, this variant has the highest effective area, the best or near-best angular resolution, and a minimum of generated stray light.