The eROSITA x-ray baffle

The X-ray baffleis an important part of the eROSITA mirror assembly as it reduces the stray lightcaused by single reflections at the Wolter 1 Mirrors by more than 90%. The stray lightproblem and possible solutions were analyzed by ray-tracing resulting in a trade-off between effective stray lightprotection and avoidance of vignetting. Possible design alternatives were considered and the influences of manufacturing tolerances were studied. Other than for XMM, the eROSITA X-ray bafflecould not be realized as sieve plates; instead a system of co-aligned “ bafflerings” was mounted onto each of the mirror modules. The mechanical design is based on concentric Invarfoils fixed by an own spider. The complete X-ray baffleswere finally mounted to the mirror module while the alignment was controlled by optical means.