Optical module HEW simulations for the X-ray telescopes SIMBOL-X, EDGE and XEUS

TL;DR

This paper presents simulations of the Half-Energy Width (HEW) for X-ray telescope optics, emphasizing the impact of surface microroughness and X-ray scattering on angular resolution across different photon energies.

Contribution

It introduces simulation methods to evaluate the X-ray scattering contribution to HEW for future X-ray telescopes, aiding in mirror surface optimization.

Findings

X-ray scattering significantly affects HEW at high energies.

Simulations help define surface finishing requirements.

HEW varies with photon energy and mirror surface quality.

Abstract

One of the most important parameters defining the angular resolution of an X-ray optical module is its Half-Energy Width (HEW) as a function of the photon energy. Future X-ray telescopes with imaging capabilities (SIMBOL-X, Constellation-X, NeXT, EDGE, XEUS,...) should be characterized by a very good angular resolution in soft (< 10 keV) and hard (> 10 keV) X-rays. As a consequence, an important point in the optics development for these telescopes is the simulation of the achievable HEW for a system of X-ray mirrors. This parameter depends on the single mirror profile and nesting accuracy, but also on the mirrors surface microroughness that causes X-ray Scattering (XRS). In particular, owing to its dependence on the photon energy, XRS can dominate the profile errors in hard X-rays: thus, its impact has to be accurately evaluated in every single case, in order to formulate surface finishing requirements for X-ray mirrors. In this work we provide with some simulations of the XRS term of the HEW for some future soft and hard X-ray telescopes.