Design and advancement status of the Beam Expander Testing X-ray facility (BEaTriX)

TL;DR

The BEaTriX facility is an advanced X-ray testing system designed to produce a broad, uniform, low-divergence beam for quality control of large X-ray optics, enabling rapid and accurate assessment of mirror modules for space observatories.

Contribution

This paper presents the final design and detailed performance simulation of the BEaTriX X-ray testing facility, a novel system for large-scale X-ray optics quality control.

Findings

Design achieves a broad, uniform X-ray beam with low divergence.

Performance simulations indicate the system meets optical quality requirements.

Facility will enable rapid, full-illumination testing of X-ray mirror modules.

Abstract

The BEaTriX (Beam Expander Testing X-ray facility) project is an X-ray apparatus under construction at INAF/OAB to generate a broad (200 x 60 mm2), uniform and low-divergent X-ray beam within a small lab (6 x 15 m2). BEaTriX will consist of an X-ray source in the focus a grazing incidence paraboloidal mirror to obtain a parallel beam, followed by a crystal monochromation system and by an asymmetrically-cut diffracting crystal to perform the beam expansion to the desired size. Once completed, BEaTriX will be used to directly perform the quality control of focusing modules of large X-ray optics such as those for the ATHENA X-ray observatory, based on either Silicon Pore Optics (baseline) or Slumped Glass Optics (alternative), and will thereby enable a direct quality control of angular resolution and effective area on a number of mirror modules in a short time, in full X-ray illumination and without being affected by the finite distance of the X-ray source. However, since the individual mirror modules for ATHENA will have an optical quality of 3-4 arcsec HEW or better, BEaTriX is required to produce a broad beam with divergence below 1-2 arcsec, and sufficient flux to quickly characterize the PSF of the module without being significantly affected by statistical uncertainties. Therefore, the optical components of BEaTriX have to be selected and/or manufactured with excellent optical properties in order to guarantee the final performance of the system. In this paper we report the final design of the facility and a detailed performance simulation.