With the support of ESA , is now under construction at INAF-Brera Astronomical Observatory the Beam Expander Testing X-ray , also called BEaTriX.
INAF-Osservatorio Astronomico Brera is building in its premises of Merate a unique pathfinder facility, named BEaTriX (the Beam Expander Testing X-ray facility). The facility will be devoted to the acceptance tests of the modules (about 700) composing the X-ray telescope ATHENA (Advanced Telescope for High-ENergy Astrophysics), the second Large mission selected by ESA within the Cosmic Vision Program, with launch foreseen for 2031.
BEaTriX will be the first equipment able to generate a parallel, uniform and expanded (170 mm x 60 mm) X-ray beam, at the energies of 1.49 and 4.51 keV, starting from the 4.51 keV beam line. The system is very compact (9 x 18 m2), reducing the evacuation time with respect to already existing and bigger facilities, used to test X-ray telescopes. The required vacuum is <= 10^-3 mbar, which can be reached in less then 1h for the entire facility. Moreover, the vacuum system is designed with modular compartments, where the vacuum can be broken independently to replace the optics under test, in less than 30min.
The expanded and parallel beam is obtained with an X-ray microfocus source placed in the focus of a paraboloidal mirror, a monochromation stage with 4 symmetrically cut crystals, and an expansion stage where the beam is diffracted and expanded by an asymmetrically-cut crystal. The key axes of all the optical components are motorized in vacuum for a proper beam alignment. The expanded beam fully illuminates the aperture of the Mirror Modules, imaging the focused beam at 12 m distance on a CCD camera, with the sensor in vacuum and motorized in air for XYZ movements.