4.51 keV line

The first BEaTriX beamline at 4.51 keV is operative since 2022 and successfully passed the ESA Acceptance Review in March 2023. A microfocus source (FWHM = 35 um) with the anode in Titanium is positioned at the focus of a grazing incidence paraboloidal mirror for beam expansion in the vertical direction. Two Channel Cut Crystals (CCC) made of Si (220) symmetrically cut are used as monochromator, and one Si crystal asymmetrically cut with respect to the (220) crystal planes is used for the beam expansion in the horizontal direction by a factor x50.
The optical design foresees two configurations, selectable by rotating one of the two CCCs of the monochromator. In the high-flux/mid-collimation configuration the flux is ∼60 ph s^-1 cm^-2 and the horizontal HEW is ∼4 arcsec (vertical < 2 arcsec); in the low-flux/high-collimation configuration the flux is ∼10 ph s^-1 cm^-2 and the horizontal HEW is reduced to 2.5 arcsec.

In 2024, BEaTriX has been used for the X-ray characterization of the first coated SPO Mirror Module, MM-0058, the first MM developed embodying the essential characteristics required for the implementation of the NewAthena telescope. A first campaign at BEaTriX was performed in February 2024 showing a good agreement with the results obtained at PANTER (MPE facility close to Munich, Germany). A second campaign on MM-0058 was performed in September-October 2024 to characterize the module over the full NewAthena MM acceptance temperature range, 20 ± 20 °C. The result of this campaign showed that the HEW of MM-0058 have a slight dependence on temperature, of the order of 0.1 arcsec per 10 °C, while the effective area and the focal lengths do not show any significant variation with temperature.