The new microfocus station for the NOTOS beamline at the ALBA synchrotron

The NOTOS beamline at ALBA combines X-ray Absorption Spectroscopy (XAS) and X-ray Diffraction (XRD) experiments, operating in the 4.5-30 keV range. Since 2022, it has offered two end stations (ES): one for metrology and XAS, and another combining XAS and XRD. To overcome the current 100×100 µm² spot size limitation, we present a third microfocus ES (µFo-ES), planned for commissioning by the end of 2025. It will provide spot sizes below 10×10 µm² with a flux >7.3·10¹³ ph/s/mm², enabling XAS in fluorescence and transmission. It uses the existing optics plus a pair of Kirkpatrick–Baez (KB) mirrors working under high vacuum. The KB positioning system is based on an in-housed developed design and the mirrors will be elliptically bent using ALBA mirror benders with sub-nanometric resolution. High-precision slits placed upstream the KB will ensure beam size, collimation, and diagnostics. The µFo-ES will integrate a compact sample environment including a ionization chamber, on-axis camera, and a fluorescence detector for variable incident angles. To ensure compatibility with downstream ES and prevent photon flux loss, the µFo-ES has been designed to be fully retractable from the beam path.