The high-dynamic cryogenic sample stage for SAPOTI/CARNAÚBA at Sirius/LNLS

SAPOTI will be the second nanoprobe to be installed at the CARNAU´ BA (Coherent X-Ray Nanoprobe Beamline) beamline at the 4th-generation light source Sirius at the Brazilian Synchrotron Light Laboratory (LNLS). Working in the energy range from 2.05 to 15 keV, it has been designed for simultaneous multi-analytical X-ray techniques, including diffraction, spec-troscopy, fluorescence and luminescence, and imaging in 2D and 3D. Highly-stable fully-coherent beam sizes between 30 and 140 nm, with monochromatic flux up to 1011ph/s/100mA/0.01%BW, are expected with an achromatic KB (Kirkpatrick-Baez) fo-cusing optics that is mounted according to an innovative mechanical design. Then, aiming at single-nanometer resolution images via high-performance 2D mapping and tomography, a new in-vacuum cryogenic sample stage has been developed. In the scan-ning stage, an XYZ mapping range within a spherical radius larger than 1.5 mm, together with positioning control errors of 1 nm RMS at a sampling rate of 10 kHz, and scanning speeds up to hundreds of micrometers per second, have been obtained via a high-dynamic decoupled mechatronic architecture. It consists of a high-bandwidth active-control stage, based on force actuators, high-speed and high-accuracy metrology, and a dynamic filter for reaction forces. Then, from high-resolution 2D maps, full to-mography can be obtained with a rotation range of 220°. Finally, to reach sample temperatures in the range of 100 K and low drift, a thermo-mechanically decoupled solution with a pulse tube cooler is adopted. This work presents a brief technical review the SAPOTI station, and summarizes the innovative mechatronic design and the thermal management of the sample stage, which has been developed according to strict precision engineering principles and a predictive design approach. The promising initial offline commissioning results are also disclosed for the first time.