LNLS, Campinas, Brazil
SAPOTI will be the second nanoprobe to be installed at the CARNAÚBA (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 absorption, diffraction, spectroscopy, fluorescence and luminescence, and imaging in 2D and 3D. Highly-stable fully-coherent beam with monochromatic flux up to 1011ph/s/100mA-/0.01%BW and size between 35 and 140 nm is expected with an achromatic KB (Kirkpatrick-Baez) focusing optics, whereas a new in-vacuum high-dynamic cryogenic sample stage has been developed aiming at single-nanometer-resolution images via high-performance 2D mapping and tomography. This work reviews and updates the entire high-performance mechatronic design and architecture of the station, as well as the integration results of its several modules, including automation, thermal management, dynamic performance, and positioning and scanning capabilities. Commissioning at the beamline is expected in early 2024.
LNLS, Campinas, Brazil
Sirius’ long beamlines are equipped with cryogenic cooled optics to take advantage of the Silicon thermal diffusivity and expansion at those temperatures, contributing to the preservation of the beam profile. A series of improvements was evaluated from the experience in the employment of such cooling systems during the early years of operation. The main topic refers to the prevention of instabilities in the temperature of the optics due to variations in the liquid nitrogen cylinder pressure, refill automation or progressive variations of the convective coefficient into the cryostat. This work discusses the performance of these systems after optimizing the pressure of the vessels and their control logics, the effectiveness of occasional purges, cool down techniques, and presents the monitoring interface and interlock architecture. Moreover, we present the reached solution for achieving higher beam stability, considering liquid nitrogen flow active control (commercial and in-house). Also propose the approach for the future 350 mA operation, including different cooling mechanisms.
