LNLS, Campinas, Brazil
Next-generation nanoprobes, empowered by diffraction-limited storage rings, as Sirius/LNLS, present high-performance requirements aiming at high spatial resolution and throughput. For the focusing optics, this means assuring a small and non-astigmatic probe, high flux density, and remarkably high position stability, while also preserving beam wavefront. At stations further dedicated to spectromicroscopy and in-situ experiments, these requirements add up to having achromatic design and suitable working distance, respectively. In this way, Kirkpatrick-Baez (KB) mirrors have been chosen as the most appropriate solution for Sirius focusing optics. At TARUMÃ*, the first delivered nanoprobe at Sirius, the KB focuses the beam down to a 120 nm spot size (>8 keV) with a 440 mm working distance. This brought the requirements on the mirror’s angular stability to less than 10 nrad RMS, surface quality to single-digit nanometers, and alignment tolerances to the range of hundreds of nrad, which can be even tighter for other nanoprobes. Such specifications are particularly challenging regarding clamping, vibration, and thermal expansion budgets, even testing optical metrology limits during alignment and validation phases. The resulting KB mechanism is an opto-mechanical system with an exactly-constrained, deterministic design**, and suspension modes well above 250 Hz, sufficiently coupling optics to sample in the same 6-DoF base. It provides low-order aberration corrections by single degree-of-freedom alignment with piezo actuators, while higher order aberrations from clamping and thermal deformations are mitigated by gluing each mirror to flexure-based mounting frames. This contribution presents the design, assembly, and commissioning of the KB system at TARUMÃ as a reference case.
*Tolentino, H.C.N., et al. "TARUMÃ station for the CARNAÚBA beamline at SIRIUS/LNLS" SPIE 11112 19
**Geraldes, R.R., et al. "The Design of Exactly-constrained X-ray Mirror Systems for Sirius." MEDSI18
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LNLS, Campinas, Brazil
TARUMÃ is the sub-microprobe station of the CARNAÚBA (Coherent X-Ray Nanoprobe Beamline) beamline at Sirius Light Source at the Brazilian Synchrotron Light Laboratory (LNLS). It has been designed to allow for simultaneous multi-analytical X-ray techniques, including diffraction, spectroscopy, fluorescence and luminescence and imaging, both in 2D and 3D. Covering the energy range from 2.05 to 15 keV, the fully-coherent monochromatic beam size varies from 550 to 120 nm after the achromatic KB (Kirkpatrick-Baez) focusing optics, granting a flux of up to 1e11ph/s/100mA at the probe for high-throughput experiments with flyscans. In addition to the multiple techniques available at TARUMÃ, the large working distance of 440 mm after the ultra-high vacuum (UHV) KB system allows for another key aspect of this station, namely, a broad range of decoupled and independent sample environments. Indeed, exchangeable modular setups outside vacuum allow for in situ, in operando, cryogenic and/or in vivo experiments, covering research areas in biology, chemistry, physics, geophysics, agriculture, environment and energy, to name a few. An extensive systemic approach, heavily based on precision engineering concepts and predictive design, has been adopted for first-time-right development, effectively achieving altogether: the alignment and stability requirements of the large KB mirrors with respect to the beam and to the sample*; and the nanometer-level positioning, flyscan, tomographic and setup modularity requirements of the samples. This work presents the overall station architecture, the key aspects of its main components, and the first commissioning results.
* G.B.Z.L. Moreno et al. "Exactly constrained KB Mirrors for Sirius/LNLS Beamlines: Design and Commissioning of the TARUMÃ Station Nanofocusing Optics at the CARNAÚBA Beamline", presented at MEDSI’20, paper TUOB01, this conference.
LNLS, Campinas, Brazil
TARUMÃ is the sub-microprobe station of CAR-NAÚBA (Coherent X-Ray Nanoprobe Beamline) at Sirius at the Brazilian Synchrotron Light Laboratory (LNLS). Covering the tender-to-hard energy range from 2.05 to 15 keV with achromatic fixed-shape optics, the fully coherent submicron focused beam can be used for multiple simultaneous advancedμand nanoscale X-ray techniques that include ptychography coherent diffraction imaging (ptycho-CDI), absorption spectroscopy (XAS), diffraction (XRD), fluorescence (XRF) and luminescence (XEOL). Among the broad range of materials of interest, studies of light elements present in soft tissues and other biological systems put TARUMÃ in a unique position in the Life and Environmental Sciences program at LNLS. Yet, to mitigate the detrimental effect of the high photon flux of the focused beam due to radiation damage, cryocooling may be required. Here we present the design and first results of a novel open-atmosphere cryogenic system for online sample conditioning down to 110 K. The high-stiffness and thermally-stable sample holder follows the predictive design approach based on precision engineering principles to preserve the nanometer-level positioning requirements, whereas a commercial nitrogen blower is used with a cold gas flow exhaustion system that has been developed in order to avoid unwanted cooling of surrounding parts and water condensation or icing.
LNLS, Campinas, Brazil
UNICAMP, Campinas, São Paulo, Brazil
CARNAÚBA (Coherent X-Ray Nanoprobe Beamline) is a state-of-the-art multi-technique beamline at the 4th-generation Sirius Light Source at the Brazilian Synchrotron Light Laboratory (LNLS), with achromatic optics and fully-coherent X-ray beam in the energy range between 2.05 and 15 keV. At the TARUMÃ station, the in-vacuum KB focusing system has been designed with a large working distance of 440 mm, allowing for a broad range of independent sample environments to be developed in open atmosphere to benefit from the spot size between 550 to 120 nm with a flux in the order of 1e11 ph/s/100mA. Hence, together with a number of different detectors that can be simultaneously used, a wide variety of studies of organic and inorganic materials and systems are possible using cutting-edge X-ray-based techniques in theμand nanoscale, including coherent diffractive imaging (CDI), fluorescence (XRF), optical luminescence (XEOL), absorption spectroscopy (XAS), and diffraction (XRD). Even though samples over the centimeter range can be taken at Tarumã, the small beam and relatively low energies point towards optimized and reduced-size sample holders for in situ experiments. This work describes two related setups that have been developed in-house: a small-volume electrochemical cell with static fluid*; and another multifunctional environment that can be used both as a microfluidic device and as an electrochemistry cell that allows for fluid control over samples deposited on a working electrode. The mechanical design of the devices, as well as the architecture for the fluid and electrical supply systems, according to the precision engineering concepts required for nanopositioning performance, are described in details.
*Vicente, Rafael A., et al., "Bragg Coherent Diffraction Imaging for In Situ Studies in Electrocatalysis," ACS nano (2021).