LNLS, Campinas, Brazil
The High-Dynamic Double-Crystal Monochromator (HD-DCM)*,** is an opto-mechatronic system with unique architecture, and deep paradigm changes as compared to traditional beamline monochromators. Aiming at unmatching scanning possibilities and positioning stability in vertical-bounce DCMs, it has been developed since 2015 for hard X-ray beamlines at Sirius Light Source at the Brazilian Synchrotron Light Laboratory (LNLS). Two units are currently operational at the MANACA (macromolecular crystallography) and the EMA (extreme conditions) undulator beamlines, whereas a model for extended scanning capabilities in the energy range between 3.1 to 43 keV, the so-called HD-DCM-Lite, is in advanced development stage for two new beamlines, namely: QUATI (quick absorption spectroscopy), with a bending-magnet source; and SAPUCAIA (small-angle scattering), with an undulator source. In this work, online commissioning and operating results of the HD-DCMs are presented with emphasis on: the 10 nrad RMS (1 Hz - 2.5 kHz) pitch-parallelism performance; energy calibration; energy-dependent beam motion at sample; and flyscan with monochromator-undulator synchronization, which is a well-known control challenge at beamlines. To conclude, the Sirius HD-DCM family prospects, including the HD-DCM-Lite, are discussed.
*Geraldes, R. R., et al. "The New High-dynamics DCM for Sirius." Proc. of MEDSI 2016.
**Geraldes, R. R., et al. "The Status of the New High-Dynamic DCM for Sirius." Proc. of MEDSI 2018.
LNLS, Campinas, Brazil
Innovative exactly-constrained thermo-mechanical de-signs for beamline X-ray mirrors have been developed since 2017 at the 4th-generation Sirius Light Source at the Brazilian Synchrotron Light Laboratory (LNLS). Due to the specific optical layouts of the beamlines, multiple systems cover a broad range of characteristics, including: power management from a few tens of mW to tens of W, via passive room-temperature operation, water cooling or indirect cryocooling using copper braids; mirror sizes ranging from 50 mm to more than 500 mm; mirrors with single or multiple optical stripes, with and without coat-ings; and internal mechanics with one or two degrees of freedom for optimized compromise between alignment features, with sub-100-nrad resolution, and high dynamic performance, with first resonances typically above 150 Hz. Currently, nearly a dozen of these in-house mirror systems is operational or in commissioning at 5 beam-lines at Sirius: MANACÁ, CATERETÊ, CARNAÚBA, EMA and IPÊ, whereas a few more are expected by the end of 2021 with the next set of the forthcoming beam-lines. This work highlights some of the design variations and describes in detail the workflow and the lessons learned in the installation of these systems, including: modal and motion validations, as well as cleaning, as-sembling, transportation, metrology, fiducialization, alignment, baking and cooling. Finally, commissioning results are shown for dynamic and thermal stabilities, and for optical performances.
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LNLS, Campinas, Brazil
CARNAÚBA (Coherent X-Ray Nanoprobe Beamline) is the longest beamline at Sirius Light Source at the Brazilian Synchrotron Light Laboratory (LNLS), working in the energy range between 2.05 and 15 keV and hosting two stations: the sub-microprobe TARUMÃ, with coherent beam size varying from 550 to 120 nm; and the nanoprobe SAPOTI, with coherent beam size varying from 150 to 30 nm. Due to the long distances from the insertion device to the stations (136 and 143 m) and the extremely small beam sizes, the mechanical stability of all opto-mechanical systems along the facility is of paramount importance. In this work we present a comprehensive set of measurements of both floor stability and modal analyses for the main components, including: two side-bounce mirror systems; the four-crystal monochromator; the Kirkpatrick-Baez (KB) focalizing optics; and the station bench and the sample stage at TARUMÃ. To complement the components analyses, we also present synchronized long-distance floor acceleration measurements that make it possible to evaluate the relative stability through different floor slabs: the accelerator slab, over which the insertion device and first mirror are installed; experimental hall slab, which accommodates the second mirror; and the slabs in satellite building, consisting of three inertial blocks lying over a common roller-compacted concrete foundation, the first with the monochromator and the remaining ones with an station each. In addition to assessing the stability across this beamline, this study benchmarks the in-house design of the recently-installed mirrors, monochromators and end-stations.
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
After successfully designing, installing, and commissioning two units of the High-Dynamic Double-Crystal Monochromator (HD-DCM) at the Brazilian Synchrotron Light Laboratory (LNLS) - Sirius, two more units are now required. Since they demand only a smaller energy range (5 to 35 keV), the total gap stroke of the new instruments can be significantly reduced, creating an opportunity to adapt the existing design towards the so-called HD-DCM-Lite. Removing the large gap adjustment mechanism allows a reduction of the main inertia by a factor of 5, enabling the HD-DCM-Lite to deliver energy flyscans of hundreds of eV reaching 20 cycles per second while keeping fixed exit and the pitch stability in the range of 10 nrad RMS (1 Hz - 2.5 kHz). Hence, an unparallel bridge between slow step-scan DCMs and fast channel-cut monochromators is created. This work presents the in-house development of the HD-DCM-Lite, focusing on its mechanical design, discussions on the ultimate scanning constraints (rotary stage torque, voice-coil forces, interferometers and encoders readout speed limits and subdivisional errors), and thermal management.
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LNLS, Campinas, Brazil
The low emittance and high photon flux beam present at the 4th-generation Sirius synchrotron light source beamlines result in high energy densities and high heat loads at some specific X-ray optics such as monochromators and white beam mirrors. This challenges the design of such systems since the introduction of thermal stresses may lead to optical surface deformation and beam degradation. Thus, to keep the systems within acceptable deformations some of the optical elements are cryogenically cooled. However, this poses the requirements of decoupling the thermal sinks (cryostats) from the optics and the mechanisms to maintain their desired degrees of freedom for alignment and dynamic operation. In this context we present the development of low-stiffness copper-braid-based heat conductors, summarizing the motivation and main aspects regarding their fabrication and application at the beamlines.
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).
LNLS, Campinas, Brazil
One of the challenges of fourth-generation synchrotron light sources as Sirius at the Brazilian Synchrotron Light Laboratory (LNLS) is the high power density that may affect the beamline optical elements by causing figure deformations that deteriorate the quality of the beam. Indeed, surface specifications for height errors of X-ray mirrors are often within a few nanometers. To deal with these thermal management challenges, thermo-mechanical designs based on cryogenic silicon have been developed, taking advantage of its high thermal conductance and low thermal expansion in temperatures of about 125 K. A liquid nitrogen (LN2) cryostat connected to the optics by copper braids has been used to handle moderate power loads, reducing costs when compared to closed-circuit LN2 cryocoolers and mechanically decoupling flow-induced vibrations from the optics. To guarantee the functionality of such systems, lumped mass thermal models were implemented together with auxiliary finite elements analyses. With the first systems in operation, it has been possible to compare and validate the developed models, and to carry out optimizations to improve them for future projects, by adjusting parameters such as emissivity, thermal contact resistance, and copper braid conductance. This work presents the updated models for CARNAÚBA and CATERETÊ beamlines as reference cases.