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
CNPEM, Campinas, SP, Brazil
Beamlines of new 4th-generation machines present high-performance requirements in terms of preserving beam quality, in particular wavefront integrity and position stability at micro and nanoprobe stations. It brings about numerous efforts to cope with engineering challenges comprehending high thermal load, cooling strategy, crystal manufacturing, vibration sources, alignment and coupled motion control. This contribution presents the design and performance of a four-bounce silicon-crystal monochromator for the Sirius beamlines at the Brazilian Synchrotron Light Source (LNLS), which is basically composed of two channel-cut crystals mounted on two goniometers that counter-rotate synchronously. The mechanical design ascertained the demands for the nanoprobe and coherent scattering beamlines - namely, CARNAÚBA and CATERETÊ - focusing on solutions to minimize misalignments among the parts, to grant high stiffness and to ensure that the thermal performance would not impair beam characteristics. Hence, all parts were carefully simulated, machined, and measured before assembling. This work details mechanical, thermal, diagnostics, and dynamic aspects of the instruments, from the design phase to their installation and initial commissioning at the beamlines.
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
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.