ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
* L. Ribó et al., "MECHANICAL DESIGN OF MIRAS, INFRARED MICROSPECTROSCOPY BEAM LINE AT ALBA SYNCHROTRON", presented at MEDSI’16, Barcelona, Spain, September 2016, doi:10.18429/JACoW-MEDSI2016-FRAA03
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LNLS, Campinas, Brazil
CNPEM, Campinas, SP, Brazil
Sirius, the Brazilian 4th-generation light source at the Brazilian Synchrotron Light Laboratory (LNLS), presents high-performance requirements in terms of preserving photon-beam quality, particularly regarding wavefront integrity and position stability. In this context, it is imperative that many silicon optical elements* be effectively cooled, such that temperatures and their control-related parameters can be precisely handled to the point in which thermal effects are acceptable concerning figure distortions and drifts at different timescales. For this class of precision equipment, the required performance can only be achieved with robust thermal management.** For this, relevant aspects related to the implementation of liquid nitrogen cooling systems need to be emphasized. Currently, two solutions are present at the first-phase beamlines, according to the component thermal load: (1) an in-house low-cost system for components under moderate loads (< 50 W), such as the mirror systems and the four-bounce monochromators, comprising a commercial cryostat connected to an instrumented vessel, whose level and pressure are controlled by the standard beamline automation system that can automatically feed it from a secondary service unit or a dedicated transfer line; (2) a commercial cryocooler for high-heat-load applications (50 - 3000 W), such as the double-crystal monochromators. This work presents the in-house solution: requirements, design aspects, operation range, as well as several discoveries and improvements deployed during the commissioning of the CATERETÊ and the CARNAÚBA beamlines, such as the prevention of ice formation, stabilization of both thermal load and flow-rate, and auto-filling parameters, among others.
*TOLENTINO. Innovative instruments (…) for the CARNAÚBA beamline at Sirius-LNLS. SRI (2018).
**VOLPE. Performance validation of the thermal model for optical components. Submit to MEDSI (2020)
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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Euclid TechLabs, Solon, Ohio, USA
ESRF, Grenoble, France
The next generation light sources will require x-ray optical components capable of handling large instantaneous and average power densities while tailoring the properties of the x-ray beams for a variety of scientific experiments. Diamond being radiation hard, low Z material with outstanding thermal properties is proposed for front pre-focusing optics applications. Euclid Techlabs had been developing x-ray refractive diamond lens to meet this need. Standard deviation of lens shape error figure gradually was decreased to sub-micron values. Post-ablation polishing procedure yields ~ 10nm surface roughness. In this paper we will report on recent developments towards beamline-ready lens including packaging and compound refractive lens stacking. Diamond lens fabrication is done by femtosecond laser micromachining. We had been using this technology for customization of other beamline components. Several application cases will be highlighted in this presentation: diamond anvils, x-ray flow cells and in-beam mirrors.
ANL, Lemont, Illinois, USA
The In Situ Nanoprobe (ISN, 19-ID) beamline will be a new best-in-class long beamline to be constructed as part of the Advanced Photon Source Upgrade (APS-U) project*,**. To achieve long working distance at high spatial resolution, the ISN instrument will be positioned 210 m downstream of the x-ray source, in a dedicated satellite building, currently under construction***. The ISN instrument will use a nano-focusing Kirkpatrick-Baez (K-B) mirror system, which will focus hard x-rays to a focal spot as small as 20 nm, with a large working distance of 61 mm. The large working distance provides space for various in situ sample cells for x-ray fluorescence tomography and ptychographic 3D imaging, allows the use of a separate, independent vacuum chambers for the optics and sample, and provides the flexibility to run experiments in vacuum or at ambient pressure. A consequence of the small spot size and large working distance is the requirement for high angular stability of the KB mirrors (5 nrad V-mirror and 16 nrad H-mirror) and high relative stability between focus spot and sample (4 nmRMS). Additional features include fly-scanning a maximum of a 2 kg sample plus in situ cell at 1 mm/s in vertical and/or horizontal directions over an area of 10 mm x 10 mm. Environmental capabilities will include heating and cooling, flow of fluids and applied fields, as required for electrochemistry and flow of gases at high temperature for catalysis. To achieve these features and precise requirements we have used precision engineering fundamentals to guide the design process. We will discuss in detail the current design of the instrument focusing on the precision engineering used to achieve the stability, metrology, and positioning requirements.
* J. Maser, et al. Metal and Mat Trans A (2014) 45: 85.
** J. Maser, et al. Microsc. Microanal. 24 (Suppl 2), 2018.
*** S. P. Kearney, et al. Synchrotron Radiat. News Volume 32 (5), 2019.
ANL, Lemont, Illinois, USA
Deformable optics, including mechanically-bent and bimorph mirrors, are essential optical elements for X-ray beam dynamical focusing and wavefront correction. Existing mechanical bender technology often suffers from poor repeatability and does not include twist compensation. We recently developed an elliptically bent mirror based on a laminar flexure bending mechanism that yielded promising results*,**. In this work, the mirror surface twist was characterized using a Fizeau interferometer under different bending conditions. By applying a shimming correction, the surface twist was successfully reduced from 50 urad to 1.5 urad. The twist angle variation from no bending to the maximum bending is less than 0.5 urad. Our simulation results show that these numbers are significantly lower than the required values to ensure optimum optical performance. The study demonstrates the effectiveness of the twist compensation procedures and validates the mirror bender design parameters.
*Shu, D. et al., AIP Conference Proceedings. Vol. 2054. No. 1, 2019.
**Anton, Jayson WJ et al., Optomechanical Engineering 2019. Vol. 11100, 2019.
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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DLS, Oxfordshire, United Kingdom
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IHEP, Beijing, People’s Republic of China
The stability of beamline optics directly affects the beamline’s performances, such as coherence, focal size, position stability of the beam and so on, it has become a serious issue for a low emittance 4th generation light source. The vibration transmitting function of supports plays a big role in the stability performance of the optics. In order to find out a stable supporting structure, several types of support structures were tested, and the transfer ratio were described. The result shows that wedge struc-tures generally have a lower transfer ratio, and point contact support structures should be avoided.
ANL, Lemont, Illinois, USA
The Advanced Photon Source Upgrade project has employed the use of high heat load dual mirror systems in the new feature beamlines being built. Due to the shallow operating angles of the mirrors at a particular beamline, XPCS, the two mirrors needed to be approximately 2.5 m apart to create a distinct offset. Two separate mirror tanks are used for this system. However, it is unclear if the vibrational performance of these tanks would be better if they were both mounted on one large plinth or each mounted on a small plinth. Using accelerometers at the installation location, the floor vibrations were measured. The resulting frequency response function was then imported into a Finite Element Analysis software to generate a harmonic response analysis. The two different plinth schemes were modeled and the floor vibration was introduced as an excitation to the analysis. The relative pitch angle (THETA Y) between the mirrors was evaluated as well as the relative gap between the mirrors (XMAG). Results showed that a single plinth reduces the relative XMAG (RMS) compared to two plinths by approximately 25%. However, the relative THETA Y (RMS), which is arguably more critical, is significantly lower by approximately 99.7% in two plinths when compared to a single plinth. Therefore, it is more effective to use two separate plinths over a longer distance as opposed to a single longer granite plinth.
ANL, Lemont, Illinois, USA
Kirkpatrick and Baez (K-B) mirror-based nanofocusing optics* will be applied to many beamlines endstation instruments for the APS-Upgrade (APS-U) project. Precision nanopositioning stages with nanometer-scale linear positioning resolution and nanoradian-scale angular stability are needed as alignment apparatus for the K-B mirror hard X-ray nanofocusing optics. For instance, at the APS-U 19-ID In Situ Nanoprobe beamline endstation**, to maintain stability of a 20-nm focal spot on the sample, nanofocusing K-B mirror system with 5-nrad angular stability is required. Similar angular resolution and stability are also required for APS-U 9-ID CSSI***, APS-U 34-ID ATOMIC**** and other beamline endstation instruments. Modular nanopositioning flexure stages have been developed for the K-B mirror nanofocusing optics, which includes: linear vertical and horizontal flexure stages, tip-tilting flexure stages, and flexure mirror benders for bendable nanofocusing K-B mirrors, to overcome the performance limitations of precision ball-bearing-based or roller-bearing-based stage systems. The mechanical design and preliminary test results are described in this paper.
* Kirkpartrick and Baez, JOSA. 1948; 38(9): 766-773.
** S. Kearney et al., this conference.
*** J. Anton et al., this conference.
**** C. Preissner et al., this conference.
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.
ANL, Lemont, Illinois, USA
A new nano-computed tomography projection microscope (n-CT) is being designed as part the Advanced Photon Source Upgrade (APS-U) beamline enhancement at sector 32-ID. The n-CT will take advantage of the APS-U source and provide new capabilities to the imaging program at 32-ID. A Kirkpatrick and Baez (KB) mirror-based nanofocusing optics [1,2] will be implemented in this design. To meet the n-CT imaging goals, it is the desire to have sub 10 nanometer vibrational and thermal drift stability over 10-minute measurement durations between the optic and the sample. In addition to the stability requirements, it is desired to have a variable length sample projection axis of up to 450 mm. Such stability and motion requirements are challenging to accomplish simultaneously due to performance limitations of traditional motion mechanics and present a significant engineering challenge. To overcome these limitations, the proposed n-CT design incorporates granite air bearing concepts initially used in the Velociprobe [3]. These types of granite stages have been incorporated into many designs at APS [4] and at other synchrotron facilities [5]. Utilizing the granite air bearing concept, in tandem with other design aspects in the instrument, the requirements become reachable. A novel multi-degree of freedom wedge configuration is also incorporated to overcome space limitations. The design of this instrument is described in this paper.
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
Cosine Measurement Systems, Warmond, The Netherlands
ESA-ESTEC, Noordwijk, The Netherlands
PTB, Berlin, Germany
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
ASCo, Clayton, Victoria, Australia
MAX IV Laboratory, Lund University, Lund, Sweden
FMB Oxford, Oxford, United Kingdom
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
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.
ANL, Lemont, Illinois, USA
Wavefront preservation is essential for numerous X-ray science applications. Research is currently underway at the Advanced Photon Source to characterize and minimize Bragg-plane slope errors in diamond crystal optics*. Understanding the effect of cooling the optics to cryogenic temperatures on Bragg-plane slope errors is of interest to this research. Through the use of a finite element model a custom, compact vacuum chamber with liquid nitrogen cooling of samples was designed and manufactured. The design process and initial results are discussed in this paper.
*P. Pradhan et al., J. of Synchrotron Radiation 6, 1553 (2020)