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.
ANL, Lemont, Illinois, USA
SLAC, Menlo Park, California, USA
The concept behind the cavity-based X-ray FELs (CBXFELs) such as the X-ray free-electron laser oscillator (XFELO)* and the X-ray regenerative amplifier free-electron laser (XRAFEL)** is to form an X-ray cavity with a set of narrow bandwidth diamond Bragg crystals. Storing and recirculating the output of an amplifier in an X- ray cavity so that the X-ray pulse can interact with following fresh electron bunches over many passes enables the development of full temporal coherence. One of the key challenges to forming the X-ray cavity is the precision of the cavity mechanical system design and construction. In this paper, we present conceptual design of the cavity mechanical system that is currently under development for use in a proof-of-principle cavity-based X-ray free electron laser experiment at the LCLS-II at SLAC.
*Kwang-Je Kim et al., TUPRB096, Proceedings of IPAC2019
**Gabe Marcus et al., TUD04, Proceedings of IPAC2019
ANL, Lemont, Illinois, USA
As part of the Advanced Photon Source Upgrade (APS-U) project, the Coherent Surface Scattering Imaging (CSSI) [1] instrument is currently being developed. One of the most important components of the CSSI instrument at the 9-ID beamline of the APS-U, the Kirkpatrick-Baez (K-B) mirror system, will focus hard X-rays to a diffrac-tion-limited size of 500 nanometers at a working distance of 550 mm. High angular stability (19 nrad for the hori-zontal mirror and 14 nrad for the vertical mirror) is speci-fied no just for the focused beamsize but, more important-ly, to ensure the beam stability at the detector position that is up to 24 m from the K-B mirrors. A large sample-to-detector distance (up to 23 m), one of the beamline’s unique features for achieving a sufficient coherent-imaging spatial oversampling, requires sample angular stability of 50 nrad. In CSSI scattering geometry, the vertically placed sample reflects X-rays in the horizontal direction at an extremely shallow angle. The design in-cludes two high-precision rotary stages for sample pitch (vertical axis) and yaw (horizontal axis). The current design of instrument’s nano-positioning stages [2] and metrology required to satisfy the stability and positioning requirements are discussed in this paper.
*T. Sun et al., Nat. Photonics 6, 586 (2012).
**D. Shu et al., this conference.
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.
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.
ANL, Lemont, Illinois, USA
An enhancement design of an existing 26-ID nanoprobe [1] instrument (NPI) at APS is being completed as part of work for the APS-Upgrade (APS-U) project. As part of this enhancement design, a new vacuum chamber geometry configuration has been implemented that balances the desired simultaneous x-ray measurement methods with accessibility and serviceability of the nanoprobe. The main enabling feature on the vacuum chamber is a slanted mid-level vacuum sealing plane. The new chamber design geometrically optimizes the ability to perform simultaneous diffraction, fluorescence and optical or laser pump probe measurements on the sample. A large diffraction door geometry is strategically placed near the sample for ease of access. The newly designed chamber can be readily serviced by removal of the upper chamber section, on which most larger instrument assemblies or beamline attachments are not interfaced. The mechanical design intent and geometry of this chamber concept is described in this paper.
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)
ANL, Lemont, Illinois, USA
The Advanced Photon Source (APS) at Argonne National Laboratory (ANL) is being upgraded to a multi-bend achromat (MBA) lattice storage ring which will increase brightness and coherent flux by several orders of magnitude. As part of this upgrade a total of 15 beamlines were selected to be enhanced to take advantage of the new source ’ these are designated as ’Enhanced Beamlines’. Among these is the enhancement to 2-ID, which includes an upgrade and move of the existing Bionanoprobe (BNP) from 9-ID [1]. This instrument will become the second generation Bionanoprobe II (BNP-II) with intent of studying cryogenic samples with sub-10 nm resolution. This upgrade requires a high performing metrology configuration and design to achieve the desired spatial resolution while adapting to the various constraints of the instrument. The cryogenic sample environment and detection constraints offer significant challenges for implementing a metrology scheme. In this paper we report on the new traveling interferometer configuration proposed for BNP-II.