TUOA —  Tuesday Contributed Oral Session A   (27-Jul-21   11:15—12:15)
Chair: K.J. Suthar, ANL, Lemont, Illinois, USA
Paper Title Page
TUOA01 Surface Twist Characterization and Compensation of an Elliptically Bent Hard X-Ray Mirror 99
  • Z. Qiao, J.W.J. Anton, L. Assoufid, S.P. Kearney, S.T. Mashrafi, J. Qian, X. Shi, D. Shu
    ANL, Lemont, Illinois, USA
  Funding: Work supported by the U.S. Department of Energy, Office of Science under Control DE-AC02-06CH11357
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.
slides icon Slides TUOA01 [2.257 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-MEDSI2020-TUOA01  
About • paper received ※ 29 July 2021       paper accepted ※ 14 October 2021       issue date ※ 28 October 2021  
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TUOA02 Conceptual Design of the Cavity Mechanical System for Cavity-Based X-Ray Free Electron Laser 103
  • D. Shu, J.W.J. Anton, L. Assoufid, W.G. Jansma, S.P. Kearney, K.-J. Kim, R.R. Lindberg, S.T. Mashrafi, X. Shi, Yu. Shvyd’ko, W.F. Toter, M. White
    ANL, Lemont, Illinois, USA
  • H. Bassan, F.-J. Decker, G.L. Gassner, Z. Huang, G. Marcus, H.-D. Nuhn, T.-F. Tan, D. Zhu
    SLAC, Menlo Park, California, USA
  Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract DE-AC02-06CH1 1357 (ANL) and DE-AC02-76SF00515 (SLAC).
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
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-MEDSI2020-TUOA02  
About • paper received ※ 02 August 2021       paper accepted ※ 05 October 2021       issue date ※ 30 October 2021  
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TUOA03 Zero-Length Conflat Fin-Type Nonevaporable Getter Pump Coated with Oxygen-Free Palladium/Titanium 107
  • Y. Sato
    Yokohama National University, Graduate School of Engineering Science, Yokohama, Japan
  • A.H. Hashimoto, M. Yamanaka
    NIMS, Tsukuba, Ibaraki, Japan
  • T. Kikuchi, K. Masepresenter
    KEK, Tsukuba, Japan
  • T. Miyazawa
    Sokendai, The Graduate University for Advanced Studies, Tsukuba, Japan
  • S. Ohno
    Yokohama National University, Yokohama, Japan
  Funding: This work was partly supported by a JSPS KAKENHI (JP19K05280), a TIA-Kakehashi (TK19-035), and the 2019 Takahashi Industrial Economic Research Foundation grant, and was supported by NIMS TEM Station.
We have developed a zero-length conflat fin-type nonevaporable getter (NEG) pump that uses oxygen-free palladium/titanium (Pd/Ti)*. After baking at 150 degrees centigrade for 12 h, the pumping speeds of the NEG pump for H2 and CO were 2350~800 L/s and 1560~20 L/s, respectively, in the pumped-quantity range 0.01~30 Pa L. The morphologies of oxygen-free Pd/Ti films on the partition plates and the base plate were examined by scanning electron microscopy, scanning transmission electron microscopy, and energy-dispersive X-ray spectroscopy. The Ti was completely coated with Pd on the bottom, whereas the partition plates were covered by Pd/Ti nanostructures. Our new NEG pump is ideal for maintaining ultrahigh vacuums in the range 10-8 to 10-9 Pa, because (a) its pumping speeds for H2 and CO are quite large, (b) it can evacuate H2O and CO2 when an ionization gauge is used in the vacuum system, (3) it can be activated by baking at 150 degrees centigrade for 12 h, (c) its pumping speed does not decrease even after 9 cycles of pumping, baking, cooling to room temperature, and exposure to air**, (5) it requires neither a dedicated power supply nor electric feedthroughs, and (6) it is space saving and lightweight.
*T. Miyazawa et al., J. Vac. Sci. Technol. A 36, 051601 (2018).
**T. Kikuchi et al., AIP Conf. Proc. 2054, 060046 (2019).
slides icon Slides TUOA03 [1.643 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-MEDSI2020-TUOA03  
About • paper received ※ 30 July 2021       paper accepted ※ 14 October 2021       issue date ※ 08 November 2021  
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