Author: Yang, X.
Paper Title Page
Current Status of Developing an Ultrafast Electron Microscope  
  • X. Yang, T.V. Shaftan, V.V. Smaluk, Y. Zhu
    BNL, Upton, New York, USA
  • P. Musumeci
    UCLA, Los Angeles, California, USA
  • W. Wan
    ShanghaiTech University, Shanghai, People’s Republic of China
  Recent studies of ultrafast electron microscopy (UEM) techniques show the use of short bunches of relativistic electrons are promising for the development of a new instrument for imaging samples of various materials. Compared to conventional electron microscopes, the main advantage of UEMs with the electron energy of a few MeV is the possibility to study thick samples. We will discuss the progress of UEM design to date, the principal challenges on the way to a high resolution, and possible methods for their mitigation including the design of low-aberration magnetic optics, RF and mechanical subsystems with high stability, and precise collimation of electrons scattered in the samples.  
slides icon Slides WEZE1 [11.286 MB]  
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WEPA71 Unified Orbit Feedback at NSLS-II 795
  • Y. Hidaka, Y. Li, R.M. Smith, Y. Tian, G.M. Wang, X. Yang
    BNL, Upton, New York, USA
  Funding: This work is supported by U.S. DOE under Contract No. DE-SC0012704.
We have developed an orbit correction / feedback program to unify the existing orbit-related feedback systems for stable beam operation at NSLS-II. Until recently only a handful of beamlines have been benefiting from long-term orbit stability provided by a local bump agent program. To expand this to all the beamlines as well as correct more frequently, a new slow orbit feedback program called unified orbit feedback (UOFB) was written from scratch that works with the fast orbit feedback transparently, while accumulated fast corrector strength is continuously shifted to the slow correctors and RF frequency is adjusted for circumference change. UOFB can lock 3 different types of local bumps to the target offsets/angles for days: those for insertion device (ID) sources with only ID RF beam position monitors (BPM) or mixtures of ID RF BPMs and X-ray BPMs, and those for bending magnet sources with arc BPMs between which orbit correctors, dipoles and quadrupoles exist. Furthermore, this feed-back can accommodate beamline user requests to enable / disable the feedback loop for their beamline and to change bump target setpoints without turning off the loop.
poster icon Poster WEPA71 [2.541 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEPA71  
About • Received ※ 02 August 2022 — Revised ※ 09 August 2022 — Accepted ※ 12 August 2022 — Issue date ※ 31 August 2022
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WEPA81 Time-Resolved Experiments at NSLS II: Motivation and Machine Capabilities 826
  • G.M. Wang, B. Bacha, G. Bassi, G.L. Carr, Y. Hidaka, Y. Hu, Y. Li, C. Mazzoli, D. Padrazo Jr, R.S. Rainer, J. Rose, J.T. Sadowski, V.V. Smaluk, Y. Tian, L. Wiegart, G. Williams, X. Yang
    BNL, Upton, New York, USA
  NSLS-II is a 3-GeV third-generation synchrotron light source at Brookhaven National Lab. The storage ring has been in routine operations for over six years and hosts 28 operating beamlines. The storage ring performance has continuously improved, including 500-mA with limited insertion devices closed, and routine 400-mA top off operation with 90% uniform filling pattern. Recently, we are exploring different operation modes, uniform multi single-bunch mode, and camshaft mode with a high single-bunch charge, to support timing-resolved user experiments. In this paper, we explore the potential for scientific experiments using the pulsed nature of the NSLS, summarize the user requirements on the beam parameters and the progress of accelerator studies.  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEPA81  
About • Received ※ 04 August 2022 — Revised ※ 12 August 2022 — Accepted ※ 13 August 2022 — Issue date ※ 22 August 2022
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