Author: Zhu, Y.
Paper Title Page
MOPAB139 High Resolution Imaging Design Using Permanent Magnet Quadrupoles at BNL UEM 485
 
  • G. Andonian, T.J. Campese, I.I. Gadjev, M. Ruelas
    RadiaBeam, Santa Monica, California, USA
  • M.G. Fedurin, K. Kusche, X. Yang, Y. Zhu
    BNL, Upton, New York, USA
  • C.C. Hall
    RadiaSoft LLC, Boulder, Colorado, USA
 
  Ultrafast electron microscopy techniques have demonstrated the potential to reach very high combined spatio-temporal resolution. In order to achieve high resolution, strong focusing magnets must be used as the objective and projector lenses. In this paper, we discuss the design and development of a high-resolution objective lens for use in the BNL UEM. The objective lens is a quintuplet array of permanent magnet quadrupoles, which in sum, provide symmetric focusing, high magnification, and control of higher order aberration terms. The application and design for a proof-of-concept experiment using a calibrated slit for imaging are presented. The image resolution is monitored as a function of beam parameters (energy, energy spread, charge, bunch length, spot size), and quintuplet lens parameters (drifts between lenses).  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB139  
About • paper received ※ 26 May 2021       paper accepted ※ 28 May 2021       issue date ※ 18 August 2021  
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TUXC06 Visualizing Lattice Dynamic Behavior by Acquiring a Single Time-Resolved MeV 1311
 
  • X. Yang, T.V. Shaftan, V.V. Smaluk, J. Tao, L. Wu, Y. Zhu
    BNL, Upton, New York, USA
  • W. Wan
    ShanghaiTech University, Shanghai, People’s Republic of China
 
  We explore the possibility of visualizing the lattice dynamic behavior by acquiring a single time-resolved MeV UED image. Conventionally, multiple UED shots with varying time delays are needed to map out the entire dynamic process. The measurement precision is limited by the timing jitter between the pulses of laser pump and UED probe. We show that, by converting the longitudinal time of an electron bunch to the transverse position of a Bragg peak on the detector, one can obtain the full lattice dynamic process in a single electron pulse. We propose a novel design of a time-resolved UED with the capability of capturing a wide range of dynamic features in a single diffraction image. The work presented here is not only an extension of the ultrashort-pulse pump/long-pulse probe scheme being used in transient spectroscopy studies for decades but also advances the capabilities of MeV UED for future applications with tunable electron probe profile and detecting time range with femtosecond resolution. Furthermore, we present numerical simulations illustrating the capability of acquiring a single time-resolved diffraction image based on the case-by-case studies of lattice dynamic behavior.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUXC06  
About • paper received ※ 14 May 2021       paper accepted ※ 28 July 2021       issue date ※ 31 August 2021  
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