1
|
Denham P, Yang Y, Guo V, Fisher A, Shen X, Xu T, England RJ, Li RK, Musumeci P. High energy electron diffraction instrument with tunable camera length. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2024; 11:024302. [PMID: 38532924 PMCID: PMC10965247 DOI: 10.1063/4.0000240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Accepted: 03/04/2024] [Indexed: 03/28/2024]
Abstract
Ultrafast electron diffraction (UED) stands as a powerful technique for real-time observation of structural dynamics at the atomic level. In recent years, the use of MeV electrons from radio frequency guns has been widely adopted to take advantage of the relativistic suppression of the space charge effects that otherwise limit the temporal resolution of the technique. Nevertheless, there is not a clear choice for the optimal energy for a UED instrument. Scaling to beam energies higher than a few MeV does pose significant technical challenges, mainly related to the inherent increase in diffraction camera length associated with the smaller Bragg angles. In this study, we report a solution by using a compact post-sample magnetic optical system to magnify the diffraction pattern from a crystal Au sample illuminated by an 8.2 MeV electron beam. Our method employs, as one of the lenses of the optical system, a triplet of compact, high field gradients (>500 T/m), small-gap (3.5 mm) Halbach permanent magnet quadrupoles. Shifting the relative position of the quadrupoles, we demonstrate tuning the magnification by more than a factor of two, a 6× improvement in camera length, and reciprocal space resolution better than 0.1 Å-1 in agreement with beam transport simulations.
Collapse
Affiliation(s)
- P. Denham
- Department of Physics and Astronomy, UCLA, Los Angeles, California 90095, USA
| | - Y. Yang
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - V. Guo
- Department of Physics and Astronomy, UCLA, Los Angeles, California 90095, USA
| | - A. Fisher
- Department of Physics and Astronomy, UCLA, Los Angeles, California 90095, USA
| | - X. Shen
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - T. Xu
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - R. J. England
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - R. K. Li
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - P. Musumeci
- Department of Physics and Astronomy, UCLA, Los Angeles, California 90095, USA
| |
Collapse
|
2
|
VandenBussche EJ, Flannigan DJ. Sources of error in Debye-Waller-effect measurements relevant to studies of photoinduced structural dynamics. Ultramicroscopy 2018; 196:111-120. [PMID: 30352384 DOI: 10.1016/j.ultramic.2018.10.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Revised: 09/23/2018] [Accepted: 10/04/2018] [Indexed: 10/28/2022]
Abstract
We identify and quantify several practical effects likely to be present in both static and ultrafast electron-scattering experiments that may interfere with the Debye-Waller (DW) effect. Using 120-nm thick, small-grained, polycrystalline aluminum foils as a test system, we illustrate the impact of specimen tilting, in-plane translation, and changes in z height on Debye-Scherrer-ring intensities. We find that tilting by less than one degree can result in statistically-significant changes in diffracted-beam intensities for large specimen regions containing > 105 nanocrystalline grains. We demonstrate that, in addition to effective changes in the field of view with tilting, slight texturing of the film can result in deviations from expected DW-effect behavior. Further, we find that in-plane translations of as little as 20 nm also produce statistically-significant intensity changes, while normalization to total image counts eliminates such effects arising from changes in z height. The results indicate that the use of polycrystalline films in ultrafast electron-scattering experiments can greatly reduce the negative impacts of these effects as compared to single-crystal specimens, though it does not entirely eliminate them. Thus, it is important to account for such effects when studying thin-foil specimens having relatively short reciprocal-lattice rods.
Collapse
Affiliation(s)
- Elisah J VandenBussche
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Ave. SE, Minneapolis, MN 55455, United States
| | - David J Flannigan
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Ave. SE, Minneapolis, MN 55455, United States.
| |
Collapse
|
3
|
Li S, Cropp F, Kabra K, Lane TJ, Wetzstein G, Musumeci P, Ratner D. Electron Ghost Imaging. PHYSICAL REVIEW LETTERS 2018; 121:114801. [PMID: 30265113 DOI: 10.1103/physrevlett.121.114801] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Indexed: 06/08/2023]
Abstract
In this Letter we report a demonstration of electron ghost imaging. A digital micromirror device directly modulates the photocathode drive laser to control the transverse distribution of a relativistic electron beam incident on a sample. Correlating the structured illumination pattern to the total sample transmission then retrieves the target image, avoiding the need for a pixelated detector. In our example, we use a compressed sensing framework to improve the reconstruction quality and reduce the number of shots compared to raster scanning a small beam across the target. Compressed electron ghost imaging can reduce both acquisition time and sample damage in experiments for which spatially resolved detectors are unavailable (e.g., spectroscopy) or in which the experimental architecture precludes full frame direct imaging.
Collapse
Affiliation(s)
- S Li
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - F Cropp
- Department of Physics and Astronomy, UCLA, Los Angeles, California 90095, USA
| | - K Kabra
- Department of Physics and Astronomy, UCLA, Los Angeles, California 90095, USA
| | - T J Lane
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - G Wetzstein
- Department of Electrical Engineering, Stanford University, Stanford, California 94305, USA
| | - P Musumeci
- Department of Physics and Astronomy, UCLA, Los Angeles, California 90095, USA
| | - D Ratner
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| |
Collapse
|
4
|
Wan W, Chen FR, Zhu Y. Design of compact ultrafast microscopes for single- and multi-shot imaging with MeV electrons. Ultramicroscopy 2018; 194:143-153. [PMID: 30142490 DOI: 10.1016/j.ultramic.2018.08.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 07/31/2018] [Accepted: 08/07/2018] [Indexed: 11/19/2022]
Abstract
Ultrafast high-energy electron microscopy, taking advantage of strong interaction of electrons with matter while minimizing space charge problems, can be used to address a wide range of grand challenges in basics energy sciences. However, MeV-electron lenses are inherently bulky and expensive, preventing them from acceptance in a broad scientific community. In this article, we report our novel design of a compact, low-cost imaging-lens system for MeV-electrons based on quadrupole multiplets, including triplet, quadruplet and quintuplet, both symmetric and asymmetric. We compare optical performance of quadrupole-based condenser, objective and projector lenses with that of the traditional round-lenses and discuss the strategy for their practical use in constructing MeV-electron microscopes for high spatial and temporal resolution single- and multi-shot imaging. Combining the compound electron-optical system with a photocathode radiofrequency (RF) gun, such a MeV electron microscope can be fit into a small-sized laboratory for ultrafast observations and measurements.
Collapse
Affiliation(s)
- Weishi Wan
- ShanghaiTech University, Shanghai, China
| | - Fu-Rong Chen
- City University of Hong Kong, Kowloon, Hong Kong
| | - Yimei Zhu
- Brookhaven National Laboratory, Upton, NY 11973, USA.
| |
Collapse
|
5
|
Zhang D, Fallahi A, Hemmer M, Wu X, Fakhari M, Hua Y, Cankaya H, Calendron AL, Zapata LE, Matlis NH, Kärtner FX. Segmented Terahertz Electron Accelerator and Manipulator (STEAM). NATURE PHOTONICS 2018; 12:336-342. [PMID: 29881446 PMCID: PMC5985934 DOI: 10.1038/s41566-018-0138-z] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 02/27/2018] [Indexed: 05/23/2023]
Abstract
Acceleration and manipulation of electron bunches underlie most electron and X-ray devices used for ultrafast imaging and spectroscopy. New terahertz-driven concepts offer orders-of-magnitude improvements in field strengths, field gradients, laser synchronization and compactness relative to conventional radio-frequency devices, enabling shorter electron bunches and higher resolution with less infrastructure while maintaining high charge capacities (pC), repetition rates (kHz) and stability. We present a segmented terahertz electron accelerator and manipulator (STEAM) capable of performing multiple high-field operations on the 6D-phase-space of ultrashort electron bunches. With this single device, powered by few-micro-Joule, single-cycle, 0.3 THz pulses, we demonstrate record THz-acceleration of >30 keV, streaking with <10 fs resolution, focusing with >2 kT/m strength, compression to ~100 fs as well as real-time switching between these modes of operation. The STEAM device demonstrates the feasibility of THz-based electron accelerators, manipulators and diagnostic tools enabling science beyond current resolution frontiers with transformative impact.
Collapse
Affiliation(s)
- Dongfang Zhang
- Center for Free-Electron Laser Science, Deutsches Elektronen
Synchrotron, Notkestrasse 85, 22607 Hamburg, Germany
- Department of Physics and The Hamburg Centre for Ultrafast Imaging,
University of Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Arya Fallahi
- Center for Free-Electron Laser Science, Deutsches Elektronen
Synchrotron, Notkestrasse 85, 22607 Hamburg, Germany
| | - Michael Hemmer
- Center for Free-Electron Laser Science, Deutsches Elektronen
Synchrotron, Notkestrasse 85, 22607 Hamburg, Germany
| | - Xiaojun Wu
- Center for Free-Electron Laser Science, Deutsches Elektronen
Synchrotron, Notkestrasse 85, 22607 Hamburg, Germany
| | - Moein Fakhari
- Center for Free-Electron Laser Science, Deutsches Elektronen
Synchrotron, Notkestrasse 85, 22607 Hamburg, Germany
- Department of Physics and The Hamburg Centre for Ultrafast Imaging,
University of Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Yi Hua
- Center for Free-Electron Laser Science, Deutsches Elektronen
Synchrotron, Notkestrasse 85, 22607 Hamburg, Germany
| | - Huseyin Cankaya
- Center for Free-Electron Laser Science, Deutsches Elektronen
Synchrotron, Notkestrasse 85, 22607 Hamburg, Germany
| | - Anne-Laure Calendron
- Center for Free-Electron Laser Science, Deutsches Elektronen
Synchrotron, Notkestrasse 85, 22607 Hamburg, Germany
- Department of Physics and The Hamburg Centre for Ultrafast Imaging,
University of Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Luis E. Zapata
- Center for Free-Electron Laser Science, Deutsches Elektronen
Synchrotron, Notkestrasse 85, 22607 Hamburg, Germany
| | - Nicholas H. Matlis
- Center for Free-Electron Laser Science, Deutsches Elektronen
Synchrotron, Notkestrasse 85, 22607 Hamburg, Germany
| | - Franz X. Kärtner
- Center for Free-Electron Laser Science, Deutsches Elektronen
Synchrotron, Notkestrasse 85, 22607 Hamburg, Germany
- Department of Physics and The Hamburg Centre for Ultrafast Imaging,
University of Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
- Research Laboratory of Electronics, MIT, Cambridge, 02139
Massachusetts, USA
| |
Collapse
|
6
|
Musumeci P, Cesar D, Maxson J. Double-shot MeV electron diffraction and microscopy. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2017; 4:044025. [PMID: 28612040 PMCID: PMC5438282 DOI: 10.1063/1.4983390] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 05/01/2017] [Indexed: 06/07/2023]
Abstract
In this paper, we study by numerical simulations a time-resolved MeV electron scattering mode where two consecutive electron pulses are used to capture the evolution of a material sample on 10 ps time scales. The two electron pulses are generated by illuminating a photocathode in a radiofrequency photogun by two short laser pulses with adjustable delay. A streak camera/deflecting cavity is used after the sample to project the two electron bunches on two well separated regions of the detector screen. By using sufficiently short pulses, the 2D spatial information from each snapshot can be preserved. This "double-shot" technique enables the efficient capture of irreversible dynamics in both diffraction and imaging modes. In this work, we demonstrate both modes in start-to-end simulations of the UCLA Pegasus MeV microscope column.
Collapse
Affiliation(s)
- P Musumeci
- Department of Physics and Astronomy, UCLA, Los Angeles, California 90095, USA
| | - D Cesar
- Department of Physics and Astronomy, UCLA, Los Angeles, California 90095, USA
| | - J Maxson
- Department of Physics and Astronomy, UCLA, Los Angeles, California 90095, USA
| |
Collapse
|
7
|
Maxson J, Cesar D, Calmasini G, Ody A, Musumeci P, Alesini D. Direct Measurement of Sub-10 fs Relativistic Electron Beams with Ultralow Emittance. PHYSICAL REVIEW LETTERS 2017; 118:154802. [PMID: 28452517 DOI: 10.1103/physrevlett.118.154802] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Indexed: 05/07/2023]
Abstract
Ultralow emittance (≤20 nm, normalized) electron beams with 10^{5} electrons per bunch are obtained by tightly focusing an ultrafast (∼100 fs) laser pulse on the cathode of a 1.6 cell radio frequency photoinjector. Taking advantage of the small initial longitudinal emittance, a downstream velocity bunching cavity is used to compress the beam to <10 fs rms bunch length. The measurement is performed using a thick high-voltage deflecting cavity which is shown to be well suited to measure ultrashort durations of bunching beams, provided that the beam reaches a ballistic longitudinal focus at the cavity center.
Collapse
Affiliation(s)
- Jared Maxson
- Department of Physics and Astronomy, UCLA, Los Angeles, California 90095, USA
| | - David Cesar
- Department of Physics and Astronomy, UCLA, Los Angeles, California 90095, USA
| | - Giacomo Calmasini
- Department of Physics and Astronomy, UCLA, Los Angeles, California 90095, USA
| | - Alexander Ody
- Department of Physics and Astronomy, UCLA, Los Angeles, California 90095, USA
| | - Pietro Musumeci
- Department of Physics and Astronomy, UCLA, Los Angeles, California 90095, USA
| | - David Alesini
- INFN-Laboratori Nazionali di Frascati, Via Enrico Fermi 40, 00044 Frascati, Rome, Italy
| |
Collapse
|