Imaging single electrons to enable the generation of ultrashort beams for single-shot femtosecond relativistic electron diffraction
- Department of Physics and Astronomy, UCLA, Los Angeles, California 90095 (United States)
- National Security Technologies, LLC, Los Alamos Operations, Los Alamos, New Mexico 87544 (United States)
The generation and control of relativistic electron beams well suited for ultrafast electron diffraction application has rapidly advanced, greatly benefiting from the overlap in techniques and expertise with the accelerator community. However, imaging the diffracted MeV electrons with high detection efficiency has remained an under-explored area. In this paper, we report on a quantitative study of the imaging of MeV electrons using a detection system consisting of a phosphor screen, a lens-coupling optics, and a charge-coupled device camera. It is shown that every MeV electron in the beam yields a signal well above the camera noise. With this detection efficiency, only {approx}10{sup 5} electrons per pulse are needed to obtain a high quality single-shot diffraction pattern from a crystalline sample. We measured that such a low charge beam can be as short as 30 fs rms. Further, we discuss the possibility of compressing these electron beams to sub-5 fs rms bunch length by velocity bunching using a short high gradient rf accelerating structure scheduled to be installed next year at the UCLA Pegasus Laboratory. This opens the possibility of single-shot determinations of structural changes in many ultrafast physical processes like nonequilibrium phonon dynamics or relaxation pathways in systems with strong electron-phonon coupling.
- OSTI ID:
- 22036741
- Journal Information:
- Journal of Applied Physics, Vol. 110, Issue 7; Other Information: (c) 2011 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
BEAM BUNCHING
BEAM MONITORING
BEAM OPTICS
BEAM PRODUCTION
CHARGE-COUPLED DEVICES
EFFICIENCY
ELECTRON BEAMS
ELECTRON DETECTION
ELECTRON DIFFRACTION
ELECTRON-PHONON COUPLING
ELECTRONS
MEV RANGE
PHONONS
PHOSPHORS
RELATIVISTIC RANGE
RELAXATION
SOLID SCINTILLATION DETECTORS