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Title: Terahertz radiation as a bunch diagnostic for laser-wakefield-accelerated electron bunches

Journal Article · · Physics of Plasmas
DOI:https://doi.org/10.1063/1.2187957· OSTI ID:20783177
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  1. Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720 (United States)

Experimental results are reported from two measurement techniques (semiconductor switching and electro-optic sampling) that allow temporal characterization of electron bunches produced by a laser-driven plasma-based accelerator. As femtosecond electron bunches exit the plasma-vacuum interface, coherent transition radiation (at THz frequencies) is emitted. Measuring the properties of this radiation allows characterization of the electron bunches. Theoretical work on the emission mechanism is presented, including a model that calculates the THz wave form from a given bunch profile. It is found that the spectrum of the THz pulse is coherent up to the 200 {mu}m thick crystal (ZnTe) detection limit of 4 THz, which corresponds to the production of sub-50 fs (rms) electron bunch structure. The measurements demonstrate both the shot-to-shot stability of bunch parameters that are critical to THz emission (such as total charge and bunch length), as well as femtosecond synchronization among bunch, THz pulse, and laser beam.

OSTI ID:
20783177
Journal Information:
Physics of Plasmas, Vol. 13, Issue 5; Other Information: DOI: 10.1063/1.2187957; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
Country of Publication:
United States
Language:
English