A kiloelectron-volt ultrafast electron micro-diffraction apparatus using low emittance semiconductor photocathodes

We report the design and performance of a time-resolved electron diffraction apparatus capable of producing intense bunches with simultaneously single digit micron probe size, long coherence length, and \(200\) fs rms time resolution. We measure the 5d (peak) beam brightness at the sample location i...

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Bibliographic Details
Published in:arXiv.org 2022-02
Main Authors: Li, W H, Duncan, C J R, Andorf, M B, Bartnik, A C, Bianco, E, Cultrera, L, Galdi, A, Gordon, M, Kaemingk, M, Pennington, C A, Kourkoutis, L F, Bazarov, I V, Maxson, J M
Format: Article
Language:English
Subjects:
Coherence length
Electron diffraction
Electrons
Emittance
Photocathodes
Photoelectric emission
Single crystals
Online Access:Get full text
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Summary:We report the design and performance of a time-resolved electron diffraction apparatus capable of producing intense bunches with simultaneously single digit micron probe size, long coherence length, and \(200\) fs rms time resolution. We measure the 5d (peak) beam brightness at the sample location in micro-diffraction mode to be \(7 \times 10^{13} \ \mathrm{A}/\text{m}^2\text{-rad}^2\). To generate high brightness electron bunches, the system employs high efficiency, low emittance semiconductor photocathodes driven with a wavelength near the photoemission threshold at a repetition rate up to 250 kHz. We characterize spatial, temporal, and reciprocal space resolution of the apparatus. We perform proof-of-principle measurements of ultrafast heating in single crystal Au samples and compare experimental results with simulations that account for the effects of multiple-scattering.
ISSN:2331-8422
DOI:10.48550/arxiv.2111.07922