Tunable Electron Beam Pulser for Picoseconds Stroboscopic Microscopy in Transmission Electron Microscopes

Published

August 26, 2019

Author(s)

June W. Lau, Michael B. Katz

Abstract

For two decades, time-resolved transmission electron microscopes (TEM) have relied on pulsed-laser photoemission to generate electron bunches to explore sub-microsecond to sub- picosecond dynamics. Despite the vast successes of photoemission time-resolved TEMs, laser- based systems are inherently complex, thus tend not to be turn-key. In this paper, we report on the successful retro t of a commercial 200KeV TEM, without an external laser, capable of producing continuously tunable pulsed electron beams with repetition rates from 0.1GHz up to 12GHz and a tunable bunch length from the repetition frequency down to 10 pico-seconds. This innovation enables temporal access into previously inaccessible regimes: i.e., high rep- etition rate stroboscopic experiments. Combination of a pair of RF-driven traveling wave stripline elements, quadruple magnets, and a variable beam aperture enables operation of the instrument in (1) continuous waveform (CW) mode as though the instrument was never unmodi ed, (2) stroboscopic (pump-probe) mode, and (3) pulsed beam mode for dose rate sensitive materials. To assess the e ect of a pulsed beam on image quality, we examined Au nanoparticles using brightfi eld, high-resolution TEM imaging and selected area diffraction in both continuous and pulsed-beam mode.

Citation

Applied Physics Letters

Volume

207

Pub Type

Journals

Download Paper

https://doi.org/10.1016/j.ultramic.2019.112829

Local Download

Keywords

TEM, UEM, stroboscopic, pulser, ultrafast

Citation

Lau, J. and Katz, M. (2019), Tunable Electron Beam Pulser for Picoseconds Stroboscopic Microscopy in Transmission Electron Microscopes, Applied Physics Letters, [online], https://doi.org/10.1016/j.ultramic.2019.112829 (Accessed September 8, 2024)