|TUPLM18||Improving Energy Resolution and Compensating Chromatic Aberration With a TM010 Microwave Cavity||411|
Funding: National Science Foundation under Award OIA-1549132, the Center for Bright Beams
The intrinsic energy spread of electron sources limits the achievable resolution of electron microscopes in both spectroscopic and spatially resolved measurements. We propose that the TM010 mode of a single radio frequency (RF) cavity be used to dramatically reduce this energy spread in a pulsed beam. We show with analytic approximations, confirmed in simulations, that the non-linear time-energy correlations that develop in an electron gun can be undone by the RF cavity running near-crest. We derive an expression that gives the required RF field strength as a function of accelerating voltage. We explore multiple applications, including EELS and SEM. By pulsing a photocathode with commercially available, high repetition-rate lasers, our scheme could yield competitive energy spread reduction at higher currents when compared with monochromated continuous-wave sources for electron microscopes.
|DOI •||reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM18|
|About •||paper received ※ 27 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019|
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