Nano-modulated electron beams via electron diffraction and emittance exchange for coherent x-ray generation

TL;DR

This paper introduces a novel method to generate relativistic electron beams with nanometer-scale current modulation by combining electron diffraction in silicon, emittance exchange, and tunable electron optics, enabling coherent hard x-ray production in a compact setup.

Contribution

It presents a new approach for creating highly modulated electron beams using diffraction and emittance exchange, with tunable periods down to a few angstroms, for coherent x-ray generation.

Findings

Simulations demonstrate effective modulation transfer from crystal diffraction to electron beams.

The method enables producing coherent hard x-rays with a compact accelerator (~10 meters).

Tunable modulation periods as short as a few angstroms are achievable.

Abstract

We present a new method for generation of relativistic electron beams with current modulation on the nanometer scale and below. The current modulation is produced by diffracting relativistic electrons in single crystal Si, accelerating the diffracted beam and imaging the crystal structure, then transferring the image into the temporal dimension via emittance exchange. The modulation period can be tuned by adjusting electron optics after diffraction. This tunable longitudinal modulation can have a period as short as a few angstroms, enabling production of coherent hard x-rays from a source based on inverse Compton scattering with total accelerator length of approximately ten meters. Electron beam simulations from cathode emission through diffraction, acceleration and image formation with variable magnification are presented along with estimates of the coherent x-ray output properties.