Kinetics of relativistic electrons passing through quasi--periodic fields

TL;DR

This paper introduces a new method to evaluate the energy spectrum of relativistic electrons emitting high-energy photons in undulators and Compton sources, accounting for quantum recoil effects across different emission regimes.

Contribution

The paper presents a novel approach that considers quantum recoil in electron energy spectrum evaluation, applicable to a wide range of emission rates in high-energy photon sources.

Findings

Spectrum of electrons mirrors emitted radiation in low emission rate regime.

Electron spectrum approaches Gaussian shape in high emission rate regime.

Recoil effects limit the coherence of high-energy electromagnetic radiation sources.

Abstract

We report a novel method for evaluating the energy spectrum of electrons emitting hard x-rays and gamma-rays in undulators and Compton sources. The method takes into account the quantum nature of recoils undergone by the electrons emitting high energy photons. The method is susceptible to evaluate a spectrum of electrons for the whole range of the emission rates per electron-pass through of the driving force, from much less than one emitted photon on average (Compton sources and short undulators) to many emitted photons (long undulators, relatively low-energy electrons). As shown in the former limiting case, the spectrum of electrons reflects the spectrum of emitted radiation whereas it is close to the Gaussian shape in the latter case. Limitation of coherency for the sources of high-energy electromagnetic radiation caused by recoils from emitted photons is also discussed.