Characterization and Application of Hard X-Ray Betatron Radiation Generated by Relativistic Electrons from a Laser-Wakefield Accelerator

TL;DR

This paper reports on the characterization of betatron x-ray radiation generated by relativistic electrons from laser-wakefield accelerators, demonstrating a novel measurement setup and comparing results with 3D simulations.

Contribution

It introduces a new experimental setup for comprehensive single-shot characterization of betatron x-ray radiation and validates it with particle-in-cell simulations.

Findings

Successful measurement of energy and spatial distribution of betatron x-rays.

Determination of polarization state for each laser shot.

Good agreement between experimental results and simulations.

Abstract

The necessity for compact table-top x-ray sources with higher brightness, shorter wavelength and shorter pulse duration has led to the development of complementary sources based on laser-plasma accelerators, in contrast to conventional accelerators. Relativistic interaction of short-pulse lasers with underdense plasmas results in acceleration of electrons and in consequence in the emission of spatially coherent radiation, which is known in the literature as betatron radiation. In this article we report on our recent results in the rapidly developing field of secondary x-ray radiation generated by high-energy electron pulses. The betatron radiation is characterized with a novel setup allowing to measure the energy, the spatial energy distribution in the far-field of the beam and the source size in a single laser shot. Furthermore, the polarization state is measured for each laser shot. In this way the emitted betatron x-rays can be used as a non-invasive diagnostic tool to retrieve very subtle information of the electron dynamics within the plasma wave. Parallel to the experimental work, 3D particle-in-cell simulations were performed, proved to be in good agreement with the experimental results.