Resonantly excited betatron hard X-Rays from Ionization Injected Electron Beam in a Laser Plasma Accelerator

TL;DR

This paper introduces a novel method using ionization injection in nitrogen gas to generate bright, high-energy betatron X-ray beams from laser plasma accelerators, significantly enhancing photon yield compared to helium-based methods.

Contribution

The study demonstrates a new scheme for producing bright hard X-rays via ionization injection in nitrogen, achieving higher yields and stability in laser plasma accelerators.

Findings

Photon yield of 8×10^8 per shot, with 10^8 above 110 keV.

X-ray spectrum exhibits synchrotron-like characteristics.

Yield is ten times higher than helium-based schemes under similar conditions.

Abstract

A new scheme for bright hard x-ray emission from laser wakefield electron accelerator is reported, where pure nitrogen gas is adopted. Intense Betatron x-ray beams are generated from ionization injected K-shell electrons of nitrogen into the accelerating wave bucket. The x-ray radiation shows synchrotron-like spectrum with total photon yield 8$\times$10$^8$/shot and $10^8$ over 110keV. In particular, the betatron hard x-ray photon yield is 10 times higher compared to the case of helium gas under the same laser parameters. Particle-in-cell simulation suggests that the enhancement of the x-ray yield results from ionization injection, which enables the electrons to be quickly accelerated to the driving laser region for subsequent betatron resonance. Employing the present scheme,the single stage nitrogen gas target could be used to generate stable high brightness betatron hard x-ray beams.