High-brilliance betatron gamma-ray source powered by laser-accelerated electrons

TL;DR

This paper introduces a hybrid plasma-based scheme that significantly enhances the photon energy and efficiency of betatron gamma-ray sources, enabling applications in dense matter probing and medical isotope production.

Contribution

A novel hybrid scheme combining low-density laser-driven and high-density beam-driven plasma accelerators to produce higher energy, more efficient betatron gamma-ray sources.

Findings

Photon energy exceeds MeV range with 15 J laser pulse.

Energy transfer efficiency to radiation is about 1%.

Potential applications include dense matter imaging and isotope production.

Abstract

Recent progress in laser-driven plasma acceleration now enables the acceleration of electrons to several gigaelectronvolts. Taking advantage of these novel accelerators, ultra-short, compact and spatially coherent X-ray sources called betatron radiation have been developed and applied to high-resolution imaging. However, the scope of the betatron sources is limited by a low energy efficiency and a photon energy in the 10's of kiloelectronvolt range, which for example prohibits the use of these sources for probing dense matter. Here, based on three-dimensional particle-in-cell simulations, we propose an original hybrid scheme that combines a low-density laser-driven plasma accelerator with a high-density beam-driven plasma radiator, and thereby considerably increases the photon energy and the radiated energy of the betatron source. The energy efficiency is also greatly improved, with about 1% of the laser energy transferred to the radiation, and the gamma-ray photon energy exceeds the megaelectronvolt range when using a 15 J laser pulse. This high-brilliance hybrid betatron source opens the way to a wide range of applications requiring MeV photons, such as the production of medical isotopes with photo-nuclear reactions, radiography of dense objects in the defense or industrial domains and imaging in nuclear physics.