Demonstration of The Brightest Nano-size Gamma Source

TL;DR

This paper reports the experimental demonstration of a highly bright, nano-sized gamma-ray source generated via laser interactions at extreme irradiance levels, surpassing previous sources in brightness and potential applications.

Contribution

It introduces a new interaction regime producing a record-bright Gamma Flash with nanometre source size, enabling advancements in various scientific and security fields.

Findings

Achieved a Gamma Flash with brightness >10^{23} photons/mm^2 mrad^2 s.

Produced a nanometre-scale gamma source with attosecond duration.

Surpassed brightness of astrophysical Gamma Ray Bursts.

Abstract

Gamma rays selectively interact with nuclei, induce and mediate nuclear reactions and elementary particle interactions, and exceed x-rays in penetrating power and thus are indispensable for analysis and modification of dense objects. Yet, the available gamma sources lack sufficient power and brightness. The predicted and highly desirable laser-driven gamma flash, from here on termed "Gamma Flash", based on inverse Compton scattering from solid targets at extreme irradiances (>$10^{23}W/cm^2$), would be the highest-power and the brightest terrestrial gamma source with a 30-40% laser-to-gamma energy conversion. However, Gamma Flash remains inaccessible experimentally due to the Bremsstrahlung background. Here we experimentally demonstrate a new interaction regime at the highest effective irradiance where Gamma Flash scaled quickly with the laser power and produced several times the number of Bremsstrahlung photons. Simulations revealed an attosecond, Terawatt Gamma Flash with a nanometre source size achieving a record brightness exceeding $~10^{23}photons/mm^2mrad^2s$ per 0.1% bandwidth at tens of MeV photon energies, surpassing astrophysical Gamma Ray Bursts. These findings could revolutionize inertial fusion energy by enabling unprecedented sub-micrometre/femtosecond resolution radiography of fuel mixing instabilities in extremely-compressed targets. The new gamma source could facilitate significant advances in time-resolved nuclear physics, homeland security, nuclear waste management and non-proliferation, while opening possibilities for spatially-coherent gamma rays.