A table-top laser-based source of femtosecond, collimated, ultra-relativistic positron beams

TL;DR

This paper reports a compact laser-based setup that produces ultra-relativistic positron beams with femtosecond duration, low divergence, and high density, resembling astrophysical jets and enabling laboratory astrophysics studies.

Contribution

It demonstrates a fully optical method to generate high-quality positron beams with properties suitable for astrophysical and particle physics research.

Findings

Positron beams with $ au_{e^+} \,\leq\, 30$ fs generated

Positron beam divergence around 3 mrad achieved

High-density positron beams comparable to astrophysical jets

Abstract

The generation of ultra-relativistic positron beams with short duration ($\tau_{e^+} \leq 30$ fs), small divergence ($\theta_{e^+} \simeq 3$ mrad), and high density ($n_{e^+} \simeq 10^{14} - 10^{15}$ cm$^{-3}$) from a fully optical setup is reported. The detected positron beam propagates with a high-density electron beam and $\gamma$-rays of similar spectral shape and peak energy, thus closely resembling the structure of an astrophysical leptonic jet. It is envisaged that this experimental evidence, besides the intrinsic relevance to laser-driven particle acceleration, may open the pathway for the small-scale study of astrophysical leptonic jets in the laboratory.