Design and expected performance of a novel hybrid detector for very-high-energy gamma astrophysics

TL;DR

This paper proposes a novel hybrid extensive air shower detector for very-high-energy gamma-ray astrophysics, combining water-Cherenkov detectors and resistive plate chambers to improve sensitivity in the sub-TeV range.

Contribution

It introduces a new hybrid detector design that enhances sensitivity and accuracy for gamma-ray detection below 1 TeV, outperforming previous wide field-of-view experiments.

Findings

Full simulation shows improved sensitivity over previous detectors.

Can detect sources fainter than the Crab Nebula within one year.

Effective in detecting transient phenomena and variable sources.

Abstract

Current detectors for Very-High-Energy $\gamma$-ray astrophysics are either pointing instruments with a small field of view (Cherenkov telescopes), or large field-of-view instruments with relatively large energy thresholds (extensive air shower detectors). In this article, we propose a new hybrid extensive air shower detector sensitive in an energy region starting from about 100 GeV. The detector combines a small water-Cherenkov detector, able to provide a calorimetric measurement of shower particles at ground, with resistive plate chambers which contribute significantly to the accurate shower geometry reconstruction. A full simulation of this detector concept shows that it is able to reach better sensitivity than any previous gamma-ray wide field-of-view experiment in the sub-TeV energy region. It is expected to detect with a $5\sigma$ significance a source fainter than the Crab Nebula in one year at $100\,$GeV and, above $1\,$TeV a source as faint as 10\% of it. As such, this instrument is suited to detect transient phenomena making it a very powerful tool to trigger observations of variable sources and to detect transients coupled to gravitational waves and gamma-ray bursts.