Reducing the background in X-ray imaging detectors via machine learning

TL;DR

This paper introduces machine learning algorithms to improve background filtering in X-ray detectors, significantly reducing cosmic ray-induced noise and enhancing sensitivity for astronomical observations.

Contribution

The study presents novel machine learning techniques for identifying and filtering cosmic ray events in X-ray detectors, outperforming traditional methods.

Findings

Reduced cosmic ray background by up to 30%

Machine learning captures correlations between secondary events

Enhanced detection sensitivity for low surface brightness sources

Abstract

The sensitivity of astronomical X-ray detectors is limited by the instrumental background. The background is especially important when observing low surface brightness sources that are critical for many of the science cases targeted by future X-ray observatories, including Athena and future US-led flagship or probe-class X-ray missions. Above 2keV, the background is dominated by signals induced by cosmic rays interacting with the spacecraft and detector. We develop novel machine learning algorithms to identify events in next-generation X-ray imaging detectors and to predict the probability that an event is induced by a cosmic ray vs. an astrophysical X-ray photon, enabling enhanced filtering of the cosmic ray-induced background. We find that by learning the typical correlations between the secondary events that arise from a single primary, machine learning algorithms are able to successfully identify cosmic ray-induced background events that are missed by traditional filtering methods employed on current-generation X-ray missions, reducing the unrejected background by as much as 30 per cent.