# Characterisation of the Particle-Induced Background of XMM-Newton EPIC-pn: Short and Long Term Variability

## TL;DR

This paper investigates the particle-induced background in XMM-Newton's EPIC-pn detector, revealing correlations with primary particles and differences from cosmic X-ray events to improve background reduction.

## Contribution

It demonstrates the spatial correlation of background events with primary particles and characterizes their spectral and pattern differences, aiding background mitigation.

## Key findings

- Background events are spatially correlated with primary particle interactions.
- Secondary particle events differ in spectrum and pattern from cosmic X-ray events.
- Results can help reduce non-X-ray background in silicon-based X-ray detectors.

## Abstract

The particle-induced background of X-ray observatories is produced by Galactic Cosmic Ray (GCR) primary protons, electrons, and He ions. Events due to direct interaction with the detector are usually removed by on board processing. The interactions of these primary particles with the detector environment produce secondary particles that mimic X-ray events from celestial sources and are much more difficult to identify. The filter wheel closed data from the XMM-Newton EPIC-pn camera in small window mode (SWM) contains both the X-ray-like background events and the events due to direct interactions with the primary particles. From this data we demonstrate that X-ray-like background events are spatially correlated with the primary particle interaction. This result can be used to further characterise and reduce the non-X-ray background in silicon-based X-ray detectors in current and future missions. We also show that spectrum and pattern fractions of secondary particle events are different from those produced by cosmic X-rays.