# The particle background of the X-IFU instrument

## TL;DR

This paper reviews the estimated particle background for the X-IFU instrument on the ATHENA mission, focusing on soft protons and cosmic rays, using Monte Carlo simulations to assess their impact on instrument sensitivity.

## Contribution

It provides updated Monte Carlo simulation estimates of particle background components affecting the X-IFU instrument, enhancing understanding of background sources for future observations.

## Key findings

- Soft protons funnelled by mirrors contribute to background counts.
- Cosmic rays deposit energy in the detector from all directions.
- Latest simulation results improve background modeling accuracy.

## Abstract

In this paper we are going to review the latest estimates for the particle background expected on the X-IFU instrument onboard of the ATHENA mission. The particle background is induced by two different particle populations: the so called "soft protons" and the Cosmic rays. The first component is composed of low energy particles (< 100s keV) that get funnelled by the mirrors towards the focal plane, losing part of their energy inside the filters and inducing background counts inside the instrument sensitivity band. The latter component is induced by high energy particles (> 100 MeV) that possess enough energy to cross the spacecraft and reach the detector from any direction, depositing a small fraction of their energy inside the instrument. Both these components are estimated using Monte Carlo simulations and the latest results are presented here.