Estimate of the impact of background particles on the X-Ray Microcalorimeter Spectrometer on IXO

TL;DR

This study estimates the residual background noise on the X-ray Microcalorimeter Spectrometer on IXO caused by galactic and solar particles, using Monte Carlo simulations to inform instrument design and performance optimization.

Contribution

It provides a detailed simulation-based assessment of particle-induced background levels for IXO's XMS, aiding in the development of more effective background rejection strategies.

Findings

Residual background levels estimated for the XMS at L2

Rejection efficiency of anticoincidence system evaluated

Results serve as conservative limits for similar missions

Abstract

We present the results of a study on the impact of particles of galactic (GCR) and solar origin for the X-ray Microcalorimeter Spectrometer (XMS) aboard an astronomical satellite flying in an orbit at the second Lagrangian point (L2). The detailed configuration presented in this paper is the one adopted for the International X-Ray Observatory (IXO) study, however the derived estimates can be considered a conservative limit for ATHENA, that is the IXO redefined mission proposed to ESA. This work is aimed at the estimate of the residual background level expected on the focal plane detector during the mission lifetime, a crucial information in the development of any instrumental configuration that optimizes the XMS scientific performances. We used the Geant4 toolkit, a Monte Carlo based simulator, to investigate the rejection efficiency of the anticoincidence system and assess the residual background on the detector.