The LOFT (Large Observatory for X-ray Timing) background simulations

TL;DR

This paper discusses detailed background simulations for the LOFT X-ray observatory, focusing on cosmic and Earth albedo contributions to optimize instrument design and scientific performance.

Contribution

It provides comprehensive Geant-4 simulation results of background environments for LOFT's detectors, aiding in mission planning and optimization.

Findings

Cosmic diffuse X-ray background is a significant contributor.

High energy cosmic rays impact the background levels.

Earth albedo emission also affects the background environment.

Abstract

The Large Observatory For X-ray Timing (LOFT) is an innovative medium-class mission selected for an assessment phase in the framework of the ESA M3 Cosmic Vision call. LOFT is intended to answer fundamental questions about the behaviour of matter in the very strong gravitational and magnetic fields around compact objects. With an effective area of ~10 m^2 LOFT will be able to measure very fast variability in the X-ray fluxes and spectra. A good knowledge of the in-orbit background environment is essential to assess the scientific performance of the mission and to optimize the instrument design. The two main contributions to the background are cosmic diffuse X-rays and high energy cosmic rays; also, albedo emission from the Earth is significant. These contributions to the background for both the Large Area Detector and the Wide Field Monitor are discussed, on the basis of extensive Geant-4 simulations of a simplified instrumental mass model.