Optimisation of the design for the LOFT Large Area Detector Module

TL;DR

This paper details the design optimization of the LOFT Large Area Detector Module, a key component of an X-ray observatory, emphasizing trade-offs and improvements for future proposals.

Contribution

It presents the rationale, characteristics, and optimization trade-offs of the LAD module design for the LOFT X-ray observatory.

Findings

Robust and well-documented LAD module design

Trade-offs optimized for future ESA calls

Design improvements for X-ray timing performance

Abstract

LOFT (Large Observatory for X-ray Timing) is an X-ray timing observatory that, with four other candidates, was considered by ESA as an M3 mission (with launch in 2022-2024) and has been studied during an extensive assessment phase. Its pointed instrument is the Large Area Detector (LAD), a 10 m 2 -class instrument operating in the 2-30 keV range, which is designed to perform X-ray timing of compact objects with unprecedented resolution down to millisecond time scales. Although LOFT was not downselected for launch, during the assessment most of the trade-offs have been closed, leading to a robust and well documented design that will be reproposed in future ESA calls. The building block of the LAD instrument is the Module, and in this paper we summarize the rationale for the module concept, the characteristics of the module and the trade-offs/optimisations which have led to the current design.