Arcus X-ray telescope performance and alignment

TL;DR

Arcus is a proposed high-resolution X-ray and UV spectroscopic mission utilizing innovative optics and alignment techniques, with detailed performance analysis and alignment tolerances.

Contribution

This paper details the design, alignment, and performance evaluation of the Arcus X-ray and UV spectrographs, including ray-tracing studies and background estimates.

Findings

Achieves spectral resolving power >3000 in 12-50 Å band

Most alignment tolerances can be met with mechanical adjustments

Provides estimates of on-orbit background noise

Abstract

Arcus is a concept for a probe class mission to deliver high-resolution FUV and X-ray spectroscopy. For X-rays, it combines cost-effective silicon pore optics (SPO) with high-throughput critical-angle transmission (CAT) gratings to achieve $R> 3000$ in a bandpass from 12-50 Angstroem. We show in detail how the X-ray and the UV spectrographs (XRS and UVS) on Arcus will be aligned to each other. For XRS we present ray-tracing studies to derive performance characteristics such as the spectral resolving power and effective area, study the effect of misalignments on the performance, and conclude that most tolerances can be achieved with mechanical means alone. We also present an estimate of the expected on-orbit background.