In-flight performance of the Canadian Astro-H Metrology System

TL;DR

The paper evaluates the in-flight performance of the Canadian Astro-H Metrology System (CAMS) on the Hitomi satellite, demonstrating its critical role in precise alignment and data quality improvement for high-resolution X-ray observations.

Contribution

This study provides the first in-flight assessment of CAMS, highlighting its effectiveness in real-time alignment and its importance for future high-resolution X-ray missions.

Findings

CAMS achieved micrometer-scale real-time positioning during deployment.

CAMS improved the data quality of hard X-ray images.

Metrology systems are essential for high angular resolution X-ray telescopes.

Abstract

The Canadian Astro-H Metrology System (CAMS) on the Hitomi X-ray satellite is a laser alignment system that measures the lateral displacement (X/Y) of the extensible optical bench (EOB) along the optical axis of the hard X-ray telescopes (HXTs). The CAMS consists of two identical units that together can be used to discern translation and rotation of the deployable element along the axis. This paper presents the results of in-flight usage of the CAMS during deployment of the EOB and during two observations (Crab and G21.5-0.9) with the HXTs. The CAMS was extremely important during the deployment operation by providing real-time positioning information of the EOB with micrometer scale resolution. In this work, we show how the CAMS improves data quality coming from the hard X-ray imagers. Moreover, we demonstrate that a metrology system is even more important as the angular resolution of the telescope increases. Such a metrology system will be an indispensable tool for future high resolution X-ray imaging missions.