The IXPE Instrument Calibration Equipment

TL;DR

This paper describes the design and implementation of specialized calibration equipment for the IXPE mission's polarization-sensitive detectors, ensuring accurate polarization measurements and low statistical uncertainty.

Contribution

It introduces a comprehensive calibration setup tailored for IXPE's unique polarization response, with versatile equipment applicable to future projects.

Findings

Calibration equipment achieved precise polarization response measurement

Equipment design ensures low statistical uncertainty in polarization detection

Versatile setup adaptable for other high-energy space missions

Abstract

The Imaging X-ray Polarimetry Explorer is a mission dedicated to the measurement of X-ray polarization from tens of astrophysical sources belonging to different classes. Expected to be launched at the end of 2021, the payload comprises three mirrors and three focal plane imaging polarimeters, the latter being designed and built in Italy. While calibration is always an essential phase in the development of high-energy space missions, for IXPE it has been particularly extensive both to calibrate the response to polarization, which is peculiar to IXPE, and to achieve a statistical uncertainty below the expected sensitivity. In this paper we present the calibration equipment that was designed and built at INAF-IAPS in Rome, Italy, for the calibration of the polarization-sensitive focal plane detectors on-board IXPE. Equipment includes calibration sources, both polarized and unpolarized, stages to align and move the beam, test detectors and their mechanical assembly. While all these equipments were designed to fit the specific needs of the IXPE Instrument calibration, their versatility could also be used in the future for other projects.