Due to be launched in late 2021, the Imaging X-ray Polarimetry Explorer (IXPE) is a NASA Small Explorer mission designed to perform polarization measurements in the 2–8 keV band, complemented with imaging, spectroscopy and timing capabilities. At the heart of the focal plane is a set of three polarization-sensitive Gas Pixel Detectors (GPD), each based on a custom ASIC acting as a charge-collecting anode.

In this paper we shall review the design, manufacturing, and test of the IXPE focal-plane detectors, with particular emphasis on the connection between the science drivers, the performance metrics and the operational aspects. We shall present a thorough characterization of the GPDs in terms of effective noise, trigger efficiency, dead time, uniformity of response, and spectral and polarimetric performance. In addition, we shall discuss in detail a number of instrumental effects that are relevant for high-level science analysis—particularly as far as the response to unpolarized radiation and the stability in time are concerned.

成像 X 射线偏振探测器 (IXPE) 将于 2021 年底发射，是 NASA 的小型探测器任务，旨在在 2-8 keV 波段进行偏振测量，并辅以成像、光谱和计时功能。焦平面的核心是一组三个偏振敏感气体像素探测器 (GPD)，每个探测器都基于用作电荷收集阳极的定制 ASIC。

在本文中，我们将回顾 IXPE 焦平面探测器的设计、制造和测试，特别强调科学驱动因素、性能指标和操作方面之间的联系。我们将在有效噪声、触发效率、死区时间、响应均匀性以及光谱和极化性能方面对 GPD 进行全面的表征。此外，我们将详细讨论一些与高水平科学分析相关的仪器效应——特别是就对非极化辐射的响应和时间稳定性而言。