Spectral performance of ECLAIRs flight detectors on SVOM mission

In this paper, we introduce the astrophysical context that led to the design of the mission, with an emphasis on the study of GRBs with ECLAIRs. We provide a detailed description of the XRDPIX hybrid modules, and we explain the experimental setup used for testing and qualifying 45 flight models. We present the results of the measurements performed to validate the module performance with a radioactive source of Americium 241. We study the spectral resolution, the low energy threshold, the gain of the detectors, and their counting performance. We also present two side studies concerning the impact of low temperatures and the stability of the performance over time. To conclude, we propose optimal settings for two key configuration parameters: the high voltage bias and the peaking time, that permit obtaining the challenging 4 keV energy threshold required for the SVOM mission.