Design and performance of the camera of the Micro-channel X-ray Telescope on-board the SVOM mission

The Microchannel X-ray Telescope (MXT) is part of the scientific payload of the SVOM Sino-French space mission to observe the early afterglow of gamma-ray bursts in the 0.2-10 keV energy range and localize them within 2 arcmin. For a total mass of 42 kg and a total power of 60 W, this instrument is composed of an optical system, a structural carbon fiber tube, a radiator, a camera and a data processing unit. The camera consists of a focal plane assembly with a detector ceramic board and thermoelectric coolers, a front-end electronics, a calibration wheel and a support structure. Spectral characterization tests of the focal plane assembly based on a 256 x 256 pixel pnCCD spectroscopic imager were performed in the laboratory, at the Metrology beamline of the SOLEIL synchrotron and at the PANTER X-ray facility. Energy resolution of 79 eV FWHM at 1.5 keV was demonstrated in the nominal flight configuration (-65 degrees C, real time event selection by the camera). The paper presents the design, the realization and the performance of the flight camera of MXT. It focuses on the technical challenges, the original implemented solutions and the custom-made setups for the validation tests.