ECLAIRs coded mask design for SVOM mission

The AstroParticle and Cosmology Laboratory is in charge of the coded mask subsystem of the ECLAIRs instrument, which is integrated into the SVOM mission. The ECLAIRs instrument is dedicated to the detection and location of gamma rays and X-rays in the energy band from 4 to 150 keV, and is being managed by the CNES. The mask pattern is determined by scientific criteria (location accuracy and sensitivity) and mechanical criteria (rigidity, mechanical strength, etc.). The low threshold of 4 keV means that the mask is self-supporting (the first time it has been done for a mask of this size). The mask has been developed and the flight model has been delivered and integrated into the ECLAIRs instrument, which is due to be launched on June 24th 2024. The aim of this document is to present the geometry of the mask, the design choices, the manufacturing processes and the feedback from this assembly.