Advances in gas pixel detectors for x-ray polarimetry: development of the bake and fill system (BFS)

Abstract

Building on the successful launch and operation of the Imaging X-ray Polarimetry Explorer (IXPE) mission,1 the Italian National Institute for Nuclear Physics (INFN) has initiated an R&D program to develop the next generation of Gas Pixel Detectors (GPDs) for X-ray polarimetry.2 To support this effort, a Bake and Fill System (BFS) was designed, integrated, and tested. The complex BFS architecture consists of various subsystems, including gas distribution and purification, thermal control, vacuum generation, leak detection and residual gas analysis (RGA), high voltage supply, scientific data acquisition, and x-ray generation (both with passive and active sources). We also implemented remote monitoring and logging of the system status and relevant environmental data. The BFS facility was successfully used to test the detector’s sub-components, fill the GPDs with several gas mixtures at different fill pressures, and conduct functional and performance acceptance tests of the detectors even before their final sealing. The BFS’s successful implementation has demonstrated its potential to support extensive qualification campaigns of detector components, besides being a reliable production facility for flight, sealed GPDs for future space missions in X-ray polarimetry. The development and utilization of the BFS represent an important step towards the production of cutting-edge X-ray polarimeters, which have a wide range of applications in astronomy and astrophysics.