The Athena X-ray Integral Field Unit: a consolidated design for the system requirement review of the preliminary definition phase
By Didier Barret
This paper describes the Athena X-ray Integral Field Unit, as presented to its system requirement review, successfully closed on September 2022. It summarises a data pack of over 100 documents, totalling more than 5000 pages. It describes the baseline configuration of X-IFU that was studied since 2014. It was based on a warm temperature cryostat and a multi-stage cooling chain, holding a 2K core. Since summer 2022, Athena has entered reformulation, and the X-IFU baseline configuration has evolved towards a cold passively cooled cryostat, a reduced number of mechanical coolers and a 4K core. The work presented in this paper is not wasted, being extensively used as a reference point in the reformulation process.