The X-ray Integral Field Unit (X-IFU) for Athena

Athena is designed to implement the Hot and Energetic Universe science theme selected by the European Space Agency for the second large mission of its Cosmic Vision program. The Athena science payload consists of a large aperture high angular resolution X-ray optics (2 m2 at 1 keV) and twelve meters away, two interchangeable focal plane instruments: the X-ray Integral Field Unit (X-IFU) and the Wide Field Imager. The X-IFU is a cryogenic X-ray spectrometer, based on a large array of Transition Edge Sensors (TES), oering 2.5 eV spectral resolution, with approximately 5" pixels, over a field of view of 5' in diameter. In this paper, we present the X-IFU detector and readout electronics princi…