The Hot and Energetic Universe: The X-ray Integral Field Unit (X-IFU) for Athena+

TL;DR

The paper describes the design, technology, and performance of the X-ray Integral Field Unit (X-IFU) for the Athena+ mission, a high-resolution cryogenic spectrometer for studying the hot and energetic universe.

Contribution

It presents the detailed design, technological advancements, and performance estimates of the X-IFU instrument, highlighting progress towards meeting its demanding scientific requirements.

Findings

Achieved 2.5 eV spectral resolution with TES array.

Developed cooling chain and readout electronics for X-IFU.

Demonstrated significant progress in TES fabrication and spectral performance.

Abstract

The Athena+ mission concept is designed to implement the Hot and Energetic Universe science theme submitted to the European Space Agency in response to the call for White Papers for the definition of the L2 and L3 missions of its science program. The Athena+ science payload consists of a large aperture high angular resolution X-ray optics and twelve meters away, two interchangeable focal plane instruments: the X-ray Integral Field Unit (X-IFU) and the Wide Field Imager (WFI). The X-IFU is a cryogenic X-ray spectrometer, based on a large array of Transition Edge Sensors (TES), offering 2.5 eV spectral resolution, with ~5" pixels, over a field of view of 5 arc minutes in diameter. In this paper, we briefly describe the Athena+ mission concept and the X-IFU performance requirements. We then present the X-IFU detector and readout electronics principles, the current design of the focal plane assembly, the cooling chain and review the global architecture design. Finally, we describe the current performance estimates, in terms of effective area, particle background rejection, count rate capability and velocity measurements. Finally, we emphasize on the latest technology developments concerning TES array fabrication, spectral resolution and readout performance achieved to show that significant progresses are being accomplished towards the demanding X-IFU requirements.