Successful coupling of the X-IFU Warm Front-End Electronics demonstrator at SRON

A major milestone has been reached beginning of October 2025 in the development of the Warm Front-End Electronics (WFEE) for the ATHENA X-IFU detection chain with the successful coupling of WFEE demonstrator model 2 (DM2) during the Focal Plane Assembly (FPA) DM1.1 test campaign at SRON (Space Research Organisation Netherlands).

The WFEE, developed by APC (AstroParticule and Cosmology) in Paris, is a key element of the X-IFU readout chain. Located at room temperature, it interfaces the cryogenic detector system with the digital electronics. Its primary functions include the low-noise amplification and conditioning of the signals coming from the SQUID-based cold readout, the provision of stable and accurate biasing current to the detectors and cold electronics, and the transmission of science and housekeeping data. The WFEE is based on a dedicated family of application specific integrated circuits (ASIC), AwaXe, specifically designed for X-IFU to meet its stringent requirements. Achieving the required performance is essential to preserve the exceptional energy resolution of the X-IFU TES microcalorimeter array.

During the focal plane assembly (FPA) DM1.1 campaign, the WFEE DM2 was successfully coupled to a representative X-IFU readout chain. This included TES detector arrays developed at NASA Goddard Space Flight Center, cold readout electronics from NIST (National Institute of Standards and Technology) and VTT (Valtion teknillinen tutkimuskeskus), SRON’s FPA and NASA’s digital electronics. The first successful coupling took place in October and resulted in a representative demonstration of the X-IFU detection chain.

The tests demonstrated the correct operation of the main WFEE functionalities, as well as the achievement of the basic performance levels required at this stage of the project. This successful integration validates the overall design choices of the WFEE and confirms its compatibility with the detector and readout subsystems developed by international partners : CNES, SRON, NASA, NIST, VTT.

This result represents an important step forward for the development of the X-IFU instrument. It provides strong confidence in the maturity of the WFEE design and ensures the continuity of the ongoing developments toward the upcoming engineering and flight models, in close collaboration with the whole European and international X-IFU consortium.

Glossary

• SQUID : Superconducting Quantum Interference Device
• TES : Transition Edge Sensor
• FPA : Focal Plane Assembly

Teams involved

• The WFEE was developed by the WFEE team at APC (AstroParticule and Cosmology).
• On the day of the coupling, personnel from SRON, NASA, CNES, and APC were present.