System performance of a cryogenic test-bed for the time-division multiplexing readout for NewAthena X-IFU

TL;DR

This paper reports on the performance testing of a cryogenic test-bed for the TDM readout system of the X-IFU instrument on the NewAthena space observatory, achieving high energy resolution with a realistic wiring harness length.

Contribution

It presents the characterization of a cryogenic test-bed TDM readout system with a wiring harness length similar to the final design, demonstrating a 2.7 eV energy resolution at 6 keV.

Findings

Achieved 2.7 eV FWHM energy resolution at 6 keV.

Validated wiring harness performance at realistic length.

Provided insights for integrating TDM readout into the X-IFU development model.

Abstract

The X-ray Integral Field Unit (X-IFU) is an instrument of ESA's future NewAthena space observatory, with the goal to provide high-energy resolution ($<$ 4 eV at X-ray energies up to 7 keV) and high-spatial resolution (9") spectroscopic imaging over the X-ray energy range from 200 eV to 12 keV, by means of an array of about 1500 transition-edge sensors (TES) read out via SQUID time-division multiplexing (TDM). A TDM-based laboratory test-bed has been assembled at SRON, hosting an array of $75\times 75\ \upmu$m$^2$ TESs that are read out via 2-column $\times$ 32-row TDM. A system component that is critical to high-performance operation is the wiring harness that connects the room-temperature electronics to the cryogenic readout componentry. We report here on our characterization of such a test-bed, whose harness has a length close to what envisioned for X-IFU, which allowed to achieve a co-added energy resolution at a level of 2.7~eV FWHM at 6~keV via 32-row readout. In addition, we provide an outlook on the integration of TDM readout into the X-IFU Focal-Plane Assembly Development Model.