Progress in the Development of Frequency-Domain Multiplexing for the X-ray Integral Field Unit on Board the Athena Mission

Abstract

Frequency domain multiplexing (FDM) is the baseline readout system for the Xray Integral Field Unit (X-IFU) on board the Athena mission. Under the FDM scheme, TESs are coupled to a passive LC filter and biased with alternating current (AC bias) at MHz frequencies. Using high-quality factor LC filters and room temperature electronics developed at SRON and low-noise two-stage SQUID amplifiers provided by VTT, we have recently demonstrated good performance with the FDM readout of Mo/Au TES calorimeters with Au/Bi absorbers. We have achieved a performance requested for the demonstration model (DM) with the single pixel AC bias (∆ E =1.8 eV) and 9 pixel multiplexing (∆ E =2.6 eV) modes. We have also demonstrated 14-pixel multiplexing with an average energy resolution of 3.3 eV, which is limited by non-fundamental issues related to FDM readout in our lab setup.

A Review of X-ray Microcalorimeters Based on Superconducting Transition Edge Sensors for Astrophysics and Particle Physics

“…The star symbol is the expected demonstration of the readout of 3168 pixels with the XIFU/Athena flight model (FM). The data points are taken from the following publications, as annotated in the bottom plot: a =[195], b =[196], c =[9], d =[133], e =[197], f =[128] (32 TESs + 8 repeats of the last row), g =[134], h =[135], i =[10], j =[198], k =[127], l =[148], m =[149], n =[114], o =[157].…”

Demonstration of MHz frequency domain multiplexing readout of 37 transition edge sensors for high-resolution x-ray imaging spectrometers

“…Previously these optimizations were hampered due to different α, β and the rather high G of the available devices. In this report, we used a factor 5 narrower electrical bandwidth configuration compared to the previous work 25 . The improvement is realized by the combination of a slower detector time constant and a different α − β relationship 20 .…”

“…Previous demonstrations with FDM readout of TES spectrometers was mainly limited by three effects 25 . These are 1.…”

High aspect ratio transition edge sensors for x-ray spectrometry

“…Base-band feedback (BBFB) is used to increase the linearity and dynamic range of the SQUIDs 31 . A more detailed explanation of the FDM readout is given by Akamatsu et al [32][33][34] . In order not to add additional complexity to the interpretation of the data, in this work the TESs are measured in single-pixel mode, where only one device is biased at a time, and all others are left in the superconducting state.…”