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Symmetric time-division-multiplexed SQUID readout with two-layer switches for future TES observatories



Malcolm Durkin, Scott Backhaus, Simon Bandler, James Chervenak, Ed Denison, W.Bertrand (Randy) Doriese, Johnathon Gard, Gene C. Hilton, Richard Lew, Tammy Lucas, Carl D. Reintsema, Dan Schmidt, Stephen Smith, Joel Ullom, Leila R. Vale, Michael Vissers, Nicholas Wakeham


Time-division multiplexing (TDM) of transition-edge-sensor (TES) microcalorimeters is being developed as the readout tech-nology for the Athena X-ray integral field unit (X-IFU) and is under consideration for future TES-bolometer missions like CMB-S4. We present an experimental demonstration of our latest TDM architecture, which has been implemented in a 4-column x 34-row chip that is fully compatible with the X-IFU design speci-fications. This new architecture is designed for differential readout and uses two-layer switches to reduce the number of row-address lines. Advances in multiplexer design since 2019 have also reduced power to roughly 40% and the total number of SQUIDs by half. With the 160 ns row durations specified for X-IFU, we obtained (2.02 ± 0.03) eV FWHM energy resolution at 5.9 keV in 2-column x 34-row TDM readout of a NASA X-IFU-like TES array, which meets the requirements of X-IFU's energy-resolution budget. Finally, a scaling analysis of our improved TDM readout chain to bolometer applications indicates that mul-tiplexing factors on the scale of several hundred are possible, de-pending on the readout requirements.
IEEE Transactions on Applied Superconductivity


transition-edge sensors, superconducting quantum interference devices, multiplexed readout


Durkin, M. , Backhaus, S. , Bandler, S. , Chervenak, J. , Denison, E. , Doriese, W. , Gard, J. , Hilton, G. , Lew, R. , Lucas, T. , Reintsema, C. , Schmidt, D. , Smith, S. , Ullom, J. , Vale, L. , Vissers, M. and Wakeham, N. (2023), Symmetric time-division-multiplexed SQUID readout with two-layer switches for future TES observatories, IEEE Transactions on Applied Superconductivity, [online],, (Accessed April 21, 2024)
Created April 4, 2023, Updated April 20, 2023