Optimization of Time- A nd Code-Division-Multiplexed Readout for Athena X-IFU

W. Bertrand Doriese, Simon R. Bandler, Saptarshi Chaudhuri, Carl S. Dawson, Edward V. Denison, Shannon M. Duff, Malcolm Durkin, Connor T. Fitzgerald, Joseph W. Fowler, Johnathon D. Gard, Gene C. Hilton, Kent D. Irwin, Young Il Joe, Kelsey M. Morgan, Galen C. O'Neil, Christine G. Pappas, Carl D. Reintsema, David A. Rudman, Stephen James Smith, Robert W. StevensDaniel S. Swetz, Paul Szypryt, Joel N. Ullom, Leila R. Vale, Joel C. Weber, Betty A. Young

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


Readout of a large, spacecraft-based array of superconducting transition-edge sensors (TESs) requires careful management of the layout area and power dissipation of the cryogenic-circuit components. We present three optimizations of our time-(TDM) and code-division-multiplexing (CDM) systems for the X-ray integral field unit (X-IFU), a several-thousand-pixel-TES array for the planned Athena-satellite mission. The first optimization is a new readout scheme that is a hybrid of CDM and TDM. This C/TDM architecture balances CDM's noise advantage with TDM's layout compactness. The second is a redesign of a component: The shunt resistor that provides a dc-voltage bias to the TESs. A new layout and a thicker Pd-Au resistive layer combine to reduce this resistor's area by more than a factor of 5. Third, we have studied the power dissipated by the first-stage superconducting quantum-interference devices (SQUIDs) and the readout noise versus the critical current of the first-stage SQUIDs. As a result, the X-IFU TDM and C/TDM SQUIDs will have a specified junction critical current of 5 μA. Based on these design optimizations and TDM experiments described by Durkin et al. (these proceedings), TDM meets all requirements to be X-IFU's backup-readout option. Hybrid C/TDM is another viable option that could save spacecraft resources.

Original languageEnglish (US)
Article number8668436
JournalIEEE Transactions on Applied Superconductivity
Issue number5
StatePublished - Aug 2019
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


  • athena satellite
  • multiplexed readout
  • superconducting quantum-interference devices
  • Transition-edge sensors
  • X-ray microcalorimeters


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