Study of Dissipative Losses in AC-Biased Mo/Au Bilayer Transition-Edge Sensors

K. Sakai, J. S. Adams, S. R. Bandler, J. A. Chervenak, A. M. Datesman, M. E. Eckart, F. M. Finkbeiner, R. L. Kelley, C. A. Kilbourne, A. R. Miniussi, F. S. Porter, J. S. Sadleir, S. J. Smith, N. A. Wakeham, E. J. Wassell, W. Yoon, H. Akamatsu, M. P. Bruijn, L. Gottardi, B. D. JacksonJ. van der Kuur, B. J. van Leeuwen, A. J. van der Linden, H. J. van Weers, M. Kiviranta

    Research output: Contribution to journalArticleScientificpeer-review

    10 Citations (Scopus)


    We are developing kilo-pixel arrays of transition-edge sensors (TESs) for the X-ray Integral Field Unit on ESA’s Athena observatory. Previous measurements of AC-biased Mo/Au TESs have highlighted a frequency-dependent loss mechanism that results in broader transitions and worse spectral performance compared to the same devices measured under DC bias. In order to better understand the nature of this loss, we are now studying TES pixels in different geometric configurations. We present measurements on devices of different sizes and with different metal features used for noise mitigation and X-ray absorption. Our results show how the loss mechanism is strongly dependent upon the amount of metal in close proximity to the sensor and can be attributed to induced eddy current coupling to these features. We present a finite element model that successfully reproduces the magnitude and geometry dependence of the losses. Using this model, we present mitigation strategies that should reduce the losses to an acceptable level.

    Original languageEnglish
    Pages (from-to)356-364
    Number of pages9
    JournalJournal of Low Temperature Physics
    Issue number3-4
    Publication statusPublished - 1 Nov 2018
    MoE publication typeNot Eligible


    • Eddy current heating
    • Frequency-division multiplexing
    • Microcalorimeters
    • Transition-edge sensors
    • OtaNano


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