Browsing by Author "Bruijn, M. P."
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Item Josephson Effects in Frequency-Domain Multiplexed TES Microcalorimeters and Bolometers(Springer, 2018-07-03) Gottardi, L.; Smith, Stephen J.; Kozorezov, A.; Akamatsu, H.; van der Kuur, J.; Bandler, S. R.; Bruijn, M. P.; Chervenak, J. A.; Gao, J. R.; den Hartog, R. H.; Jackson, B. D.; Khosropanah, P.; Miniussi, Antoine; Nagayoshi, K.; Ridder, M.; Sadleir, J.; Sakai, Kazuhiro; Wakeham, NicholasFrequency-division multiplexing is the baseline read-out system for large arrays of superconducting transition-edge sensors (TES’s) under development for the X-ray and infrared instruments like X-IFU (Athena) and SAFARI, respectively. In this multiplexing scheme, the sensors are ac-biased at different frequencies from 1 to 5MHz and operate as amplitude modulators. Weak superconductivity is responsible for the complex TES resistive transition, experimentally explored in great detail so far, both with dc- and ac-biased read-out schemes. In this paper, we will review the current status of our understanding of the physics of the TES’s and their interaction with the ac bias circuit. In particular, we will compare the behaviour of the TES nonlinear impedance, across the superconducting transition, for several detector families, namely: high-normal-resistance TiAu TES bolometers, low-normal-resistance MoAu TES microcalorimeters and high-normal-resistance TiAu TES microcalorimeters.Item Progress in the Development of Frequency‑Domain Multiplexing for the X‑ray Integral Field Unit on Board the Athena Mission(Springer, 2020-01-28) Akamatsu, H.; Gottardi, L.; van der Kuur, J.; de Vries, C. P.; Bruijn, M. P.; Chervenak, J. A.; Kiviranta, M.; van den Linden, A. J.; Jackson, B. D.; Miniussi, Antoine; Ravensberg, K.; Sakai, Kazuhiro; Smith, S. J.; Wakeham, NicholasFrequency-domain multiplexing (FDM) is the baseline readout system for the X-ray Integral Field Unit on board the Athena mission. Under the FDM scheme, TESs are coupled to a passive LC flter and biased with alternating current (AC bias) at MHz frequencies. Using high-quality-factor LC flters and room-temperature electronics developed at SRON and low-noise two-stage SQUID amplifers 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 with the single-pixel AC bias (ΔE = 1.8 eV) and nine-pixel multiplexing (ΔE = 2.6 eV) modes. We have also demonstrated 14-pixel multiplexing with an average energy resolution of 3.3 eV, which is limited by nonfundamental issues related to FDM readout in our laboratory setup.