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Code-division SQUID multiplexing



Michael D. Niemack, Kent D. Irwin, Joern Beyer, Hsiao-Mei Cho, William B. Doriese, Gene C. Hilton, Carl D. Reintsema, Daniel R. Schmidt, Joel N. Ullom, Leila R. Vale


Multiplexed superconducting quantum interference device (SQUID) readout systems are a critical technology for measuring large arrays of superconducting transition-edge sensor (TES) detectors. Current successful SQUID multiplexing architectures are modulated in time and frequency. We present a SQUID multiplexing architecture that is modulated by Walsh codes and will enable scaling to much larger TES arrays. Measurements and simulations of a prototype four channel code-division multiplexer show that this modulation scheme enables precise timing resolution of incident pulses for microcalorimeter applications, is not degraded by SQUID noise aliasing, suppresses noise pickup in the readout circuit and has low-levels of crosstalk between channels. Furthermore, the modulation of the signal before it couples to the SQUID suppresses 1/f noise to below 20 mHz, suggesting the use of this circuit for 1/f mitigation in more general SQUID readout applications.
Applied Physics Letters


SQUID measurement, transition-edge sensor, detector array, noise mitigation


Niemack, M. , Irwin, K. , Beyer, J. , Cho, H. , Doriese, W. , Hilton, G. , Reintsema, C. , Schmidt, D. , Ullom, J. and Vale, L. (2010), Code-division SQUID multiplexing, Applied Physics Letters, [online], (Accessed June 20, 2024)


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Created April 23, 2010, Updated February 19, 2017