Digital Frequency Multiplexer for TES Detectors—Path to Flight

• Published in: Journal of Low Temperature Physics
• Main Authors: Dobbs, M., Aubin, F., de Haan, T., Hanany, S., Harrington, N., Holzapfel, W., Hubmayr, J., Lee, A., Lueker, M., Macdermid, K., Smecher, G.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Springer 2012
• Subjects: South Pole; South pole
• Online Access: https://authors.library.caltech.edu/31816/; https://resolver.caltech.edu/CaltechAUTHORS:20120605-110629004

Frequency-domain multiplexing has been used for reading out ∼1000 detectors on the APEX-SZ and South Pole Telescope receiver for half a decade and produced many high-impact science papers. A new digital FPGA-based backend reduces the power consumption and system-size by an order of magnitude. This Digital Frequency-domain Multiplexer (DfMUX) was operated successfully in a space-like environment during the stratospheric balloon test-flight of the EBEX polarimeter, saw first light on the POLARBEAR experiment in 2010, and will be deployed for the South Pole Telescope polarimeter and ASTE sub-mm continuum camera. We are presently developing a new generation DfMUX targeting a factor 5 lower power consumption and robustness for satellite platforms. The system will incorporate new technology for identifying and correcting radiation induced errors in the FPGA logic, higher bandwidth to accommodate a multiplexing factor of 64, and Digital Active Nulling (DAN) feedback. DAN linearizes the SQUID system response while dramatically reducing its input impedance.