Abstract
A technological milestone for experiments employing transition edge sensor bolometers operating at sub-Kelvin temperature is the deployment of detector arrays with 100s-1000s of bolometers. One key technology for such arrays is readout multiplexing: the ability to read out many sensors simultaneously on the same set of wires. This paper describes a frequency-domain multiplexed readout system which has been developed for and deployed on the APEX-SZ and South Pole Telescope millimeter wavelength receivers. In this system, the detector array is divided into modules of seven detectors, and each bolometer within the module is biased with a unique ∼MHz sinusoidal carrier such that the individual bolometer signals are well separated in frequency space. The currents from all bolometers in a module are summed together and pre-amplified with superconducting quantum interference devices operating at 4K. Room temperature electronics demodulate the carriers to recover the bolometer signals, which are digitized separately and stored to disk. This readout system contributes little noise relative to the detectors themselves, is remarkably insensitive to unwanted microphonic excitations, and provides a technology pathway to multiplexing larger numbers of sensors.
Original language | English (US) |
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Article number | 073113 |
Journal | Review of Scientific Instruments |
Volume | 83 |
Issue number | 7 |
DOIs | |
State | Published - Jul 2012 |
Bibliographical note
Funding Information:The National Science Foundation (NSF) funds APEX-SZ through Grant Nos. AST-0138348 and AST-0709497 and the South Pole Telescope through Grant Nos. ANT-0638937 and ANT-0130612. Work at LBNL is supported by the U.S. Department of Energy (DOE) under Contract No. DE-AC02-05CH11231. The McGill team acknowledges funding from the Natural Sciences and Engineering Research Council of Canada, Canadian Institute for Advanced Research, and the Canadian Foundation for Innovation. M.D. acknowledges support from the Canada Research Chairs program and a Sloan Fellowship.