Time-division superconducting quantum interference device multiplexer for transition-edge sensors

Abstract

We report on the design and performance of our second-generation 32-channel time-division multiplexer developed for the readout of large-format arrays of superconducting transition-edge sensors. We present design issues and measurement results on its gain, bandwidth, noise, and cross talk. In particular, we discuss noise performance at low frequency, important for long uninterrupted submillimeter/far-infrared observations, and present a scheme for mitigation of low-frequency noise. Also, results are presented on the decoupling of the input circuit from the first-stage feedback signal by means of a balanced superconducting quantum interference device pair. Finally, the first results of multiplexing several input channels in a switched, digital flux-lock loop are shown.

Optimizing Feedhorn-Coupled TES Polarimeters for Balloon and Space-Based CMB Observations

“…The normal resistance, R N , of these devices is 4.5±1.5 m (limited by uncertainty in the shunt resistor). 2 This resistance is compatible with reading out the devices by use of the well-demonstrated time-division multiplexing [13] (TDM) or next-generation microwave frequency-division multiplexing [14] that use the software-defined radio Fig. 3 (Color online) Multiplexed noise spectra from the two bolometers in a polarimeter (green dot-dashes and red dashes) exhibit 1/f with a knee frequency ∼1 Hz (blue dots).…”

Antenna-coupled TES bolometers for the SPIDER experiment

“…The current SQUID MUX can multiplex up to 32 channels. 5 In the future, the microwave frequency domain SQUID MUX 19 with reflectometer readout might be able to multiplex hundreds or even thousands of detectors, with electronics at a much lower cost.…”

“…This is achieved by superconducting quantum interference device (SQUID) multiplexers. 5,6 In a microstrip-coupled bolometer, only the mechanically robust slot antenna scale with wavelength, therefore the entire frequency range (∼ 30 GHz to 500 GHz) of interest in CMB science can be covered by the same technology.…”

Antenna-coupled TES Arrays For The BICEP2∕Keck and SPIDER polarimeters

“…The detector arrays are integrated with the SQUID time-domain multiplexer developed at NIST [6] using a simple scheme. Each detector wafer, stacked together with a X/4 quartz anti-reflection wafer and a X/4 backshort, is firmly mounted on a gold plated OFHC copper plate and connected to a printed circuit board via Al wirebonds.…”

“…Single 96 GHz and 145 GHz devices have already been successfully tested, showing good electrical and optical performances [4,5]. We have since built focal planes for both B1CEP2 and SPIDER, integrating the detector arrays with a timedomain SQUID multiplexer [6] and using the MultiCharmel Electronics (MCE) [7] to readout the detectors. The uniformity of detector electrical and optical performances across the arrays is essential in order to achieve target sensitivities.…”