A squid multiplexer
DOI: 10.1063/1.4796296
Has been demonstrated that can service an array of low-temperature sensors. A SQUID (superconducting quantum interference device) can detect very small currents or magnetic fields by monitoring tunneling Cooper pairs of electrons. Physicists at the University of California, Berkeley, inductively coupled eight low-temperature sensors, using eight different AC frequencies, to a single superconducting current loop. The researchers then coupled a single readout SQUID to the loop to examine the output of any or all of the sensors. The number of sensors that can be multiplexed in this way is limited mainly by the slew rate of the SQUID. The device might be used in biomagnetic imaging or astronomical instrumentation. (J. Yoon et al., Appl. Phys. Lett. 78 , 371, 2001 http://dx.doi.org/10.1063/1.1338963 .)
