Bandwidth breakthrough could help track nuclear material

A 33-channel SQUID multiplexer chip (20 mm x 4 mm) along with its microwave response showing the associated resonances (Credit: J.A.B. Mates, University of Colorado)

The device, described in Applied Physics Letters, consists of 128 superconducting sensors. Up until now, array size has been restricted by the bandwidth available to combine signals into a limited number of output channels. But the researchers, from the University of Colorado and the National Institute of Standards and Technology (NIST), were able to deliver a 100-fold bandwidth improvement.

The breakthrough was achieved by using extremely cold superconducting microwave circuitry and superconducting quantum interference device amplifiers, or SQUIDs. The device uses radiofrequency SQUIDs to regulate high-quality microwave resonators, improving the intensity of small signals. When these resonators are coupled to a common microwave feed line, with each resonator tuned to a different frequency, all sensors can be simultaneously monitored.