Sensor array uses superconducting quantum interference

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A sensor array-based instrument that offers ultra-low noise detection of small amounts of energy has been demonstrated by scientists at the University of Colorado, Boulder and the National Institute of Standards and Technology.

According to the researchers, the device allows for the collection of data from many more detectors than was previously possible and is expected to enable applications in fields such as nuclear materials accounting, astrophysics and X-ray spectrometry.

The instrument is said to consists of 128 superconducting sensors and combines their output into a single channel provided by a pair of coaxial cables.

In the past, array size was limited by the bandwidth available to combine signals into a reasonable number of output channels. The team claims the new research demonstrates a hundred-fold bandwidth improvement.

To overcome the bandwidth barrier, the researchers used cold superconducting microwave circuitry and superconducting quantum interference device amplifiers, known as SQUIDs, capable of boosting the intensity of small signals.

According to the team, the device uses radiofrequency SQUIDs to regulate microwave resonators. 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.

"It's as if one were trying to listen to hundreds of radio stations at one time through one radio receiver," said lead author John Mates from the University of Colorado.

He explained that the SQUID resonators boost the signal in each channel, allowing simultaneous readout of all the radio stations at once.

Versions of the new instrument are said to detect signals over a range of frequencies, from short-wavelength gamma or X-rays to long-wavelength microwaves.