Tiny superconducting thermometer monitors ultracold temperatures
Some advanced electronic devices, such as superconductors and quantum computers, can currently only function at extremely cold temperatures. Now engineers at the National Institute of Standards and Technolgy (NIST) have developed a tiny cryogenic thermometer that can keep an eye on these sensitive instruments without taking up much room.
Most electronics can handle slight changes in temperature, but for those that require cryogenic temperatures to function, fractions of a degree can be enough to throw them off. Monitoring the temperature is critical, but thermometers that are sensitive enough can be bulky, intruding on the device itself.
The new thermometer measures just 2.5 x 1.15 mm (0.1 x 0.05 in) and is inexpensive, making it perfect to neatly embed in or attach to chips and other electronics. The thermometer can measure temperatures as cold as 50 milliKelvin (-273.1 °C, -459.58 °F), which is just a hair above absolute zero, the coldest temperature possible.
The device works by tapping into a completely different physical mechanism to other sub-Kelvin thermometers, which usually measure changes in electrical resistance. The new thermometer is made up of a superconducting niobium resonator, coated in silicon dioxide. The frequency at which the resonator naturally vibrates is known to change with the temperature, so the thermometer can measure those changes and determine the temperature.
The team says that the new thermometer doesn’t require extra electronic components, keeping it small and easy to integrate into the systems it’s monitoring. Plus, it can make its measurements in as little as five milliseconds, hundreds of times faster than resistive thermometers.
“The thermometer allows researchers to measure the temperature of a wide range of components in their test packages at very little cost and without introducing a large number of additional electrical connections,” says Joel Ullom, leader of the study. “This has the potential to benefit researchers working in quantum computing or using low-temperature sensors in a wide range of fields.”
The research was published in the journal Applied Physics Letters.