Researchers at NIST in Maryland are developing a nanoscale array of ultra-sensitive temperature sensors that can be embedded in all kinds of materials.The system will be the first to make real-time measurements of temperature on the microscopic scale in an opaque 3D volume, which could include medical implants, refrigerators, electronics and potentially the human body.
The Thermal Magnetic Imaging and Control (Thermal MagIC) project could revolutionize temperature measurements in many fields: biology, medicine, chemical synthesis, refrigeration, the automotive industry, plastic production, says the team. "Pretty much anywhere temperature plays a critical role," said NIST physicist Cindi Dennis. "And that's everywhere."
Thermal MagIC will work by using nanometer-sized objects whose magnetic signals change with temperature. These sensors would be incorporated into the liquids or solids being studied, for example in melted plastic that might be used as part of an artificial joint replacement, or the liquid coolant being recirculated through a refrigerator. A remote sensing system would then pick up these magnetic signals, meaning the system being studied would be free from wires or other bulky external objects.
The final product could make temperature measurements that are 10 times more precise than state-of-the-art techniques, accurate to within 25 millikelvin in 100ms. The measurements would be traceable to the International System of Units (SI); in other words, its readings could be accurately related to the fundamental definition of the kelvin, the world's basic unit of temperature.
The system aims to measure temperatures over the range from 200 to 400 kelvin (K), -73 to 126C. There is potential for a much larger temperature range, stretching from 4K to 600K, but that is not a part of current development plans.
"This is a big enough sea change that we expect that if we can develop it -- and we have confidence that we can -- other people will take it and really run with it and do things that we currently can't imagine," Dennis said.
The first step is creating the nanoscale magnets that will give off strong magnetic signals in response to temperature changes. These need to be 10 times more sensitive to temperature changes than any objects that currently exist and so will use multiple magnetic materials.