Brrr…it’s cold in there

Some of the most interesting condensed matter physics occurs at very low temperatures and physicists need accurate ways of knowing just how cold their samples are. Traditionally, this has meant spending hours building, calibrating and troubleshooting temperature measurement and control systems — instead of actually doing the experiments.

Those days are over in many labs — at least according to Shane Hritz of Lake Shore Cryotronics. Hritz was in town to talk to physicists about the company’s cryogenic sensors, temperature control systems and magnetic measurement systems. He believes that physicists are hesitant to commit valuable resources to building and maintaining laboratory equipment. Instead, they want off-the-shelf kit that works the first time.

Resistance bridge: Lake Shore’s
Shane Hritz shows off the company’s
latest equipment for measuring
temperatures as low as 20mK.

The company has just launched a new ruthenium oxide temperature sensor that is said to be the first commercial system calibrated down to 20mK — its last sensor was calibrated down to 50mK. “This doesn’t sound like much,” said Hritz, “but at these temperatures heat transfer through the leads becomes a big problem — any small bit of energy that gets into the sample can affect its temperature.”

Hritz say the company is now working on a sensor that is calibrated down to 10mK.