Using Thin-Film Thermometers as Heaters in Thermal Control Applications

NASA's Jet Propulsion Laboratory, Pasadena, California

A cryogenic sensor maintains calibration at ≈4.2 K to better than 2 mK (<0.5 percent resistance repeatability) after being heated to ≈40 K with ≈0.5 W power. The sensor withstands 4 W power dissipation when immersed in liquid nitrogen with verified resistance reproducibility of, at worst, 1 percent. The sensor maintains calibration to 0.1 percent after being heated with 1-W power at ≈77 K for a period of 48 hours.

When operated with a readout scheme that is capable of mitigating the self-heating calibration errors, this and similar sensors can be used for precision (mK stability) temperature control without the need of separate heaters and associated wiring/cabling.

This work was done by Hyung J. Cho, Konstantin Penanen, Kalyani G. Sukhatme, and Warren A. Holmes of Caltech, and Scott Courts of Lake Shore Cryotronics for NASA’s Jet Propulsion Laboratory. For more information, download the Technical Support Package (free white paper) at www.techbriefs.com/tsp under the Physical Sciences category. NPO-46882