Vapor pressure thermometry at room temperature

TLDR: A thermometer that measures changes in the vapor pressure of a volatile substance to infer the temperature of its liquid phase and provides a noise-equivalent-temperature resolution of 16 μK over a 1 Hz bandwidth — an order of magnitude improvement over previous vapor-pressure thermometers.

Abstract: Many calorimetric sensing applications, such as measurement of heat exchange in chemical reactions or of the heat production of biological specimens, require high-resolution temperature sensors suitable for use at or near room temperature. We have developed a thermometer that measures changes in the vapor pressure of a volatile substance to infer the temperature of its liquid phase. Our prototype sensor provided a noise-equivalent-temperature resolution of 16 μK over a 1 Hz bandwidth — an order of magnitude improvement over previous vapor-pressure thermometers. The thermometer design enables temperature-resolution that has the potential to be extended to the microkelvin range, and imposes minimal thermal load on the heat source. Furthermore, the sensing element responsible for transduction of temperature changes into movement is inexpensive, enabling the possibility of disposable transducing elements in a sensor system. While this thermometer demonstrates the feasibility of the modality for high-resolution measurements of temperature change, without further advances in methodology current construction techniques limit the reproducibility between sensors, which may constrain the wide applicability of the sensor system.