Evaluation of pressure effects on acoustic thermometer with a single waveguide

Abstract

This paper presents the implementation and testing of an acoustic thermometer with a single waveguide. The proposed design has several specific advantages compared to other acoustic designs with waveguides, such as its smaller size, improved sensitivity, and the same common sound path. This paper describes each advantage and the tests used to determine their usefulness. It also shows how to deal with the disadvantages of this design, such as its weak return signals and possible coincidences concerning the return signals. The instrument was calibrated at ice point and then tested in an oil bath from -30 °C to 120 °C. In steady state, it had a standard deviation of 0.050 °C, with 66 independent readings per second. The stability of the bath was 10 mK and the uncertainty of the reference thermometer was 0.003 °C.