Advances in temperature measurement

The need for temperature measurement is ever present in science and industry from requirements for monitoring processes, in the management of quality control and research. Temperature can be measured by means of direct contact between the medium of interest and the measuring device or by remote observation of a temperature-dependent parameter. The range of devices with which temperature can be measured is extensive, not surprisingly because most physical parameters exhibit a dependency on temperature. In recent years the dominant position of liquid-in-glass and bimetallic thermometers, thermocouples, and resistant temperature detectors has been challenged as the common choice for temperature measurement by infrared thermometers and an increasing array of other noninvasive techniques. This chapter outlines the principal techniques available for the measurement of temperature, describing the physical phenomena exploited, the temperature range of use, equipment required, and typical applications. Recent trends in requirements for traceability and quantification of uncertainty, as well as developments in the areas of instrumentation capability and technique, are described.