ABSTRACT
In conventional resistor thermal gauges, called Pirani gauges, the sensing elements are metallic filament resistors, and phenomenon used for pressure measurement is molecular thermal conductivity of gases at high-vacuum condition. Thermal gauges were designed to operate in a pulse regime, or they were constructed to sense visible light emission as a function of pressure instead of the resistance and associated parameters, and they have been constructed as microdevices. All these devices represent qualitatively different vacuum pressure sensors, though the principle of heat transfer in place. The response time to pressure change of thermal gauges, especially those operated in constant temperature mode, is very fast, which makes these gauges suitable for the protection of other vacuum instruments. The designs may require multipin feedthroughs that enlarge vacuum flange and determine the size of the gauge. The integration of gauges with different sensitivities on a single chip may be suitable for partial pressure analysis.
