MKS Instruments, Inc.
Thermal conductivity gauge

Abstract:

A thermal conductivity gauge measures gas pressure within a chamber. A sensor wire and a resistor form a circuit coupled between a power input and ground, where the sensor wire extends into the chamber and connects to the resistor via a terminal. A controller adjusts the power input, as a function of a voltage at the terminal and a voltage at the power input, to bring the sensor wire to a target temperature. Based on the adjusted power input, the controller can determine a measure of the gas pressure within the chamber.