Patent ID: 11948774
Assignee: SERVOMEX GROUP LIMITED
Field: Measurement (Instruments)
Classification: CPC H  G | IPC G  H

Claim 0:
1. A method comprising:
generating one or more oscillating electromagnetic fields within a plasma cell to excite particles within the cell, to produce a glow discharge plasma in the plasma cell, and controlling the operating conditions for the plasma cell while flowing a gas mixture through the plasma cell to maintain glow discharge optical emissions from the plasma within a desired operating range; and
monitoring one or more glow discharge optical emissions from the plasma in the plasma cell;
wherein said monitoring of the optical emissions comprises measuring the optical emissions, or measuring a signal that correlates with the optical emissions, at twice the plasma excitation frequency; and
processing the measured optical emissions or signal during each excitation cycle of the electromagnetic excitation, to determine the concentration of a gas within a gas mixture flowing through the plasma cell.