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

Claim 19:
20. A system comprising:
a plasma cell with an inlet and an outlet for flowing a gas mixture through the plasma cell;
an electromagnetic field generator for generating one or more oscillating electromagnetic fields within the plasma cell, to excite particles within the cell to produce a glow discharge plasma in the plasma cell;
a controller for controlling 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
one or more optical detectors coupled to one or more measurement circuits configured to monitor 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;
wherein the system comprises a signal processor configured to process the measured optical emissions or measured 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.