Systems and methods for internal surface conditioning assessment in plasma processing equipment

A plasma source, comprising:

• a first perforated electrode comprising a first planar surface that is configured for transfer of one or more plasma source gases through first perforations therein;
• a second perforated electrode comprising a second planar surface that is configured for movement of plasma products therethrough toward a process chamber, the second electrode being held at electrical ground;
• an insulator having upper and lower surfaces that are disposed in contact with the first and second planar surfaces about a periphery of the first perforated electrode and a periphery of the second perforated electrode, such that the first and second perforated electrodes and the insulator define a plasma generation cavity;
• and
• a power supply that provides electrical power across the first and second perforated electrodes to ignite a plasma with the one or more plasma source gases in the plasma generation cavity to produce the plasma products;
• wherein the insulator includes a port that provides an optical signal from the plasma, the port comprising:
• a radial aperture formed within the insulator;
• an optical window that is sealable to the insulator across an outer opening of the radial aperture, and
• a fixture that positions a fiber optic adjacent the optical window such that optical emissions from the plasma propagate into the fiber optic to form the optical signal, the fiber being oriented such that the optical signal is limited to optical emissions originating within the plasma generation cavity.