Capacitive sensor housing for chamber condition monitoring

A sensor assembly, comprising:

• a shaft with a first end and a second end, wherein the shaft is hollow;
• a capacitor on a first surface of a substrate, wherein a second surface of the substrate interfaces with the first end of the shaft;
• and
• a cap over the first end of the shaft, wherein the cap secures the substrate against the first end of the shaft, and wherein an opening through the cap exposes the capacitor.

A sensor assembly, comprising:

• a vacuum electrical feedthrough, wherein the vacuum electrical feedthrough comprises a first flange where the first flange has a first hole;
• a housing body attached to the vacuum electrical feedthrough, wherein the housing body has an internal volume, a first end, and a second end, and wherein the housing body comprises a second flange on the first end of the housing body, where the second flange has a second hole that is aligned with the first hole on the vacuum electrical feedthrough;
• a shaft having a first end and a second end, wherein the first end of the shaft is attached to the second end of the housing body, wherein the shaft is hollow;
• and
• a capacitive sensor secured against the second end of the shaft by a cap, wherein the cap comprises an opening to expose a first electrode and a second electrode of the capacitive sensor.