Photoionization detector having improved gain and reduced humidity sensitivity

A planar photoionization detector sensor comprising

• a plate having a top surface and a bottom surface and being comprised of an electrically insulating substrate,
• a plurality of circular openings for UV light to pass through,
• a negative electrical potential pattern on the top surface,
• an electron collecting electrode pattern on the bottom surface, and
• a grounded potential conductive pattern on the top surface,
• wherein
• the plurality of circular openings form an approximate circle,
• the negative electrical potential pattern includes a circular void in its center,
• the circular void surrounds the plurality of circular openings,
• the circular void of the negative electrical potential pattern is comprised of a hydrophobic material,
• the negative electrical potential pattern is at least a first distance away from every edge of the plurality of circular openings,
• the electron collecting electrode pattern is comprised of a core and a connection,
• the core of the electron collecting electrode pattern substantially fills an area surrounding the plurality of circular openings,
• the connection connects the core to an electron collecting electrode feed-thru pin,
• a diameter of the core of the electron collecting electrode pattern is smaller than a diameter of the circular void, and
• the grounded potential conductive pattern is interposed between the negative electrical potential pattern and the electron collecting electrode feed-thru pin.

A planar photoionization detector sensor comprising:

• a plate having a top surface and a bottom surface and being comprised of an electrically insulating substrate,
• at least one opening for UV light to pass through,
• a negative electrical potential pattern on the top surface, and
• an electron collecting electrode pattern on the bottom surface,
• wherein
• the negative electrical potential pattern includes a void in its center,
• the void surrounds the at least one opening,
• the negative electrical potential pattern and the electron collecting electrode pattern are offset relative to each other,
• the negative electrical potential pattern is located along, without touching, at least portions of at least three of four edges of the sensor,
• the negative electrical potential pattern is located along an entire first edge of the sensor,
• the negative electrical potential pattern is located along a portion of a second and a third edge of the sensor, and
• the first edge of the sensor is between the second and third edges of the sensor.