Partial pressure gauge assembly for process contaminant detection using photoionization and associated method

A photoionization sensor assembly configured to measure an analyte gas in a presence of non-analyte gases, comprising:

• a housing defining a chamber with a first end and an opposing second end, wherein the chamber is permeable to molecules of the analyte gas and non-analyte gases surrounding the housing;
• a radiation source configured to emit photons into the chamber;
• a first conductive electrode positioned towards the first end of the chamber;
• a second conductive electrode positioned in the chamber;
• a third conductive electrode positioned towards the second end of the chamber;
• and
• a controller in communication with at least the first and second conductive electrodes,
• wherein the emitted photons ionize at least some molecules of the analyte gas, wherein the emitted photons are insufficient to ionize molecules of the non-analyte gases,
• wherein the emitted photons strike the third conductive electrode resulting in ejection of photoelectrons,
• wherein the controller is configured to:
• receive a measurement of a total pressure of the analyte gas and the non-analyte gases,
• electrically bias the first, second and third conductive electrodes such that the photoelectrons are attracted toward and collected on the first and second conductive electrodes in a ratio that is dependent on the total pressure of the analyte gas and the non-analyte gases,
• measure an electrical current generated on the first and second conductive electrodes,
• determine the ratio of the ejected photoelectrons that are collected on the first and second conductive electrodes at the total pressure, and
• determine an amount of electrical current due to ionization of the analyte gas by correcting the measured current using the determined ratio to subtract an electrical current caused by the photoelectrons from the measured electrical current.

A method for measuring an analyte gas in a presence of non-analyte gases, comprising:

• structuring a photoionization sensor to comprise,
• a housing defining a chamber with a first end and an opposing second end, wherein the chamber is permeable to molecules of the analyte gas and non-analyte gas surrounding the housing;
• a radiation source configured to emit photons;
• a first conductive electrode positioned towards the first end of the chamber;
• a second conductive electrode positioned in the chamber;
• a third conductive electrode positioned towards the second end of the chamber;
• and
• a controller in communication with at least the first and second conductive electrode,
• emitting photons from the radiation source into the chamber to ionize at least some molecules of the analyte gas, wherein the emitted photons are insufficient to ionize molecules of the non-analyte gases,
• emitting photons from the radiation source into the chamber to strike the third conductive electrode and cause an ejection of photoelectrons,
• wherein the controller:
• receives a measurement of a total pressure of the analyte gas and the non-analyte gases,
• electrically biases the first, second and third conductive electrodes such that the photoelectrons are attracted toward and collected on the first and second conductive electrodes in a ratio that is dependent on the total pressure of the analyte gas and the non-analyte gases,
• measures an electrical current generated on the first and second conductive electrodes,
• determines the ratio of the ejected photoelectrons that are collected on the first and second conductive electrodes at the total pressure, and
• determines an amount of electrical current due to ionization of the analyte gas by correcting the measured current using the determined ratio to remove an electrical current caused by the photoelectrons.

A method of measuring a total pressure of a gas, comprising:

• structuring a photoionization sensor assembly to comprise, a housing defining a chamber including a first end and an opposing second end,
• wherein the chamber is permeable to molecules of the gas surrounding the housing,
• a radiation source configured to emit photons into the chamber,
• a first electrode positioned towards the first end of the chamber,
• a second electrode positioned in the chamber,
• a third electrode positioned towards the second end of the chamber, and
• a controller in communication with at least the first and second electrodes;
• striking the third electrode with the emitted photons to cause ejecting of photoelectrons;
• and
• wherein the controller:
• electrically biases the first, second and third conductors such that the ejected photoelectrons are attracted toward and collected on the first and second electrodes in a ratio that is dependent on a total pressure of the gas, wherein the photoelectrons generate an electrical current on the first and second electrodes,
• measures the electrical current generated on the first and second electrodes, and
• determines the total pressure of the gas based on the electrical current generated on the first and second electrodes.