Alternating current discharge ionization detector

A detector comprising:

• working gas supply;
• a sampling system;
• a plurality of sensors coupled to the working gas supply and the sampling system, each sensor comprising:
• a buffer chamber for receiving a working gas from the working gas supply;
• a discharge chamber that receives the working gas from the buffer chamber;
• discharge electrodes in the discharge chamber;
• and
• an ionization chamber that receives sample gas from the sampling system and active species from the discharge chamber;
• and
• an alternating current power supply coupled to drive the discharge electrodes in the sensors and thereby create an AC discharge that creates the active species.

A method for detecting a target gas in a sample gas, comprising:

• providing a sensor comprising:
• a buffer chamber;
• an ionization chamber;
• and
• a discharge chamber disposed between and coupled to the buffer chamber and the ionization chamber, the discharge chamber being narrower than both the buffer chamber and the ionization chamber and including discharge electrodes;
• supplying a first working gas to the buffer chamber of the sensor;
• supplying the sample gas to the ionization chamber of the sensor;
• driving the electrodes with an AC power supply to cause an AC electric discharge between the electrodes whereby the AC electric discharge through the first working gas creates first ionizing agents;
• exposing the sample gas to the first ionizing agents in the ionization chamber;
• and
• measuring a first current resulting from ions created in the sample gas by the first ionizing agent.