Photoionization detector and method for gas sample analysis

A PID comprising:

• an ionization chamber configured to receive a gas sample, the ionization chamber defining an ionization region and a detection region;
• a UV radiation source configured to generate UV radiation, the UV radiation source comprising an optical window configured to transmit at least part of the UV radiation into the ionization chamber to irradiate the gas sample in the ionization region, wherein the optical window is made of a window material comprising sapphire (Al2O3);
• an electric-field ionization source configured to apply an ionizing electric field to the gas sample in the ionization region, wherein the ionizing electric field is configured to combine with the transmitted UV radiation to ionize the gas sample into an ionized gas sample;
• and
• an ion detector configured to detect, in the detection region, an ionization current resulting from the ionized gas sample.

A method of analyzing a gas sample, comprising:

• flowing the gas sample through an ionization chamber comprising an ionization region and a detection region;
• subjecting, in the ionization region, the gas sample to ionizing radiation and an ionizing electric field to ionize the gas sample into an ionized gas sample;
• and
• detecting, in the detection region, an ionization current resulting from the ionized gas sample to produce a detection signal conveying information about the gas sample.