A xenon gas purity monitor for EXO

Understand

We discuss the design, operation, and calibration of two versions of a xenon gas purity monitor (GPM) developed for the EXO double beta decay program.

• The devices are sensitive to concentrations of oxygen well below 1 ppb at an ambient gas pressure of one atmosphere or more.
• The theory of operation of the GPM is discussed along with the interactions of oxygen and other impurities with the GPM's tungsten filament.
• Lab tests and experiences in commissioning the EXO-200 double beta decay experiment are described.