Measurement of Cl2 Concentration in a XeCl Hollow Cathode Discharge Including the Effect of H2 Addition

摘要

A hollow cathode discharge tube was used to excite a Hcl/Xe/Ne gas mixture of 4%/16%/80%. Total gas pressures of 4 and 6 Torr and discharge currents ranging from 200, 300, 400, and 500 m/A were investigated. A photon counting technique was used in a U.V. absorption spectroscopy experiment to determine the partial pressure of Cl2 as a function of current and pressure and for monitoring the 308 mn emission of XeCl for these conditions. XeCl emission decreased with time as a result of the introduction of additional chlorine to the system from the discharge tube surface. Both this surface supplied chlorine and that originating from the HCl in the original mix resulted in a substantial concentration of Cl2 being observed. The surface desorption rate increased with current and was dramatically enhanced by the addition of small amounts of H2 to the discharge mix. (author)