Intensities of 2288 Å and 3261 Å Radiation from Low-Pressure Cadmium Rare-Gas Discharges

The uv power radiated, at 3261 Å and 2288 Å, and the input power to the positive column of Cd-1.6-Torr Ar and Cd-5-Torr Ne discharges are presented for both ac and dc currents. The maximum 3261-Å radiation output occurs at a Cd pressure in the range from 5 to 10 mTorr, the same pressure range as found for Hg in the Hg rare-gas low-pressure discharge. The Cd discharge is compared with the well-known Hg-3-Torr Ar discharge, using a simplified model for the discharge. It is believed that the Cd-1.6-Torr Ar data presented here are near the optimum uv production efficiency for the Cd rare-gas discharge.