Cold cathodes for sealed off CO2 lasers

Experimental results of a group of theoretically selected cold cathode materials are presented. These tests indicate Ag-CuO, Cu and Pt-Cu as three new cold cathode materials for sealed off CO2 lasers. The power output of a test with an Ag-CuO cathode and a gas volume of only 50 cubic centimeters varied from 0.72 W to 1.1 W at 3000 hours and yields still 0.88 W after 8000 hours. Gas discharge tubes with Cu cathodes and a volume of 25 cubic centimeters yield life times in excess of 10,000 hours. Gas analysis results, obtained from a similar tube over a period of 3000 hours, look most promising. A Pt-Cu alloy cathode shows an extremely promising V-I characteristic over a period of 2800 hours.