Decay Rate Measurements of Upper Laser Levels in He-Ne and He-Se Lasers

The decay rates of the upper laser levels of SeII and NeI have been measured by the magnetic-field dip method. These decay rates are found to vary lineary with the He pressure. The radiative linewidths of SeII are estimated from the decay rates at the zero-pressure limit and found to be in units of MHz; 26.4 (5p2D5/2); 19.9 (5p4P3/2); 16.0 (5p4P5/2); 14.9 (5p4D5/2); 10.3 (5p4D7/2); 13.4 (5p2D3/2). The collision cross sections for these excited Se ions with He atoms are also estimated from the slopes of the He pressure dependences and found to be 5.85, 7.95, 7.43, 8.25, 8.65, and 8.15 respectively in units of 10-15 cm2. The radiative linewidth of the Ne 3s2 state is 11.8 MHz. The collision cross sections for the Ne 3s2 state atoms with He and Ne atoms are 2.52 and 12.2 respectively in units of 10-15 cm2.