Excitation processes in a Pb‐He discharge
| Autor: | Lee A. Cross, M. Cem Gokay |
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| Rok vydání: | 1978 |
| Předmět: | |
| Zdroj: | Journal of Applied Physics. 49:2639-2650 |
| ISSN: | 1089-7550 0021-8979 |
| DOI: | 10.1063/1.325207 |
| Popis: | Measurements of the emission from Pb+ in the afterglow of a pulsed He : Pb discharge in a large‐bore tube and of the intensities of Pb+ and Pb emission lines in a small‐bore dc discharge tube have been made to clarify the excitation mechanism of the He : Pb laser. In both He : pure Pb and He : Pb containing a low concentration of Cd to act as a probe, the rate constants for the decay of the Pb+ and Cd+ emission lines obtained using the large‐bore tube indicated that the only excitation mechanism was thermal charge exchange between 2S1/2He+ and ground‐state Pb atoms. The collision cross section for the He+‐Pb reaction was determined to be 4.0×10−16 cm2 from measurements of the variations of the decay rates of the 5608.8‐A Pb+, 4386.4‐A Pb+, and 5378‐A Cd+ emission lines with Pb concentration. The variation of the rate constant of the 4416‐A Cd+ line indicated that the collision cross section for the 2s 3S1 He‐Pb Penning ionization is 14.8×10−16 cm2. In a small‐bore tube, Penning ionization was verified to... |
| Databáze: | OpenAIRE |
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