Abstract
The time dependences of the ion wall currents in a 76 °K helium afterglow were measured with a quadrupole mass-filter system. The species observed were , , , , and metastable atoms. The results of the present work are a zero-field mobility, , of 14.4 ± 0.3 , and a three-body conversion frequency of into of , where is the density in atoms/. The diffusion coefficient that describes the late-time behavior of was found to be 95.3 ± 8.6 Torr. The metastable helium atoms at 76 °K were found to have a diffusion coefficient given by Torr. Evidence is presented for the presence of helium negative ions in the 76 °K helium afterglow.
- Received 5 April 1971
DOI:https://doi.org/10.1103/PhysRevA.4.2027
©1971 American Physical Society