The Use of Carbon-Cathode Penning Discharge Cells to Evacuate Xenon over a Pressure Range of 10{sup}(-3)-10{sup}(-4) Torr

摘要

Experimental data are presented as proof that the Penning discharge in a carbon-cathode cell can be used to reduce (or regulate) the Xe pressure in the working chamber of an ultrahigh vacuum system from 2 × 10{sup}(-3) to 2 × 10{sup}(-4) Torr. Sorption of Xe is attributed to the implantation of accelerated ions in the porous structure of the surface carbon layers formed while the cathodes are being prepared from a powdered material and under ion bombardment. As the Xe pressure is lowered within the above limits, the evacuation rate decreases from ≈0.045 L/s to zero. The time dependence of the evacuation rate is governed by the initial Xe pressure.