Electron emission from sharp points in liquid argon

Electron charge injection from a point electrode in gaseous and in liquid argon has been observed and its characteristics studied. In liquid argon, as we have observed, the charge dependence on applied voltage is governed by space charge limitation. The emission was found to take place (with the electrode in liquid phase) not continuously but as a pulsed injection. The pulsing rate has been studied as a function of the voltage, time and electrode separation. The measurements done so far have been performed in a closed environment with an impurity content of argon of the order of some tenth of p.p.b. (oxygen, CO2, etc.). Possible applications in liquid-argon purification and particle detection is presented.