The Mean Free Path of the Alkali Ions in Different Gases

Abstract

Retardation and neutralization of caesium and sodium ions in traversing hydrogen, helium and argon.—With caesium ions of 90 volt velocity in hydrogen there is very little neutralization or scattering of the ions even when their path is twenty times the mean free path for a xenon atom in hydrogen. There is a loss of velocity of 1.3 volts per collision. Similar phenomena were observed in helium. Caesium rays of 35 volts velocity in hydrogen are slowly weakened by neutralization or scattering. Sodium ions of 455 volt velocity are also weakened in hydrogen, but the free path for a collision that removes the ion from the bundle is 26 times that of a neon atom in hydrogen. In argon, caesium ions of 90, 35 and 20 volt velocities are rapidly neutralized with a free path only 3.4, 2.6 and 2.3 times that of a xenon atom in argon.