Charge Exchange Cross Sections for Electron Loss from B+, P+, and N+ on N2

Abstract

The cross sections for electron loss from singly ionized B, N, and P ions at 100 keV, 200 keV, and 300 keV in collisions with N2 have been measured. The cross sections for a singly ionized projectile to become doubly ionized, σ12, are (10−16 cm2 per molecule): σ12 (B, 100 keV) = 2.0, σ12 (B, 200 keV) = 3.4, σ12 (B, 300 keV) = 4.4, σ12 (N, 100 keV) = 2.2, σ12 (N, 200 keV) = 3.4, σ12 (N, 300 keV) = 4.6, σ12 (P, 100 keV) = 4.3, σ12 (P, 200 keV) = 6.6, and σ12 (P, 300 keV) = 8.7. The cross sections for double electron loss were also measured. The observed cross section for P+→P2+ indicates that for a 1% contamination of a 300-keV P+ ion beam with P2+, the pressure times path length of the beam is 3.5×10−6 Torr m.