Z2 and energy dependence of range distributions and stopping powers for nitrogen ions in solids

Range distributions of nitrogen ions implanted in solid targets have been studied as a function of target material and projectile energy and for both atomic- and molecular-ion species. These profiles were determined by a nuclear resonance reaction technique in which the 14N( p,γ)15O reaction at 1058 keV was used. At a single energy of 800 keV, 14N+ ions were implanted in 24 elemental targets from carbon through lead. From these range distributions electronic stopping powers were inferred which show the familiar periodic structure with target atomic number. For three targets, iron, nickel, and zirconium, the energy dependence of the range distributions was studied for incident 14N+ ions from 200 to 2000 keV. The data suggest that the electronic stopping power has the same energy dependence for each target and is consistent with being proportional to velocity. For these three targets and for gold also, the range distributions were determined for both atomic and molecular nitrogen-ion beams of equal energy per atom. The data suggest that at higher particle energies the molecular beam gives rise to slightly more shallow distributions