Charge Exchange of Carbon and Nitrogen Ions in Nitrogen Gas

Electron loss and capture cross section of carbon and nitrogen ions were measured at 3.5∼7 MeV/nucl., i.e. velocities of 2.6∼3.7×10 9 cm/sec in nitrogen gas. Cross sections obtained were σ 45 , σ 56 , σ 65 , for carbon ions and ∑ k =5 7 σ4 k for nitrogen ions when they passed through the charge exchange (collision) chamber. Cross sections of single electron loss σ 45 and σ 56 are nearly proportional to v 0 / v and those of single electron capture σ 65 are proportional to ( v 0 / v ) 6 , where v 0 is the atomic unit of velocity and v is ion velocity. This paper reports also on the comparison between the beam attenuation of N 4+ ions, which were accelerated in the IPCR 160 cm cyclotron, caused by charge exchange at collisions with residual gases, and the attenuation calculated from measured ∑ k =5 7 σ4 k in nitrogen gas.