Charge Changing of Energetic Heavy Ions in Gases

Abstract

The electron loss and capture cross sections of carbon (σ 45 , σ 56 , σ 65 ) and of nitrogen ions (σ 45 , σ 56 , σ 67 , σ 76 ) in H 2 , He, N 2 , Ne, Ar, Kr and Xe gases were measured at energies of 3.5 to 7.5 MeV/nucl. As the result, it has been found that cross sections for singly electron loss of those energetic heavy ions agree nearly with a formula given by N. Bohr and generalized by I.S. Dmitriev who derived the formula for electron loss in a free collision approximation through a classical treatment, and that from the relation between the electron loss cross sections and the atomic number of gaseous medium Z med , the shielding effect of target gas was observed obviously in the region of \(Z_{\text{med}}{\gtrsim}10\). Cross sections for electron capture could not fit to previous theories, but agreed well with the calculation derived by Urata and Watanabe recently using an impulse approximation.