Elastic Scattering of Heavy Ions from Several Gas Targets

The absolute differential cross section for the elastic scattering of oxygen by gaseous targets of helium, nitrogen, and neon and of carbon by nitrogen were measured from about 4 to {~}20 degrees in the center-of-mass system. The energy of the incident heavy ions was {~}10 Mev per atomic mass unit. The ratio of the elastic cross section to the Coulomb cross section exhibits diffraction-like oscillations which damp out as η=Z₁Z₂e²v increases from {~}1 to {~}4. The results are compared with the predictions of a simple diffraction model, a sharp-cutoff model, and a modified-cutoff model. Reasonably good agreement is obtained in predicting the angular position of the maxima and minima, but not the absolute cross section. The modified-cutoff model appears to apply only if η is greater than about 2.5. The value of r₀ found for the O¹⁶-Ne scattering is 25% greater than for the remaining three reactions.