Multiple scattering of heavy ions through ΔE Si surface barrier detectors

The multiple scattering of 30-60 MeV 12C ions and 40-70 MeV 16 O ions by ΔE Si surface barrier detectors of thicknesses 10.3 μm and 14 μm was measured with a position sensitive detector. The horizontal spatial distributions of the heavy ions were extracted from position measurements made both with and without the ΔE counter in place. Calculations based on the theories of Moliere and Nigam, Sundaresan, and Wu (NSW) were made and compared to the data. The much simpler form of the NSW theory predicted fwhm which were much too large when compared to the experimental data while the Moliere theory gave a reasonable description of the experimental distributions at the higher incident particle energies. However, the Moliere calculations overestimated the fwhm by 28% in the case of 30 MeV 12C ions incident upon the 10.3 μm detector. Particle detection efficiencies for a typical time-of-flight system are presented. (Auth.)