Complementary scattered and recoiled ion data from ToF- E heavy ion elastic recoil detection analysis

Abstract

The advantage of Time of Flight and Energy (ToF- E) Heavy Ion Elastic Recoil Detection Analysis (HIERDA) over Rutherford Backscattering (RBS) analysis is its mass and energy dispersive capabilities. RBS cannot separate signals from very heavy elements; the limitation is a result of physical principles of the two-body collision process. The mass resolution of ToF- E HIERDA deteriorates for very heavy elements; the limitation is related to the poor energy resolution of Si detectors for heavy ions. Very high ion energies improve the energy resolution and consequently the mass resolution of HIERDA, but significantly lower the cross section. Usually the energy spectra from ToF- E HIERDA data are used to extract depth profiles. In this work, the benefits of using the time spectra of both the recoiled and the scattered ions are discussed. The advantages are: (i) improved depth resolution by using the time spectra, and (ii) although the energy of very heavy recoils decreases with increasing mass, the energies of scattered ions increase. Time and energy projections of spectra, which have overlapping signals provide complementary data for analysis.