H recoil cross-sections for 7Li ions at 30° and 45° in the energy interval from 2.28 to 5.70 MeV

Elastic recoil detection analysis (ERDA) using a He ion beam and a detector with a stopper foil is a common technique for the analysis of hydrogen and its isotopes. A good alternative to He ERDA, for laboratories not equipped with a He ion source, is the use of Li ions. These may be beneficial because of an increased depth resolution due to the larger stopping power and higher cross-section for hydrogen recoils. Deviations from the Rutherford cross-section at 30 degrees can be expected for energies above 2.9 MeV. However, as far as the authors know, ERDA cross-sections for H with Li ions at energies above this critical energy are not available in the literature. Therefore, differential proton recoil cross-sections for incident 7 Li ions were measured in this work in an energy range between 2.28 and 5.70 MeV at recoil angles of 30 degrees and 45 degrees. Thin melamine foils (similar to 50 mu g/cm(2)) evaporated on thin Al (similar to 50 mu g/cm(2)) backings were used for the measurements. Special care was taken to monitor hydrogen loss during the measurement. (c) 2004 Elsevier B.V. All rights reserved.