Elastic Recoil Detection Analysis

Abstract

In 1976, a Canadian group described in detail for the first time a new ion beam analytical method based on the elastic recoil of target nuclei collided with high energy heavy incident ions. In this case 25–40‐MeV 35 Cl impinged on a multilayer C or Cu (backing)/LiF or LiOH/Cu (30–150 nm)/LiF or LiOH and H, Li, O and F recoiled atoms were detected. These exemplified the main characteristics of elastic recoil detection analysis (ERDA): its sensitivity to depth distribution and its ability to detect light elements in heavy substrates. In 1979, the use of megaelectronvolt energy 4 He beams permitted the use of ERDA to be extended to depth profiling of hydrogen isotopes in the near surface region of solids. ERDA has rapidly been revealed to be an excellent alternative to resonant nuclear reaction spectrometry for hydrogen determination in solids. Despite its less advantageous performance with respect to its lower depth resolution, lower analyzable depth, comparable sensitivity and more restricting irradiation and detection geometry, some ERDA features have made its development in ion beam analysis (IBA) laboratories worldwide easier; these are simultaneous access to 1 H and 2 H depth distributions, access to single‐ended Van de Graaff accelerators compared with tandem or cyclotrons, the ability to be combined with Rutherford backscattering spectrometry (RBS) and a less damaging effect on the investigated targets compared to those generated by heavy ions. The development of detection devices and the analytical capabilities offered by high‐energy heavy ion‐induced ERDA in material sciences for profiling light, medium and large mass number elements give this method a wide area in which to progress as illustrated by discussions at ion beam‐related technique conferences.