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RESEARCH PRODUCT

Elastic Recoil Detection Analysis

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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 35Cl 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 4He 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 (see Nuclear Reaction Analysis) 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 1H and 2H depth distributions, access to single-ended Van de Graaff accelerators compared with tandem accelerators or cyclotrons, and the ability to be combined with Rutherford backscattering spectrometry (RBS) (see Rutherford Backscattering Spectroscopy). 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 high mass number elements give this method a wide area in which to progress. The main advantage of heavy-ion ERDA and quite unique feature among analysis techniques is the fact that all sample elements can be depth profiled in one measurement by single detector telescope. By means of Monte Carlo (MC) simulations, the interpretation and reliability of the results have increased greatly over the last few years.