Forward recoil elastic scattering

This technique is known by a host of terms. As well as ERD, one sees it referred to as "forward scattering analysis, Forward Recoil Elastic Scattering (FRES) and Elastic Recoil Detection Analysis (ERDA). 

Forward recoil spectrometry (FRS) [33], also known as elastic recoil detection analysis (ERDA), is fiindamentally the same as RBS with the incident ion hitting the nucleus of one of the atoms in the sample in an elastic collision. In this case, however, the recoiling nucleus is detected, not the scattered incident ion. RBS and FRS are near-perfect complementary teclmiques, with RBS sensitive to high-Z elements, especially in the presence of low-Z elements. In contrast, FRS is sensitive to light elements and is used routinely in the detection of Ft at sensitivities not attainable with other techniques [M]- As the teclmique is also based on an incoming ion that is slowed down on its inward path and an outgoing nucleus that is slowed down in a similar fashion, depth infonuation is obtained for the elements detected. 

Scanning tunneling microscopy Light-scattering Ion beam analysis (forward recoil spectrometry) Chaudhury-Whitesides apparatus Atomic resolution, relatively inexpensive Determines interior surface areas Surface composition and diffusion coefficients can be determined Measures adhesion forces nondestructively Resolution limited with insulating materials Secondary scattering must be eliminated Length scale resolution 150 A at best Polymer must be in the rubber-elastic state... 

Elastic Recoil Detection (ERD) also referred to as Elastic Recoil Detection Analysis (ERDA), Elastic Recoil Scattering (ERS), Eorward Recoil Scattering (FRS), Forward Recoil Spectrometry (FReS), and Hydrogen Forward Scattering (HFS)... 

Forward recoil spectrometry (FRES, FReS or FRS), which is also referred to as elastic recoil detection analysis (ERDA or ERD), is a member of a family of techniques collectively termed ion beam analysis (IBA). FRES is a powerful, standard-free absolute method for the measurement of atomic composition and impurity concentrations in the near-surface region of solids, and is considered a fully non-invasive technique. However, in the case of polymeric materials this assumption is not entirely true, since the projectile ions cause a breaking of covalent bonds (vide infra). The method is based on scattering of an incident accelerated-ion beam by the sample, due to nuclear and electrostatic interactions. The collision of the ions with the specimen results - in addition to scattered incident ions - in the ejection of photons, ions, or nuclear decay products, as shown schematically in Figure 23.28 [110]. 

The use of nuclear techniques allows the determination of C, N, H, O, and heavier contaminants relative fractions with great accuracy, and of the elements depth profile with moderate resolution (typically 10 nm). Rutherford backscattering spectroscopy (RBS) of light ions (like alpha particles) is used for the determination of carbon and heavier elements. Hydrogen contents are measured by forward scattering of protons by incident alpha particles (ERDA) elastic recoil detection analysis [44,47]. 

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