Rutherford backscattering studies

M. L. Polignano and G. Queirolo, Studies of the Stripping Hall Effect in Ion-Implanted Silicon J. Stoemenos, Transmission Electron Microscopy Analyses R. Nipoti and M. Servidori, Rutherford Backscattering Studies of Ion Implanted Semiconductors... 

The corrosion resistance of an industrial magnesium alloy (AZ31B) could be significantly increased by plasma oxidation in oxygen and water plasmas. Corresponding electrochemical studies, Rutherford backscattering spectrometry and x-ray diffractometry at grazing incidence results were published by Tian et al. [221],... 

The essentially non-destmetive nature of Rutherford backscattering spectrometry, combmed with the its ability to provide botli compositional and depth mfomiation, makes it an ideal analysis tool to study thm-film, solid-state reactions. In particular, the non-destmetive nature allows one to perfomi in situ RBS, thereby characterizing both the composition and thickness of fomied layers, without damaging the sample. Since only about two minutes of irradiation is needed to acquire a Rutherford backscattering spectmm, this may be done continuously to provide a real-time analysis of the reaction [6]. 

Chaimelling phenomena were studied before Rutherford backscattering was developed as a routine analytical tool. Chaimelling phenomena are also important in ion implantation, where the incident ions can be steered along the lattice planes and rows. Channelling leads to a deep penetration of the incident ions to deptlis below that found in the nonnal, near Gaussian, depth distributions characterized by non-chaimelled energetic ions. Even today, implanted chaimelled... 

A variety of other techniques have been used to investigate ion transport in conducting polymers. The concentrations of ions in the polymer or the solution phase have been monitored by a variety of in situ and ex situ techniques,8 such as radiotracer studies,188 X-ray photoelectron spectroscopy (XPS),189 potentiometry,154 and Rutherford backscatter-ing.190 The probe-beam deflection method, in which changes in the density of the solution close to the polymer surface are monitored, provides valuable data on transient ion transport.191 Rotating-disk voltammetry, using an electroactive probe ion, provides very direct and reliable data, but its utility is very limited.156,19 193 Scanning electrochemical microscopy has also been used.194... 

Cherniak D.J. and Ryerson F.J. (1993) A study of strontium diffusion in apatite using Rutherford backscattering spectroscopy and ion implantation. Geochim. Cosmochim. Acta 57, 4653-4662. 

Zhang, Y., et al., Damage Evolution and Recovery on Both Si and C Sublattices in Al-Implanted 4H-SiC Studied by Rutherford Backscattering Spectroscopy and Nuclear Reaction Analysis, J. Appl. Phys., Vol. 91, No. 10, 2002, pp. 6388-6395. 

Techniques based on the interaction of ions with solids, such as secondary ion mass spectrometry (SIMS) and low-energy ion scattering (LEIS) have undoubtedly been accepted in catalyst characterization, but are by no means as widely applied as for example X-ray photoelectron spectroscopy (XPS) or X-ray diffraction (XRD). Nevertheless, SIMS, with its unsurpassed sensitivity for many elements, may yield unique information on whether or not elements on a surface are in contact with each other. LEIS is a surface technique with true outer layer sensitivity, and is highly useful for determining to what extent a support is covered by the catalytic material. Rutherford backscattering (RBS) is less suitable for studying catalysts, but is indispensable for determining concentrations in model systems, where the catalytically active material is present in monolayer (ML)-like quantities on the surface of a flat model support. 

In situ methods permit the examination of the surface in its electrolytic environment with application of the electrode potential of choice. Usually they are favored for the study of surface layers. Spectroscopic methods working in the ultra high vacuum (UHV) are a valuable alternative. Their detailed information about the chemical composition of surface films makes them an almost inevitable tool for electrochemical research and corrosion studies. Methods like X-ray Photoelectron Spectroscopy (XPS), UV Photoelectron Spectroscopy (UPS), Auger Electron Spectroscopy (AES) and the Ion Spectroscopies as Ion Scattering Spectroscopy (ISS) and Rutherford Backscattering (RBS) have been applied to metal surfaces to study corrosion and passivity. 

On top of the newly developed supports a steam-stable intermediate layer was coated. The preparation of these layers is treated in detail in chapter 5. After this, the permselective silica layer was applied, which should be resistant against high temperature and steam-containing environments as well. The experimental procedure together with some transport and Rutherford BackScattering (RBS) studies are described in chapter 6. 

In this study modified silica layers were applied on undoped, flat Y-AI2O3 membranes, as described in chapter 5. Rutherford Backscattering (RBS) on some selected doped membranes was used to reveal the location of the dopants in the membrane structure. 

Sample preparation. Thin films of PBTMSS for Rutherford backscattering spectroscopy (RBS) and general plasma etching studies were spun on polished silicon wafers from a 3.5% solution in chlorobenzene using a photoresist spinner. The films were baked for 10 to 20 min. at 105-120 X in air. PBTMSS films for Auger electron spectroscopy (AES) studies were spin-coated on silicon wafers previously coated with 2000 A of gold. Films for IR studies were spin-coated onto NaCl plates. 

Cherniak D. J. and Watson E. B. (1992) A study of strontium diffusion in K-feldspar, Na—K feldspar and anorthite using Rutherford backscattering spectroscopy. Earth and Planetary Science Letters 113, 411—425. 

The potential role of humic substances and colloids on the fate of radiotoxic pollutants should be evaluated in particular around a nuclear waste repository. The different processes involving these entities such as complexation or sorption can strongly affect the behavior of radionuclides. In particular, results on the complexation of actinides with humic substances, investigated by laser induced fluorescence and spectrophotometry will be presented as well as data on the retention of colloids in the presence or not of heavy elements on mineral surfaces measured by Rutherford Backscattering spectrometry. From these studies, the impact of colloids and humic substances on radiotoxic element behavior will be discussed in terms of confinement or enhancement of migration in the geological media. 

Laboratory experiments with model systems under static conditions have been aimed at the determination of the retention mechanisms of colloids and pseudocolloids (association of a heavy element with a colloid) onto mineral surfaces. This will give a better understanding of the fate of radioelements associated with colloids upon interaction with mineral surfaces as it will occur in the water fiow across fissures and fractures around a radwaste repository. In these studies, polished cm-sized monoliths are used to simulate macroscopic surfaces of fine particles or as mineral surfaces. Rutherford Backscattering Spectrometry BS) is the technique chosen to determine accurately the amount of elements fixed on the monolith. 

In discussing electronic effects and Fig. 2, a number of references have been made to model catalysts formed by deposition of metal from the vapor phase onto an inert support. An attempt is made to simulate the surface of a real catalyst so that it can be better studied by XPS and electron microscopy. In addition, Masson et al. (78, 79) have developed techniques to control and make almost uniform the size of the particles. Rutherford backscattering is used to find the total number of atoms deposited, and the number of nuclei that grows into discrete metal particles is found by electron microscopy. From these measurements the average number of atoms per particle is obtained. Longer deposition times give larger particles. 

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