The motion of energetic charged particles inside a monocrystalline solid can be strongly influenced by channeling and blocking effects. The present article reviews the theory, the experimental studies, and some of the applications of these effects. The coverage of the published literature extends through June 1973.

Channeling and related effects in the motion of charged particles through crystals

Energy loss, range, path length, time-of-flight, straggling, multiple scattering, and nuclear interaction probability: In two parts. Part 1. For 63 compounds Part 2. For elements 1 ⩽ Z ⩽ 92

A model is presented which allows planar-channeling data to be used to deduce the parameters of the interaction potential between the channeled ions and the atoms of the solid and which relates the stopping power of channeled ions to that of randomly directed ones. The analysis is based on the experimental observation of the proportionality between the stopping power and the transverse oscillation frequency of ions traversing the planar channels of thin crystal targets. It is applied to data on He, O, and I ions transmitted through the {111} and {100} channels of Au crystals and on H ions transmitted through the {111} and {110} channels of Si crystals. For both targets, the screening constants of the interaction potentials are in excellent agreement with recent Hartree calculations. The same potentials allow the calculation of random stopping powers from the channeling data which are in good agreement with observation, especially when account is taken of thermal vibrations of the lattice atoms.

Deduction of Interaction Potentials from Planar-Channeling Experiments

A quantitative study of vacancy defects in quenched platinum by field ion microscopy and electrical resistivity—I. Experimental results

During the past decade analytical field-ion microscopy comprising field-ion microscopy (FIM) in combination with single-atom mass spectroscopy (atom-probe techniques) has been developed to become a powerful micro analytical tool in physical metallurgy, particularly suited to the detection of ultra-fine defects in metals and alloys, and to the analysis of their chemistry. In this article we have attempted to cover all aspects and recent developments in analytical field-ion microscopy which are relevant to the application of this technique to problems in physical metallurgy. Emphasis is made on the discussion of various methods for the quantitative analysis of short-ranged or long-ranged composition fluctuations such as those resulting from various phase transformations in alloys, and also on the discussion of factors which govern the spatial resolution of the atom-probe. Insight into the range of applicability of the various field-ion-microscope techniques is gained from a comprehensive discussion of recent results from investigations utilizing these techniques to study point defect-configurations, the structure and topography of interfaces, and various kinds of phase transformations in metals and alloys, and also to investigate metallic glasses and semiconductors.

Field-Ion Microscopy in Materials Science

The energy loss of protons channelled along the [001] direction in 500 A thick gold is analysed as a function of emergence angle. For a given emergence angle, the energy loss can be related to a particular path along the channel and, by applying Poisson's equation to the interatomic potential, to the local electron density. The small thickness of the samples used in the present investigation, compared to prior investigations, allows a relatively simpler and more unequivocal interpretation of the experimental data than previously possible. The relative variation in the stopping power due to channelling turns out to be much smaller than the variation in the local electron density, in satisfactory agreement with recent theoretical expectations (Bonsignori and Desalvo 1969). Also, our measurements distinguish between not too different approximations to the interatomic potential : Lindhard's potential yields agreement with experiment and Nielsen's does not.

Energy loss of protons channelling through very thin gold

[111] Proton channeling in very thin gold crystals

Short-range order measurements in dilute solutions (Gold and Machlin 1968) have been analysed to obtain oscillations in the interaction energy between solutes as a function of distance from a solute atom at the origin. The results are consistent with theory (Blandin and Deplante 1962).

E. S. Machlin

Papers

Energy loss of protons channelling through very thin gold

[111] Proton channeling in very thin gold crystals

On friedel oscillations and short-range order in dilute solutions