[en] The spontaneous radiation of electrons in planar and axial channeling has been investigated theoretically in crystals with a superlattice under resonance conditions when the energy difference of two levels of the transverse motion in the averaged potential of the channel is approximately equal to a multiple of 2πhc/l, where l is the period of the superlattice along the channel axis. It is shown that the total energy levels of the electrons are split under the action of the spatially periodic perturbation. This changes the spectral and angular characteristics of the radiation substantially. In particular, resonance splitting of individual bands of the quasicharacteristic radiation is predicted. The magnitude of this splitting is estimated. It is established that there is no observable splitting in the channeling of positrons

[en] Briefly reviewed are the papers in which a new method of structural investigation of crystals-protonography has been develope in recent years. The method is based on the application of channeling and shadow effects. It is noted that the analysis of linear and point reflexes of the protonograms on the light testifies to the fact that they have fine structure. This peculiarity of the protonograms can give additional data on defects of the crystal lattice. A table of the basic characteristics of the structural analysis methods is presented

[en] The possibilities of applications of the 200 KeV Cockcroft-walton accelerator for D-D neutron measurements, ion implantation, Rutherford backscattering analysis, ion channeling and proton induced X-ray analysis are discussed

[en] Theory of P-noninvariant rotation of spin of charged particles, channeled in straight crystals was constructed. Quantitative description of the effect was conducted

No abstract available

[en] Theoretical models are presented based on the impact parameter picture for the energy losses of channeled ions. The conceptual simplicity afforded by such an approach is quite appealing. In addition, it is found that calculations based on these models provide reasonable predictions for, and agreement with, a variety of experimental data. A useful approach is provided for meeting the challenges to theory afforded by experimental measurements on channeling phenomena

[en] Electronic stopping powers S of solids for penetrating ions are analyzed on the basis of effective-charge theory, and comprehensive comparisons are made to available data for random stopping. The effective projectile-ion charges Z/sup asterisk/₁e, extracted from the data agree to within experimental uncertainties with those calculated in a statistical model, for projectile atomic number ranging from Z₁ = 1 to Z₁ = 92 and for projectile velocity v₁ > or approx. = v₀ equivalent e²/h. The rise of Z/sup asterisk/₁ with v₁ fully accounts for an often-quoted apparent deviation of heavy-ion stopping power from the behavior expected in the limit v₁ → 0. The Bloch and the Z³₁ corrections to the usual formula for S are calculated and found to make no appreciable contribution to presently available data, save possibly to one bromine datum. When v/sub o/ 9 or approx. = v₁ 9 or approx. = 3v₀ the analysis requires, and provides, and empirical velocity-dependent proton effective charge Z/sup asterisk//sub p/e. A theoretical account of Z/sup asterisk/p is given in terms of velocity and energy criteria for electron stripping. Thomas-Fermi densities for heavy ions are used to calculate Z/sup asterisk/₁. Our results lead to an interpolation linear in v₁ for the range 0 < or = v₁ 9 or approx. = v/sub o/ which gives satisfactory values for S in this low-velocity regime

[en] A theory recently developed by the authors for slow and fast electrons is shown to be also applicable to channeled ions and to explain the experimental results about electron loss phenomena as a whole. The theory is based on the fundamental hypothesis of the nonadiabaticity of the ion-target interactions. How essential an exponential form of the interaction pseudo-potential is in explaining the energy exchange mechanism at the walls may be deduced from a quasi-classical development of the quantum model. The theory also allows a number of new experiments to be envisaged in the field of surface electron states

[en] The model used by Briggs and Pathak to calculate the electronic energy loss of low-velocity channeled heavy ions has been explored further to study the velocity dependence of Z₁ oscillations in electronic stopping power. For increasing ion velocities, where the validity of neglecting the target-electron velocities increases, it is found that the magnitude of Z₁ oscillations decreases and by about 2-a.u. velocity the first maxima at Z₁=6 and the first minima at Z₁=10 are washed out completely

[en] A versatile specimen manipulator for use in UHV is described, based on the principle of a ball joint. It allows rotation of the target around three mutually independent perpendicular axes with high accuracy. Two rotations are computer-controlled; the third one is operated manually. The manipulator as a whole can be shifted horizontally and rotated with respect to its base flange. The target can be heated up to 500⁰C. Cooling facilities can be provided for. (author)