A polarized deuteron target in the d(e,e′)np reaction

Asymmetries for scattering of longitudinally polarized electrons from deuterons with a vector polarization as well as asymmetries for scattering of unpolarized electrons from deuterons with a tensor polarization have been considered for inclusive elastic ed scattering. The sensitivity of all asymmetries considered to the electric form factor of the neutron and to the spin structure of the deuteron wave function has been investigated.     

Analysis of the spin polarization of secondary electrons emitted from Au/Fe

The spin polarization of secondary electrons emitted from Au thin films on an Fe substrate is studied with a Monte Carlo simulation of electron scattering. The magnetic information depth of the secondary electrons is estimated by fitting the exponential function to the calculated data and we found that the magnetic information depth increases with the primary electron energy from 11.5 at 0.3 to 26.3 Å at 4 keV. This result agrees fairly with the experimental one for the same nonmagnetic/magnetic bilayer system and it is much larger than that reported so far for bulk magnetic materials.     

Observation of a high spin polarization of secondary electrons from single crystal Fe and Co

The spin polarization of secondary electrons with nearly zero kinetic energy from Fe (100) and Co (10$\text{1}$0), excited with photons of energy between 20 and 60 eV, was found to be 45%±5% for Fe and 35%±5% for Co. This value is higher than the average valence band spin polarization P_b=n_b/n=2.2/8=27% and 1.7/9=19% for Fe and Co, respectively. With increasing kinetic energy, the spin polarization of the secondaries decreases to the value of P_b within the first 5 eV, remaining constant (within statistical error) at higher kinetic energies. As a spin dependent scattering process we propose excitations within the d-bands, which can be shown to be asymmetric with respect to the electron spin. The high net spin polarization of the slowest emitted electrons is obtained by filtering out monitory-spin electrons at the vacuum barrier.     

Influence of exchange and polarization on the elastic scattering of slow electrons from rare gases and mercury

The elastic scattering of slow electrons from A, Kr and Hg is calculated by means of phase shift analysis. In addition to the Hartree potentials radial symmetric potentials are used simulating electron exchange and polarization of the shell electrons. It is found that spin polarization and differential cross-section are in relatively good agreement with the experimental results.     

Einfluß der Mehrfachstreuung auf Polarisation und Winkelverteilung bei der Streuung langsamer Elektronen

The influence of plural scattering on the angular distribution and spin polarization of slow electrons scattered by mercury atoms has been investigated at 180, 300 and 900 eV. Especially the high polarization peaks are very sensitive to plural scattering, while lower polarization values remain relatively unaffected. A simple explanation of the results is given.     

Capture of polarized electrons into excited atomic states in grazing scattering from a magnetized Ni(110) surface

The spin polarization of electrons captured into excited atomic levels of atoms during the scattering of fast ions from a magnetized Ni(110) surface under a grazing angle of incidence is deduced from the polarization of the fluorescence light. In our studies we have investigated the dependence of the spin polarization on projectile velocity and angle of incidence and observed generally small polarizations for captured electrons.     

Spin-polarized electrons in collisions of multicharged nitrogen ions with a magnetized Fe(001) surface

We report on the first spin-resolved energy spectra for the emission of electrons during grazing scattering of 150 keV multicharged nitrogen ions from a magnetized Fe(001) surface. A substantial spin polarization for KLL Auger electrons emitted in the final stage of the neutralization sequence during the interaction of multicharged ions with a metal surface is observed. We conclude from our data that the projectile L shell is dominantly populated by electrons from the conduction band of the target. For low energy electrons we find an increase of their spin polarization with an increase of the projectile charge.     

Photon polarization effects in compton scattering on relativistic electrons

Photon polarization effects in Compton scattering on unpolarized electrons are calculated in the first Born approximation by using the covariant formalism. The general expressions are specialized with regard to the production of hardγ-rays by the scattering of laser photons by relativistic electrons. Results are given for various polarizations of the initial photon and three electron energies in the GeV region.     

Spin-polarized injection into a p-type GaAs layer from a Co2 MnAl injector

Electric luminescence and its circular polarization in a Co2 MnAl injector-based light emitting diode (LED) has been detected at the transition of e-A0 C , where injected spin-polarized electrons recombine with bound holes at carbon acceptors. A spin polarization degree of 24.6% is obtained at 77 K after spin-polarized electrons traverse a distance of 300 nm before they recombine with holes bound at neutral carbon acceptors in a p + -GaAs layer. The large volume of the p + -GaAs layer can facilitate the detection of weak electric luminescence (EL) from e-A 0C emission without being quenched at higher bias as in quantum wells. Moreover, unlike the interband electric luminescence in the p+ -GaAs layer, where the spin polarization of injected electrons is destroyed by a very effective electron-hole exchange scattering (BAP mechanism), the spin polarization of injected electrons seems to survive during their recombination with holes bound at carbon acceptors.     

Polarization bremsstrahlung in α decay

A mechanism of formation of electromagnetic radiation that accompanies α decay and is associated with the emission of photons by electrons of atomic shells due to the scattering of α particles by these atoms (polarization bremsstrahlung) is proposed. It is shown that, when the photon energy is no higher than the energy of K electrons of an atom, polarization bremsstrahlung makes a significant contribution to the bremsstrahlung in α decay.     

Elastic scattering of electrons by deuterons in the framework of the source theory by J. Schwinger

Cross sections of the elastic scattering of electrons from the deuterons are calculated with the concept of primitive interaction, disregarding the form factors of the deuteron. Formulas are derived for the various possibilities of the electron and deuteron polarization. Numerical results are given for 175 MeV scattering in the rest frame.     

Spin polarization measurements of secondary electrons as a tool to study scattering mechanisms in a solid

Energy, angle, and spin resolved measurements of secondary electrons from Au(110) excited with an unpolarized beam of primaries indicate that the secondary electrons are mostly produced in a two-step scattering event. A calculation reproducing the experimental results is presented.     

Fluctuations of polarization energy as an important scattering mechanism in the quasi-one-dimensional organic solids

The interaction of electrons with thermally induced fluctuations of the local polarization energy is proposed as an important scattering mechanism in the observed electrical resistivity of quasi-one-dimensional solids. Application is made to TTF-TCNQ.     

Untersuchung der Polarisationsebene von Photonen nach Compton-Streuung an polarisierten Elektronen

Two polarization phenomena in Compton scattering by polarized electrons were investigated. In the first experiment, the rotation of the polarization plane of photons passing through magnetized iron and gadolinium was measured. This effect arises from a spin dependence of the Compton forward scattering amplitude. For 228 and 333 keV photons and iron absorbers, the observed rotation angles areφ ₀=(3.90±0.57) ×10^?3 rad · cm^?2 and (4.75±0.58)×10^?3 rad · cm^?2, respectively. Secondly, the orientation of the photon polarization plane after scattering of unpolarized photons by polarized electrons was measured. This experiment tests time reversal invariance in quantum electrodynamics. No dependence of the polarization plane on the direction of the electron spin was found within 2×10^?3.     

Elastic-scattering cross-section for electrons and positrons from atomic hydrogen

The differential cross-sections of atomic hydrogen for elastic scattering of electrons and positrons have been rederived with the help of a method using a single parameter-dependent unitary shift operator for the calculation of the direct contribution. When the parameter approaches zerc the new method leads to the well-known conventional Glauber results. The numerical calculations include polarization effects and the exchange corrections obtained according to alternative approximation methods. Results calculated with Franco’s exchange show a definite improvement over the earlier results for medium energy electrons at large angles of scattering. Total elastic cross-sections have been calculated for 50 and 100eV electrons and positrons.     

Polarized electron scattering on spin zero and polarized spin-1/2 targets: Deep inelastic scattering,elastic electron-muon scattering,and elastic electron-nucleon scattering

A covariant formulation is developed and used to derive cross sections for the analysis of experiments in which polarized electrons (muons) are scattered from spin-zero and from polarized spin-1/2 targets. The analysis is based upon the single virtual photon representation of the electromagnetic interaction, initially, neither high-energy nor low-energy approximations are made so that one may derive results in which the orientation of the polarization vectors of the interacting particles changes as a result of the scattering. The general formulation is valid for all polarization configurations for the electron and nucleon in deep inelastic scattering, and for all polarization configurations for the initial and final state particles in elastic scattering. From the general covariant results, specific cross sections are derived for deep inelastic scattering as well as elastic scattering of electrons on muons, nucleons, and spin zero targets. In the latter case, the actual polarization vector for the scattered electron is determined. In the other cases discussed, this vector may be obtained from the cross sections. In addition, a method is presented for defining covariant cross sections, and this method is used to obtain results in the center-of-mass system as well as the laboratory system. Furthermore, explicit cross sections for virtual photon absorption are derived. Finally, in the appendices, an alternative method for the evaluation of traces is given as well as a discussion of the relativistic limit.     

低杂波电流驱动中的雪崩逃逸增强及鱼骨不稳定性

等离子体中存在的一定数量的高能逃逸电子（E≥1MeV)通过大角度库仑散射从等离子体中碰撞出二次电子，二次电子被低杂波有效地加速成为逃逸电子，这些逃逸电子又被正反馈回等离子体，形成雪崩现象。在此过程中，一部分获得较大横向动量的二次电子或由低杂波驱动的高能电子可能被香蕉轨道捕获，这些被捕获在磁岛中的电子与某种模式的磁场扰动共振时，就出现鱼骨不稳定现象。     

Time-dependent polarization in Mössbauer experiments with synchrotron radiation (II)

The resonant forward scattering of X-rays from⁵⁷Fe nuclei is strongly polarization dependent. The broad band excitation provided by synchrotron radiation (SR) results in an interesting time-dependent polarization mixing. This mixing can be used to substantially reduce the nonresonant (nonrotated) scattering from electrons. The presented technique will allow the full utilization of next-generation synchrotron facilities as a source for Mössbauer experiments.     

Elastic scattering of an electron by the negative lithium ion

In the framework of the many-body theory, the differential and total cross sections of elastic scattering of slow electrons by the negative lithium ion Li⁻ are obtained. Calculations are performed both in the Hartree-Fock single-particle approximation and with regard to many-electron correlations, which take into account the dynamic polarization of the core. Features observed in the behavior of the phases and cross sections for p and d partial waves are associated with resonance scattering of electron waves. Considering the dynamic polarization of the core by an incident electron heightens the diffraction character of the scattering. The real process is compared with particle scattering in models with a repulsive potential.