ISSN:0033-7579    

DOI:10.1080/00337577208231172

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

A measurement of the tensor polarization of deuterons which are channeled through a magnetised Ni single crystal and emerge as deuterium atoms is described. The results are in qualitative agreement with the surprisingly large polarization first observed by Karninsky. Experimental details and various control experiments are discussed.

ISSN:0033-7579    

DOI:10.1080/00337577208231173

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

Distributions of charge carriers in silicon implanted with boron and phosphorus at room temperature and annealed atTann800°C, have rather long tails. The possible mechanisms for their formation are channeling and different kinds of anomalous diffusion. The purpose of this work is to investigate the contribution of these factors.

ISSN:0033-7579    

DOI:10.1080/00337577208231174

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

The dechannelled fraction vs. penetration depthsX(z)has been measured for 0.3 to 1.5 MeV protons impinging along the {110} plane of Si and Ge.

ISSN:0033-7579    

DOI:10.1080/00337577208231175

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

Conducting, semiconducting and nonconducting targets were bombarded at an angle of 45° to the surface with a beam of Ar+ions, characterized by a beam density of 100pA/cm2and a beam energy of 40 keV. The residual gas pressure was 5×10−4torr. The ion yield or the degree of ionization of sputtered atoms from the three kinds of targets were measured. The results indicate that the emission of secondary ions from the three types of bombarded surfaces can be described using the same model. The degree of ionization and the energy distribution of the sputtered target atoms confirm that the emission is a combination of two mechanisms: (i) momentum transfer by the primary ions to target atoms, and (ii) strong local overheating of sputtered centres. The yield of various secondary ion species from compound targets is not proportional to the concentration of the respective atoms in the targets.

ISSN:0033-7579    

DOI:10.1080/00337577208231176

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

Energy loss measurements are reported for 21.6–60 MeV127I and 3 MeV4He ions transmitted through thin single crystals of Au and Ag along directions parallel or nearly parallel to ⟨110⟩ directions in the crystals. A systematic investigation of 21.6 MeV127I ions in Ag indicates that for incidence angles within 0.12° of [O11] up to 10 percent of the transmitted ions have energy losses significantly lower than that for ions transmitted parallel to (111). The behavior of these ions is consistent with that expected for ions which are confined within one particular axial channel throughout the crystal. This specific type of axial channeling we call hyperchanneling. The data for hyperchanneled 21.6 MeV127I in Ag are analyzed in detail and discussed in terms of a theory developed on the basis of potential energy contours obtained from the continuum potentials of the surrounding rows of atoms. Comparison of theory and experiment suggests that these ions undergo more multiple scattering than can be accounted for and that potentials for interactions of ions and free atoms are not entirely adequate for interactions of ions and atoms in a solid.

ISSN:0033-7579    

DOI:10.1080/00337577208231177

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

An experiment was performed to investigate several effects caused by correlated successive collisions of fast ions at crystalline surfaces. Predictions of simple models for ion scattering processes are examined qualitatively, and the obtained experimental data are discussed in the framework of these models. As targets, faces of copper, silicon and germanium single crystals were used. The bombarding ions were 5-30 keV argon ones.

ISSN:0033-7579    

DOI:10.1080/00337577208231178

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

The stopping powers of C, N, and O ions in Cr, Fe, Co, Ni, Cu and Zn in the energy range 500 keV to 2 MeV have been measured relative to that for He ions in the same material. The measurements were made utilizing energy spectra of particles backscattered from thick substrates of the target material into which a heavy material (Bi) had been previously implanted to a shallow depth. Assuming that dE/dxfor He is known, the dose of implanted Bi can be determined from a He backscattering spectrum. Then this dose is used to calculate the unknown stopping power from a backscattering spectrum of the ion to be studied.

ISSN:0033-7579    

DOI:10.1080/00337577208231179

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

Periodic variations in theZ1dependence of the interatomic potential has recently bevlen revealed by a channeling technique. To search for oscillations of similar kind in a target of randomly arranged atoms we have made systematic measurements on the scattering distributions of energetic (32–56 keV) ions in amorphous carbon. Our technique was to transmit light mass ions through carbon foils with a thickness of 2–4 μg/cm2. The atomic number of the ions, Z, ranged from 3 to 18. The scattering distribution of the transmitted particles was recorded. From these curves the angular halfwidth,ψ1/2, and the relative intensity at a scattering angle 2.5 timesψ1/2was determined. The experimental values are in good agreement with theoretical calculations based on the Thomas-Fermi and Lenz- Jensen potentials. Furthermore, the saturation value of the mean nuclear stopping cross sections for ions scattered in the straight forward direction with a mean energy of 50 keV are given. No evidence for aZ1oscillatory behaviour could be found in any of the three parameters investigated.

ISSN:0033-7579    

DOI:10.1080/00337577208231180

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

This paper describes experimental studies of the multiple scattering of 14 different heavy ions with 1≤Z1≤18 in the energy range 300–1000 keV, transmitted through thin (500 Å−1500 Å) polycrystalline gold films. The experimental data are compared with calculations of the multiple scattering using the Thomas-Fermi potential. Rather large deviations from theoretical predictions are found, in contrast to the case for lighter targets.

ISSN:0033-7579    

DOI:10.1080/00337577208231181

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor