摘要:

We have measured the energy dependence of the trapping probability for sputtered235U atoms striking an oxidized aluminum collector surface at energies between 1 eV and 184 eV. At the lowest energies approximately 10% of the uranium atoms are not trapped, while above 10 eV essentially all of them stick. In addition, we present trapping probabilities averaged over the sputtered energy distribution for uranium incident on gold and mica.

ISSN:0033-7579    

DOI:10.1080/00337578008237483

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

Recent measurements of the sputtering of frozen gases by MeV ions exhibit yields that are several orders of magnitude larger than predicted by collision cascade theory. Of the models considered, only a “thermal spike” model is consistent with our experimental observations. The various experimental parameters studied include the energy (0.3–2.0 MeV), atomic number (H+. He+. N+and Ar+). angle of incidence and current density of the incident ion beam. the thermal conductivity of the substrate, and the temperature and thickness of the frozen film. Calculations for 1.0 MeV He+in Xe. based on a thermal spike mechanism, indicate that a localized cylindrical region around each incident ion track is raised to a temperature sufficiently high to evaporate a significant quantity of the frozen gas film.

ISSN:0033-7579    

DOI:10.1080/00337578008237484

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

Near surface and bulk radiation enhanced self-diffusion of Ni0.3in nickel was measured after irradiations with 2 MeV electrons. In the temperature range between 550 and 800°K the bulk diffusion coefficient is DRad= 1.347 × 10−12exp (-0.41/kT cm2/s) for a flux of 20 μA/cm2. The measured diffusion coefficients are at least two orders of magnitude larger than those predicted by theories based either on the one- or the two- interstitial model. This discrepancy between experiment and theory is resolved for the two-interstitial model by considering the interactions between sell-interstitials and vacancies during their life times. These interactions led to an effective migration energy of self-interstitials ofEMeff, = 0.82 eV. which is smaller thanEM=1.0 eV. The experimental data can be described by DRadα2nf(Kvell1)12.

ISSN:0033-7579    

DOI:10.1080/00337578008237485

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

The residual resistivity of Cu-Ni alloys with Ni contents between 42 and 71 at % has been investigated upon isochronal annealing after 3 MeV electron irradiation at 4 K and 200 K. The clustering of vacancies was studied by positron annihilation measurements on a 50 at. % Ni alloy after 3 MeV electron irradiation at 80 K.

ISSN:0033-7579    

DOI:10.1080/00337578008237486

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

A computer simulation is used to calculate the reflection coefficients of low energy4“<200 eV” ions in the presence of a structureless surface attractive field for the model system of hydrogen atoms impinging on amorphous titanium. Significant trapping effects are observed which modify both the magnitude and the functional behaviour of the reflection coefficients. It is concluded that such surface fields must be taken into account in models of low energy reflection processes.

ISSN:0033-7579    

DOI:10.1080/00337578008237487

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

The sticking probabilities for sputtered atoms of93Nb and103Rh incident on Al2O3surfaces have been measured using the backscattering of MeV heavy ions. In the circumstance where the collecting surface has become thickly covered, the sticking probabilities integrated over the energy distribution of sputtered atoms are 0.97 ± 0.01 and 0.95 ± 0.01 for93Nb and103Rh, respectively. In the limit of negligible areal coverage of the collector. the accuracy is less; in this case the sticking probabilities are 0.97+0.08and 0.95+0.050.08.

ISSN:0033-7579    

DOI:10.1080/00337578008237488

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

The recovery spectrums of Me. Zr and Ti are studied by means of measurements of the electrical resistivity after fast neutron irradiation at ∼5 K.

ISSN:0033-7579    

DOI:10.1080/00337578008237489

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

A simple analytical treatment of trajectory focusings of semichanneled ions is developed. and a new semichanneling effect in the azimuthal angle-dependence of the reflection coefficient is theoretically predicted.

ISSN:0033-7579    

DOI:10.1080/00337578008237490

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

ISSN:0033-7579    

DOI:10.1080/00337578008237491

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

SYNCHROTRON RADIATION INSTRUMENTATION AND NEW DEVELOPMENTS, Proc. of Int. Conf. Orsay, France, Sept. 12–14, 1977, Edited by F. Wuilleumier and Y. Farge. North-Holland Publishing Company, 1978. 339 pp. ($66.75, D.FI. 150.00).

ISSN:0033-7579    

DOI:10.1080/00337578008237492

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor