摘要:

The paper presents an approximate solution of the Focker-Planck kinetic equation with an allowance for the unharmonic potential. This solution is obtained by using asymptotic methods of non-linear mechanics. It is shown that the perturbation theory method is inapplicable for this problem.

ISSN:0033-7579    

DOI:10.1080/00337577608233510

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

A simple model for blistering mechanism is proposed for energies higher than 20 keV. The model assumes that through the nucleation of smaller bubbles, a critical bubble radius is reached. The planar stress results of Jeffery for a semi-infinite plate with a circular hole subject to a uniform inner normal pressure are roughly taken as valid for the three-dimensional case. Under this assumption, the thickness of the blister's cover and critical ion dose for blister formation are calculated from the knowledge of the mean projected range of ions and blister diameter taken from experimental results. The resulting values are in agreement with the experimental values reported. The model can qualitatively explain breakage at the top of the dome-shaped blisters observed in molybdenum at 1100 K.

ISSN:0033-7579    

DOI:10.1080/00337577608233511

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

The expression for void growth rate

ISSN:0033-7579    

DOI:10.1080/00337577608233512

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

In materials under irradiation Frenkel Pairs are produced at a rate proportional to the irradiating flux. Of these defects a fraction (1-α') suffer immediate recombination, and, under neutron or heavy ion irradiation a further fraction of the vacancies condense into vacancy dislocation loops. The effective defect production rates are therefore substantially less than those assumed in previous studies. Moreover the fraction α' is not the same for different types of irradiation. Under electron irradiation the effective biasBbecomesBeff= α'electronBwhile under ion or neutron irradiationBeffbecomesBeff= (α'hB—f) where α'electron # α'h.

ISSN:0033-7579    

DOI:10.1080/00337577608233513

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

The damage produced by 20–40 keV He+, N+and Zn+irradiations of Si, GaAs and GaP at 50°K has been measured in-situ by 1.0–1.5 MeV He+channeling techniques along both (111) and (110) directions. It has been found that the measured damage increases significantly when the analysing beam is misaligned by angles up to 0.36 ψ1. The magnitude of the effect decreases with cascade damage fraction and total disorder level. Significant deviations occur between the measured disorder and that predicted by binary collision theory. It appears that the measured damage is the result of the collision cascade initiating inter-and/or intra-cascade processes which can result in a much larger number of displaced atoms than predicted.

ISSN:0033-7579    

DOI:10.1080/00337577608233514

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

Using a flexible model of scattering for atomic collisions and the continuous energy loss approximation for electronic stopping, we have obtained exact solutions of the time-energy distribution of atoms slowing down in cascade from a primary knock on. The time moments are constructed from which the slowing down time and relative variance may be calculated. Some results of Sanders and Winterbon are generalized and the connection between the backward equation of conventional damage theory and the partial adjoint of the forward equation are pointed out. We also discuss two complementary methods for calculating energy deposition by atoms as they slow down.

ISSN:0033-7579    

DOI:10.1080/00337577608233515

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

We have separated the sputtering patterns of NaCl irradiated with low energy electrons into component features from the directional ejection of halogen atoms and a random evaporation of the metal atoms. The sputtering yields anti-correlate with exciton luminescence. Lifetime studies reveal the presence of several exciton states with different diffusion energies. The sputtering yield shows a resonance with the production of surface excitons.

ISSN:0033-7579    

DOI:10.1080/00337577608233516

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

The approximate calculation of ion energy deposition profiles is briefly discussed. It is pointed out that the frequently used approximation of Kulcinskiet al.5for calculating energy straggling of beam ions may introduce errors in the surface region. It is proposed that the more accurate approximation of Johnstonet al.6be used in such calculations.

ISSN:0033-7579    

DOI:10.1080/00337577608233517

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

ISSN:0033-7579    

DOI:10.1080/00337577608233518

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor