摘要:

The objective of this article is to review the effects of high density cascades in solids. Such cascades can be separated into those occurring in which “high density” refers to either the density of atomic collision events or to the density of ionization. Both types of cascade are discussed with reference to their effects in the bulk (i.e. damage production and inert gas detrapping) and on the surface properties (i.e. sputtering, secondary ion and electron emission). The appropriate experimental data are reviewed and discussed in relation to the various proposed spike models; i.e. displacement, thermal, plasticity and ionization spikes.

ISSN:0033-7579    

DOI:10.1080/00337578108229885

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The processes of migration and redistribution of point defects, generated in GaAs as a result of irradiation and released during annealing of the main isolated radiation defects, were studied.

ISSN:0033-7579    

DOI:10.1080/00337578108229886

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The theories of trajectory focusing (Mukherjee and Thompson, Paper I, Ref. 1) are used to interpret channelling experiments with 1.7 MeV H+incident near the ⟨100⟩ axis of MgO. Quantitative explanations are found for the following phenomena: deviations from circular symmetry in the axial channelling dip, high dechannelling during the transition from axial to planar channelling, the anomalous values of backscattering maxima in directions between low-index planar channels just outside the axial dip and the onset of channelling within narrow planar channels farther away from the axis. Agreement is also excellent with dechannelling data around ⟨100⟩Wobtained by Anderson and Uggerhøj (1968), with simulated dechannelling data around ⟨110⟩ Al by Barrett (1968) and other axial to planar channelling transition data available in the literature. The success of the focusing theory makes it suitable for interpreting lattice site location studies in the future.

ISSN:0033-7579    

DOI:10.1080/00337578108229887

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Consideration is given to the rate of radiation creep of materials taking into account microscopic processes which occur in the dislocation cores. Expressions have been obtained for the bias factors of dislocations of different orientations with reference to an external uniaxial load at arbitrary relations between the mean free path of a point defect in the dislocation core and the average distance between the jogs on the dislocation. The expressions obtained are used to determine the rate of radiation creep of the material. It is shown that in the case where the average distance between the jogs on the dislocation significantly exceeds the mean paths of point defects along the dislocation there occurs a dependence of the creep rate on irradiation temperature, which is in good agreement with the available experirriental data.

ISSN:0033-7579    

DOI:10.1080/00337578108229888

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Quantitative techniques for neutron-induced autoradiography (NIAR) of plutonium in soft biological tissues are used to determine an equivalent fission fragment range in mouse liver tissue of 47 μm thickness. An evaluation of the range variation of fission fragments in tissue shows that measurement on a tissue section is representative of the whole organ. Evidence is obtained of the even distribution of plutonium throughout the liver parenchymal tissue.

ISSN:0033-7579    

DOI:10.1080/00337578108229889

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The kinetic Eq. (2) is derived governing the flux density of moving atoms in a radiation cascade with account of scattering of moving atoms, ejection of host atoms and formation of dynamic crowdions. The solution of Eq. (2) is presented as a series expansion in orthogonal polynoms. Lindhard's interaction cross-section of moving atoms with hosts is used. The zeroth-order moment of the flux density determines the flux of moving atoms with energy ϵ and the cascade function. The spatial distribution of moving atoms is obtained in the zeroth-order approximation.

ISSN:0033-7579    

DOI:10.1080/00337578108229890

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The spatial distribution of vacancies and interstitials in radiation cascades in crystals is calculated with account of instantaneous recombination of Frenkel pairs during the formation of the cascade. Analytical expressions (15), (18) are obtained for the shape of the depleted zone.

ISSN:0033-7579    

DOI:10.1080/00337578108229891

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Heavy ion stopping power has been expressed as the sum of a modified Bethe formula and a modified Lindhard-Scharff-Schiøtt (LSS) formula. In the modified Bethe formula, Bohr stripping criterion has been applied to both projectiles and target atoms. In the modified LSS formula, a quasi-molecule criterion has been introduced similar to that of Bohr criterion. The calculated results are in good agreement with experimental data for various ions and targets to within 10–20%.

ISSN:0033-7579    

DOI:10.1080/00337578108229892

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Transverse vibrations of thinly metallized reeds of γ-irradiated polyethylene were excited electrically and detected capacitively over a relaxation range of temperature. The real part of Young's modulus at low strains was determined from the resonance frequency and the resonance width.

ISSN:0033-7579    

DOI:10.1080/00337578108229893

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

As a continuing investigation of the effect of carbon on void formation in metals, 4 MeV Ni++ions were used to bombard three grades of nickel to 25 dpa at 594°C after helium implantation to 15 appm at room temperature. All irradiated specimens showed dense void formation irrespective of the carbon content. The present study thus reveals that the carbon effect disappears at high damage doses because too many vacancies are produced in comparison with the number of carbon atoms present in the matrix and also because the trapping of vacancies by the carbon atoms is not assisted by recombinations. Meanwhile, the dual-irradiated Ni specimens displayed unusual behavior of void formation and denudation along twin and grain boundaries. The one-side appearance of void denudation along many grain boundaries and the formation of unusually large voids at the edge of the denuded zone are particularly conspicuous and may have repercussions on the use of the denudation phenomenon to partially solve the swelling problem caused by voids.

ISSN:0033-7579    

DOI:10.1080/00337578108229894

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor