摘要:

The use of the 1793 keV resonance of the1H(11B, : alpha;)αα reaction and of the He+channelled backscattering, allows us to determine various parameters about hydrogen implantation in silicon in the low energy range from 1.5 to 60 keV. We have determined the range profiles and the damage distribution of implanted protons. We have also measured the stopping power of protons (1.5–60 keV) and11B ions (2 MeV) in silicon. Annealing of the implanted layer, blister formation and gas release have been investigated and it is shown that this method may be used to localize hydrogen in the silicon lattice.

ISSN:0033-7579    

DOI:10.1080/00337577608243025

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

The transport equation satisfied by the distribution in path lengths is : educed to a second order partial differential equation, for cases where the mass relation of projectile and target is very different from unity. The analytical solution obtained has the same first and second order moments as those resulting from the continuous slowing down approximation, and presents a marked asymmetry. Direct comparison with measured penetration profiles for heavy projectiles on light targets shows a satisfactory agreement.

ISSN:0033-7579    

DOI:10.1080/00337577608243026

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

The mean and the most probable stopping cross-section for 50- to 150-: eV sodium and 50- to 300-keV argon projectiles in carbon have been measured as functions of the foil thickness. The results are interpreted on the basis of results from a recent simulation study by Skoog. The various methods for separating the experimental stopping cross-section into an elastic and an electronic part are discussed. Both stopping cross-sections have been deduced from the experimental results.

ISSN:0033-7579    

DOI:10.1080/00337577608243027

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

The diffusion of channelled beams determined from the continuum : odel is studied analytically taking into account a real discontinuous potential. In usual channelling conditions the diffusion due to the discontinuity considered here does not have a negligible effect on dechannelling. An analytical expression for the diffusion coefficient in dechannelling theory is given. We show that the diffusion considered here is one reason for the very weak temperature-dependence of planar-dechannelling.

ISSN:0033-7579    

DOI:10.1080/00337577608243028

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

During low temperature reactor irradiation up to a neutron dose of 2.7 : times; 1018cm−2the electrical resistivity increase was measured at 19 K on purified niobium and niobium doped with nitrogen up to 850 at. ppm. From the equality of the extrapolated saturation value of the resistivity with that after electron irradiation it is concluded that the defect cascades are loosely packed. A strong initial decrease of the damage rate of the purified Nb can be quantitatively accounted for by assuming that a relatively large fraction of the self-interstitials is produced by means of long range focusing collision sequences. A pronounced increase of the damage rate with nitrogen content is discussed in terms of capturing of focusing collision sequences at interstitial impurities and of a reduction of the fraction of self-interstitials produced by such collision sequences.

ISSN:0033-7579    

DOI:10.1080/00337577608243029

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

It has been shown that neutron irradiation of silicon carbide results in : isordering of its crystal lattice. The data are given showing the effect of the irradiation temperature and thermal annealing on disordering. Irradiation to the neutron fluence of 3.2 × 1021n/cm2(E> 75 eV) at 120°C causes disordering when about 18% of lattice sites that should be occupied by the atoms of one type are actually occupied by the atoms of another type.

ISSN:0033-7579    

DOI:10.1080/00337577608243030

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

Thiamine and other vitamins of the B complex group are highly : ensitive to γ-radiation in aqueous solution owing to their high reactivity with the primary species formed by radiolysis of water, viz. hydrated electrons and hydroxyl radicals. In order to protect these compounds from radiolytic degradation, nitrous oxide and oxygen have been used as scavengers for the hydrated electrons and glucose for the hydroxyl radicals. By comparison of uv spectra it is shown that the above vitamins do not undergo radiolytic degradation in presence of nitrous oxide and glucose or oxygen and glucose. The importance of these results in connection with the sterilization of vitamin preparations is discussed.

ISSN:0033-7579    

DOI:10.1080/00337577608243031

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

This paper deals with experimental and computer studies of sputtering : nd scattering of ions with energies of several keV from Cu and InSb single crystals. A substantial importance of the ejected particle channelling for the formation of some peaks in the patterns of spatial distribution of scattered ions and sputtered atoms has been shown.

ISSN:0033-7579    

DOI:10.1080/00337577608243032

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

A strong correlation is shown to exist throughout the periodic table : etween theZ2dependence of the electronic stopping cross-sections for4He ions of a given velocity and theZdependence of the atomic potentials at a certain radius. An empirical formula is presented which allows the extrapolation of stopping cross-section data for any ion at a given velocity in some elements, to elements for which experimental data are not available. This study covers the energy interval 100 <E/m< 1000 keV/amu.

ISSN:0033-7579    

DOI:10.1080/00337577608243033

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

A highly collimated accelerator beam line facility is described, : riginally designed to measure stopping power for low energy ions by transmission through thin specimens of semiconductors in channelled and unchannelled directions. The facility has been used to study energy loss and straggling in thin amorphous solid absorbers of Melinex, aluminium, copper, gold, and lead at proton energies of 1.0 and 1.6 MeV. The absorbers were produced by various methods and comparisons are made of straggling observed in rolled and electrodeposited aluminium. Expected differences in energy straggling have been observed for the two proton energies, but the relationship between straggling and absorber atomic number is not simple. Cyclic variations related to stopping power at low energies may be partly responsible for the observations.

ISSN:0033-7579    

DOI:10.1080/00337577608243034

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor