摘要:

Nous avons étudié, par diffusion des rayons X aux petits angles des échantillons de mica muscovite irradiés par des ions Krypton, Argon, Néon, d'énergie 1 MeV par nucléon et par des ions Oxygèene d'énergies 2 et 5 MeV par nucléon. Il se forme à la fois des défauts ponctuels et des défauts étendus de forme isotrope dont le rayon varie de 10 Å à 30 Å selon les irradiations. Ce sont ces défauts étendus, qui au cours de l'attaque chimique ultéricure à l'irradiation, donnent naissance aux traces visibles au microscope. La concentration volumique de ces défauts est importante et pour des doses élevées (1014à 1015ions par cm2) les échantillons deviennent amorphes.

ISSN:0033-7579    

DOI:10.1080/10420157408230814

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Computer calculations have been made of the fraction of interstitial atoms and vacancies that directly recombine by diffusion in a damage cascade, neglecting the effect of defect clustering. The shape of the cascade is idealized to be either cylindrical or spherical, which should provide a useful guide to the more complicated shapes occurring in practice, and the point defects are given a gaussian distribution initially. A special feature of the calculations is that the initial spread of the interstitials is allowed to exceed that of the vacancies, due to the propagation of dynamic crowdions during the formation of the cascade. The present calculations have the merit that (i) a rapid estimate of the recombination can be made, (ii) a complete anneal is performed whereas often only partial anneals can be achieved with more sophisticated atomic models, and (iii) allowance is made for the trapping of interstitial atoms at other sinks.

ISSN:0033-7579    

DOI:10.1080/10420157408230815

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

The effect of gamma rays on aqueous solutions of orthochlorobenzoic acid (OCBA), metachlorobenzoic acid (MCBA) and parachlorobenzoic acid (PCBA) have been studied. The H atom rate constants for OCBA and MCBA have been determined in a degassed solution of 0.8 N H2SO4using isopropanol as the competitor and determiningG(H2) at different concentration ratios of the competitors. Similarly, the OH radical rate constants have been determined for all three chlorobenzoic acids at pH 7.0 in oxygenated solution using isopropanol as the competitor and measuring acetone yields at different concentration ratios of the chlorobenzoic acids and isopropanol. The hydrated electron rate constants were measured at pH 11 by measuring the decay of thee−aqin presence of the chlorobenzoic acids.G(CO2),G(H2O2) andG(Cl−) have also been measured and their yields have been discussed. Paper chromatography of the products revealed 4–6 components in each case.

ISSN:0033-7579    

DOI:10.1080/10420157408230816

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

The electrical properties of Sin− andp−channel junction field effect transistors (JFET's) were measured after irradiation with fast neutrons and 1 MeV electrons, before and after annealing up to 675 K. A pulse technique was used to measure the energy levels of the radiation defects. It was found that one of the defects in then−channel JFET's had an energy level at approximatelyEC−0.4 eV and, in the case of electron damage, annealed sharply at about 425 K. These properties suggest that the defect is the Si‐E centre. The energy level of the major source of damage in thep−channel JFET's could not be measured by the techniques used but the annealing temperature of 600–675 K agreed with that of the Si‐K centre. Considerable recovery in properties of the neutron damagedp−channel devices can be achieved by forward biasing the gate at room temperature.

ISSN:0033-7579    

DOI:10.1080/10420157408230817

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

A unifying interpretation is presented for a number of different studies concerned with the lattice location and diffusivity of boron implanted into silicon. It is suggested that the nonsubstitutional boron present after a room temperature implantation consists mostly of boron-vacancy complexes, together with a relatively small number of boron interstitials. The boron interstitials anneal at 200–300°C without long-range migration, whereas the boron-vacancy complexes are thermally very stable (possibly due to an extended defect configuration) and anneal to produce substitutional boron atoms only at high temperatures where silicon self-interstitials take over as the dominant intrinsic point defect. This model explains numerous experimental observations in a manner which both reconciles a number of apparent conflicts between different types of experiment, and is consistent with an interstitial mechanism for self-and boron diffusion in silicon at high temperatures:

ISSN:0033-7579    

DOI:10.1080/10420157408230818

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Data of static magnetic susceptibility measurements on γ-irradiated single crystals of magnesium fluoride are reported for doses up to 1 × 1011rad. The susceptibility was interpreted to consist of three parts: (1) a diamagnetic partxd=-0.384 × 10−6emu/g, due to the normal MgF2matrix; (2) a temperature-dependent paramagnetic part, obeying the Curie law, arising from unpaired electrons; and (3) a temperature‐independent paramagnetic part which is attributed to the presence of metallic magnesium. The results show that the radiation damage process in MgF2is strikingly similar to that in LiF.

ISSN:0033-7579    

DOI:10.1080/10420157408230819

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Internal friction measurements on boron-implanted silicon recently performed by Tan and Berry are analyzed in terms of self- and boron-interstitial properties. It is shown that the observed internal friction peaks can be assigned to the reorientation of electrically neutral and singly negatively charged ⟨100⟩-split boron-interstitials and of singly positively charged ⟨110⟩-split and electrically neutral ⟨100⟩-split silicon self-interstitials. An empirical relation between the measured activation energies of reorientation of these defects and their electronic properties is sugested and used to get information about the distribution of the electrical charge of these interstitials. A self-consistent set of values for the migration energies of boron- and self-interstitials and for the activation energies of local decay of boron-interstitials is presented. The present results support and extend a model of the properties of self-interstitials in elemental semiconductors sugested previously by Seeger and Frank.

ISSN:0033-7579    

DOI:10.1080/10420157408230820

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

In studies of ion-irradiation effects in silicon it has been usually assumed that initial elastic ion-atom collisions are responsible for defect production. Our results for light-ion irradiation of silicon suggest that inelastic, ionization effects can be important.

ISSN:0033-7579    

DOI:10.1080/10420157408230821

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

The low temperature radiation damage in rhenium caused by 2.8 MeV electron irradiation at 4.5 K has been studied by means of electrical resistivity measurements. The samples were Marz Grade foils supplied by Materials Research Corporation (U.S.A.) with a thickness of 0.03 mm. After a 30 minutes pulse at 2100 K in a vacuum of 2·10−10Torr, the electrical resistivity ratio amounted to about 800.

ISSN:0033-7579    

DOI:10.1080/10420157408230822

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor