摘要:

Energy loss spectra of 1000 keV electrons transmitted by [111]-: riented thin silicon crystals were observed by an energy analyzer attached to the HVEM. The crystals were set to the systematic 220 Bragg reflection. Measurements were made for crystal thickness ranging from 1000 to 10,000 Å, which were determined by observations of pendellösung fringes.

ISSN:0033-7579    

DOI:10.1080/00337577508234741

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

X-ray diffraction, electron microscope and optical studies have been : ade on zircons damaged by fission fragments derived from the action of neutrons on uranium impurities in the zircon lattice. A dosage of about 1014fission events · cm−3was required to produce diffuse x-ray scattering, observable by conventional photographic methods, and a dosage of about 1016fission events · cm−3appears to be required to render a zircon amorphous. An optical absorption band, generated apparently by γ-rays, was observed near 270 nm in undoped zircon. The valence state of the uranium impurities was unchanged by irradiation with 1014fission events · cm−3, 2 × 1018nvt of fast neutrons, or ∼1010R of γ-rays. A fission event in zircon was deduced to produce ∼104times more displacement damage than an α-recoil atom. Individual fission tracks were observed directly by electron microscopy after dosage of 1010-1013fission events - cm−3, the tracks being similar in appearance to those found by other workers in other materials. With increasing dosage, fission fragment uradiation appears to produce a progressive disordering of the lattice, as was previously deduced for the case of α-recoil irradiation, rather than the formation of new crystallographic phases.

ISSN:0033-7579    

DOI:10.1080/00337577508234742

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

Production rates of dislocation pinning points have been measured at : 8 K and 400 K in Cu irradiated with electrons of various energies between 0.25 MeV and 2.8 MeV. At 78 K the energy dependence was found to coincide exactly with the energy dependence of resistivity damage rates. At 400 K a threshold energy for pinning point production of less than 8.5 eV was found. The interstitial displacement probabilityP(e), however, is as small as 10−5near this threshold.P(e) rises into the order of magnitude of 10−2at about 15 eV. Between 20 eV and 40 eV the 400 K displacement probability is slightly enhanced when compared with the 78 K one. The lowered threshold energy and the enhanced displacement probability is explained by a thermally activated escape from correlated recombination of those interstitials which belong to close pairs or which recombine spontaneously at 78 K or lower temperatures.

ISSN:0033-7579    

DOI:10.1080/00337577508234743

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

A scanning electron microscope supplied with a discharge system for : nsulating materials has been used to observe LiF crystals bombarded with 2 MeV protons, 60 MeV oxygen ions and 56 MeV chlorine ions. The damaged zone gives a clear contrast which allows a direct measure of the penetration depth of the incident ions. This contrast has been attributed to the defects which were also revealed by means of optical absorption measurements. The bleaching of defects during thermal annealings allows the observation of the stopping zone of the incident ions. In this case, the observed contrast is due to the variation of the mean atomic number in the implanted zone. This permits a direct measure of straggling. For light implanted ions (2 MeV protons) the contrast of the stopping zone can be attributed to an escape of fluorine atoms from this heavily damaged zone. For heavy implanted ions (56 MeV chlorine ions) the chemical contrast is due to the implanted ions themselves.

ISSN:0033-7579    

DOI:10.1080/00337577508234744

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

The use of a helium probe technique to determine the number of single : acancies in the damage state produced by ion bombardment is described. The technique is applied to (2–7) keV Ne on Ni(100) and to 5 keV Kr on W(100). In particular it is found that after a 5 keV Ne ion bombardment (8 × 1010/cm2) on Ni(100) there remains approximately 1 vacancy/ion in the damaged state whereas after a 5 keV Kr ion bombardment on W(100) there remains approximately (0.8–1.1) vacancies/ion.

ISSN:0033-7579    

DOI:10.1080/00337577508234745

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

Phosphorus ions at energies of 100, 200 and 300 keV and doses : etween 5 × 1014and 5 × 1015at/cm2have been implanted into silicon crystals along the [110] axis.

ISSN:0033-7579    

DOI:10.1080/00337577508234746

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

A new method of deriving the random fraction in a disordered channel : rom dechanneling experiments is described. In this method backscattering spectra obtained at two different doses are employed, with an assumption on the dose dependence of the defect concentration. The method is applied to the experimental data forB-implanted Si and it is found that the obtained random fraction is similar to the result of the diffusion calculation made by the present authors. The depth profiles of defects are also obtained and compared with the result of theoretical calculations.

ISSN:0033-7579    

DOI:10.1080/00337577508234747

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

Experiments have been carried out to detect23He particles and : rotons having energies up to 10 MeV/nucleon by using Kodak CA80-15, cellulose nitrate plastic track detector. Various etching conditions were tried in order to develop tracks for whole of the energy range considered. Detailed analysis seems to indicate that at high energies, the tracks are mainly produced by “secondaries” (elastically scattered nuclei of C, N, O and H, and other reaction products) while in the low energy region, the slowed down “primaries” play the dominant role. The prolonged etching factors of these detectors for different types of tracks have also been obtained and used to derive their average etchable ranges in the materials concerned.

ISSN:0033-7579    

DOI:10.1080/00337577508234748

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

The depth distributions of ions implanted into solids is evaluated : heoretically for the situation where, following implantation and degradation to rest, each ion can diffuse in the solid whilst simultaneously the surface of the solid is eroded via the sputtering process. Time dependent and equilibrium solutions of the depth distribution or concentration profiles and the total quantities of trapped atoms are determined for cases where (a) the surface is a perfectly transparent boundary for diffusing ions, allowing immediate escape by diffusion only, and (b) the escape of diffusing ions takes place by surface erosion only, the diffusion rate becoming zero at the surface. Two methods of approach for situation (a) are examined-the Laplace transformation technique of the defining partial differential equation and a novel image method. Solutions are compared with earlier work and shown to correspond where appropriate.

ISSN:0033-7579    

DOI:10.1080/00337577508234749

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

The amount of damage present in germanium (and silicon) following : mplants of 200 keV H+or 300 keV D+at temperatures between 40–300°K has been measured using the channeling technique. The damage level is observed to increase strongly with decreasing implantation temperature. Damage profiles were obtained from the data by considering various scattering mechanisms, including single and plural scattering and a steady increase approximation treatment. For equal dose implants, deuterons create considerably more damage in germanium than protons. The ratio of deuteron damage to proton damage is significantly greater than the ratio of energy deposited in nuclear events for the two ions. The results of isochronal anneals at temperatures from 40 to 325°K on Ge crystals implanted at 40°K are also reported. A strong annealing stage is observed around 175°K; this is in good agreement with previous optical absorption studies of proton damage in germanium.

ISSN:0033-7579    

DOI:10.1080/00337577508234750

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor