摘要:

The lattice disorder produced in germanium by 56keV boron-ion bombardment has been measured using the channeling-effect technique. The dependence on dose (1014-1016ions/cm2) and implantation temperature (−90 °C to +130°C) has been studied. It is found that at room-temperature, each incident boron ion creates −10 times more disorder in germanium than in silicon. It is remarked that, contrary to the present results, previously established anneal stages generally occur at significantly lower temperatures in germanium than in silicon.

ISSN:0033-7579    

DOI:10.1080/00337577008236267

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

The main features of heavy-ion track registration in nonconductor minerals are presented. In particular, experimental results obtained recently by several authors are used to identify those features which are directly related to the radiation damage mechanism producing the tracks, rather than to the decoration process employed to observe them.

ISSN:0033-7579    

DOI:10.1080/00337577008236268

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

The mechanism of track formation in muscovite mica was studied using X-ray small angle scattering. The samples were irradiated with Argon ions of minimum energy 1 MeV/nucleon, the integrated doses ranging from 3 × 1012to 1013Argon ions/cm2.

ISSN:0033-7579    

DOI:10.1080/00337577008236269

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

The diffusion of Kr in RbCl single crystals was studied following Kr implantation at 15 keV and doses of 3.7 × 1013to 3.7 × 1015ions/cm2. The compound exponential depth distribution was utilized by comparing ordinarily implanted specimens with others having the outermost ∼ 2000 Å removed inn-butanol so as to leave only the deeply channeled portion of the incident beam in an ambient of low damage concentration. Two diffusion mechanisms were found, one at 150–300 °C, with an activation enthalpy of 1.21 ±0.07 eV, and one at 300–450 °C, with an activation enthalpy of 2.3±0.2 eV. The first process corresponds reasonably well to Norgett and Lidiard's description of interstitial diffusion in the presence of extrinsic or collisionally-produced single-vacancy traps, for which an activation enthalpy of 1.28–1.78 eV was calculated. The second process is not so easily interpreted but possibly corresponds to interstitial diffusion in the presence of small vacancy clusters or small gas clusters, with or without concurrent radiation-damage annealing. A comparison of the pre-exponential factors for the first process as a function of dose allows the single-vacancy concentrations in the bombarded regions to be estimated, and evidence is presented that the concentration saturates at about 2 × 10−2±1atomic fraction for doses in excess of 5 × 1015ions/cm2. It is shown that the interstitial frequency factorr0works out to about 1 × 1012±lsec−lon the basis of the proposed diffusion mechanism. This is a reasonable value and tends to confirm the model.

ISSN:0033-7579    

DOI:10.1080/00337577008236270

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

The formation of particle tracks, and such phenomena as the detection of charged particles, and the damage produced by charged particles, are intimately related to the spatial distribution of ionization energy deposited by δ-rays. Changes in the spectrum of δ-rays with the velocity of the primary particle, imply that linear measures of the interaction of the primary particle with the medium, such as specific energy loss, or primary ionization, are unsatisfactory measures of effects produced in the medium, for they contain no knowledge of the spatial deposition of the lost energy.

ISSN:0033-7579    

DOI:10.1080/00337577008236271

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

A theoretical study of the scattering of an energetic He ion from a (110) row of gold atoms, to which it is incident normally, has been made. Single collisions of the ion with one gold atom or a succession of two collisions with adjacent gold atoms were investigated, using a Born-Mayer potential to define the interaction and approximate analytical expressions for the scattering equations for this potential form. The predicted trimodel dependence of the energy of the backscattered ion as a function of impact Parameter on a gold atom is shown to agree well with computer based calculations of the exact ion trajectories.

ISSN:0033-7579    

DOI:10.1080/00337577008236272

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

The γ-ray oxidation of 2-methyl tetrahydrofuran proceeds with a chain reaction giving an organic hydroperoxide as the major product at low doses. The rate of peroxide formation is given byand the rate constant ratio for the chain propagation to the chain termination is given byat room temperature. An ionic chain termination by O2- was found to be important only in aqueous solutions but not in pure MTHF or mixtures of cyclohexane + MTHF where the low dielectric constant of the medium seems to inhibit the O2- formation in appreciable yield.

ISSN:0033-7579    

DOI:10.1080/00337577008236273

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

Resistivity change as a function of electron irradiation near 8 °K and of annealing after irradiation has been measured on zirconium. Damage rates were measured as a function of incident electron energy from 0.70 to 1.9 MeV. A value of 24 eV for the displacement threshold energy was determined by extrapolation of the damage rate curve to zero damage production. A fit between the theoretical and experimental values of displacement cross section was achieved with an effective threshold energy of 28 eV, yielding 35 × 10−4Ω-cm/fractional concentration for the Frenkel resistivity. The damage-rate curve indicates no tailing due to subthreshold displacements. Recovery in Zr is analogous to that of fcc and bcc elements studied, but with six substages in Stage I. Substage If (analogous to Iein other materials) was analyzed by using the serpentine plot, which gives an indication of long-range migration of an interstitial between 120 and 150 °K, with an activation energy of 0.26 eV (second order kinetics is assumed). Stage III is in the temperature range 250 to 310 °K. The activation energy of Stage III was analyzed by use of the Meechan-Brinkman and second-order methods; this results in an average energy of 0.57 eV. The order of reaction kinetics was found to be a function of recovery.

ISSN:0033-7579    

DOI:10.1080/00337577008236274

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

The microstructural defects produced in molybdenum by neutron irradiation in the temperature range 50 °C to 800 °C have been characterized by transmission electron microscopy. At a low irradiation temperature, 50 °C, a large number of small dislocation loops, presumably interstitial, form within a complex dislocation network. At intermediate temperatures, 400–600 °C, small interstitial loops agglomerate into rafts. At high temperatures, 600–800 °C, the small loops which comprise a raft are sufficiently mobile to form large loops which interact with each other to produce a coarse dislocation network. The migration of small loops through the lattice by a combination of prismatic glide and conservative climb accounts for the observed microstructures. Vacancy loops are the only identifiable vacancy defects at temperatures ≥ 500. Between 575–650 °C, both vacancy loops and voids exist. Above 650 °C to at least 800 °C, voids are the exclusive vacancy defect. Information on the effect of impurities and grain boundaries on the configuration and distribution of visible defects is presented.

ISSN:0033-7579    

DOI:10.1080/00337577008236275

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

By measuring the oxygen consumption during dissolution of irradiated solid compounds in water with different oxygen concentrations, the ratio of the radical-oxygen and radical-radical reaction rates can be obtained. In a series of six compounds with molecular weights from 75 to 504 the ratio of the reaction rates increased from 2–3 to over 20. The increasing dominance of the radical-oxygen reaction rate over the radical-radical one at increasing molecular size probably depends on a combination of diffusion and steric factors. The radical concentration of the irradiated solid compound can be evaluated by a linear extrapolation of the oxygen consumption to infinite oxygen concentration in the dissolution water. The radiation-induced radical yields, measured in this manner, agree well with results obtained by ESR investigations.

ISSN:0033-7579    

DOI:10.1080/00337577008236276

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor