摘要:

Release behaviour of fission Xe-133 from sintered ThO2−1% :235UO2pellets and powders has been studied as a function of burnup in the range of 2 × 1014to 2 × 1018Fissions/cc by post-irradiation annealing at 1000[ddot]C. It has been observed that below 2 × 1015fissions/cc the apparent diffusivity and initial burst,F', is more or less dose independent. However, with increase of burnup beyond this level bothDnandF'decrease sharply. The effect is more pronounced for the powder than for the pellets.

ISSN:0033-7579    

DOI:10.1080/00337577508234731

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

The four oxides Bi2O2, MoO3, TeO2, and :2O5we characterized by high values for the ratio (crystallization temp.)/(melting temp.), as well as by low ionicities. They would therefore be expected to amorphize on ion impact. Such amorphization is shown to occur readily following the impact of 10–40 ke V Kr ions. This was demonstrated firstly in that the gas-release spectra contained components having a dose dependence and temperature width suggestive of out-diffusion due to crystallization. Secondly, the amorphization was revealed by reflection electron diffraction at 60 or 80 kV. The doses for amorphization were lowest with TeO2and V2O5, and these, along with U3O8and SiO2, must be regarded as the substances most prone to bombardment-induced amorphization. The crystallization temperatures in °C were 260 for Bi2O3, 250 for MoO3, 260 for TeO2, and 310 for V2O5and are thus amongst the lowest known with oxides. Bi2O3crystallizes homogeneously to a cubic phase (δ-Bi2O3) different from the original, whereas MoO3, TeO2, and V2O5crystallize by interface motion to the original structures.

ISSN:0033-7579    

DOI:10.1080/00337577508234732

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

In-depth profiles of 20–140 keV107Ag ions implanted in Si and : iO2were measured by elastic backscattering of 1 MeV α-particles. The results were compared with the theory of Brice. For silicon the experimental values of projected ranges and range stragglings are in good agreement with the predictions of the theory. For SiO2the experimental values are systematically greater than the theoretical by a factor of about 1.4.

ISSN:0033-7579    

DOI:10.1080/00337577508234733

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

The nucleation and growth of interstitial loops during irradiation has a : ontrolling effect on the subsequent swelling behaviour of metals. In nickel based alloys containing ordered γ' precipitate (Ni3Al, Ti), interactions occur between the nucleated loops and γ' particles. This effect has been studied in two nickel based alloys using a High Voltage Electron Microscope.

ISSN:0033-7579    

DOI:10.1080/00337577508234734

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

The effect of thermal annealing (up to 2000 °C) on the structure : nd physical properties of irradiated graphite has been investigated.

ISSN:0033-7579    

DOI:10.1080/00337577508234735

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

The γ-radiolysis of hydrogen sulphide in the excess of xenon : as studied as a function of added HBr, N2O, CCl4and SF6. Addition of HBr results in the considerable increase of H2yield while addition of excess of N2O, CGl4and SF6reducesG(H2)to almost zero. When N2O is present, the N2yield also varies with the H2S/N2O ratio, being uninfluenced by the addition of small amounts of SF6Consideration of possible ionic and nonionic reactions leads to the conclusion that hot hydrogen atoms play a major role in the formation both of hydrogen and nitrogen. The mechanism of electron attachment and ion recombination processes is proposed which is consistent with all the obtained data.

ISSN:0033-7579    

DOI:10.1080/00337577508234736

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

Features of small-angle scattering of charged particles by the crystal : tructure and two-dimensional angular distributions are studied on the basis of Monte-Carlo calculations of 20 MeV electron and positron transmission through a (001) MgO single crystal. An accurate method for calculation of the charged particle scattering in a heterogeneous electron gas in the crystal is proposed. The analytical conditions under which the string-effect influences the small angle scattering are derived and comparison is carried out with well-known experimental data.

ISSN:0033-7579    

DOI:10.1080/00337577508234737

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

The depth of the layer ofF-centers created by protons in the : nergy intervals 0.5 to 2.3 MeV and 4 to 15 MeV was measured in single crystal KG. Photomicrographs were taken of irradiated crystals usingF-band light. The optical density of the negatives was measured and calibrated to give a graph of optical density versus distance into the crystal. Using the stopping power of pro to ns in argon, a “theoretical” range-energy curve was calculated. Experimental results correspond to this curve within experimental error. The damage profiles produced by protons in the high energy interval showed Bragg peaks, consistent with the rise in energy-loss-rates of slowing protons. The damage profiles produced by protons in the low energy interval did not exhibit Bragg peaks, a feature attributed to the combined effect of reducedF-center production efficiency of low energy protons and saturation in theF-center concentration.

ISSN:0033-7579    

DOI:10.1080/00337577508234738

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

Color-center effects unique to crystals irradiated to high fluence : 1016particles/cm2) are reported for KCl and other alkali halides. These include (1) a minimum inF-center concentration at the end of the proton range and (2) an n-center distribution profile which changes with time in the dark at room temperature after irradiation. The first effect is due to annihilation ofFcenters by hydrogen atom capture (U-center formation) and the second is due toF-center diffusion and aggregation in a heavily damaged region of the crystal.

ISSN:0033-7579    

DOI:10.1080/00337577508234739

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

MOLECULAR REACTION DYNAMICS, by R. D. Levine and R. B. Bernstein. Oxford University Press, New York, N.Y. 1974 (£5.00).

ISSN:0033-7579    

DOI:10.1080/00337577508234740

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor