No abstract available

[en] Bubble lattice formation is one of the common features resulting from high-dose inert gas implantations into metals at ambient temperatures. In this paper we describe the bubble lattice alignment found during an investigation into the precipitation of krypton ions in titanium at 300 K. The bubbles were shown to be ordered into planes or sheets, parallel with the basal plane of the hexagonal-close-packed structure of the host matrix; however, within each bubble plane the bubble positions were random. This work adds to the sparse data on bubble lattices (a) in hcp metals, and (b) formed with inert gases other than helium. The hcp result appears important in assessing the two recent models of cavity lattice formation based on anisotropic interstitial diffusion. (orig.)

[en] The visible light emissions from the sputtered Al species and the neutralized projectiles during Kr¹³⁺ ions bombarding the Al surface have been measured in the wavelength range of 300–600 nm. The three spectral lines belonging to transitions of Al I 3p ²P_3/2^o–3d ²D_5/2 at 309.0, Al II 3d ³D₁–4f ²F₂^o at 358.5 and Al I 3p ²P_3/2^o–4s ²S_1/2 at 396.1 nm have been observed, as well as five spectral lines from the incident ion attributing to transitions of Kr I 5s ²[3/2]₁^o–5p ²[1/2]₁ at 587.9, Kr II 4d ⁴D_1/2–5p ²S_1/2 at 485.8, Kr II 4d ³D₂^o–5p ³D₃ at 434.3, Kr II 5s ²P_3/2–5p ⁴S_3/2^o at 430.1 and Kr II 5s ⁴P_1/2–5p ²D_3/2^o at 409.9 nm

[en] Nanochannel tungsten (W) film is a promising candidate as an alternative to bulk W for use in fusion applications. In previous work it has been shown to have good radiation resistance under helium (He) irradiation. To further understand the influence of the irradiation-induced displacement cascade damage on helium retention behaviour in a fusion environment, in this work, nanochannel W film and bulk W were pre-irradiated by 800 keV Kr²⁺ ions to the fluence of 2.6  ×  10¹⁵ ions cm⁻² and subsequently irradiated by 40 keV He⁺ ions to the fluence of 5  ×  10¹⁷ ions cm⁻². The Kr²⁺ ion pre-irradiation greatly increases helium retention in the form of small clusters and retards the formation of large clusters. It can effectively inhibit surface helium blistering under high temperature annealing. Compared with bulk W, no cracks were found in the nanochannel W film post-irradiated by He⁺ ions at high fluence. The release of helium from the nanochannel W film is more than one order of magnitude higher than that of bulk W whether they are irradiated by single He⁺ ions or sequentially irradiated by Kr²⁺ and He⁺ ions. Moreover, swelling of the bulk W is more serious than that of the nanochannel film. Therefore, nanochannel W film has a higher radiation tolerance performance in the synergistic irradiation. (paper)

[en] Recent measurements of the 3d¹⁰nf ²F_J (n=4,5,6,7) levels in Kr⁷⁺ show a fine structure inversion however previous experimental results predict that the 3d¹⁰5f ²F_J levels are normal. Single configurational Dirac-Fock calculations predict that the levels are inverted but the effects are so small that configuration interaction could have a significant effect. To investigate this anomaly fully, multiconfigurational Dirac-Fock calculations including the most important core-excitation effects have been performed. Dirac-Fock calculations may predict fine structure inversion because the use of different radial wavefunctions for electrons with different j values effectively includes the major core polarisation effects which are known to induce fine structure inversion. To investigate this hypothesis, Hartree-Fock calculations including core polarisation potentials are being performed and the results will be presented

[en] The black-white (B-W) stereo technique has been critically assessed and applied to the determination of the nature of small point-defect clusters in copper produced by Kr⁺ heavy-ion irradiation at room temperature. Several precautions were introduced in an attempt to improve the reliability of the analysis. It was found that most defects lying in the first approximately 10 nm of the foil are vacancy in nature, together with some of the deeper clusters. There was no unequivocal evidence for interstitial clusters. Some were more likely to be interstitial than vacancy on the criteria chosen, although the evidence is weak. Defects sometimes showed inconsistent contrast from one imaging condition to another, demonstrating the difficulty of placing them in the layer structure with complete confidence. The near impossibility of establishing that interstitial clusters are not present is shown by the fact that over half (53%) the total number of clusters could not be analysed because they did not show clear B-W contrast in a minimum number of imaging conditions. Various correlations are made between parameters such as defect sizes with the depths of the defects in the foil. (Author)

[en] A general formula for data analysis in conductometric experiments on latent track structure has been obtained without any pore shape assumption. An iterative equation, which was derived from pore geometry defined in a rest frame model, enables us to estimate the precise pore shape of the latent tracks during an etching. Polyethylene terephthalate (PET) films irradiated by Kr ions have been studied by this iteration technique. Radial etch rates reach convergence after a few iteration cycles and are less affected by the error of the breakthrough time. The iteration technique also reveals that a cylinder approximation, which is widely used for calculating a pore size, overestimates the transverse size of etched heavy ion tracks in the range less than 10 nm

[en] The use of energetic noble gas atoms for ion beam mixing studies or the modification of materials necessitates an understanding of the effects produced by the retained gas atoms. A systematic study of the microstructural evolution in Al after 65 keV Kr⁺ implantation (dose range 2x10¹⁶ Kr⁺ m^-2 <= phi <= 6x10²⁰ Kr⁺ m^-2, at ambient temperature was performed using transmission electron microscopy (TEM) and Rutherford backscattering (RBS). (orig./RK)

[en] Multi-charged Kr ions have been measured using monochromatized undulator radiation combined with a coincidence technique. The coincidence measurements between multi-charged ions and energy-selected Auger electrons have clarified decay processes, as follows. The Auger final states formed through L₃M₄₅M₄₅ decays turn significantly into Kr⁴⁺ and those through L₃M₂₃M₄₅ decays generate Kr⁵⁺ mainly. The Auger decays of L₃M₂₃M₂₃ types yield Kr⁶⁺ dominantly. These findings are consistent with the consideration on energy levels of Kr ions

[en] The desorption of atomic and molecular species from surfaces bombarded by fast heavy ions (Z ≥ 20; E ≥ 0.5 MeV/amu) is attractive for surface and microscopic characterization. Only a low-intensity probe beam is needed, the escape depth of desorbed species is shallow (ca. 10 A), and desorbed ions are efficiently detected with a time-of-flight mass spectrometer. Thus, particle-induced desorption mass spectrometry (PDMS) maintains sample integrity and charging effects are avoided. PDMS is useful for surface analysis of glasses and plastics by using californium-252 fission fragments for bombardment. Inorganic and organic surface constituents can be detected simultaneously; mass resolution is good. For lithium in glass, the detection limit is about 1 pg (ca. 100 μg g^-1). The PDMS technique can be combined with sequential ion etching for depth profiling. The feasibility of PDMS for microscopic analysis with a collimated 84-MeV Kr⁷⁺ beam (target diameter ca. 11 μm) is discussed. 11 refs.; 8 figs.; 1 table