[en] The gyromagnetic ratio of the 3₁⁺ state (937-keV excitation energy) in ¹⁸F was measured by the time-integral IMPAC technique following implantation in a magnetically saturated Fe foil. The ¹⁶O(³He,pγ) reaction was employed using 3.75-MeV ³He⁺ beams. Measurements of the angular distribution of the de-excitation γ ray from this level to the ground state and of its precession in the hyperfine field were carried out in coincidence with backward-emitted reaction protons. The sign and magnitude determined for the g-factor of this state is g = +0.54+-0.06. Shell-model calculations of the g-factor of this level have been performed and are evaluatively compared with experiment

[en] Geological samples are complex materials, which often involve intricate textures of crystalline and amorphous components. Inclusions may preserve samples of melts and fluids responsible for evolution of the Earth's mantle and crust. Analysis of these samples helps improve our understanding of geological processes and provides a basis for new mineral exploration approaches and improved mineral processing techniques. The penetration of a MeV proton microbeam permits the non-destructive in situ imaging and analysis of buried structures such as mineral, melt and fluid inclusions. IBA techniques permit standardless analysis and non-destructive imaging for virtually arbitrary sample composition. Rutherford backscattering and resonant nuclear reactions can be used for the analysis of diffusion depth profiles, as can elastic recoil methods, particularly for hydrogen analysis. And many of these techniques can be combined with crystal channelling. These techniques available on easily accessible machines gives IBA a firm place amongst the spectrum of complementary analysis tools available to geology

[en] The velocity-dependence of the transient hyperfine magnetic field acting at nuclei of ¹⁹⁶Pt ions rapidly recoiling through thin magnetized Fe was investigated at a number of recoil velocities. The state of interest (2₁⁺) was populated by Coulomb excitation using beams of 80- and 120-MeV ³²S and 150- and 220-MeV ⁵⁸Ni ions. The 2₁⁺→0₁⁺ γ-ray angular distribution precession measurements were carried out in coincidence with backscattered projectiles. From these results, the strength of the transient field acting on Pt ions recoiling through magnetized Fe with average velocities in the extended range 2.14<=v/vsub(o)<=4.82 (vsub(o) = c/137) was found to be consistent with a linear velocity dependence and to be incompatible with the specific vsup(0.45+-0.18) dependence which has been previously reported to account well for all ions in the mass range from oxygen through samarium. This seemingly singular behaviour for Pt and other ions in the Pt mass vicinity is discussed

[en] The gyromagnetic ratios of the 2₂⁺ and 4₁⁺ states in ¹⁹⁶Pt were measured relative to that of its 2₁⁺ level. The thin-foil IMPAC technique was employed utilizing the enhanced transient hyperfine magnetic field present at the nuclei of swiftly recoiling ions traversing magnetized ferromagetic materials. The states of interest were populated by Coulomb excitation using beams of 220-MeV ⁵⁸Ni ions. For g(2₁⁺) taken as 0.326+-0.014, the present measurements yielded g(2₂⁺) = 0.30+-0.06 and g(4₁⁺) 0.30+-0.05. These results and those reported by prior workers for the g-factors of corresponding levels in ¹⁹²Pt, ¹⁹⁴Pt, ¹⁹⁸ Pt are used to trace the systematics of the magnetic moments of these low-lying levels in the even ¹⁹²-¹⁹⁸Pt isotopes. Interacting Boson Approximation model-based calculations of the g-factors of these states were also carried out. The experimental theoretical results are compared

[en] The gyromagnetic ratios of the 2₂⁺ and 4₁⁺ states in ¹⁹²Os were measured relative to that of its 2₁⁺ level. The thin-foil, perturbed γ-ray angular distribution technique was employed utilizing the enhanced transient hyperfine magnetic field present at the nuclei of these ions as they swiftly recoiled through a thin, magnetized Co foil. The states of interest were Coulomb excited using a beam of 220-MeV ⁵⁸Ni ions. The present measurements yielded ratios g(2₂⁺)/g(2₁⁺) = 0.68 +- 0.08 and g(4₁⁺)/g(2₁⁺) = 1.00 +- 0.12. The sizable disparity in the measured g-factors of the levels of the two low-lying bands is compared with interacting boson approximation model-based calculations, as well as with a Nilsson basis single-particle model description

[en] Precessions were measured of the 2₁⁺ states in ¹⁹²Os and ¹⁹⁸Pt in the enhanced transient field in thin cobalt foils and comparison made with similar recent studies of ¹⁸⁸Os and ¹⁹⁴Pt ions in Fe foils. It is concluded that (i) the transient field acting on Pt in Fe is singularly anomalous, and (ii) recent contention that the g-factors of even Pt 2₁⁺ states may be substantially lower than reported earlier cannot be sustained

[en] The High-Energy Stereoscopic System (H.E.S.S.), located in the Khomas Highland of Namibia, is an array of four imaging atmospheric-Cherenkov telescopes designed to detect gamma-rays in the very-high-energy (VHE;E>100 GeV) domain. Its high sensitivity and large field-of-view (5 ) make it an ideal instrument to perform a comprehensive survey of the Galaxy. Using data collected in 2004, the Galactic Plane Survey (GPS) of the inner Galaxy led to the detection of 14 VHE gamma-ray-emitting sources within the region of Galactic longitude vertical stroke l vertical stroke <30 and latitude vertical stroke b vertical stroke <3 . Since then, the H.E.S.S. GPS has been extended significantly in longitude, out to l=275 and l=60 . The effective exposure has also greatly increased in the originally surveyed region. This extended, deeper survey now encompasses most of the first and fourth Galactic quadrants and has led to the discovery of numerous additional VHE gamma-ray emitters with high statistical significance. The current status and latest results of the extended H.E.S.S. GPS are presented.

[en] Dynamic Analysis (DA) is a method for projecting quantitative major and trace element images from PIXE event data-streams (off-line or on-line) obtained using the Nuclear Microprobe. The method separates full elemental spectral signatures to produce images that strongly reject artifacts due to overlapping elements, detector effects (such as escape peaks and tailing) and background. The images are also quantitative, stored in ppm-charge units, enabling images to be directly interrogated for the concentrations of all elements in areas of the images. Recent advances in the method include the correction for changing X-ray yields due to varying sample compositions across the image area and the construction of statistical variance images. The resulting accuracy of major element concentrations extracted directly from these images is better than 3% relative as determined from comparisons with electron microprobe point analysis. These results are complemented by error estimates derived from the variance images together with detection limits. This paper provides an update of research on these issues, introduces new software designed to make DA more accessible, and illustrates the application of the method to selected geological problems.

[en] In complex multi-elemental samples it is often necessary to determine the presence of various chemical phases. More complexity arises if it is also necessary to determine the spatial distribution of these phases. Here we present a new technique, based on the elemental maps, for the study of the phase distribution of multi-elemental samples. This technique uses the elemental maps obtained with nuclear microscopy to extract the spatially distributed phase information. We will explain the basic technique of phase correlation mapping, and then provide simulated and experimental results to demonstrate its capability in materials analysis. The simulations show the effect of the beam spatial resolution on the correlation maps and the experimental results show the phase correlation maps of elements in an array of phosphors from a video tube

[en] Ionoluminescence (IL) performed with a nuclear microprobe is potentially a highly sensitive method for measuring optically active impurities and defects in diamonds. In this study, a Sumitomo synthetic diamond sample grown in the presence of a Ni catalyst is imaged with IL and particle induced X-ray emission (PIXE). Ni impurities incorporated during the growth are identified with IL spectroscopy, and shown to segregate into <1 1 1> growth sectors with IL imaging. This finding is consistent with previously published luminescence results. PIXE analysis performed on the same regions of the sample confirm the presence of Ni. PIXE and IL analyses are compared and used to show that the improved sensitivity of IL over PIXE is ideal for imaging such optically active impurities in diamonds