Search results for "Secondary Ion Mass Spectrometry"
showing 10 items of 38 documents
Structural and in depth characterization of newly designed conducting/insulating TiN O /TiO2 multilayers obtained by one step LP-MOCVD growth
2001
Abstract TiNxOy/TiO2 multilayers have been grown by LP-MOCVD using titanium isopropoxide (TIP) precursor during the whole growth, but with an ammonia flow interrupted for the TiO2 layers. The one step growth process used to grow these structures allowed to stack the conducting and insulating layers without any growth breakdown. SIMS and TEM analyses showed the presence of an alternated insulating/conducting layers structure. Moreover, electrical measurements allowed to measure the dielectric part of insulating TiO2 stacked in these structures, whose permittivity was found to be about 80 for a MOS structure. Thus, such multilayers may lead to very promising applications in the microelectroni…
Mass spectrometry of atomic ions produced by in-trap decay of short-lived nuclides
2005
The triple-trap mass spectrometer ISOLTRAP at ISOLDE/CERN has demonstrated the feasibility of mass spectrometry of in-trap-decay product ions. This novel technique gives access to radionuclides, which are not produced directly at ISOL-type radioactive ion beam facilities. As a proof of principle, the in-trap decay of $^{37}K^+$ has been investigated in a Penning trap filled with helium buffer gas. The half-life of the mother nuclide was confirmed and the recoiling $^{37}Ar^+$ daughter ion was contained within the trap. The ions of either the mother or the daughter nuclide were transferred to a precision Penning trap, where their mass was determined.
Position-sensitive ion detection in precision Penning trap mass spectrometry
2009
A commercial, position-sensitive ion detector was used for the first time for the time-of-flight ion-cyclotron resonance detection technique in Penning trap mass spectrometry. In this work, the characteristics of the detector and its implementation in a Penning trap mass spectrometer will be presented. In addition, simulations and experimental studies concerning the observation of ions ejected from a Penning trap are described. This will allow for a precise monitoring of the state of ion motion in the trap.
A highly selective laser ion source for bunched, low emittance beam release
2004
A novel type of resonance ionization laser ion source (RILIS) is under development, which combines the advantages of laser ionization with those of a source-implemented ion trap. This laser ion source trap (LIST) system, based on a gas-filled linear radio-frequency quadrupole ion trap, decouples the evaporation and ionization process by introduction of a primary surface ion repeller. Apart from significantly enhancing the selectivity in radioactive ion beam production, optimum control on the temporal pulse structure and the emittance of the generated laser ion bunch is obtained. A variety of operational modes from quasi-dc to microseconds-bunched ion beams with variable repetition rate can …
Diffusion of Oxygen in Thermally Grown Oxide Scales
2009
High temperature reactivity of materials under oxidizing atmospheres is based on the formation of protective oxide scales. The protectiveness is obtained when the thermally grown oxide scales are dense, continuous and adherent to the metallic substrates (even during thermal shocks); as a matter of fact, the growth of the scale has to be governed by diffusion of species across the growing scale. The diffusing species are coming from the substrate (metallic ions) and/or from the oxidizing atmosphere (oxygen ions). The understanding of growth mechanisms can be reached by making two stage oxidation experiments, using oxygen isotopes. The experiment consists in oxidizing first the metallic subst…
Resonant laser–SNMS for spatially resolved and element selective ultra-trace analysis of radionuclides
2018
The newly developed resonant laser–SNMS system at the IRS Hannover combines the high spatial and decent mass resolution of a TOF-SIMS instrument with the element-selective process of resonant laser ionization. This setup was characterized by use of synthetic uranium, plutonium and technetium samples to prepare and demonstrate the performance for measurements on environmental samples. The laser–SNMS system will be applied for the detection, visualization and ultra-trace analysis of radionuclide containing nanoparticles in environmental samples with strongly reduced or even completely omitted chemical preparation. The necessary suppression of isobaric contamination was demonstrated as well as…
RADIOISOTOPE MASS SPECTROMETRY
2003
Mass spectrometric methods are very sensitive and enable in many cases a multielement determination of trace and ultratrace elements combined with a good isotopic analysis ( Bacon et al. , 2001 ). Therefore, these techniques are also applied for the detection of long-lived radionuclides ( Becker and Dietze, 2000 ) mainly in environmental samples ( Adriaens et al. , 1992 ; Bailey et al. , 1993 ; Bibler et al. , 1998 ; Eroglu et al. , 1998 ; Edmonds et al. , 1998 ; Becker and Dietze, 1999 ; Wendt et al. , 1999 ), nuclear materials ( Betti, 1997 ; Chartier et al. , 1999 ), glass and ceramics ( Rohr et al. , 1994 ; Fukuda and Sayama, 1997 ), and in high-purity substances ( Beer and Heumann, 199…
High-sensitivity U–Pb rutile dating by secondary ion mass spectrometry (SIMS) with an O2+ primary beam
2012
Abstract We present a secondary ionization mass spectrometry (SIMS) technique for U–Pb geochronology of rutile at high spatial resolution and sensitivity using an O2+ primary ion beam coupled with surficial O2 gas deposition (O2 flooding). The O2+ beam is ~ 10 × more intense than conventionally applied O− or O2− beams at the same lateral resolution. Natural and synthetic rutile was determined to be conductive under O2+ bombardment, permitting higher excavation (sputter) rates than conventional SIMS using negatively charged O-beams without detrimental effects of sample charging. The main advantage of O2+ is rapid sputtering at shallow primary ion penetration depths. This minimizes the contri…
Cluster isobars for high-precision mass spectrometry
1991
Doublet mass measurements of the isobars28Si3 and12C7 are performed by use of a Penning trap mass spectrometer and the Fourier transform ion cyclotron resonance (FT-ICR). The carbon and silicon cluster ions are produced by laser ablation. Results of these preliminary measurements are presented.
The use of local electrochemical probes and surface analysis methods to study the electrochemical behaviour and pitting corrosion of stainless steels
2007
Abstract In this paper, the electrochemical microcell technique is combined with ex situ (SIMS and XPS) and in situ (SVET) techniques to study the electrochemical behaviour and pitting corrosion of inclusion-contaning stainless steels. Dissolution of metallurgical heterogeneities, depassivation and pitting mechanisms are first discussed in 1 M NaClO4, pH 3, and 1 M NaCl, pH 3, by considering the chemical composition and morphology of inclusions. The influence of the chemical composition of passive films on the electrochemical reactions and the microgalvanic coupling processes occurring at the corrosion potential is also investigated on the same specimen microstructure.