Search results for " abl"
showing 10 items of 296 documents
A mass-independent expanded Dunham analysis of aluminum monoxide and aluminum monosulfide
2018
Abstract Pure rotational transitions of 27Al16O, 27Al18O, 27Al32S, and 27Al34S are recorded in the vibrational ground state and singly excited vibrational state using a mm-wavelength supersonic jet spectrometer in combination with a laser ablation source. In total 275 rotational transitions have been assigned. For the first time, mass-independent expanded Dunham analyses are performed using isotopologues of aluminum monoxide and aluminum monosulfide. The breakdown of the Born-Oppenheimer approximation is observed. Based on these mass-independent analyses, frequency positions of pure rotational transitions of the rare radioactive isotopologues 26AlO and 26AlS are predicted with uncertainties…
Fabrication and Characterization of Epitaxial NbN/TaN/NbN Josephson Junctions Grown by Pulsed Laser Ablation
2009
We report fabrication and characterization of epitaxial NbN/TaN/NbN Josephson junctions grown by pulsed laser ablation. These SNS junctions can be used as elements of rapid-single-flux-quantum (RSFQ) logic, which is a promising technology for high speed digital electronic devices. The NbN/TaN/NbN trilayer films were prepared on a single crystal MgO substrate by pulsed laser ablation, and patterned into junctions using a novel process utilizing e-beam lithography, chemical vapor deposition and e-beam evaporation. The quality of junctions was tested by measuring the temperature dependence of the junctions' IcRn values, observed to be quite close to theoretical values.
Assessment of Five Monazite Reference Materials for U-Th/Pb Dating Using Laser-Ablation ICP-MS
2019
Monazite is a common accessory phosphate mineral that occurs under a wide range of pressure and temperature conditions in sedimentary, metamorphic and igneous rocks. Monazite contains high amounts of Th and U, rendering single monazite grains suitable for in-situ U-Th/Pb dating using laser ablation inductively-coupled mass spectrometry (LA-ICP-MS). Two key aspects of monazite dating that are critical for accurate age data with maximum precision are (i) optimized instrumental conditions to minimize analytical scatter and (ii) a well characterized reference material to ensure the accuracy of the obtained aged. Here, we analyzed five monazite reference materials (USGS 44069, 94-222, MAdel, Moa…
Comparison of Two Aerodynamic Lenses as an Inlet for a Single Particle Laser Ablation Mass Spectrometer
2008
By means of a newly designed portable aerosol mass spectrometer SPLAT (Single Particle Laser Ablation Time-of-flight mass spectrometer) for the analysis of single atmospheric aerosol particles we investigated the system performance in dependency on two different aerodynamic lenses (Liu and Schreiner type) capable of focusing particles with diameters ranging from 80 nm to 800 nm and 300 nm to 3000 nm, respectively. By using the pressure regulated Schreiner lens, the instrument is independent of variations in atmospheric pressure which would lead to changing dynamical properties of the aerosol particles. Active pressure control inside the inlet system facilitates airborne measurements without…
Comparative LA-ICP-IDMS determinations of trace elements in powdered samples using laser ablation systems with low and high ablation rates
2004
The results of laser ablation inductively coupled plasma isotope dilution mass spectrometry (LA-ICP-IDMS) with a special laser ablation system with high ablation rates (LINA-Spark-Atomiser), which was constructed for bulk analyses of solid samples, are compared with those obtained by one of the commonly used LA systems (UP213). Using different reference materials for validation it was demonstrated that the accuracy of LA-ICP-IDMS determinations of elements like Fe, Cu, Pb, and Zn by both systems is comparable in the concentration range of 10−2–10−6 g g−1, but the LINA-Spark-Atomiser also provides accurate results in the sub-μg g−1 range. IDMS enables accurate calibration of LA-ICP-MS determ…
Some aspects of pulsed laser deposition of Si nanocrystalline films
2009
International audience; Nanocrystalline silicon films were deposited by a picosecond laser ablation on different substrates in vacuum at room temperature. A nanocrystalline structure of the films was evidenced by atomic force microscopy (AFM), optical and Raman spectroscopies. A blue shift of the absorption edge was observed in optical absorption spectra, and a decrease of the optical phonon energy at the Brillouin zone centre was detected by Raman scattering. Early stages of nanocrystalline film formation on mica and HOPG substrates were studied by AFM. Mechanism of nanocrystal growth on substrate is discussed.
High-resolution records of past and modern Pb exposure: Laser-ablation ICPMS profiles from tooth enamel
2006
We present compositional and isotopic profiles of past and modern tooth enamel aimed at reconstructing in-vivo Pb exposure at high spatial and time resolution. Focus is on dental enamel because of its sequential mineralization preserving time-series information, and due to its resistance to post-mortem diagenetic alteration. Examples include medieval Pb–Ag miners from SW Germany (Black Forest), the port of ancient Rome (Isola Sacra) for an assessment of the ‘Pb poisoning hypothesis’, and a modern Pb–Zn smelter village in NE NSW. (Sub-)ppb levels of U, LREEs, Y in soil-buried enamel resembling modern enamel are utilized as indicators for the preservation of pristine in-vivo concentrations. T…
Non-Matrix-Matched Calibration for the Multi-Element Analysis of Geological and Environmental Samples Using 200 nm Femtosecond LA-ICP-MS: A Compariso…
2014
LA-ICP-MS is one of the most promising techniques for in situ analysis of geological and environmental samples. However, there are some limitations with respect to measurement accuracy, in particular for volatile and siderophile/chalcophile elements, when using non-matrix-matched calibration. We therefore investigated matrix-related effects with a new 200 nm femtosecond (fs) laser ablation system (NWRFemto200) using reference materials with different matrices and spot sizes from 10 to 55 μm. We also performed similar experiments with two nanosecond (ns) lasers, a 193 nm excimer (ESI NWR 193) and a 213 nm Nd:YAG (NWR UP-213) laser. The ion intensity of the 200 nm fs laser ablation was much l…
On the topographic and energetic surface modifications induced by laser treatment of metallic substrates before plasma spraying
2003
Abstract Laser surface cleaning has been proven as a very suitable technique for the substitution of some surface preparation steps, such as wet cleaning and grit blasting. The mechanisms involved in short pulsed laser ablation include the absorption of the laser light and conversion into heat via collisional processes. Ejection of matter is achieved either by direct vaporization or hydrodynamical sputtering. This article aims at clarifying the laser–matter interaction mechanisms and effects on metallic materials for different surfaces initial roughness and laser beam energy densities. Both topographic and energetic modifications are investigated by SEM observations, roughness characterizat…
Transport and magnetic properties of La1−xCaxMnO3-films (0.1<x<0.9)
2000
Abstract By laser ablation we prepared thin films of the colossal magnetoresistive compound La1−xCaxMnO3 with doping levels 0.1 10 13 Ω have been measured with an electrometer setup. While the transport data indicate polaronic transport for the metallic samples above the Curie temperature the low-doped ferromagnetic insulating samples show a variable range hopping like transport at low-temperature.