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Sample records for zircon ion microprobe

  1. U-Pb geochronology of zircons form lunar Breccia 73217 using a sensitive high mass-resolution ion microprobe

    International Nuclear Information System (INIS)

    Compston, W.; Williams, I.S.

    1984-01-01

    U-Pb age determinations on four lunar zircons from existing thin-sections of one highland breccia, 73217, using the recently constructed ion microprobe SHRIMP, are reported. The analytical reproducibility of SHRIMP is demonstrated, and procedures for measuring Pb/U, Th/U, and corecting for initial Pb are explained. Electron microprobe analyses for the zircons are also reported. The results show that the four zircons survived the lunar cataclysm without any identifiable effects on their U-Pb systematics. All four indicate a single age of 4356 +23 or -14 m.y. The zircons have experienced small variable amounts of Pb loss since crystallization, from almost zero up to about 10 percent. If this occurred during one later event, then age of the latter is between 1100 and 2300 m.y. 18 references

  2. Evolution of the Gondwanaland Archaean Shield: ion microprobe zircon dating and southwestern Australia/Wilkes Land, Antartica

    International Nuclear Information System (INIS)

    Lovering, J.F.; Comaford, D.J.

    1979-01-01

    The ion microprobe has been used to study 207 Pb/ 206 Pb ages on 20μm-sized sites on single zircon grains from coastal rocks on either side of the rift in the Gondwanaland Archaean Shield between southwestern Australia and Wilkes Land, Antarctica. The ages on individual sites on zircon grains from a variety of rock types from southwestern Australia show a range from 1600 m.y. to about 3400 m.y., with an inverse dependence on the uranium abundance at each site. Ages of zircons from rocks from the Antartic region show a range from 1600 m.y. to 3100 m.y

  3. Ion microprobes

    International Nuclear Information System (INIS)

    Coles, J.N.; Long, J.V.P.

    1977-01-01

    An ion microprobe is described that has an ion extraction arrangement comprising two separate paths for ions and electrons diverging from a common point. A cone shaped or pyramidal guard electrode surrounds each path the apex angles being equal and coinciding with the said point. The guard electrodes are positioned to lie tangentially to each other and to a planar surface including the said point. An aperture is provided for the two paths at the apexes of both guard electrodes, and electrical connections between the guard electrodes enable the same potential to be applied to both guard electrodes. Means are provided for generating oppositely polarised electric fields within the guard electrodes, together with means for causing a focused ion beam to strike the common point without suffering astigmatism. The means for causing a focused ion beam to strike the said point includes an ion gun for directing an ion beam along one of the paths and means to provide an axial accelerating field there along. Optical viewing means are also provided. Existing designs enable only ions or electrons, but not both, to be extracted at any one time. (U.K.)

  4. CL-imaging and ion microprobe dating of single zircons from a high-grade rock from the Central Zone, Limpopo Belt, South Africa: Evidence for a single metamorphic event at ˜2.0 Ga

    Science.gov (United States)

    Mouri, H.; Brandl, G.; Whitehouse, M.; de Waal, S.; Guiraud, M.

    2008-02-01

    The combination of ion microprobe dating and cathodoluminescence (CL) imaging of zircons from a high-grade rock from the Central Zone of the Limpopo Belt were used to constrain the age of metamorphic events in the area. Zircon grains extracted from an orthopyroxene-gedrite-bearing granulite were prepared for single crystal CL-imaging and ion microprobe dating. The grains display complex zoning when using SEM-based CL-imaging. A common feature in most grains is the presence of a distinct core with a broken oscillatory zoned structure, which clearly appears to be the remnant of an original grain of igneous origin. This core is overgrown by an unzoned thin rim measuring about 10-30 μm in diameter, which is considered as new zircon growth during a single metamorphic event. Selected domains of the zircon grains were analysed for U, Pb and Th isotopic composition using a CAMECA IMS 1270 ion microprobe (Nordsim facility). Most of the grains define a near-concordant cluster with some evidence of Pb loss. The most concordant ages of the cores yielded a weighted mean 207Pb/ 206Pb age of 2689 ± 15 (2 σ) Ma, interpreted as the age of the protolith of an igneous origin. The unzoned overgrowths of the zircon grains yielded a considerably younger weighted mean 207Pb/ 206Pb age of ˜2006.5 ± 8.0 Ma (2 σ), and these data are interpreted to reflect closely the age of the ubiquitous high-grade metamorphic event in the Central Zone. This study shows clearly, based on both the internal structure of the zircons and the data obtained by ion microprobe dating, that only a single metamorphic event is recorded by the studied 2.69 Ga old rocks, and we found no evidence of an earlier metamorphic event at ˜2.5 Ga as postulated earlier by some workers.

  5. Ion microprobe (SHRIMP) dating of detrital zircon grains from quartzites of the Eckergneiss Complex, Harz Mountains (Germany): implications for the provenance and the geological history

    Science.gov (United States)

    Geisler, Thorsten; Vinx, Roland; Martin-Gombojav, Nergui; Pidgeon, Robert T.

    2005-07-01

    The Eckergneiss Complex (EGC) is a geologically unique medium- to high-grade metamorphic unit within the Rhenohercynian domain of the Mid-European Variscides. A previously, poorly defined conventional lower U Pb intercept age of about 560 Ma from detrital zircons of metasedimentary rocks has led to speculations about an East Avalonian affinity of the EGC. In order to unravel the provenance and to constrain the age of the sediment protolith, we carried out sensitive high-resolution ion microprobe U Pb analyses on detrital zircons from five different EGC quartzite occurrences. The obtained age spectrum indicates a SW Baltica provenance of the detritus. Sveconorwegian ages between 0.9 1.2 Ga are particularly well represented by analyses from metamorphic recrystallization/alteration zones penetrating into igneous zircon. Cadomian (Pan-African) ages, which might reflect a metamorphic event, could not be substantiated. Instead, zircons of igneous origin yielded concordant Lower Devonian and Silurian ages of 410±10, 419±10, and 436±6 Ma (1σ), implying that sedimentation of the EG protolith must have taken place after 410±10 Ma. The lower age limit of the EGC metamorphism is constrained by 295 Ma intrusion ages of the adjacent, nonmetamorphosed Harzburg Gabbronorite and Brocken Granite. Sedimentation and metamorphism must thus have taken place between about 410 Ma and 295 Ma. Given that this time span coincides with most of the sedimentation within the virtually nonmetamorphosed (lowest grade) Rhenohercynian in the Harz Mountains, including the direct vicinity of the EGC, along with the high-grade metamorphism, the EGC can hardly be seen as uplifted local basement. A possible candidate for the root region is an easterly, concealed marginal segment of the Rhenohercynian domain of the Variscides, which is tectonically overridden and suppressed by the Mid-German Crystalline Rise during continent collision. However, based on the concept of strike-slip movement of Variscan

  6. Use of the ion microprobe in geological dating

    International Nuclear Information System (INIS)

    Compston, W.; Williams, I.S.; Black, L.P.

    1983-01-01

    SHRIMP, the Sensitive High Resolution Ion Microprobe with computerised control and data acquisition system, has recently been commissioned. It is used within the Research School of Earth Sciences, Australian National University, for the isotopic analysis of geological samples. Principles of operation and geological applications are outlined. One example described is the application to Pb-U dating of zircon

  7. Ion microprobe analysis of metallic pigments

    International Nuclear Information System (INIS)

    Pelicon, P.; Simcic, J.; Budnar, M.; Klanjsek-Gunde, M.; Kunavaer, M.

    2001-01-01

    Full text: Metallic paints consist of metallic flakes dispersed m a resinous binder, i.e. a light-element polymer matrix. The spatial distribution and orientation of metallic flakes inside the matrix determines the covering efficiency of the paint, glossiness, and its angular-dependent properties such as lightness flop or color flop (two-tone). Such coatings are extensively used for a functional (i.e. security) as well as decorative purpose. The ion microbeam analysis of two types of silver paint with imbedded metallic flake has been performed to test the ability of the ion microbeam spectroscopic methods on this type of samples. The average sizes of the aluminium flakes were 23 (size distribution 10-37) and 49 (size distribution 34-75) micrometers, respectively. The proton beam with the size of 2x2 micrometers at Ljubljana ion microprobe has been used to scan the surface of the pigments. PIXE mapping of Al Kα map shows lateral distribution of the aluminum flakes, whereas the RBS slicing method reveals tomographic image of the flakes in uppermost 5 micrometers of the pigment layer. The flake distribution in the larger layer depths has been accessed by RBS analysis in a point mode. (author)

  8. Optimization of the electrostatic structure of the ion microprobe

    Directory of Open Access Journals (Sweden)

    I. G. Ignat'ev

    2012-03-01

    Full Text Available The paper presents optimization data obtained for an immersion probe-forming system of the ion microprobe to be used in 3 MeV H+ ion accelerator generating 0,4 μm beam spot for normalized acceptance of 7 μm2 · mrad2 · MeV. To achieve higher microprobe resolution it is intended to place an electrostatic lens between the collimators and the accelerating tube.

  9. Pb, U, Ti, Hf and Zr distributions in zircons determined by proton microprobe and fission track techniques

    International Nuclear Information System (INIS)

    Clark, G.J.; Gulson, B.L.; Cookson, J.A.

    1979-01-01

    A proton microprobe has been used to determine Pb, Tl, Hf and Zr distributions across four single zircon crystals separated from a 'rapakivi' granite. The Pb and Zr data are quantitative: Pb and Tl concentrations were below the measurable limits for determinations in situ by most other techniques. The distribution of U in the same crystals was determined by the fission track technique. Limits on precision of U allow only a qualitative correlation of U and Pb, whereas the Tl and Pb correlation is more exactly determined. Zircons with distinct cores and overgrowths exhibited uniform Zr and Hf concentrations across the crystals, whereas the high U rims and 'inclusions' (domains) also had high Tl and Pb contents. Since almost all the Pb in these zircons is derived by radioactive decay of U, the Tl substitution has paralleled that of U. The results indicate that the high U domains are 'hot spots' rather than a separate mineral phase. The strong positive correlation of U and Pb indicates that there is little U daughter product migration relative to U, within the crystal. However, for the zircon population investigated here, the data are equivocal on the question of whether U addition to zircon crystals is associated with new zircon growth or not. In either case, the heterogeneous U and Pb distributions complicate any interpretations of U-Pb isotopic analysis for such zircon populations. (author)

  10. Applications of the ion microprobe to geochemistry and cosmochemistry

    International Nuclear Information System (INIS)

    Shimizu, N.; Hart, S.R.

    1982-01-01

    When a solid surface is subjected to a bombardment of energetic ions, material is ejected from the surface in a process known as sputtering. A part of the sputtered material is ionized and these secondary ions can be analyzed with a mass spectrometer according to a technique known as secondary ion mass spectrometry (SIMS). A description is presented of the present status of geochemical and cosmochemical applications of the ion microprobe. Attention is given to the sputtering event, molecular ion interferences, aspects of isotopic fractionation, secondary ion intensities in polycomponent materials, and questions of trace element analysis. Geochemical applications of the ion microprobe are based on certain advantages over other analytical techniques. These advantages are related to high sensitivity, low background, and the capability of in situ analysis of isotopic composition. The distribution of trace elements in minerals is considered, along with isotope anomalies, isotope zoning, diffusion studies, and depth profiling

  11. Digital pulse processor for ion beam microprobe imaging

    International Nuclear Information System (INIS)

    Bogovac, M.; Jaksic, M.; Wegrzynek, D.; Markowicz, A.

    2009-01-01

    Capabilities of spectroscopic ion beam analysis (IBA) techniques that are available in ion microprobe facilities can be greatly improved by the use of digital pulse processing. We report here development of a digital multi parameter data acquisition system suitable for IBA imaging applications. Input signals from charge sensitive preamplifier are conditioned by using a simple circuit and digitized with fast ADCs. The digitally converted signals are processed in real time using FPGA. Implementation of several components of the system is presented.

  12. Wavelength dispersive μPIXE setup for the ion microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Fazinić, S., E-mail: stjepko.fazinic@irb.hr [Laboratory for Ion Beam Interactions, Division of Experimental Physics, Rudjer Bošković Institute, Bijenicka cesta 54, 10000 Zagreb (Croatia); Božičević Mihalić, I.; Tadić, T.; Cosic, D.; Jakšić, M. [Laboratory for Ion Beam Interactions, Division of Experimental Physics, Rudjer Bošković Institute, Bijenicka cesta 54, 10000 Zagreb (Croatia); Mudronja, D. [Croatian Conservation Institute, Grškovićeva 23, 10000 Zagreb (Croatia)

    2015-11-15

    We have developed a small wavelength dispersive X-ray spectrometer to explore the possibility of performing chemical speciation on microscopic samples utilizing focused ion beams available at the Rudjer Boskovic Institute ion microprobe. Although PIXE spectra are in principle chemically invariant, small influence of chemical effects could be observed even with Si(Li) or SDD detectors. Such chemical effects can be clearly seen with high resolution crystal X-ray spectrometers having energy resolution of several eV. A dedicated vacuum chamber, housing the diffraction crystal, sample holder and CCD X-ray detector, was constructed and positioned behind the main ion microprobe vacuum chamber. Here we will briefly describe the spectrometer, and illustrate its capabilities on measured K X-ray spectra of selected sulfur compounds. We will also demonstrate its abilities to resolve K and M X-ray lines irresolvable by solid state ED detectors usually used in PIXE.

  13. Applications of heavy ion microprobe for single event effects analysis

    International Nuclear Information System (INIS)

    Reed, Robert A.; Vizkelethy, Gyorgy; Pellish, Jonathan A.; Sierawski, Brian; Warren, Kevin M.; Porter, Mark; Wilkinson, Jeff; Marshall, Paul W.; Niu, Guofu; Cressler, John D.; Schrimpf, Ronald D.; Tipton, Alan; Weller, Robert A.

    2007-01-01

    The motion of ionizing-radiation-induced rogue charge carriers in a semiconductor can create unwanted voltage and current conditions within a microelectronic circuit. If sufficient unwanted charge or current occurs on a sensitive node, a variety of single event effects (SEEs) can occur with consequences ranging from trivial to catastrophic. This paper describes the application of heavy ion microprobes to assist with calibration and validation of SEE modeling approaches

  14. Ion microprobe U-Pb dating of a dinosaur tooth

    International Nuclear Information System (INIS)

    Sano, Yuji; Terada, Kentaro; Ly, Chi V.; Park, Eun Ju

    2006-01-01

    Ion microprobe U-Pb dating of apatite is applied to a fossil tooth of a Allosaurid derived from the Hasandong Formation in the Gyeongsang basin, southeastern Korea. Twelve spots on a single fragment of the fossil dentine yield a Tera-Wasserburg concordia intercept age of 115±10 Ma (2σ, MSWD=0.59) on a 238 U/ 206 Pb- 207 Pb/ 206 Pb- 204 Pb/ 206 Pb diagram. The age provides a constraint on the depositional age of the fossil in its host Hassandong Formation as Early Aptian. The success of the ion microprobe dating depends on the heterogeneities of diagenetically incorporated U and Pb at the few hundred μm scale, the consequent variations in Pb isotopic compositions due to radioactive decay and the closed-system behavior of U and Pb. There are at least three end-members to explain the variations of minor chemical components such as FeO, SiO 2 and Al 2 O 3 , and trace elements as Th, U and rare earth elements (REE) in the sample by a simple mixing model. They are (1) very low minor and REE, very high common Pb with variable U abundances, (2) low common Pb, high minor, REE, and U abundances, and (3) low minor, common Pb, and U with intermediate REE abundances, even though groups (2) and (3) may consist of a larger group. Various contributions of the three (and/or two) end-members during diagenetic processes may cause the elemental fractionation of U and Pb in a fossil tooth. (author)

  15. Raman microprobe measurements of stress in ion implanted materials

    Energy Technology Data Exchange (ETDEWEB)

    Nugent, K W; Prawer, S; Weiser, P S; Dooley, S P [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1994-12-31

    Raman microprobe measurements of ion implanted diamond and silicon have shown significant shifts in the Raman line due to stresses in the materials. The Raman line shifts to higher energy if the stress is compressive and to lower energy for tensile stress{sup 1}. The silicon sample was implanted in a 60 {mu}m square with 2.56 x 10{sup 17} ions per square centimeter of 2 MeV Helium. This led to the formation of raised squares with the top 370mm above the original surface. In Raman studies of silicon using visible light, the depth of penetration of the laser beam into the sample is much less than one micron. It was found that the Raman line is due to the silicon overlying the damage region. The diamond sample was implanted with 2 x 10{sup 15} ions per square centimeter of 2.8 MeV carbon. It was concluded that the Raman spectrum could provide information concerning both the magnitude and the direction of stress in an ion implanted sample. It was possible in some cases to determine whether the stress direction is parallel or perpendicular to the sample surface. 1 refs., 2 figs.

  16. Raman microprobe measurements of stress in ion implanted materials

    Energy Technology Data Exchange (ETDEWEB)

    Nugent, K.W.; Prawer, S.; Weiser, P.S.; Dooley, S.P. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1993-12-31

    Raman microprobe measurements of ion implanted diamond and silicon have shown significant shifts in the Raman line due to stresses in the materials. The Raman line shifts to higher energy if the stress is compressive and to lower energy for tensile stress{sup 1}. The silicon sample was implanted in a 60 {mu}m square with 2.56 x 10{sup 17} ions per square centimeter of 2 MeV Helium. This led to the formation of raised squares with the top 370mm above the original surface. In Raman studies of silicon using visible light, the depth of penetration of the laser beam into the sample is much less than one micron. It was found that the Raman line is due to the silicon overlying the damage region. The diamond sample was implanted with 2 x 10{sup 15} ions per square centimeter of 2.8 MeV carbon. It was concluded that the Raman spectrum could provide information concerning both the magnitude and the direction of stress in an ion implanted sample. It was possible in some cases to determine whether the stress direction is parallel or perpendicular to the sample surface. 1 refs., 2 figs.

  17. Study of ion tracks by micro-probe ion energy loss spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Vacík, Jiří; Havránek, Vladimír; Hnatowicz, Vladimír; Horák, Pavel; Fink, Dietmar; Apel, P. Yu.

    2014-01-01

    Roč. 332, AUG (2014), s. 308-311 ISSN 0168-583X. [21st International Conference on Ion Beam Analysis (IBA). Seattle, 23.06.2013-28.06.2013] R&D Projects: GA ČR(CZ) GBP108/12/G108; GA MŠk(XE) LM2011019 Institutional support: RVO:61389005 Keywords : ion energy loss spectrometry * single ion track * microprobe * tomography Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.124, year: 2014

  18. Using the ion microprobe mass analyser for trace element analysis

    International Nuclear Information System (INIS)

    Schilling, J.H.

    1978-01-01

    Most techniques for the analysis of trace elements are capable of determining the concentrations in a bulk sample or solution, but without reflecting their distribution. In a bulk analysis therefore elements which occur in high concentration in a few precipitates would still be considered trace elements even though their local concentration greatly exceed the normally accepted trace elements concentration limit. Anomalous distribution is also shown by an oxide layer, a few hundred Angstrom thick, on an aluminium sample. A low oxide concentration would be reported if it were included in the bulk analysis, which contradicts the high surface concentration. The importance of a knowledge of the trace element distribution is therefore demonstrated. Distributional trace element analysis can be carried out using the ion microprobe mass analyser (IMMA). Since the analytical technique used in this instrument, namely secondary ion mass spectrometry (SIMS), is not universally appreciated, the instrument and its features will be described briefly followed by a discussion of quantitative analysis and the related subjects of detection limit and sample consumption. Finally, a few examples of the use of the instrument are given

  19. Single ion hit detection set-up for the Zagreb ion microprobe

    Science.gov (United States)

    Smith, R. W.; Karlušić, M.; Jakšić, M.

    2012-04-01

    Irradiation of materials by heavy ions accelerated in MV tandem accelerators may lead to the production of latent ion tracks in many insulators and semiconductors. If irradiation is performed in a high resolution microprobe facility, ion tracks can be ordered by submicrometer positioning precision. However, full control of the ion track positioning can only be achieved by a reliable ion hit detection system that should provide a trigger signal irrespectively of the type and thickness of the material being irradiated. The most useful process that can be utilised for this purpose is emission of secondary electrons from the sample surface that follows the ion impact. The status report of the set-up presented here is based on the use of a channel electron multiplier (CEM) detector mounted on an interchangable sample holder that is inserted into the chamber in a close geometry along with the sample to be irradiated. The set-up has been tested at the Zagreb ion microprobe for different ions and energies, as well as different geometrical arrangements. For energies of heavy ions below 1 MeV/amu, results show that efficient (100%) control of ion impact can be achieved only for ions heavier than silicon. The successful use of the set-up is demonstrated by production of ordered single ion tracks in a polycarbonate film and by monitoring fluence during ion microbeam patterning of Foturan glass.

  20. Improved 206Pb/238U microprobe geochronology by the monitoring of a trace-element-related matrix effect; SHRIMP, ID-TIMS, ELA-ICP-MS and oxygen isotope documentation for a series of zircon standards

    Science.gov (United States)

    Black, L.P.; Kamo, S.L.; Allen, C.M.; Davis, D.W.; Aleinikoff, J.N.; Valley, J.W.; Mundil, R.; Campbell, I.H.; Korsch, R.J.; Williams, I.S.; Foudoulis, C.

    2004-01-01

    Precise isotope dilution-thermal ionisation mass spectrometry (ID-TIMS) documentation is given for two new Palaeozoic zircon standards (TEMORA 2 and R33). These data, in combination with results for previously documented standards (AS3, SL13, QGNG and TEMORA 1), provide the basis for a detailed investigation of inconsistencies in 206Pb/238U ages measured by microprobe. Although these ages are normally consistent between any two standards, their relative age offsets are often different from those established by ID-TIMS. This is true for both sensitive high-resolution ion-microprobe (SHRIMP) and excimer laser ablation-inductively coupled plasma-mass spectrometry (ELA-ICP-MS) dating, although the age offsets are in the opposite sense for the two techniques. Various factors have been investigated for possible correlations with age bias, in an attempt to resolve why the accuracy of the method is worse than the indicated precision. Crystallographic orientation, position on the grain-mount and oxygen isotopic composition are unrelated to the bias. There are, however, striking correlations between the 206Pb/238U age offsets and P, Sm and, most particularly, Nd abundances in the zircons. Although these are not believed to be the primary cause of this apparent matrix effect, they indicate that ionisation of 206Pb/238U is influenced, at least in part, by a combination of trace elements. Nd is sufficiently representative of the controlling trace elements that it provides a quantitative means of correcting for the microprobe age bias. This approach has the potential to reduce age biases associated with different techniques, different instrumentation and different standards within and between laboratories. Crown Copyright ?? 2004 Published by Elsevier B.V. All rights reserved.

  1. NENIMF: Northeast National Ion Microprobe Facility - A Multi-User Facility for SIMS Microanalysis

    Science.gov (United States)

    Layne, G. D.; Shimizu, N.

    2002-12-01

    The MIT-Brown-Harvard Regional Ion Microprobe Facility was one of the earliest multi-user facilities enabled by Dan Weill's Instrumentation and Facilities Program - and began with the delivery of a Cameca IMS 3f ion microprobe to MIT in 1978. The Northeast National Ion Microprobe Facility (NENIMF) is the direct descendant of this original facility. Now housed at WHOI, the facility incorporates both the original IMS 3f, and a new generation, high transmission-high resolution instrument - the Cameca IMS 1270. Purchased with support from NSF, and from a consortium of academic institutions in the Northeast (The American Museum of Natural History, Brown University, The Lamont-Doherty Earth Observatory, MIT, Rensselaer Polytechnic Institute, WHOI) - this latest instrument was delivered and installed during 1996. NENIMF continues to be supported by NSF EAR I&F as a multi-user facility for geochemical research. Work at NENIMF has extended the original design strength of the IMS 1270 for microanalytical U-Pb zircon geochronology to a wide variety of novel and improved techniques for geochemical research. Isotope microanalysis for studies in volcanology and petrology is currently the largest single component of facility activity. This includes the direct measurement of Pb isotopes in melt inclusions, an application developed at NENIMF, which is making an increasingly significant contribution to our understanding of basalt petrogenesis. This same technique has also been extended to the determination of Pb isotopes in detrital feldspar grains, for the study of sedimentary provenance and tectonics of the Himalayas and other terrains. The determination of δ11B in volcanic melt inclusions has also proven to be a powerful tool in the modeling of subduction-related magmatism. The recent development of δ34S and δ37Cl determination in glasses is being applied to studies of the behavior of these volatile elements in both natural and experimental systems. Other recent undertakings

  2. Ion beam induced luminescence from diamond using an MeV ion microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Bettiol, A A; Jamieson, D N; Prawer, S; Allen, M G [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1994-12-31

    Analysis of the luminescence induced by a MeV ion beam offers the potential to provide useful information about the chemical properties of atoms in crystals to complement the information provided by more traditional Ion Beam Analysis (IBA) such as Rutherford Backscattering Spectrometry (RBS), ion channeling and Particle Induced X-ray Emission (PIXE). Furthermore, the large penetration depth of the MeV ion beam offers several advantages over the relatively shallow penetration of keV electrons typically employed in cathodoluminescence. An Ion Beam Induced Luminescence (IBIL) detection system was developed for the Melbourne microprobe that allows the spatial mapping of the luminescence signal along with the signals from RBS and PIXE. Homoepitaxial diamond growth has been studied and remarkable shifts in the characteristic blue luminescence of diamond towards the green were observed in the overgrowth. This has been tentatively identified as being due to transition metal inclusions in the epitaxial layers. 8 refs., 2 refs.

  3. Ion beam induced luminescence from diamond using an MeV ion microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Bettiol, A.A.; Jamieson, D. N.; Prawer, S.; Allen, M.G. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1993-12-31

    Analysis of the luminescence induced by a MeV ion beam offers the potential to provide useful information about the chemical properties of atoms in crystals to complement the information provided by more traditional Ion Beam Analysis (IBA) such as Rutherford Backscattering Spectrometry (RBS), ion channeling and Particle Induced X-ray Emission (PIXE). Furthermore, the large penetration depth of the MeV ion beam offers several advantages over the relatively shallow penetration of keV electrons typically employed in cathodoluminescence. An Ion Beam Induced Luminescence (IBIL) detection system was developed for the Melbourne microprobe that allows the spatial mapping of the luminescence signal along with the signals from RBS and PIXE. Homoepitaxial diamond growth has been studied and remarkable shifts in the characteristic blue luminescence of diamond towards the green were observed in the overgrowth. This has been tentatively identified as being due to transition metal inclusions in the epitaxial layers. 8 refs., 2 refs.

  4. Ion microprobe imaging of 44Ca-labeled mammalian chromosomes

    International Nuclear Information System (INIS)

    Levi-Setti, R.; Gavrilov, K.L.; Strissel, P.L.; Strick, R.

    2004-01-01

    In our previous investigation, we showed for the first time high-resolution analytical images of the cation composition of mammalian interphase and mitotic cells as well as of isolated metaphase chromosomes using the University of Chicago scanning ion microprobe (UC-SIM). In order to preserve the ionic integrity of the analyzed cells and prevent the well known occurrence of analytical artifacts due to the high diffusivity of cations in biological samples we used fast cryo-preservation methods (freeze-drying and freeze fracture), without any pre-fixations or washes. We identified the role of the cations in chromosome structure and maintenance using SIMS imaging and immunfluorescence methodologies. Importantly, we determined that the above cations are essential participants in chromosome condensation and maintenance of chromatin higher order structure, through their presumed function in DNA electrostatic neutralization and the direct interaction of Ca 2+ , in particular, with structural proteins. In addition, both Ca 2+ and Mg 2+ showed the same cell cycle regulation where during interphase both cations were enriched in the cytosol, particularly in organelles then at mitosis became specifically bound to chromatin. Our present research interest focuses on a more detailed analysis of the distribution of Ca 2+ throughout the different cell cycle stages, e.g. G1, G2 and mitosis. We have chosen the stable isotope 44 Ca as a tracer to follow Ca 2+ throughout the cell cycle. This nuclide occurs naturally in the ratio 44 Ca/ 40 Ca+ 44 Ca of 2.06%, so that incorporation at higher concentrations into chromatin or other cellular components should be easily detected by SIMS. Such incorporation can be obtained either by growing cells in a medium where ordinary Ca is replaced entirely by 44 Ca, or by replacing the cell culture medium with the 44 Ca medium for a gated time span (pulsing), after appropriate cell cycle stage synchronization. In this paper, we describe our

  5. Scanning deep level transient spectroscopy using an MeV ion microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Laird, J S; Bardos, R A; Saint, A; Moloney, G M; Legge, G F.J. [Melbourne Univ., Parkville, VIC (Australia)

    1994-12-31

    Traditionally the scanning ion microprobe has given little or no information regarding the electronic structure of materials in particular semiconductors. A new imaging technique called Scanning Ion Deep Level Transient Spectroscopy (SIDLTS) is presented which is able to spatially map alterations in the band gap structure of materials by lattice defects or impurities. 3 refs., 2 figs.

  6. Scanning deep level transient spectroscopy using an MeV ion microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Laird, J.S.; Bardos, R.A.; Saint, A.; Moloney, G.M.; Legge, G.F.J. [Melbourne Univ., Parkville, VIC (Australia)

    1993-12-31

    Traditionally the scanning ion microprobe has given little or no information regarding the electronic structure of materials in particular semiconductors. A new imaging technique called Scanning Ion Deep Level Transient Spectroscopy (SIDLTS) is presented which is able to spatially map alterations in the band gap structure of materials by lattice defects or impurities. 3 refs., 2 figs.

  7. New 2-stage ion microprobes and a move to higher energies

    Energy Technology Data Exchange (ETDEWEB)

    Legge, G.J.F.; Dymnikov, A.; Moloney, G.; Saint, A. [Melbourne Univ., Parkville, VIC (Australia). School of Physics; Cohen, D. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

    1996-12-31

    Recent moves in Ion Beam Microanalysis towards the use of a rapidly growing number of very high resolution, low current and single ion techniques has led to the need for high demagnification and greatly improved beam quality. There is also a move to apply Microbeams at higher energies and with heavier ions. This also puts demands on the focusing system and beam control. This paper describes the recent development of 2-stage lens systems to be applied here and overseas, both at very high resolution and at high energies with heavy ions. It looks at new ion beam analysis applications of such ion microprobes. 8 refs., 1 tab., 1 fig.

  8. New 2-stage ion microprobes and a move to higher energies

    Energy Technology Data Exchange (ETDEWEB)

    Legge, G J.F.; Dymnikov, A; Moloney, G; Saint, A [Melbourne Univ., Parkville, VIC (Australia). School of Physics; Cohen, D [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

    1997-12-31

    Recent moves in Ion Beam Microanalysis towards the use of a rapidly growing number of very high resolution, low current and single ion techniques has led to the need for high demagnification and greatly improved beam quality. There is also a move to apply Microbeams at higher energies and with heavier ions. This also puts demands on the focusing system and beam control. This paper describes the recent development of 2-stage lens systems to be applied here and overseas, both at very high resolution and at high energies with heavy ions. It looks at new ion beam analysis applications of such ion microprobes. 8 refs., 1 tab., 1 fig.

  9. CONCH: A Visual Basic program for interactive processing of ion-microprobe analytical data

    Science.gov (United States)

    Nelson, David R.

    2006-11-01

    A Visual Basic program for flexible, interactive processing of ion-microprobe data acquired for quantitative trace element, 26Al- 26Mg, 53Mn- 53Cr, 60Fe- 60Ni and U-Th-Pb geochronology applications is described. Default but editable run-tables enable software identification of secondary ion species analyzed and for characterization of the standard used. Counts obtained for each species may be displayed in plots against analysis time and edited interactively. Count outliers can be automatically identified via a set of editable count-rejection criteria and displayed for assessment. Standard analyses are distinguished from Unknowns by matching of the analysis label with a string specified in the Set-up dialog, and processed separately. A generalized routine writes background-corrected count rates, ratios and uncertainties, plus weighted means and uncertainties for Standards and Unknowns, to a spreadsheet that may be saved as a text-delimited file. Specialized routines process trace-element concentration, 26Al- 26Mg, 53Mn- 53Cr, 60Fe- 60Ni, and Th-U disequilibrium analysis types, and U-Th-Pb isotopic data obtained for zircon, titanite, perovskite, monazite, xenotime and baddeleyite. Correction to measured Pb-isotopic, Pb/U and Pb/Th ratios for the presence of common Pb may be made using measured 204Pb counts, or the 207Pb or 208Pb counts following subtraction from these of the radiogenic component. Common-Pb corrections may be made automatically, using a (user-specified) common-Pb isotopic composition appropriate for that on the sample surface, or for that incorporated within the mineral at the time of its crystallization, depending on whether the 204Pb count rate determined for the Unknown is substantially higher than the average 204Pb count rate for all session standards. Pb/U inter-element fractionation corrections are determined using an interactive log e-log e plot of common-Pb corrected 206Pb/ 238U ratios against any nominated fractionation-sensitive species pair

  10. Data acquisition and analysis system for the ion microprobe mass analyzer

    International Nuclear Information System (INIS)

    Darby, D.M.; Cristy, S.S.

    1979-02-01

    A computer was interfaced to an ion microprobe mass analyzer for more rapid data acquisition and analysis. The interface is designed to allow data acquisition, independent of the computer. A large data analysis package was developed and implemented. Performance of the computerized system was evaluated and compared to manual operation

  11. U/Th dating by SHRIMP RG ion-microprobe mass spectrometry using single ion-exchange beads

    Science.gov (United States)

    Bischoff, J.L.; Wooden, J.; Murphy, F.; Williams, Ross W.

    2005-01-01

    We present a new analytical method for U-series isotopes using the SHRIMP RG (Sensitive High mass Resolution Ion MicroProbe) mass spectrometer that utilizes the preconcentration of the U-series isotopes from a sample onto a single ion-exchange bead. Ion-microprobe mass spectrometry is capable of producing Th ionization efficiencies in excess of 2%. Analytical precision is typically better than alpha spectroscopy, but not as good as thermal ionization mass spectroscopy (TIMS) and inductively coupled plasma multicollector mass spectrometry (ICP-MS). Like TIMS and ICP-MS the method allows analysis of small samples sizes, but also adds the advantage of rapidity of analysis. A major advantage of ion-microprobe analysis is that U and Th isotopes are analyzed in the same bead, simplifying the process of chemical separation. Analytical time on the instrument is ???60 min per sample, and a single instrument-loading can accommodate 15-20 samples to be analyzed in a 24-h day. An additional advantage is that the method allows multiple reanalyses of the same bead and that samples can be archived for reanalysis at a later time. Because the ion beam excavates a pit only a few ??m deep, the mount can later be repolished and reanalyzed numerous times. The method described of preconcentrating a low concentration sample onto a small conductive substrate to allow ion-microprobe mass spectrometry is potentially applicable to many other systems. Copyright ?? 2005 Elsevier Ltd.

  12. U and Pb isotope analysis of uraninite and galena by ion microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Evins, L.Z.; Sunde, T.; Schoeberg, H. [Swedish Museum of Natural History, Stockholm (Sweden). Laboratory for Isotope Geology; Fayek, M. [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Geological Sciences

    2001-10-01

    Accurate isotopic analysis of minerals by ion microprobe, or SIMS (Secondary Ion Mass Spectrometry) usually requires a standard to correct for instrumental mass bias effects that occur during analysis. We have calibrated two uraninite crystals and one galena crystal to be used as ion probe standards. As part of this study we describe the analytical procedures and problems encountered while trying to establish fractionation factors for U and Pb isotopes measured in galena and uraninite. Only the intra-element isotopic mass fractionation is considered and not the interelement fractionation. Galena and uraninite were analysed with TIMS (Thermal Ionisation Mass Spectrometry) prior to SIMS. One uraninite crystal (P88) comes from Sweden and is ca 900 Ma old, the other from Maine, USA (LAMNH-30222) and is ca 350 Ma old. The galena sample comes from the Paleoproterozoic ore district Bergslagen in Sweden. SIMS analyses were performed at two different laboratories: the NORDSM facility in Stockholm, which has a high resolution Cameca IMS 1270 ion microprobe, and the Oak Ridge National Laboratory (ORNL) in Tennessee, which has a Cameca IMS 4f ion microprobe. The results show that during the analysis of galena, Pb isotopes fractionate in favour of the lighter isotope by as much as 0.5%/amu. A Pb isotope fractionation factor for uraninite was more difficult to calculate, probably due to the formation of hydride interferences encountered during analysis with the Cameca IMS 1270 ion microprobe. However, drying the sample in vacuum prior to analysis, and using high-energy filtering and a cold trap during analysis can minimise these hydride interferences. A large fractionation of U isotopes of ca 1.4%/amu in favour of the lighter isotope was calculated for uraninite.

  13. U and Pb isotope analysis of uraninite and galena by ion microprobe

    International Nuclear Information System (INIS)

    Evins, L.Z.; Sunde, T.; Schoeberg, H.; Fayek, M.

    2001-10-01

    Accurate isotopic analysis of minerals by ion microprobe, or SIMS (Secondary Ion Mass Spectrometry) usually requires a standard to correct for instrumental mass bias effects that occur during analysis. We have calibrated two uraninite crystals and one galena crystal to be used as ion probe standards. As part of this study we describe the analytical procedures and problems encountered while trying to establish fractionation factors for U and Pb isotopes measured in galena and uraninite. Only the intra-element isotopic mass fractionation is considered and not the interelement fractionation. Galena and uraninite were analysed with TIMS (Thermal Ionisation Mass Spectrometry) prior to SIMS. One uraninite crystal (P88) comes from Sweden and is ca 900 Ma old, the other from Maine, USA (LAMNH-30222) and is ca 350 Ma old. The galena sample comes from the Paleoproterozoic ore district Bergslagen in Sweden. SIMS analyses were performed at two different laboratories: the NORDSM facility in Stockholm, which has a high resolution Cameca IMS 1270 ion microprobe, and the Oak Ridge National Laboratory (ORNL) in Tennessee, which has a Cameca IMS 4f ion microprobe. The results show that during the analysis of galena, Pb isotopes fractionate in favour of the lighter isotope by as much as 0.5%/amu. A Pb isotope fractionation factor for uraninite was more difficult to calculate, probably due to the formation of hydride interferences encountered during analysis with the Cameca IMS 1270 ion microprobe. However, drying the sample in vacuum prior to analysis, and using high-energy filtering and a cold trap during analysis can minimise these hydride interferences. A large fractionation of U isotopes of ca 1.4%/amu in favour of the lighter isotope was calculated for uraninite

  14. IMAP: A complete Ion Micro-Analysis Package for the nuclear microprobe

    International Nuclear Information System (INIS)

    Antolak, A.J.; Hildner, M.L.; Morse, D.H.; Bench, G.S.

    1993-01-01

    Microprobe techniques using scanned, focused MeV ions are routinely used in Livermore for materials characterization. Comprehensive data analysis with these techniques is accomplished with the computer software package IMAP, for Ion Micro-Analysis Package. IMAP consists of a set of command language procedures for data processing and quantitative spectral analysis. Deconvolution of the data is achieved by spawning sub-processes within IMAP which execute analysis codes for each specific microprobe technique. IMAP is structured to rapidly analyze individual spectra or multi-dimensional data blocks which classify individual events by the two scanning dimensions, the energy of the detected radiation and, when necessary, one sample rotation dimension. Several examples are presented to demonstrate the utility of the package

  15. Optical system optimization of the microprobe beamline of the Ion Implantation Laboratory (IF-UFRGS), Brazil

    International Nuclear Information System (INIS)

    Bauer, Deiverti de Vila

    2015-01-01

    The aim of the present work is to optimize the microprobe beamline of the Ion Implantation Laboratory (IF-UFRGS). In short, an ion microprobe consists of charged particles focused to the dimensions of a few micrometers. The focusing system is made of two slits for demagnification, a set of magnetic lenses with scanning capability and a reaction chamber. By changing the parameters related to this system, one can optimize the features of the beam. To that end, samples of poly(tereftalate etylene) were irradiated with 2.2 MeV H+ ions and etched, yielding 2D microstructures with high aspect ratio. The analysis of the structures with Scanning Electron Microscopy proved to be an important tool in order to establish a correlation between the size of the microstructures and the parameters of the focusing system. In this work, the causes leading to a beam enlargement are discussed, as well as the aberrations which affect the system. Finally, the advantages of using ions for lithography purposes is pointed out. (author)

  16. Cometary and interstellar dust grains - Analysis by ion microprobe mass spectrometry and other techniques

    Science.gov (United States)

    Zinner, Ernst

    1991-01-01

    A survey of microanalytical measurements on interplanetary dust particles (IDPs) and interstellar dust grains from primitive meteorites is presented. Ion-microprobe mass spectrometry with its capability to determine isotopic compositions of many elements on a micron spatial scale has played a special role. Examples are measurements of H, N, and O isotopes and refractory trace elements in IDPs; C, N, Mg, and Si isotopes in interstellar SiC grains; and C and N isotopes and H, N, Al, and Si concentrations in interstellar graphite grains.

  17. A digital squarer system for positive mass identification on the ARL ion microprobe mass analyser

    International Nuclear Information System (INIS)

    Woods, K.N.; Grant, L.D.V.; Rawsthorne, E.D.; Strydom, H.J.; Gries, W.H.

    1984-01-01

    The original analogue squarer for mass scale linearisation in the Ion Microprobe Mass Analyser (IMMA) has been replaced by a programmable digital squarer system which permits reliable mass number identification throughout the tested range 1 to 240. The digital squarer provides signals to both a digital direct reading mass number display and to an X-Y recorder where it provides a linear mass scale correct to within 0,3 mass units. An additional output to a computer can provide binary or BCD mass number data

  18. The new confocal heavy ion microprobe beamline at ANSTO: The first microprobe resolution tests and applications for elemental imaging and analysis

    Science.gov (United States)

    Pastuovic, Z.; Siegele, R.; Cohen, D. D.; Mann, M.; Ionescu, M.; Button, D.; Long, S.

    2017-08-01

    The Centre for Accelerator Science facility at ANSTO has been expanded with the new NEC 6 MV ;SIRIUS; accelerator system in 2015. In this paper we present a detailed description of the new nuclear microprobe-Confocal Heavy Ion Micro-Probe (CHIMP) together with results of the microprobe resolution testing and the elemental analysis performed on typical samples of mineral ore deposits and hyper-accumulating plants regularly measured at ANSTO. The CHIMP focusing and scanning systems are based on the OM-150 Oxford quadrupole triplet and the OM-26 separated scan-coil doublet configurations. A maximum ion rigidity of 38.9 amu-MeV was determined for the following nuclear microprobe configuration: the distance from object aperture to collimating slits of 5890 mm, the working distance of 165 mm and the lens bore diameter of 11 mm. The overall distance from the object to the image plane is 7138 mm. The CHIMP beamline has been tested with the 3 MeV H+ and 6 MeV He2+ ion beams. The settings of the object and collimating apertures have been optimized using the WinTRAX simulation code for calculation of the optimum acceptance settings in order to obtain the highest possible ion current for beam spot sizes of 1 μm and 5 μm. For optimized aperture settings of the CHIMP the beam brightness was measured to be ∼0.9 pA μm-2 mrad-2 for 3 MeV H+ ions, while the brightness of ∼0.4 pA μm-2 mrad-2 was measured for 6 MeV He2+ ions. The smallest beam sizes were achieved using a microbeam with reduced particle rate of 1000 Hz passing through the object slit apertures several micrometers wide. Under these conditions a spatial resolution of ∼0.6 μm × 1.5 μm for 3 MeV H+ and ∼1.8 μm × 1.8 μm for 6 MeV He2+ microbeams in horizontal (and vertical) dimension has been achieved. The beam sizes were verified using STIM imaging on 2000 and 1000 mesh Cu electron microscope grids.

  19. Ion channelling analysis of pre-amorphised silicon diodes using a nuclear microprobe

    International Nuclear Information System (INIS)

    Thornton, J.; Paus, K.C.

    1988-01-01

    Aligned and random ion channelling analysis was performed on p + n diode structures in silicon, with the Surrey nuclear microprobe. Three different types of diode were investigated, each pre-amorphised by a different ion (Si + , Ge + or Sn + ) before the p + region was formed by BF 2 + implantation. The ion channelling measurements are presented and compared with previously published electrical measurements on these diodes. Relatively large residual disorder and junction leakage currents were found for the Si + pre-amorphised diodes; however, all the diodes were leaky. The results are consistent with dislocation loops within the depletion regions of the diodes causing both the residual disorder and the large leakage currents. Cross-sectional transmission electron microscopy studies support this model. (author)

  20. Millimeter length micromachining using a heavy ion nuclear microprobe with standard magnetic scanning

    International Nuclear Information System (INIS)

    Nesprías, F.; Debray, M.E.; Davidson, J.; Kreiner, A.J.

    2013-01-01

    In order to increase the scanning length of our microprobe, we have developed an irradiation procedure suitable for use in any nuclear microprobe, extending at least up to 400% the length of our heavy ion direct writing facility using standard magnetic exploration. Although this method is limited to patterns of a few millimeters in only one direction, it is useful for the manufacture of curved waveguides, optical devices such Mach–Zehnder modulators, directional couplers as well as channels for micro-fluidic applications. As an example, this technique was applied to the fabrication of 3 mm 3D-Mach–Zehnder modulators in lithium niobate with short Y input/output branches and long shaped parallel-capacitor control electrodes. To extend and improve the quality of the machined structures we developed new scanning control software in LabView™ platform. The new code supports an external dose normalization, electrostatic beam blanking and is capable of scanning figures at 16 bit resolution using a National Instruments™ PCI-6731 High-Speed I/O card. A deep and vertical micromachining process using swift 35 Cl ions 70 MeV bombarding energy and direct write patterning was performed on LiNbO 3 , a material which exhibits a strong natural anisotropy to conventional etching. The micromachined structures show the feasibility of this method for manufacturing micro-fluidic channels as well

  1. Millimeter length micromachining using a heavy ion nuclear microprobe with standard magnetic scanning

    Energy Technology Data Exchange (ETDEWEB)

    Nesprías, F. [Gerencia de Investigación y Aplicaciones, Comisión Nacional de Energía Atómica, Av. Gral Paz 1499 (1650), San Martín, Buenos Aires (Argentina); Debray, M.E., E-mail: debray@tandar.cnea.gov.ar [Gerencia de Investigación y Aplicaciones, Comisión Nacional de Energía Atómica, Av. Gral Paz 1499 (1650), San Martín, Buenos Aires (Argentina); Escuela de Ciencia y Tecnología. Universidad Nacional de Gral. San Martín, M. De Irigoyen 3100 (1650), San Martín, Buenos Aires (Argentina); Davidson, J. [Gerencia de Investigación y Aplicaciones, Comisión Nacional de Energía Atómica, Av. Gral Paz 1499 (1650), San Martín, Buenos Aires (Argentina); CONICET, Avda. Rivadavia 1917 (C1033AAJ), Ciudad Autónoma de Buenos Aires (Argentina); Kreiner, A.J. [Gerencia de Investigación y Aplicaciones, Comisión Nacional de Energía Atómica, Av. Gral Paz 1499 (1650), San Martín, Buenos Aires (Argentina); Escuela de Ciencia y Tecnología. Universidad Nacional de Gral. San Martín, M. De Irigoyen 3100 (1650), San Martín, Buenos Aires (Argentina); CONICET, Avda. Rivadavia 1917 (C1033AAJ), Ciudad Autónoma de Buenos Aires (Argentina); and others

    2013-04-01

    In order to increase the scanning length of our microprobe, we have developed an irradiation procedure suitable for use in any nuclear microprobe, extending at least up to 400% the length of our heavy ion direct writing facility using standard magnetic exploration. Although this method is limited to patterns of a few millimeters in only one direction, it is useful for the manufacture of curved waveguides, optical devices such Mach–Zehnder modulators, directional couplers as well as channels for micro-fluidic applications. As an example, this technique was applied to the fabrication of 3 mm 3D-Mach–Zehnder modulators in lithium niobate with short Y input/output branches and long shaped parallel-capacitor control electrodes. To extend and improve the quality of the machined structures we developed new scanning control software in LabView™ platform. The new code supports an external dose normalization, electrostatic beam blanking and is capable of scanning figures at 16 bit resolution using a National Instruments™ PCI-6731 High-Speed I/O card. A deep and vertical micromachining process using swift {sup 35}Cl ions 70 MeV bombarding energy and direct write patterning was performed on LiNbO{sub 3}, a material which exhibits a strong natural anisotropy to conventional etching. The micromachined structures show the feasibility of this method for manufacturing micro-fluidic channels as well.

  2. Ion microprobe mass analysis of plagioclase from 'non-mare' lunar samples

    Science.gov (United States)

    Meyer, C., Jr.; Anderson, D. H.; Bradley, J. G.

    1974-01-01

    The ion microprobe was used to measure the composition and distribution of trace elements in lunar plagioclase, and these analyses are used as criteria in determining the possible origins of some nonmare lunar samples. The Apollo 16 samples with metaclastic texture and high-bulk trace-element contents contain plagioclase clasts with extremely low trace-element contents. These plagioclase inclusions represent unequilibrated relicts of anorthositic, noritic, or troctolitic rocks that have been intermixed as a rock flour into the KREEP-rich matrix of these samples. All of the plagioclase-rich inclusions which were analyzed in the KREEP-rich Apollo 14 breccias were found to be rich in trace elements. This does not seem to be consistent with the interpretation that the Apollo 14 samples represent a pre-Imbrium regolith, because such an ancient regolith should have contained many plagioclase clasts with low trace-element contents more typical of plagioclase from the pre-Imbrium crust. Ion-microprobe analyses for Ba and Sr in large plagioclase phenocrysts in 14310 and 68415 are consistent with the bulk compositions of these rocks and with the known distribution coefficients for these elements. The distribution coefficient for Li (basaltic liquid/plagioclase) was measured to be about 2.

  3. Ion Irradiation Damage in Zirconate and Titanate Ceramics for Pu Disposition

    International Nuclear Information System (INIS)

    Stewart, Martin W.; Begg, Bruce D.; Finnie, K.; Colella, Michael; Li, H.; McLeod, Terry; Smith, Katherine L.; Zhang, Zhaoming; Weber, William J.; Thevuthasan, Suntharampillai

    2004-01-01

    In this paper, we discuss the effect of ion irradiation on pyrochlore-rich titanate and defect-fluorite zirconate ceramics designed for plutonium immobilization. Samples, with Ce as an analogue for Pu, were made via oxide routes and consolidated by cold-pressing and sintering. Ion irradiation damage was carried out with 2 MeV Au2+ ions to a fluence of 5 ions nm-2 in the accelerator facilities within the Environmental Molecular Sciences Laboratory at Pacific Northwest National Laboratory. Irradiated and non-irradiated samples were examined by x-ray diffraction, scanning and transmission electron microscopy, x-ray photoelectron and infrared spectroscopy, and spectroscopic ellipsometry. Samples underwent accelerated leach testing at pH 1.75 (nitric acid) at 90 C for 28 days. The zirconate samples were more ion-irradiation damage resistant than the titanate samples, showing little change after ion-irradiation whereas the titanate samples formed an amorphous surface layer ∼ 500 nm thick. While all samples had high aqueous durability, the titanate leach rate was ∼ 5 times that of the zirconate. The ion-irradiation increased the leach rate of the titanate without impurities by ∼ 5 times. The difference in the leach rates between irradiated and unirradiated zirconate samples is small. However, the zirconates were less able to incorporate impurities than the titanate ceramics and required higher sintering temperatures, ∼ 1500 C compared to 1350 C for the titanates.

  4. Determination of trace element mineral/liquid partition coefficients in melilite and diopside by ion and electron microprobe techniques

    Science.gov (United States)

    Kuehner, S. M.; Laughlin, J. R.; Grossman, L.; Johnson, M. L.; Burnett, D. S.

    1989-01-01

    The applicability of ion microprobe (IMP) for quantitative analysis of minor elements (Sr, Y, Zr, La, Sm, and Yb) in the major phases present in natural Ca-, Al-rich inclusions (CAIs) was investigated by comparing IMP results with those of an electron microprobe (EMP). Results on three trace-element-doped glasses indicated that it is not possible to obtain precise quantitative analysis by using IMP if there are large differences in SiO2 content between the standards used to derive the ion yields and the unknowns.

  5. Development of a shielded ion microprobe analyzer (SIMA) and its application to fast reactor fuel elements

    International Nuclear Information System (INIS)

    Yuji, E.; Junji, K.; Sadamu, Y.; Toshiyuki, I.

    1983-01-01

    A shielded ion microprobe analyzer for elemental and isotopic analyses of irradiated fast reactor fuel and fuel component has been developed and installed in an alpha-gamma hot cell. Radiation shielding of the equipment ensures the radiation dose of -7 C/kg) for 5 Ci (1.85 x 10 11 Bq) of a 60 Co source. Hot samples can be automatically transferred from the cell to the sample chamber of the analyzer. Contamination inside the equipment through sputtering of the radioactive materials can be reduced with a special device. Distribution and migration of fission products, such as 137 Cs, 138 Ba, and 90 Sr, and of fissile materials, such as 235 U and 239 Pu in irradiated mixed-oxide fuel, and isotopic ratios of the elements can be obtained very precisely and quickly

  6. Development of a shielded ion microprobe analyzer (SIMA) and its application to fast reactor fuel elements

    International Nuclear Information System (INIS)

    Enokido, Y.; Itaki, T.; Komatsu, J.; Yamanouchi, S.

    1983-01-01

    A shielded ion microprobe analyzer for elemental and isotopic analyses of irradiated fast reactor fuel and fuel component has been developed and installed in an alpha-gamma hot cell. Radiation shielding of the equipment ensures the radiation dose of -7 C/kg) for 5 Ci (1.85 X 10 11 Bq) of a 60 Co source. Hot samples can be automatically transferred from the cell to the sample chamber of the analyzer. Contamination inside the equipment through sputtering of the radioactive materials can be reduced with a special device. Distribution and migration of fission products, such as 137 Cs, 138 Ba, and 90 Sr, and of fissile materials, such as 235 U and 239 Pu in irradiated mixed-oxide fuel, and isotopic ratios of the elements can be obtained very precisely and quickly

  7. Characterisation of Inorganic Pigments Used by Selected Painters by Using Ion Microprobe and Other Complementary Techniques

    International Nuclear Information System (INIS)

    Fazinic, S.; Pastuovic, Z.; Jaksic, M.; Kusijanovic, K.; Mudronja, D.; Braun, M.; Desnica, V.

    2011-01-01

    The aim of the presentation is to show results of the collaboration between the Croatian Conservation Institute (CCI) and the Laboratory for Ion Beam Interactions of the Rudjer Boskovic Institute (RBI) established within the present CRP. CCI is the central Croatian institution for conservation and restoration of cultural heritage objects. Prior to restoration/conservation CCI performs scientific analysis of an object, primarily to enable selection of the best strategy for its restoration/conservation. In many occasions such analysis is also helpful to resolve issues such as clarification of authenticity and/or authorship of an object. CCI has its analytical laboratory which is fully dedicated to the analysis of cultural heritage and art objects. CCI analytical laboratory is equipped with various microscopy techniques, photography methods, portable X-ray Fluorescence Spectrometer (XRF) and X-ray radiography instrumentation. Access to complementary microanalytical techniques like Raman Spectroscopy or Ion Beam Analytical (IBA) techniques is provided through already long and successful collaboration with RBI. The RBI Laboratory for Ion Beam Interactions provides complementary analysis of layered microsamples by using IBA techniques, such as Particle Induced X-ray Emission (PIXE) and Rutherford Back-scattering (RBS), and for the miniature samples by using ion microprobe. (author)

  8. New improvements in the characterization of refractory gold in pyrites: an electron microprobe, Moessbauer spectrometry and ion microprobe study

    International Nuclear Information System (INIS)

    Marion, P.; Holliger, P.; Boiron, M.C.; Cathelineau, M.; Wagner, F.E.

    1991-01-01

    Studies of pyrites by Moessbauer spectroscopy have shown the presence of gold in a combined state probably inserted within the lattice. In order to enhance detection limits for in-situ quantitative gold analyses, new SIMS investigations have been made thanks to a Resistive Anode Encorder record of the ion emissions, which provides digital images or scans of any part of the analyzed volume. Quantitative analysis of gold have been carried out thanks to 2 MeV ion implantation of gold in reference sulfide crystals, and the bulk composition of a pyrite grain has been determined. Some strong enrichments in gold and arsenic at the crystal margin attest fluctuations in the fluid chemistry and may be interpreted as a final growth zone, which is similar to that observed on arsenopyrite crystals. This multidisciplinary approach constitutes a powerful tool for the investigation of the insertion and distribution of trace elements within crystals, especially gold in sulfides at low contents down to a few ppm. (author)

  9. Ion beam analysis - development and application of nuclear reaction analysis methods, in particular at a nuclear microprobe

    International Nuclear Information System (INIS)

    Sjoeland, K.A.

    1996-11-01

    This thesis treats the development of Ion Beam Analysis methods, principally for the analysis of light elements at a nuclear microprobe. The light elements in this context are defined as having an atomic number less than approx. 13. The work reported is to a large extent based on multiparameter methods. Several signals are recorded simultaneously, and the data can be effectively analyzed to reveal structures that can not be observed through one-parameter collection. The different techniques are combined in a new set-up at the Lund Nuclear Microprobe. The various detectors for reaction products are arranged in such a way that they can be used for the simultaneous analysis of hydrogen, lithium, boron and fluorine together with traditional PIXE analysis and Scanning Transmission Ion Microscopy as well as photon-tagged Nuclear Reaction Analysis. 48 refs

  10. Ion microprobe analyses of aluminous lunar glasses - A test of the 'rock type' hypothesis

    Science.gov (United States)

    Meyer, C., Jr.

    1978-01-01

    Previous soil survey investigations found that there are natural groupings of glass compositions in lunar soils and that the average major element composition of some of these groupings is the same at widely separated lunar landing sites. This led soil survey enthusiasts to promote the hypothesis that the average composition of glass groupings represents the composition of primary lunar 'rock types'. In this investigation the trace element composition of numerous aluminous glass particles was determined by the ion microprobe method as a test of the above mentioned 'rock type' hypothesis. It was found that within any grouping of aluminous lunar glasses by major element content, there is considerable scatter in the refractory trace element content. In addition, aluminous glasses grouped by major elements were found to have different average trace element contents at different sites (Apollo 15, 16 and Luna 20). This evidence argues that natural groupings in glass compositions are determined by regolith processes and may not represent the composition of primary lunar 'rock types'.

  11. Optimization of the working distance of an ion microprobe-forming system

    International Nuclear Information System (INIS)

    Melnik, K.I.; Magilin, D.V.; Ponomarev, A.G.

    2009-01-01

    A high-resolution ion microprobe necessitates the use of a small working distance (the distance from the final quadrupole lens of a probe-forming system to the specimen) in order to produce a large demagnification. But at the same time a small working distance is a source of a number of practical difficulties. We have presented an approach for determining a working distance that provides the best spatial resolution with the main practical limitations taken into account. We used a probe-forming system acceptance as a criterion of optimality. The calculations have revealed the existence of an optimal working distance in a set of common probe-forming systems, but it can be achieved only after changing of a design of a final quadrupole lens. We proposed a possible design of conic lens that allows solving the problem of detectors location and creating a short focus system. Three-dimensional calculations of magnetic field within this lens predicted a good quality of field structure.

  12. Structure of heavy-ion tracks in zircon

    International Nuclear Information System (INIS)

    Braunshausen, G.; Bursill, L.A.; Vetter, J.; Spohr, R.

    1990-01-01

    Gem quality zirconas (ZrSiO 4 ) were irradiated with 14MeV/u Pb ions. Observations of heavy-ion tracks confirmed that fission or heavy-ion irradiation damage is confined to a 50-100 Aangstroem core region, which has undergone a crystalline-glass phase transition. 3 refs., 3 figs

  13. Redeposition of sputtered material in a glow-discharge lamp measured by means of an ion microprobe mass analyser

    International Nuclear Information System (INIS)

    Ferreira, N.P.; Bueger, P.A.

    1978-01-01

    The redeposition of sputtered material on the target in a Grimm-type glow-discharge lamp was studied by means of an ion microprobe mass analyser (IMMA) using 16 O 2 + ions as bombarding species. The target was an aluminium disc with a cylindrical copper insertion, one mm in diameter. The lamp was operated at currents of 50 mA and 100 mA and a voltage of 1200 V. It is estimated that 17% of the copper atoms sputtered are redeposited and may be resputtered. (orig.) [de

  14. Sulphur isotope variations in the mantle from ion microprobe analyses of micro-sulphide inclusions

    International Nuclear Information System (INIS)

    Chaussidon, M.; Albarede, F.; Sheppard, S.M.F.

    1989-01-01

    21 samples of sulphide trapped either as liquid globules or grains in various minerals (olivine, pyroxenes, ilmenite and garnet) or rocks (basalt glasses, peridotites, eclogites and kimberlites) of mantle origin, have been analysed for their sulphur isotope, and their Cu, Ni, Fe compositions by ion microprobe. The results show a wide range of δ 34 S values between -4.9±1 and +8±1per mille. Sulphides with high nickel contents (up to 40% pentlandite), corresponding mostly to residual peridotites, have δ 34 S values ranging from -3.2per mille to +3.6per mille with a mode of +3±1per mille, compared to low Ni content sulphides, mostly contained in pyroxenites, OIB and kimberlites, ranging from -3.6per mille to +8per mille with a mode of +1±1per mille. The δ 34 S of sulphides originating from within the mantle are variable. The sulphide globules with high Ni contents and δ 34 S values close to +3per mille, are probably produced by 10-20% partial melting of a mantle source containing 300 ppm sulphur as an upper limit and having a δ 34 S value of +0.5±0.5per mille. This difference in δ 34 S values suggests a high-temperature S-isotope fractionation of ≅+3per mille between liquid sulphide and the sulphur dissolved in the silicate liquid. The sulphur isotopes balance in the system upper mantle + oceanic crust + continental crust + seawater requires a mean δ 34 S value of the primitive upper mantle of +0.5per mille, slightly but significantly different from that of chondrites (+0.2±0.2per mille). (orig.)

  15. Zircon-scale insights into the history of a Supervolcano, Bishop Tuff, Long Valley, California, with implications for the Ti-in-zircon geothermometer

    Science.gov (United States)

    Reid, M.R.; Vazquez, J.A.; Schmitt, A.K.

    2011-01-01

    Zircon has the outstanding capacity to record chronological, thermal, and chemical information, including the storage history of zoned silicic magma reservoirs like the one responsible for the Bishop Tuff of eastern California, USA. Our novel ion microprobe approach reveals that Bishop zircon rims with diverse chemical characteristics surround intermediate domains with broadly similar compositions. The highest Y, REE, U, and Th concentrations tend to accompany the largest excesses in Y + REE3+:P beyond what can be explained by xenotime substitution in zircon. Apparent Ti-in-zircon temperatures of Ti-in-zircon temperatures are probably better explained by sources of inaccuracy in the temperature estimates. After apparently nucleating from different melts, zircons from across the Bishop Tuff compositional spectrum may have evolved to broadly similar chemical and thermal conditions and therefore it is possible that there was no significant thermal gradient in the magma reservoir at some stage in its evolution. There is also no compelling evidence for punctuated heat ?? chemical influxes during the intermediate stages of zircon growth. Judging by the zircon record, the main volume of the erupted magma evolved normally by secular cooling but the latest erupted portion is characterized by a reversal in chemistry that appears to indicate perfusion of the magma reservoir by-or zircon entrainment in-a less evolved melt from the one in which the zircons had previously resided. ?? 2010 Springer-Verlag.

  16. Ti-in-zircon thermometry: applications and limitations

    Science.gov (United States)

    Fu, Bin; Page, F. Zeb; Cavosie, Aaron J.; Fournelle, John; Kita, Noriko T.; Lackey, Jade Star; Wilde, Simon A.; Valley, John W.

    2008-08-01

    The titanium concentrations of 484 zircons with U-Pb ages of ˜1 Ma to 4.4 Ga were measured by ion microprobe. Samples come from 45 different igneous rocks (365 zircons), as well as zircon megacrysts (84) from kimberlite, Early Archean detrital zircons (32), and zircon reference materials (3). Samples were chosen to represent a large range of igneous rock compositions. Most of the zircons contain less than 20 ppm Ti. Apparent temperatures for zircon crystallization were calculated using the Ti-in-zircon thermometer (Watson et al. 2006, Contrib Mineral Petrol 151:413-433) without making corrections for reduced oxide activities (e.g., TiO2 or SiO2), or variable pressure. Average apparent Ti-in-zircon temperatures range from 500° to 850°C, and are lower than either zircon saturation temperatures (for granitic rocks) or predicted crystallization temperatures of evolved melts (˜15% melt residue for mafic rocks). Temperatures average: 653 ± 124°C (2 standard deviations, 60 zircons) for felsic to intermediate igneous rocks, 758 ± 111°C (261 zircons) for mafic rocks, and 758 ± 98°C (84 zircons) for mantle megacrysts from kimberlite. Individually, the effects of reduced a_{TiO2} or a_{SiO2}, variable pressure, deviations from Henry’s Law, and subsolidus Ti exchange are insufficient to explain the seemingly low temperatures for zircon crystallization in igneous rocks. MELTs calculations show that mafic magmas can evolve to hydrous melts with significantly lower crystallization temperature for the last 10-15% melt residue than that of the main rock. While some magmatic zircons surely form in such late hydrous melts, low apparent temperatures are found in zircons that are included within phenocrysts or glass showing that those zircons are not from evolved residue melts. Intracrystalline variability in Ti concentration, in excess of analytical precision, is observed for nearly all zircons that were analyzed more than once. However, there is no systematic change in Ti

  17. EFFECT OF FLUORINE AND CHLORINE IONS ON THE REACTION SINTERING OF MECHANICALLY ACTIVATED ZIRCON-ALUMINA MIXTURE

    Directory of Open Access Journals (Sweden)

    R. Zamani Foroshani

    2015-09-01

    Full Text Available The aim of this work was to study the effect of fluorine and chlorine ions on the formation of mullite during the reaction sintering of mechanically activated zircon-alumina powder mixture. The results showed that mechanical activation of zirconalumina powder mixture for 20 h led to grain refinement and partial amorphization. In the presence of fluorine and chlorine ions, complete formation of mullite in the mechanically activated sample occurred after 2 h of reaction sintering at 1300oC and 1400oC, respectively. In the sample lacking fluorine and chlorine ions, mullitization was not completed even after 2 h of reaction sintering at 1400oC. It was concluded that presence of fluorine and chlorine ions enhance the dissociation of zircon and formation of mullite during the reaction sintering of mechanically activated zircon-alumina mixture.

  18. Optically continuous silcrete quartz cements of the St. Peter Sandstone: High precision oxygen isotope analysis by ion microprobe

    Science.gov (United States)

    Kelly, Jacque L.; Fu, Bin; Kita, Noriko T.; Valley, John W.

    2007-08-01

    A detailed oxygen isotope study of detrital quartz and authigenic quartz overgrowths from shallowly buried (ratio by laser fluorination, resulting in an average δ 18O of 10.0 ± 0.2‰ (1SD, n = 109). Twelve thin sections were analyzed by CAMECA-1280 ion microprobe (6-10 μm spot size, analytical precision better than ±0.2‰, 1SD). Detrital quartz grains have an average δ 18O of 10.0 ± 1.4‰ (1SD, n = 91) identical to the data obtained by laser fluorination. The ion microprobe data reveal true variability that is otherwise lost by homogenization of powdered samples necessary for laser fluorination. Laser fluorination uses samples that are one million times larger than the ion microprobe. Whole rock (WR) samples from the 53 rocks were analyzed by laser fluorination, giving δ 18O between 9.8‰ and 16.7‰ ( n = 110). Quartz overgrowths in thin sections from 10 rocks were analyzed by ion microprobe and average δ 18O = 29.3 ± 1.0‰ (1SD, n = 161). Given the similarity, on average, of δ 18O for all detrital quartz grains and for all quartz overgrowths, samples with higher δ 18O(WR) values can be shown to have more cement. The quartz cement in the 53 rocks, calculated by mass balance, varies from outlier at 33 vol.% cement. Eolian samples have an average of 11% cement compared to marine samples, which average 4% cement. Two models for quartz cementation have been investigated: high temperature (50-110 °C) formation from ore-forming brines related to Mississippi Valley Type (MVT) mineralization and formation as silcretes at low temperature (10-30 °C). The homogeneity of δ 18O for quartz overgrowths determined by ion microprobe rules out a systematic regional variation of temperature as predicted for MVT brines and there are no other known heating events in these sediments that were never buried to depths >1 km. The data in this study suggest that quartz overgrowths formed as silcretes in the St. Peter Sandstone from meteoric water with δ 18O values of -10

  19. Development of a new measurement method for fast breeder reactor fuel burnup using a shielded ion microprobe analyzer

    International Nuclear Information System (INIS)

    Mizuno, M.; Enokido, Y.; Itaki, T.; Kono, K.; Unno, I.; Yamanouchi, S.

    1985-01-01

    A new method of burnup measurement using a shielded ion microprobe analyzer (SIMA) has been developed. The method is based on the isotope analysis of uranium, plutonium, and fission products in irradiated mixed oxide fuel by means of secondary ion mass spectrometry (SIMS). Fourteen samples irradiated in the Japanese experimental fast reactor JOYO were examined. The maximum local burnup of JOYO MK-I core fuels was about5.1 at. %. The axial burnup distribution of the fuel pin was in good agreement with that of the sibling pin in the same subassembly, measured by surface ionization mass spectrometry, which requires the chemical separation of fission products and heavy metals. The new method facilitates the rapid and accurate measurement of fast breeder reactor fuel burnup without human radiation exposure during sample preparation and analysis

  20. Isotopic Investigations of Nebular and Parent Body Processes with a High Sensitivity Ion Microprobe

    Science.gov (United States)

    McKeegan, Kevin D.

    2005-01-01

    NASA supported the development of the CAMECA ims 1270 ion microprobe at UCLA for applications in cosmochemistry. The primary investigations centered on measuring the microscopic distributions of key isotopic abundances in primitive meteoritic materials as a means of constraining the nature of important thermal and chemical processes in the solar nebula and the timescales associated with those processes. Our prior work on oxygen isotope anomalies in a wide variety of meteoritic materials had led us to a view of a spatially heterogeneous nebula, and in particular, a restricted region for CAI formation that is characterized by O-16-rich gas. Because of its production of CAIs in the energetic local environment near the protosun, the existence of a natural transport mechanism via bipolar outflows, and a general astrophysical plausibility, we were attracted to the fluctuating X-wind model which had been put forward by Frank Shu, Typhoon Lee, and colleagues. With our collaborators, we undertook a series of investigations to test the viability of this hypothesis; this work led directly to the discovery of live Be in CAIs and a clear demonstration of the existence of 160-rich condensates, which necessarily implies an O-16-rich gaseous reservoir in the nebula. Both of these observations fit well within the context of X-wind type models, i.e. formation of CAIs (or condensation of their precursors) in the reconnection ring sunward of the inner edge of the accretion disk, however much work remains to be done to test whether the physical parameters of the model can quantitatively predict not only the thermal histories of CAIs but also their radioactivity. The issue of spatial heterogeneity in the nebula, central to the X-wind model, is also at the heart of any chronology based on short-lived radioisotopes. In this work, we followed up on strong hints for presence of exireme:j: (53 day) short-lived Be-7, and have prepared a manuscript (in revision). We also measured A1-Mg

  1. Structural and electrical properties of Nd ion modified lead zirconate titanate nanopowders and ceramics

    International Nuclear Information System (INIS)

    Da-Wei, Wang; De-Qing, Zhang; Quan-Liang, Zhao; Hong-Mei, Liu; Zhi-Ying, Wang; Mao-Sheng, Cao; Jie, Yuan

    2009-01-01

    A modified sol-gel method is used for synthesizing Nd ion doped lead zirconate titanate nanopowders Pb 1–3x/2 Nd x Zr 0.52 Ti 0.48 O 3 (PNZT) in an ethylene glycol system with zirconium nitrate as zirconium source. The results show that it is critical to add lead acetate after the reaction of zirconium nitrate with tetrabutyl titanate in the ethylene glycol system for preparing PNZT with an exact fraction of titanium content. It has been observed that the dopant of excess Nd ions can effectively improve the sintered densification and activity of the PNZT ceramics. Piezoelectric, dielectric and ferroelectric properties of the PNZT ceramics are remarkably enhanced as compared with those of monolithic lead zirconate titanate (PZT). Especially, the supreme values of piezoelectric constant (d 33 ) and dielectric constant ( element of ) for the PNZT are both about two times that of the monolithic PZT and moreover, the remnant polarization (P r ) also increases by 30%. According to the analysis of the structures and properties, we attribute the improvement in electrical properties to the lead vacancies caused by the doping of Nd ions

  2. Output characteristics of piezoelectric lead zirconate titanate detector using high-energy heavy-ion beam

    International Nuclear Information System (INIS)

    Takechi, Seiji; Sekiguchi, Masahiro; Miyachi, Takashi; Kobayashi, Masanori; Hattori, Maki; Okudaira, Osamu; Shibata, Hiromi; Fujii, Masayuki; Okada, Nagaya; Murakami, Takeshi; Uchihori, Yukio

    2014-01-01

    A radiation detector fabricated using piezoelectric lead zirconate titanate (PZT) has been studied by irradiating it with a 400 MeV/n xenon (Xe) beam. The beam diameter was controlled to change the irradiation conditions. It was found that the magnitude of the output observed from the PZT detector may be related to the number of Xe ions per unit area per unit time within the limits of the experimental conditions. -- Highlights: • The performance of PZT detector was studied by irradiation of a 400 MeV/n Xe beam. • The beam diameter was controlled to change the irradiation conditions. • By the control, the number of Xe ions per one pulse was changed from ∼500 to ∼1500. • The output of the PZT detector was not always larger with more intense beam. • The energy of Xe ions per unit area per unit time may determine the output

  3. Temperature and ion-mass dependence of amorphization dose for ion beam irradiated zircon (ZrSiO4)

    International Nuclear Information System (INIS)

    Wang, L.M.; Ewing, R.C.; Eby, R.K.

    1992-12-01

    The temperature dependence of amorphization dose for zircon under 1.5 MeV Kr ion irradiation has been investigated using the ANL HVEM-Tandem Facility. Three regimes were observed in the amorphization dose-temperature curve. In the first regime (15 to 300 K), the critical amorphization dose increased from 3.06 to 4.5 ions/nm 2 . In the second regime (300 to 473 K), there is little change in the amorphizationdose. In the third regime (> 473 K), the amorphization dose increased exponentially to 8.3 ions/nm 2 at 913 K. This temperature dependence of amorphization dose can be described by two processes with different activation energies (0.018 and 0.31 eV respectively) which are attributed to close pair recombination in the cascades at low temperatures and radiation-enhanced epitaxial recrystallization at higher temperatures. The upper temperature limit for amorphization of zircon is estimated to be 1100 K. The ion-mass dependence of the amorphization dose (in dpa) has also been discussed in terms of the energy to recoils based on data obtained from He, Ne, Ar, Kr, Xe irradiations and a 238 Pu-doped sample

  4. Electron Microprobe

    Data.gov (United States)

    Federal Laboratory Consortium — The JEOL JXA-8600 is a conventional hairpin filament thermal emission electron microprobe that is more than 20 years old. It is capable of performing qualitative and...

  5. Ion microprobe analyses of oxygen three-isotope ratios of chondrules from the Sayh al Uhaymir 290 CH chondrite using a multiple-hole disk

    Digital Repository Service at National Institute of Oceanography (India)

    Nakashima, D.; Ushikubo, T.; Gowda, R.N.; Kita, N.T.; Valley, J.W.; Naga, K.

    Author version: Meteorit. Planet. Sci., vol.46(6); 2011; 857-874 Ion microprobe analyses of oxygen three isotope ratios of chondrules from the Sayh al Uhaymir 290 CH chondrite using a multiple-hole disk Daisuke Nakashima 1,2,* , Takayuki Ushikubo...

  6. Planktonic foraminiferal oxygen isotope analysis by ion microprobe technique suggests warm tropical sea surface temperatures during the Early Paleogene

    Science.gov (United States)

    Kozdon, Reinhard; Kelly, D. Clay; Kita, Noriko T.; Fournelle, John H.; Valley, John W.

    2011-09-01

    Cool tropical sea surface temperatures (SSTs) are reported for warm Paleogene greenhouse climates based on the δ18O of planktonic foraminiferal tests. These results are difficult to reconcile with models of greenhouse gas-forced climate. It has been suggested that this "cool tropics paradox" arises from postdepositional alteration of foraminiferal calcite, yielding erroneously high δ18O values. Recrystallization of foraminiferal tests is cryptic and difficult to quantify, and the compilation of robust δ18O records from moderately altered material remains challenging. Scanning electron microscopy of planktonic foraminiferal chamber-wall cross sections reveals that the basal area of muricae, pustular outgrowths on the chamber walls of species belonging to the genus Morozovella, contain no mural pores and may be less susceptible to postdepositional alteration. We analyzed the δ18O in muricae bases of morozovellids from the central Pacific (Ocean Drilling Program Site 865) by ion microprobe using 10 μm pits with an analytical reproducibility of ±0.34‰ (2 standard deviations). In situ measurements of δ18O in these domains yield consistently lower values than those published for conventional multispecimen analyses. Assuming that the original δ18O is largely preserved in the basal areas of muricae, this new δ18O record indicates Early Paleogene (˜49-56 Ma) tropical SSTs in the central Pacific were 4°-8°C higher than inferred from the previously published δ18O record and that SSTs reached at least ˜33°C during the Paleocene-Eocene thermal maximum. This study demonstrates the utility of ion microprobe analysis for generating more reliable paleoclimate records from moderately altered foraminiferal tests preserved in deep-sea sediments.

  7. SHRIMP U-Pb zircon dating of Archean core complex formatio and pancratonic strike-slip deformation in the East Pilbara Granite-Greenstone Terrain

    NARCIS (Netherlands)

    Zegers, T.E.; Nelson, D.R.; Wijbrans, J.R.; White, S.H.

    2001-01-01

    Sensitive high-resolution ion microprobe (SHRIMP) U-Pb dating of zircons from granitic rocks in the East Pilbara Granite-Greenstone Terrain has provided time constraints for main tectonic events in the Shaw Granitoid Complex and has shown that deformation was intricately related to granitoid

  8. Multicolor tunable emission induced by Cu ion doping of perovskite zirconate

    Energy Technology Data Exchange (ETDEWEB)

    Lee, D.J. [Department of Physics, Soongsil University, Seoul 156-743 (Korea, Republic of); Lee, Y.S., E-mail: ylee@ssu.ac.kr [Department of Physics, Soongsil University, Seoul 156-743 (Korea, Republic of); Noh, H.-J. [Department of Physics, Chonnam National University, Gwangju 500-757 (Korea, Republic of)

    2016-01-15

    We report on a multicolor tunable emission induced by Cu ion doping of perovskite zirconate SrZrO{sub 3} with a fairly large bandgap (5.6 eV). X-ray photoelectron spectroscopy of our samples revealed the existence of two mixed valence states of the doped Cu ions, +1 and +2, with a ratio of 3:1. In photoluminescence excitation spectroscopy the absorption structures of the 3d states in monovalent Cu{sup +} and divalent Cu{sup 2+} were identified near 5 eV and 3.5 eV, respectively. Interestingly, in relation to the valence states of the Cu ions, the emission spectra depended strongly on the photo-excitation energy (E{sub ex}). For E{sub ex}<3.8 eV (UVA) two orange and green emissions were observed with the involvement of the Cu{sup 2+} state. For E{sub ex}>3.8 eV (UVB/UVC), however, the Cu{sup +} state, instead of the Cu{sup 2+} state, was dominant in the emission process, causing the visible emission to be turned into violet. Our results were indicative of the complementary role of the different Cu-ion valence states in a wide range of visible emission with respect to E{sub ex}. - Highlights: • Visible emission induced by the Cu doping of SrZrO3. • Tunable colors from orange to violet with respect to the photo-excitation energy. • Multicolor emission should be related to the mixed valence states of the doped Cu ions.

  9. Assembling of a low energy ion beam analysis facility and use of Nuclear Microprobe techniques in geological studies

    Energy Technology Data Exchange (ETDEWEB)

    Utui, R

    1996-11-01

    In this work, both PIXE and ion beam induced luminescence, or just Ionoluminescence (IL) were used for geochemical studies. The possibility of rapid absolute quantification of elements in the ppm level by PIXE combined with the yet higher sensitivity of IL to transition metals and Rare Earth Elements (REE) activators, in the absence of quenching phenomena, allow for a synergic use of the two methods in geological applications with enhanced sensitivity. IL and PIXE were combined for studying REE distribution in apatite minerals and ion beam induced damage in inorganic material in general with emphasis to synthetically grown zircon crystals doped with REE. Due to the sensitivity of IL to changes in chemical bonding in the material, beam damage effects can be studied even at low integrated doses, through wavelength shift or fading of the induced light. Micro PIXE technique was used for studying profile concentrations of trace elements in pyrite grains and of elements used as geothermometers. Geothermometry allowed to assess the cooling rates in iron meteorites and the mineralization conditions in metamorphic rocks, attempting to describe the tectonic history of the terranes, with application in petrologic studies and geological prospecting. 148 refs.

  10. Assembling of a low energy ion beam analysis facility and use of Nuclear Microprobe techniques in geological studies

    International Nuclear Information System (INIS)

    Utui, R.

    1996-11-01

    In this work, both PIXE and ion beam induced luminescence, or just Ionoluminescence (IL) were used for geochemical studies. The possibility of rapid absolute quantification of elements in the ppm level by PIXE combined with the yet higher sensitivity of IL to transition metals and Rare Earth Elements (REE) activators, in the absence of quenching phenomena, allow for a synergic use of the two methods in geological applications with enhanced sensitivity. IL and PIXE were combined for studying REE distribution in apatite minerals and ion beam induced damage in inorganic material in general with emphasis to synthetically grown zircon crystals doped with REE. Due to the sensitivity of IL to changes in chemical bonding in the material, beam damage effects can be studied even at low integrated doses, through wavelength shift or fading of the induced light. Micro PIXE technique was used for studying profile concentrations of trace elements in pyrite grains and of elements used as geothermometers. Geothermometry allowed to assess the cooling rates in iron meteorites and the mineralization conditions in metamorphic rocks, attempting to describe the tectonic history of the terranes, with application in petrologic studies and geological prospecting. 148 refs

  11. Sulfur isotope composition of orogenic spinel lherzolite massifs from Ariege (north-eastern pyrenees, France): An ion microprobe study

    Energy Technology Data Exchange (ETDEWEB)

    Chaussidon, M. (Centre de Recherches Petrographiques et Geochimiques, Vandoeuvre-les-Nancy (France)); Lorand, J. (Unite associee au CNRS, Paris (France))

    1990-10-01

    The orogenic spinel lherzolite massifs from Ariege, which represent tectonically emplaced fragments of the sub-continental upper mantle, are composed mainly of variously depleted peridotites. These rocks are crosscut by two generations of pyroxenites. The first is made up of layered pyroxenites, which are interpreted either as crystal segregates from Triassic continental tholeiites or as subducted parts of the oceanic crust re-injected within the upper mantle. The second consists of amphibole-rich dikes separated from Cretaceous alkali basalts. Forty sulfide grains, occurring either as inclusions within silicates or as interstitial grains, were investigated by ion microprobe for their sulfur isotopic compositions. Comparison between sulfide inclusions in silicates and interstitial sulfide grains strongly suggests that serpentinization and pyrenean metamorphism had no significant effect don the {delta}{sup 34}S values. Likewise, these values are broadly independent of the degree of partial melting. The negative {delta}{sup 34}S values of the massive peridotites could represent an ancient depletion event in the upper mantle. By contrast, the positive {delta}{sup 34}S values observed in the layered pryoxenites and the amphibole-rich dikes indicate that the two parent magmas had in common a mantle source variously enriched in {sup 34}S. Therefore, the present study reveals two extreme reservoirs characterized by different {delta}{sup 34}S values in the upper mantle. This range of variations can explain most {delta}{sup 34}S values found in MORB, continental tholeiites, and alkali basalts.

  12. Develop techniques for ion implantation of PLZT [lead-lanthanum-zirconate-titanate] for adaptive optics

    International Nuclear Information System (INIS)

    Batishko, C.R.; Brimhall, J.L.; Pawlewicz, W.T.; Stahl, K.A.; Toburen, L.H.

    1987-09-01

    Research was conducted at Pacific Northwest Laboratory to develop high photosensitivity adaptive optical elements utilizing ion implanted lanthanum-doped lead-zirconate-titanate (PLZT). One centimeter square samples were prepared by implanting ferroelectric and anti-ferroelectric PLZT with a variety of species or combinations of species. These included Ne, O, Ni, Ne/Cr, Ne/Al, Ne/Ni, Ne/O, and Ni/O, at a variety of energies and fluences. An indium-tin oxide (ITO) electrode coating was designed to give a balance of high conductivity and optical transmission at near uv to near ir wavelengths. Samples were characterized for photosensitivity; implanted layer thickness, index of refraction, and density; electrode (ITO) conductivity; and in some cases, residual stress curvature. Thin film anti-ferroelectric PLZT was deposited in a preliminary experiment. The structure was amorphous with x-ray diffraction showing the beginnings of a structure at substrate temperatures of approximately 550 0 C. This report summarizes the research and provides a sampling of the data taken during the report period

  13. An experimental study of hydroxyl in quartz using infrared spectroscopy and ion microprobe techniques

    Energy Technology Data Exchange (ETDEWEB)

    Rovetta, M. R.; Blacic, J. D.; Hervig, R. L.; Holloway, J. R.

    1989-05-10

    We have measured the concentrations of hydroxyl, deuterium, Al, Fe, Li,Na, K, and Rb in a natural quartz crystal before and after hydrothermaltreatment at 1.5 GPa and 800/degree/--1050 /degree/C. We employed microbeam infraredspectroscopy and ion probe techniques to avoid impurities trapped in healedcracks and fluid inclusions that might bias a normal bulk analysis.The /ital f//sub H/sub 2// of our experiments were buffered to thehematite-magnetite-(OH)fluid, nickel-nickel oxide-(OH)fluid, oriron-wustite-(OH)fluid phase assemblages. After hydrothermal treatment,the samples contained local concentrations of hydrogen or deuterium ofseveral hundred atoms/10/sup 6/ Si (the starting crystal contained 45 H/10/sup 6/ Si).We did several experiments with Al/sub 2/O/sub 3/ or RbCl added to the sample chargeand found local Al enrichment where the deuterium concentration was highbut no Rb enrichment. Finally, we measured trace elements and hydroxyl in aquartz sample after plastic deformation in a talc furnace assembly; inregions of the sample containing basal and prismatic deformation lamellae(but no visible healed microcracks at 400/times/ optical magnification)hydroxyl had increased to /similar to/200 oO/10/sup 6/ Si with no increase in Al or Fe.Samples enriched in hydroxyl but not Al (including the plastically strainedsample) gave infrared spectra resembling natural amethyst crystals.

  14. An ion microprobe study of CAIs from CO3 meteorites. [Abstract only

    Science.gov (United States)

    Russell, S. S.; Greenwood, R. C.; Fahey, A. J.; Huss, G. R.; Wasserburg, G. J.

    1994-01-01

    When attempting to interpret the history of Ca, Al-rich inclusions (CAIs) it is often difficult to distinguish between primary features inherited from the nebula and those produced during secondary processing on the parent body. We have undertaken a systematic study of CAIs from 10 CO chondrites, believed to represent a metamorphic sequence with the goal of distinguishing primary and secondary features. ALHA 77307 (3.0), Colony (3.0), Kainsaz (3.1), Felix (3.2), ALH 82101 (3.3), Ornans (3.3), Lance (3.4), ALHA 77003 (3.5), Warrenton (3.6), and Isna (3.7) were examined by Scanning Electron Microscopy (SEM) and optical microscopy. We have identified 141 CAIs within these samples, and studied in detail the petrology of 34 inclusions. The primary phases in the lower petrologic types are spinel, melilite, and hibonite. Perovskite, FeS, ilmenite, anorthite, kirschsteinite, and metallic Fe are present as minor phases. Melilite becomes less abundant in higher petrologic types and was not detected in chondrites of type 3.5 and above, confirming previous reports that this mineral easily breaks down during heating. Iron, an element that would not be expected to condense at high temperatures, has a lower abundance in spinel from low-petrologic-type meteorites than those of higher grade, and CaTiO3 is replaced by FeTiO3 in meteorites of higher petrologic type. The abundance of CAIs is similar in each meteorite. Eight inclusions have been analyzed by ion probe. The results are summarized. The results obtained to date show that CAIs in CO meteorites, like those from other meteorite classes, contain Mg* and that Mg in some inclusions has been redistributed.

  15. Mixture modeling of multi-component data sets with application to ion-probe zircon ages

    Science.gov (United States)

    Sambridge, M. S.; Compston, W.

    1994-12-01

    A method is presented for detecting multiple components in a population of analytical observations for zircon and other ages. The procedure uses an approach known as mixture modeling, in order to estimate the most likely ages, proportions and number of distinct components in a given data set. Particular attention is paid to estimating errors in the estimated ages and proportions. At each stage of the procedure several alternative numerical approaches are suggested, each having their own advantages in terms of efficency and accuracy. The methodology is tested on synthetic data sets simulating two or more mixed populations of zircon ages. In this case true ages and proportions of each population are known and compare well with the results of the new procedure. Two examples are presented of its use with sets of SHRIMP U-238 - Pb-206 zircon ages from Palaeozoic rocks. A published data set for altered zircons from bentonite at Meishucun, South China, previously treated as a single-component population after screening for gross alteration effects, can be resolved into two components by the new procedure and their ages, proportions and standard errors estimated. The older component, at 530 +/- 5 Ma (2 sigma), is our best current estimate for the age of the bentonite. Mixture modeling of a data set for unaltered zircons from a tonalite elsewhere defines the magmatic U-238 - Pb-206 age at high precision (2 sigma +/- 1.5 Ma), but one-quarter of the 41 analyses detect hidden and significantly older cores.

  16. Single-zircon dating by stepwise Pb-evaporation constrains the Archean history of detrital zircons from the Jack Hills, Western Australia

    International Nuclear Information System (INIS)

    Kober, B.; Lippolt, H.J.; Pidgeon, R.T.

    1989-01-01

    Pb isotope analyses have been carried out on 42 zircon grains from a Western Australian metaconglomerate using stepwise Pb-evaporation directly in the ion source of a thermal ionization mass spectrometer. The metaconglomerate is from the Archean Jack Hills Metasedimentary Belt, and is known from ion microprobe (''SHRIMP'') analyses to contain a complex zircon population with ages between 4.2 Ga and 3.1 Ga. The same complex pattern of ages is found by the Pb evaporation studies. Five grains yielded minimum crystallization ages from 4.17 Ga to 4.07 Ga. The main population appears significantly younger, having been generated at about 3.55-3.3 Ga. The agreement between the two analytical approaches confirms the SHRIMP results and demonstrates the value of the stepwise-evaporation technique in determining the age patterns of mixing zircon populations. In many of the evaporative Pb isotope records the 207/206 ratios remained constant for all evaporation steps, which we interpret as evaporation from concordant zircon phases. However, for the majority of zircons 207/206 ratios increased with increasing evaporation temperature, and usually approached constant values during evaporation at the highest temperatures. This can be attributed to mixing of different radiogenic Pb components from either crystalline zircon phases of different ages or from domains of isotopically disturbed metamict zircon. Present results confirm > 4 Ga zircon ages in the metaconglomerate from the Hack Hills and substantiate formation of crust at a very early stage in the evolution of the earth. Results also confirm a major crust-forming event 3.55-3.3 Ga ago. (orig.)

  17. Complementary microanalysis of Zn, Mn and Fe in the chelicera of spiders and scorpions using scanning MeV-ion and electron microprobes

    International Nuclear Information System (INIS)

    Schofield, R.; Lefevre, H.; Shaffer, M.

    1989-01-01

    Energy-loss scanning transmission ion microscopy (ELSTIM or just STIM), PIXE and electron microprobe techniques are used to investigate certain minor element accumulations in a few spiders and scorpions. STIM and PIXE are used to survey the unsectioned specimens, while electron microprobe techniques are used for higher resolution investigations of several sections of the specimens. Concentration values measured using STIM and PIXE are found to be in satisfactory agreement with those measured using electron probe microanalysis. A garden spider Araneous diadematus is found to contain high concentrations of zinc in a thin layer near the surface of its fangs (reaching 23% of dry weight), and manganese in its marginal teeth (about 5% of dry weight). A wolf spider Alopecosa kochi is found to have similar concentrations of zinc in a layer near the surface of it's fang, and concentrations of manganese reaching 1.5% in a layer beneath the zinc containing layer. A scorpion Centruroides sp. is found to contain high concentrations of iron (reaching 8%) and zinc (reaching 24%) in the tips of teeth on the cheliceral fingers, and manganese (about 5%) in the stinger. The hypothesis that these elements simply harden the cuticle does not appear to explain their segregation patterns. (orig.)

  18. The Stanford-U.S. Geological Survey SHRIMP ion microprobe--a tool for micro-scale chemical and isotopic analysis

    Science.gov (United States)

    Bacon, Charles R.; Grove, Marty; Vazquez, Jorge A.; Coble, Matthew A.

    2012-01-01

    Answers to many questions in Earth science require chemical analysis of minute volumes of minerals, volcanic glass, or biological materials. Secondary Ion Mass Spectrometry (SIMS) is an extremely sensitive analytical method in which a 5–30 micrometer diameter "primary" beam of charged particles (ions) is focused on a region of a solid specimen to sputter secondary ions from 1–5 nanograms of the sample under high vacuum. The elemental abundances and isotopic ratios of these secondary ions are determined with a mass spectrometer. These results can be used for geochronology to determine the age of a region within a crystal thousands to billions of years old or to precisely measure trace abundances of chemical elements at concentrations as low as parts per billion. A partnership of the U.S. Geological Survey and the Stanford University School of Earth Sciences operates a large SIMS instrument, the Sensitive High-Resolution Ion Microprobe with Reverse Geometry (SHRIMP–RG) on the Stanford campus.

  19. A petrologic and ion microprobe study of a Vigarano Type B refractory inclusion - Evolution by multiple stages of alteration and melting

    Science.gov (United States)

    Macpherson, Glenn J.; Davis, Andrew M.

    1993-01-01

    A Type B Ca-, Al-rich 6-m-diam inclusion (CAI) found in the Vigarano C3V chondrite was inspected using optical and scanning electron microscopies and ion microprobe analyses. It was found that the primary constituents of the CAI inclusion are (in percent), melilite (52), fassaite, (20), anorthite (18), spinel (10), and trace Fe-Ni metal. It is noted that, while many of the properties of the inclusion indicate solidification from a melt droplet, the Al-26/Mg-26 isotopic systematics and some textural relationships are incompatible with single-stage closed system crystallization of a homogeneous molten droplet, indicating that the history of this inclusion must have been more complex than melt solidification alone. Moreover, there was unusually high content of Na in melilite, suggesting that the droplet did not form by melting of pristine high-temperature nebular condensates.

  20. U-Pb Dating of Zircons and Phosphates in Lunar Meteorites, Acapulcoites and Angrites

    Science.gov (United States)

    Zhou, Q.; Zeigler, R. A.; Yin, Q. Z.; Korotev, R. L.; Joliff, B. L.; Amelin, Y.; Marti, K.; Wu, F. Y.; Li, X. H.; Li, Q. L.; hide

    2012-01-01

    Zircon U-Pb geochronology has made a great contribution to the timing of magmatism in the early Solar System [1-3]. Ca phosphates are another group of common accessory minerals in meteorites with great potential for U-Pb geochronology. Compared to zircons, the lower closure temperatures of the U-Pb system for apatite and merrillite (the most common phosphates in achondrites) makes them susceptible to resetting during thermal metamorphism. The different closure temperatures of the U-Pb system for zircon and apatite provide us an opportunity to discover the evolutionary history of meteoritic parent bodies, such as the crystallization ages of magmatism, as well as later impact events and thermal metamorphism. We have developed techniques using the Cameca IMS-1280 ion microprobe to date both zircon and phosphate grains in meteorites. Here we report U-Pb dating results for zircons and phosphates from lunar meteorites Dhofar 1442 and SaU 169. To test and verify the reliability of the newly developed phosphate dating technique, two additional meteorites, Acapulco, obtained from Acapulco consortium, and angrite NWA 4590 were also selected for this study as both have precisely known phosphate U-Pb ages by TIMS [4,5]. Both meteorites are from very fast cooled parent bodies with no sign of resetting [4,5], satisfying a necessity for precise dating.

  1. Biological analysis with a nuclear microprobe

    International Nuclear Information System (INIS)

    Cookson, J.A.; Legge, G.J.F.

    1975-01-01

    Most low-energy nuclear accelerators are now partly used on analytical studies in support of sciences other than nuclear physics. This paper gives a short review of such analytical techniques (X-ray analysis, elastic scattering analysis, nuclear reaction analysis, and the nuclear microprobe) with particular reference to biological applications and also emphasizes the role of the positional analysis that can be performed with a focused beam of ions - the nuclear microprobe. (author)

  2. Beam optics on the Melbourne proton microprobe

    International Nuclear Information System (INIS)

    Jamieson, D.N.; Colman, R.A.; Allan, G.L.; Legge, G.J.F.

    1985-01-01

    This review paper summarises results of ion optics development work conducted on the Melbourne Proton Microprobe and the associated Pelletron accelerator. The properties of a field ionization ion source have been investigated with the aim of replacing the existing R.F. ion source in the accelerator in order to obtain a brighter beam for the microprobe. The electrostatic emitter lens in the terminal of the accelerator has also been investigated with the aim of improving the focus of the accelerated beam. Finally, the aberrations of the probe forming lens system have been studied and it is shown how some of these may be corrected with an octupole lens

  3. Chemical abrasion-SIMS (CA-SIMS) U-Pb dating of zircon from the late Eocene Caetano caldera, Nevada

    Science.gov (United States)

    Watts, Kathryn E.; Coble, Matthew A.; Vazquez, Jorge A.; Henry, Christopher D.; Colgan, Joseph P.; John, David A.

    2016-01-01

    Zircon geochronology is a critical tool for establishing geologic ages and time scales of processes in the Earth's crust. However, for zircons compromised by open system behavior, achieving robust dates can be difficult. Chemical abrasion (CA) is a routine step prior to thermal ionization mass spectrometry (TIMS) dating of zircon to remove radiation-damaged parts of grains that may have experienced open system behavior and loss of radiogenic Pb. While this technique has been shown to improve the accuracy and precision of TIMS dating, its application to high-spatial resolution dating methods, such as secondary ion mass spectrometry (SIMS), is relatively uncommon. In our efforts to U-Pb date zircons from the late Eocene Caetano caldera by SIMS (SHRIMP-RG: sensitive high resolution ion microprobe, reverse geometry), some grains yielded anomalously young U-Pb ages that implicated Pb-loss and motivated us to investigate with a comparative CA and non-CA dating study. We present CA and non-CA 206Pb/238U ages and trace elements determined by SHRIMP-RG for zircons from three Caetano samples (Caetano Tuff, Redrock Canyon porphyry, and a silicic ring-fracture intrusion) and for R33 and TEMORA-2 reference zircons. We find that non-CA Caetano zircons have weighted mean or bimodal U-Pb ages that are 2–4% younger than CA zircons for the same samples. CA Caetano zircons have mean U-Pb ages that are 0.4–0.6 Myr older than the 40Ar/39Ar sanidine eruption age (34.00 ± 0.03 Ma; error-weighted mean, 2σ), whereas non-CA zircons have ages that are 0.7–1.3 Myr younger. U-Pb ages do not correlate with U (~ 100–800 ppm), Th (~ 50–300 ppm) or any other measured zircon trace elements (Y, Hf, REE), and CA and non-CA Caetano zircons define identical trace element ranges. No statistically significant difference in U-Pb age is observed for CA versus non-CA R33 or TEMORA-2 zircons. Optical profiler measurements of ion microprobe pits demonstrate consistent depths of ~ 1.6

  4. Materials analysis with a nuclear microprobe

    International Nuclear Information System (INIS)

    Maggiore, C.J.

    1980-01-01

    The ability to produce focused beams of a few MeV light ions from Van de Graaff accelerators has resulted in the development of nuclear microprobes. Rutherford backscattering, nuclear reactions, and particle-induced x-ray emission are used to provide spatially resolved information from the near surface region of materials. Rutherford backscattering provides nondestructive depth and mass resolution. Nuclear reactions are sensitive to light elements (Z < 15). Particle-induced x-ray analysis is similar to electron microprobe analysis, but 2 orders of magnitude more sensitive. The focused beams are usually produced with specially designed multiplets of magnetic quadrupoles. The LASL microprobe uses a superconducting solenoid as a final lens. The data are acquired by a computer interfaced to the experiment with CAMAC. The characteristics of the information acquired with a nuclear microprobe are discussed; the means of producing the beams of nuclear particles are described; and the limitations and applications of such systems are given

  5. SHRIMP U-Pb dating of detrital zircons in metamorphic rocks from northern Kyushu, western Japan

    International Nuclear Information System (INIS)

    Tsutsumi, Yukiyasu; Yokoyama, Kazumi; Terada, Kentaro; Sano, Yuji

    2003-01-01

    Radiometric ages of detrital zircons in psammitic schists from the Nagasaki, Kurume, Konoha and Kiyama areas, northern Kyushu, were obtained from 238 U/ 206 Pb ratio and isotopic compositions of Pb using a Sensitive High Resolution Ion Microprobe (SHRIMP II). Zircons from the Nagasaki, Kurume and Konoha areas show bimodal age distribution with peaks at ca. 1900 Ma and 250 Ma. It is suggested from this study that the older zircons were derived from Proterozoic landmass and the Korean Peninsula. Zircons from the Kiyama metamorphic rock show a different pattern with ages concentrated at 380-590 Ma. Such zircons are rare in rock samples from the Nagasaki, Kurume and Konoha areas, indicating that Kiyama rocks and a different origin than those from the other three areas. The youngest zircons from the Kiyama, Nagasaki, Kurume and Konoha areas show ages of 382±23 Ma, 238±13 Ma, 249±13 Ma, and 175±4 Ma, respectively, These data mark the upper age limit of their deposition. Since a continuous igneous activity occurred during the period from 300 to 170 Ma in Far East Asia, and the metamorphic age has been close to the zircon age of each area, these youngest ages for the Nagasaki, Kurume and Konoha areas are considered nearly contemporary to the depositional ages. An evaluation of the nature of metamorphism and available ages suggest the possibility that the Nagasaki metamorphic rocks as well as the schist from the Kurume area belong to the Suo zone of the Sangun belt, whereas the metamorphic rocks in the Konoha area may belong to the Ryoke belt or Suo zone of the Sangun belt. (author)

  6. Positron annihilation microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Canter, K F [Brandeis Univ., Waltham, MA (United States)

    1997-03-01

    Advances in positron annihilation microprobe development are reviewed. The present resolution achievable is 3 {mu}m. The ultimate resolution is expected to be 0.1 {mu}m which will enable the positron microprobe to be a valuable tool in the development of 0.1 {mu}m scale electronic devices in the future. (author)

  7. Mass-spectrometric mining of Hadean zircons by automated SHRIMP multi-collector and single-collector U/Pb zircon age dating: The first 100,000 grains

    Science.gov (United States)

    Holden, Peter; Lanc, Peter; Ireland, Trevor R.; Harrison, T. Mark; Foster, John J.; Bruce, Zane

    2009-09-01

    The identification and retrieval of a large population of ancient zircons (>4 Ga; Hadean) is of utmost priority if models of the early evolution of Earth are to be rigorously tested. We have developed a rapid and accurate U-Pb zircon age determination protocol utilizing a fully automated multi-collector ion microprobe, the ANU SHRIMP II, to screen and date these zircons. Unattended data acquisition relies on the calibration of a digitized sample map to the Sensitive High Resolution Ion MicroProbe (SHRIMP) sample-stage co-ordinate system. High precision positioning of individual grains can be produced through optical image processing of a specified mount location. The focal position of the mount can be optimized through a correlation between secondary-ion steering and the spot position on the target. For the Hadean zircon project, sample mounts are photographed and sample locations (normally grain centers) are determined off-line. The sample is loaded, reference points calibrated, and the target positions are then visited sequentially. In SHRIMP II multiple-collector mode, zircons are initially screened (ca. 5 s data acquisition) through their 204Pb corrected 207Pb/206Pb ratio; suitable candidates are then analyzed in a longer routine to obtain better measurement statistics, U/Pb, and concentration data. In SHRIMP I and SHRIMP RG, we have incorporated the automated analysis protocol to single-collector measurements. These routines have been used to analyze over 100,000 zircons from the Jack Hills quartzite. Of these, ca. 7%, have an age greater than 3.8 Ga, the oldest grain being 4372 +/- 6 Ma (2[sigma]), and this age is part of a group of analyses around 4350 Ma which we interpret as the age when continental crust first began to coalesce in this region. In multi-collector mode, the analytical time taken for a single mount with 400 zircons is approximately 6 h; whereas in single-collector mode, the analytical time is ca. 17 h. With this productivity, we can produce

  8. Ion microprobe Sr isotope analysis of carbonates with about 5 {mu}m spatial resolution: An example from an ayu otolith

    Energy Technology Data Exchange (ETDEWEB)

    Sano, Yuji [Center for Advanced Marine Research, Ocean Research Institute, University of Tokyo, Nakano-ku, Tokyo 164-8639 (Japan)], E-mail: ysano@ori.u-tokyo.ac.jp; Shirai, Kotaro [International Coastal Research Center, Ocean Research Institute, University of Tokyo, Otsuchi, Iwate 028-1102 (Japan); Takahata, Naoto; Amakawa, Hiroshi [Center for Advanced Marine Research, Ocean Research Institute, University of Tokyo, Nakano-ku, Tokyo 164-8639 (Japan); Otake, Tsuguo [International Coastal Research Center, Ocean Research Institute, University of Tokyo, Otsuchi, Iwate 028-1102 (Japan)

    2008-08-15

    A high lateral resolution secondary ion mass spectrometer (NanoSIMS NS50 ion microprobe) has been used to measure {sup 87}Sr/{sup 86}Sr ratios in natural CaCO{sub 3} samples. A {approx}2 nA O{sup -} primary beam was used to sputter a 5-7-{mu}m diameter crater on the sample surface and secondary positive ions were extracted for mass analysis using an accelerating voltage of 8 kV and a Mattauch-Herzog geometry. The multi-collector system was adjusted to detect {sup 43}Ca{sup +} (by a detector EM2), {sup 80}Ca{sub 2}{sup +} (EM3), {sup 86}Sr{sup +} (EM4), and {sup 87}Sr{sup +} (EM4b) ions at the same time. Then the magnetic field was scanned for the EM4 to detect {sup 85}Rb{sup +}, {sup 86}Sr{sup +} and {sup 87}Sr{sup +}, while the EM4b can measure {sup 86}Sr{sup +}, {sup 87}Sr{sup +} and {sup 88}Sr{sup +}, respectively. A mass resolution of 3600 at 10% peak height was attained with a flat peak top, while the sensitivity of Sr was about 10 cps/nA/ppm. An aragonite sample (coral skeleton standard; JCp-1) was used as a reference for Sr isotope ratio calibration. Repeated analyses of the JCp-1 show that the {sup 87}Sr/{sup 86}Sr ratio agrees well with the seawater signature within a precision of 0.3 per mille at 2{sigma}, after the series of corrections such as the Ca dimer, {sup 87}Rb, and a mass bias estimated by the {sup 88}Sr/{sup 86}Sr ratio. The method was applied to an otolith (ear-stone) from ayu (Plecoglossus altivelis altivelis) collected from the Yodo river, Japan. Although experimental errors are relatively large, up to 3 per mille at 2{sigma}, the ratios of the core region are higher than the seawater signature while more distal values agree well with seawater. The very outermost part again shows the relatively higher {sup 87}Sr/{sup 86}Sr ratios. The spatial variation of {sup 87}Sr/{sup 86}Sr ratios was consistent with amphidromous migration of the fish, namely, born in the lake and grown in the coastal sea and finally collected in a river.

  9. Ion microprobe Sr isotope analysis of carbonates with about 5 μm spatial resolution: An example from an ayu otolith

    International Nuclear Information System (INIS)

    Sano, Yuji; Shirai, Kotaro; Takahata, Naoto; Amakawa, Hiroshi; Otake, Tsuguo

    2008-01-01

    A high lateral resolution secondary ion mass spectrometer (NanoSIMS NS50 ion microprobe) has been used to measure 87 Sr/ 86 Sr ratios in natural CaCO 3 samples. A ∼2 nA O - primary beam was used to sputter a 5-7-μm diameter crater on the sample surface and secondary positive ions were extracted for mass analysis using an accelerating voltage of 8 kV and a Mattauch-Herzog geometry. The multi-collector system was adjusted to detect 43 Ca + (by a detector EM2), 80 Ca 2 + (EM3), 86 Sr + (EM4), and 87 Sr + (EM4b) ions at the same time. Then the magnetic field was scanned for the EM4 to detect 85 Rb + , 86 Sr + and 87 Sr + , while the EM4b can measure 86 Sr + , 87 Sr + and 88 Sr + , respectively. A mass resolution of 3600 at 10% peak height was attained with a flat peak top, while the sensitivity of Sr was about 10 cps/nA/ppm. An aragonite sample (coral skeleton standard; JCp-1) was used as a reference for Sr isotope ratio calibration. Repeated analyses of the JCp-1 show that the 87 Sr/ 86 Sr ratio agrees well with the seawater signature within a precision of 0.3 per mille at 2σ, after the series of corrections such as the Ca dimer, 87 Rb, and a mass bias estimated by the 88 Sr/ 86 Sr ratio. The method was applied to an otolith (ear-stone) from ayu (Plecoglossus altivelis altivelis) collected from the Yodo river, Japan. Although experimental errors are relatively large, up to 3 per mille at 2σ, the ratios of the core region are higher than the seawater signature while more distal values agree well with seawater. The very outermost part again shows the relatively higher 87 Sr/ 86 Sr ratios. The spatial variation of 87 Sr/ 86 Sr ratios was consistent with amphidromous migration of the fish, namely, born in the lake and grown in the coastal sea and finally collected in a river

  10. Dating of zircon from high-grade rocks: Which is the most reliable method?

    Directory of Open Access Journals (Sweden)

    Alfred Kröner

    2014-07-01

    Full Text Available Magmatic zircon in high-grade metamorphic rocks is often characterized by complex textures as revealed by cathodoluminenscence (CL that result from multiple episodes of recrystallization, overgrowth, Pb-loss and modifications through fluid-induced disturbances of the crystal structure and the original U-Th-Pb isotopic systematics. Many of these features can be recognized in 2-dimensional CL images, and isotopic analysis of such domains using a high resolution ion-microprobe with only shallow penetration of the zircon surface may be able to reconstruct much of the magmatic and complex post-magmatic history of such grains. In particular it is generally possible to find original magmatic domains yielding concordant ages. In contrast, destructive techniques such as LA-ICP-MS consume a large volume, leave a deep crater in the target grain, and often sample heterogeneous domains that are not visible and thus often yield discordant results which are difficult to interpret. We provide examples of complex magmatic zircon from a southern Indian granulite terrane where SHRIMP II and LA-ICP-MS analyses are compared. The SHRIMP data are shown to be more precise and reliable, and we caution against the use of LA-ICP-MS in deciphering the chronology of complex zircons from high-grade terranes.

  11. Proterozoic to Mesozoic evolution of North-West Africa and Peri-Gondwana microplates: Detrital zircon ages from Morocco and Canada

    Science.gov (United States)

    Marzoli, Andrea; Davies, Joshua H. F. L.; Youbi, Nasrrddine; Merle, Renaud; Dal Corso, Jacopo; Dunkley, Daniel J.; Fioretti, Anna Maria; Bellieni, Giuliano; Medina, Fida; Wotzlaw, Jörn-Frederik; McHone, Greg; Font, Eric; Bensalah, Mohamed Khalil

    2017-05-01

    The complex history of assemblage and disruption of continental plates surrounding the Atlantic Ocean is in part recorded by the distribution of detrital zircon ages entrained in continental sedimentary strata from Morocco (Central High Atlas and Argana basins) and Canada (Grand Manan Island, New Brunswick). Here we investigate detrital zircon from the latest Triassic (ca. 202 Ma) sedimentary strata directly underlying lava flows of the Central Atlantic magmatic province or interlayered within them. SHRIMP (Sensitive High-Resolution Ion MicroProbe) and LA-ICP-MS (Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry) U-Pb ages for zircon range from Paleozoic to Archean with a dominant Neoproterozoic peak, and significant amounts of ca. 2 Ga zircon. These ages suggest a prevailing West African (Gondwanan) provenance at all sampling sites. Notably, the Paleoproterozoic zircon population is particularly abundant in central Morocco, north of the High Atlas chain, suggesting the presence of Eburnean-aged rocks in this part of the country, which is consistent with recent geochronologic data from outcropping rocks. Minor amounts of late Mesoproterozoic and early Neoproterozoic zircon ages (ca. 1.1-0.9 Ga) in Moroccan samples are more difficult to interpret. A provenance from Avalonia or Amazonia, as proposed by previous studies is not supported by the age distributions observed here. An involvement of more distal source regions, possibly located in north-eastern Africa (Arabian Nubian Shield) would instead be possible. Paleozoic zircon ages are abundant in the Canadian sample, pointing to a significant contribution from Hercynian aged source rocks. Such a signal is nearly absent in the Moroccan samples, suggesting that zircon-bearing Hercynian granitic rocks of the Moroccan Meseta block were not yet outcropping at ca. 200 Ma. The only Moroccan samples that yield Paleozoic zircon ages are those interlayered within the CAMP lavas, suggesting an increased dismantling

  12. Changes in seasonal climate patterns from 34-4 ka in a Soreq Cave (Israel) speleothem: Sub-annual resolution by ion microprobe and CLFM

    Science.gov (United States)

    Orland, I. J.; Bar-Matthews, M.; Kita, N.; Ayalon, A.; Valley, J. W.

    2009-12-01

    Speleothems provide an important proxy-record of paleoclimate. Isotopic data from calcite-dominated cave formations have been used to identify changes in annual rainfall, monsoon strength, telecommunication of Northern Hemisphere climate aberrations, changes in vegetation cover, and other region-specific paleoclimate time-series over annual to millennial timescales. As more research is devoted to understanding abrupt climate change events, there is a need to develop high-temporal-resolution records from continental regions. However, in most isotopic studies, seasonality information is lost due to technical limitations. This study focuses on a speleothem from the semi-arid Eastern Mediterranean region (Soreq Cave, Israel) where prior research shows that conventional drill-sampling methods permit a temporal resolution of ~10-50 years in speleothem paleoclimate records. The WiscSIMS lab has developed analytical protocols for ion microprobe analysis that yield a precision of ~0.3‰ (2 s.d.) in δ18O from 10 μm-diameter spots, which permit multiple analyses/year in many speleothems. Orland et al. (2009, Quat. Res.) establish the methodology for the current study by identifying seasonal variability using a combination of confocal laser fluorescent microscopy (CLFM) and ion microprobe analysis in a younger (~2-1 ka) Soreq speleothem that has a consistent bright-grading-to-dark fluorescence pattern within each annual band. Further, Orland et al. define a quantitative measure of seasonality, Δ18O, that measures the difference in δ18O between bright and dark fluorescent portions of individual annual growth bands [Δ18O = δ18Odark - δ18Obright]. Smaller values of Δ18O are interpreted to be caused by dry years. The current study employs the aforementioned methods to examine seasonality trends in a sample that covers a much longer time period. We report δ18O from >1000 spots across a radial traverse of Soreq Cave sample 2N matched to imaging of annual growth bands by

  13. Broad Beam and Ion Microprobe Studies of Single-Event Upsets in High Speed 0.18micron Silicon Germanium Heterojunction Bipolar Transistors and Circuits

    Science.gov (United States)

    Reed, Robert A.; Marshall, Paul W.; Pickel, Jim; Carts, Martin A.; Irwin, TIm; Niu, Guofu; Cressler, John; Krithivasan, Ramkumar; Fritz, Karl; Riggs, Pam

    2003-01-01

    structures and map out the spatial sensitivities using the Sandia Focused Heavy Ion Microprobe Facility s Ion Beam Induced Charge Collection (IBICC) technique. Combining the two data sets offers insights into the charge collection mechanisms responsible for circuit level response and provides the first insights into the SEE characteristics of this latest version of IBM s commercial SiGe process.

  14. Detrital zircon ages from southern Norway - implications for the Proterozoic evolution of the southwestern Baltic Shield

    Science.gov (United States)

    Knudsen, T.-L.; Andersen, T.; Whitehouse, M. J.; Vestin, J.

    An ion-microprobe (SIMS) U-Pb zircon dating study on four samples of Precambrian metasediments from the high-grade Bamble Sector, southern Norway, gives the first information on the timing of discrete crust-forming events in the SW part of the Baltic Shield. Recent Nd and Pb studies have indicated that the sources of the clastic metasediments in this area have crustal histories extending back to 1.7 to 2.1Ga, although there is no record of rocks older than 1.6Ga in southern Norway. The analysed metasediments are from a sequence of intercalated, centimetre to 10-metre wide units of quartzites, semi-metapelites, metapelites and mafic granulites. The zircons can be grouped in two morphological populations: (1) long prismatic; (2) rounded, often flattened. The BSE images reveal that both populations consist of oscillatory zoned, rounded and corroded cores (detrital grains of magmatic origin), surrounded by homogeneous rims (metamorphic overgrowths). The detrital zircons have 207Pb/206Pb ages between 1367 and 1939Ma, with frequency maxima in the range 1.85 to 1.70Ga and 1.60 to 1.50Ga. There is no correlation between crystal habit and age of the zircon. One resorbed, inner zircon core in a detrital grain is strongly discordant and gives a composite inner core-magmatic outer core 207Pb/206Pb age of 2383 Ma. Two discrete, unzoned zircons have 207Pb/206Pb ages of 1122 and 1133Ma, representing zircon growth during the Sveconorwegian high-grade metamorphism. Also the μm wide overgrowths, embayments in the detrital cores and apparent ``inner cores'' which represent secondary metamorphic zircon growth in deep embayments in detrital grains, are of Sveconorwegian age. The composite-detrital-metamorphic zircon analyses give generally discordant 206Pb/238U versus 207Pb/235U ratios and maximum 207Pb/206Pb ages of 1438Ma. These data demonstrate the existence of a protocrust of 1.7 to 2.0Ga in the southwestern part of the Baltic Shield, implying a break in the overall westward

  15. Mixed beams for the nuclear microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Saint, A.; Breese, M.B.H.; Legge, G.L.F. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1996-12-31

    Recently the Micro-Analytical Research Centre (MARC) at Melbourne University has developed a technique to provide mixed beams of ions for a magnetically focussed nuclear microprobe. Such a mixed beam is defined as two (or more) beams of different species ions that can quickly and easily be made to have the same magnetic rigidity R{sub m} = (mE/q{sup 2}) and therefore be transported, focused and scanned the same in a magnetic nuclear microprobe. The production of mixed beams in an electrostatically focussed micro- probe have already been demonstrated. This paper will show how mixed beams can be produced on a single-ended accelerator. Indications of how to produce them on a tandem will also be given. Applications of these mixed beams in micro-lithography, scanning transmission ion microscopy (STIM) imaging and ion beam induced charge (IBIC) imaging will also be presented. 3 refs., 3 figs.

  16. Mixed beams for the nuclear microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Saint, A; Breese, M B.H.; Legge, G L.F. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1997-12-31

    Recently the Micro-Analytical Research Centre (MARC) at Melbourne University has developed a technique to provide mixed beams of ions for a magnetically focussed nuclear microprobe. Such a mixed beam is defined as two (or more) beams of different species ions that can quickly and easily be made to have the same magnetic rigidity R{sub m} = (mE/q{sup 2}) and therefore be transported, focused and scanned the same in a magnetic nuclear microprobe. The production of mixed beams in an electrostatically focussed micro- probe have already been demonstrated. This paper will show how mixed beams can be produced on a single-ended accelerator. Indications of how to produce them on a tandem will also be given. Applications of these mixed beams in micro-lithography, scanning transmission ion microscopy (STIM) imaging and ion beam induced charge (IBIC) imaging will also be presented. 3 refs., 3 figs.

  17. Dedicated accelerator and microprobe line

    International Nuclear Information System (INIS)

    Malmqvist, K.G.; Hylten, G.; Hult, M.; Haakansson, K.; Knox, J.M.; Larsson, N.P.O.; Nilsson, C.; Pallon, J.; Schofield, R.; Swietlicki, E.; Tapper, U.A.S.; Yang Changyi

    1993-01-01

    The development of a dedicated facility for nuclear microprobe analysis and the experiences from using it are discussed. The general properties of the present Lund nuclear microprobe will be described and the advantages of using a dedicated accelerator discussed. (orig.)

  18. Characterization of flux-grown Trace-element-doped titanite using the high-mass-resolution ion microprobe (SHRIMP-RG)

    Science.gov (United States)

    Mazdab, F.K.

    2009-01-01

    Crystals of titanite can be readily grown under ambient pressure from a mixture of CaO, TiO2 and SiO2 in the presence of molten sodium tetraborate. The crystals produced are euhedral and prismatic, lustrous and transparent, and up to 5 mm in length. Titanite obtained by this method contains approximately 4300 ppm Na and 220 ppm B contributed from the flux. In addition to dopant-free material, titanite containing trace alkali and alkaline earth metals (K, Sr, Ba), transition metals (Sc, Cr, Ni, Y, Zr, Nb, Hf and Ta), rare-earth elements (REE), actinides (Th, U) and p-block elements (F, S, Cl, Ge, Sn and Pb) have been prepared using the same procedure. Back-scattered electron (BSE) imaging accompanied by ion-microprobe (SHRIMP-RG) analysis confirms significant incorporation of selected trace-elements at structural sites. Regardless of some zonation, the large size of the crystals and broad regions of chemical homogeneity make these crystals useful as experimental starting material, and as matrix-matched trace-element standards for a variety of microbeam analytical techniques where amorphous titanite glass, heterogeneous natural titanite or a non-titanite standard may be less than satisfactory. Trace-element-doped synthetic crystals can also provide a convenient proxy for a better understanding of trace-element incorporation in natural titanite. Comparisons with igneous, authigenic and high-temperature metasomatic titanite are examined. The use of high-mass-resolution SIMS also demonstrates the analytical challenges inherent to any in situ mass-spectrometry-based analysis of titanite, owing to the production of difficult-to-resolve molecular interferences. These interferences are dominated by Ca-Ca, Ca-Ti and Ti-Ti dimers that are significant in the mass range of 80-100, affecting all isotopes of Sr and Zr, as well as 89Y and 93Nb. Methods do exist for the evaluation of interferences by these dimers and of polyatomic interferences on the LREE.

  19. The Melbourne proton microprobe

    International Nuclear Information System (INIS)

    Legge, G.J.F.; McKenzie, C.D.; Mazzolini, A.P.

    1979-01-01

    A scanning proton microprobe is described which operates in ultra-high vacuum with a resolution of ten microns. The operating principles and main features of the design are discussed and the ability of such an instrument to detect trace elements down to a few ppm by mass is illustrated

  20. Preparation and properties of calcium zirconate

    International Nuclear Information System (INIS)

    Dudek, M.; Bucko, M.; Rog, G.

    2001-01-01

    Dense samples of calcium zirconate were prepared. Electrical conductivity of the samples were measured in the temperature range 873 - 1273 K by both the d.c. four probe and the impedance spectroscopy methods. Calcium zirconate with small excess of calcium oxide appeared to be oxygen ion conductor. It was applied as an electrolyte in solid-state galvanic cells. (author)

  1. The upgraded Amsterdam nuclear microprobe

    International Nuclear Information System (INIS)

    Vis, R.D.; Kramer, J.L.A.M.; Tros, G.H.J.; Langevelde, F. van; Mars, L.

    1993-01-01

    The improvement of the facilities at our University consists of three phases. In phase 1, a 1.7 MV NEC tandem-Pelletron accelerator has been installed. The accelerator serves as injector for two beam lines, subsequently for macro- and micro-analysis. Moreover, an interconnection has been made with a beam line from our 400 kV high voltage Van de Graaff accelerator in order to enable injection of these very intense low energy beams in these two lines. Apart from new vacuum equipment and conventional beam steering and focussing elements, the experimental facilities are replaced from the cyclotron experimental hall to the newly organised experimental hall. In the phases 2 and 3, which are not yet completed, a second ion source for the Pelletron and a new or extended focussing unit for the microprobe will complete the overall operation. (orig.)

  2. High resolution techniques using scanning proton microprobe (SPM)

    International Nuclear Information System (INIS)

    Cholewa, M.; Saint, A.; Prawer, S.; Laird, J.S.; Legge, G.J.F.; Bardos, R.A.; Moorhead, G.F.; Taylor, G.N.; Stuart, S.A.; Howard, J.

    1994-01-01

    The very high resolution (down to 50 nm) achieved with low beam currents (fA) in a scanning ion microprobe have lead to many nondestructive techniques of microanalysis. This paper discusses recent developments and applications in the use of 3-D STIM (scanning transmission ion microscopy) Tomography, channeling STIM and IBIC (ion beam induced charge). (orig.)

  3. Applications of nuclear microprobes in the semiconductor industry

    International Nuclear Information System (INIS)

    Takai, M.

    1996-01-01

    Possible nuclear microprobe applications in semiconductor industries are discussed. A unique technique using soft-error mapping and ion beam induced current measurements for reliability testing of dynamic random access memories such as soft-error immunity and noise carrier suppression has been developed for obtaining design parameters of future memory devices. Nano-probes and small installation areas are required for the use of microprobes in the semiconductor industry. Issues arising from microprobe applications such as damage induced by the probe beam are clarified. (orig.)

  4. Zircon-rutile-ilmenite froth flotation process

    International Nuclear Information System (INIS)

    Schmidt, R.; Denham, D.L. Jr.

    1992-01-01

    This patent describes a method for separating a mixture of minerals comprising at least zircon, ilmenite and rutile. It comprises adding an acid solution to the mixture to acidify to a pH of between about 2.0 and 6.0; adding starch to the mixture to depress the ilmenite and the rutile; adding a source of fluoride ions to the mixture to provide a negative surface charge on the zircon surface to activate the zircon; adding an amine cationic collector to the mixture to float the activated zircon; subjecting the mixture containing the added acid solution, the fluoride ions, the starch and the cationic collector, to froth flotation; and withdrawing a float product comprising the zircon and a sink product comprising the ilmenite and rutile

  5. In situ Raman spectroscopic studies on concentration change of electrolyte salt in a lithium ion model battery with closely faced graphite composite and LiCoO2 composite electrodes by using an ultrafine microprobe

    International Nuclear Information System (INIS)

    Yamanaka, Toshiro; Nakagawa, Hiroe; Tsubouchi, Shigetaka; Domi, Yasuhiro; Doi, Takayuki; Abe, Takeshi; Ogumi, Zempachi

    2017-01-01

    The concentration of ions in the electrolyte solution in lithium ion batteries changes during operation, reflecting the resistance to ion migration and the positions of diffusion barriers. The change causes various negative effects on the performance of batteries. Thus, it is important to elucidate how the concentration changes during operation. In this work, the concentration change of ions in the electrolyte solution in deep narrow spaces in a realistic battery was studied by in situ ultrafine microprobe Raman spectroscopy. Graphite composite and LiCoO 2 composite electrodes, which are the most commonly used electrodes in practical batteries, were placed facing each other and their distance was set to 80 μm, which is close to the distance between electrodes in practical batteries. After repeated charge/discharge cycles, the concentration of ions increased and decreased greatly during charging and discharging, respectively. The maximum concentration was more than three-times higher than the minimum concentration. The rate of changes in concentration increased almost linearly with increase in current density. The results have important implications about concentration changes of ions occurring in practical batteries.

  6. Automated electron microprobe

    International Nuclear Information System (INIS)

    Thompson, K.A.; Walker, L.R.

    1986-01-01

    The Plant Laboratory at the Oak Ridge Y-12 Plant has recently obtained a Cameca MBX electron microprobe with a Tracor Northern TN5500 automation system. This allows full stage and spectrometer automation and digital beam control. The capabilities of the system include qualitative and quantitative elemental microanalysis for all elements above and including boron in atomic number, high- and low-magnification imaging and processing, elemental mapping and enhancement, and particle size, shape, and composition analyses. Very low magnification, quantitative elemental mapping using stage control (which is of particular interest) has been accomplished along with automated size, shape, and composition analysis over a large relative area

  7. Beam developments for the Harwell microprobe system

    International Nuclear Information System (INIS)

    Read, P.M.; Cookson, J.A.; Alton, G.D.

    1986-01-01

    A consequence of the rapid development of micron and submicron size electronic devices is the diminished applicability of high energy ion microprobes with their present resolution limitations to the study of such components. Although submicron beams have been reported the available beam current is barely sufficiently for PIXE and is not adequate for RBS. This lack of lateral resolution is due to low beam brightness at the microprobe object and aberrations in the focusing elements. As part of a program to address these problems the Harwell microprobe lens has been relocated on a new 5 MV Laddertron accelerator. The increased brightness and improved stability of this facility has so far led to a reduction in beam size from 3 x 3 μm 2 to about 2 x 2 μm 2 . The feasibility of using a liquid metal ion source has been examined with a view to achieving more substantial increases in brightness. While such sources have brightness approximately 10 5 times greater than conventional gaseous sources the highly divergent nature of the beam presents problems for the beam transport system. The use of a liquid metal source on the accelerator has been successfully demonstrated but it indicates the need for a special low aberration injection lens if brightness is to be maintained

  8. New generation nuclear microprobe systems

    International Nuclear Information System (INIS)

    Jamieson, David N.

    2001-01-01

    Over the past 20 years, the minimum probe size for nuclear microscopy has stayed around 1 μm with only a few groups reporting a sub-micron probe size around 0.5 μm. No breakthroughs in nuclear microprobe design have been forthcoming to produce dramatic improvements in spatial resolution. The difficulties of breaking the constraints that are preventing reduction of the probe size have been well recognised in the past. Over the past 5 years it has become clear that some of these constraints may not be as limiting as first thought. For example, chromatic aberration clearly is not as significant as implied from first-order ion optics calculations. This paper reviews the constraints in view of the increased understanding of the past 5 years and looks at several new approaches, presently being evaluated in Melbourne and elsewhere, on how to make progress. These approaches include modified RF ion sources for improved beam brightness and exploitation of relaxed constraints on some lens aberrations allowing the use of high demagnification probe forming lens systems

  9. SHRIMP U-Pb zircon dating of Pedras Grandes Suite, southern Santa Catarina State, Brazil

    Directory of Open Access Journals (Sweden)

    Andréa R. Jelinek

    2005-03-01

    Full Text Available Two major magmatic pulses of the granitic Florianópolis Batholith in Santa Catarina State, southern Brazil, occurred between 613±5Ma and 595±5 Ma, during the Neoproterozoic Brasiliano Cycle. These ages were obtained by U-Pb isotopic determinations with the sensitive high mass-resolution ion microprobe on igneous zircons from Pedras Grandes Suite in Santa Catarina State. Euhedral zircons remained unaltered close to a fluorite vein deposited at 180?C or more. These ages suggest a northern limit for the Pedras Grandes Suite, explaining the spatial relationship between the fluorite veins and the source rock.Dois dos principais pulsos da atividade granítica no Batólito Florianópolis em Santa Catarina ocorreram entre 613 ±5 Ma e 595 ±5 Ma, durante o Neoproterozóico do Ciclo Brasiliano. Estas idades foram obtidas a partir dedeterminações isotópicas U-Pb em cristais de zircão da Suite Pedras Grandes por "Sensitive high-resolution íon microprobe" - SHRIMP II. Os cristais de zircão permaneceram inalterados mesmo mediante condições hidrotermais com temperaturas iguais e, até mesmo, superiores a 180ºC. Estas idades sugerem a delimitação norte do Maciço Pedras Grandes, explicando a relação espacial existente entre os filões de fluorita e a rocha fonte destas mineralizações.

  10. Ion microprobe assessment of the heterogeneity of Mg/Ca, Sr/Ca and Mn/Ca ratios in Pecten maximus and Mytilus edulis (bivalvia shell calcite precipitated at constant temperature

    Directory of Open Access Journals (Sweden)

    P. S. Freitas

    2009-07-01

    Full Text Available Small-scale heterogeneity of biogenic carbonate elemental composition can be a significant source of error in the accurate use of element/Ca ratios as geochemical proxies. In this study ion microprobe (SIMS profiles showed significant small-scale variability of Mg/Ca, Sr/Ca and Mn/Ca ratios in new shell calcite of the marine bivalves Pecten maximus and Mytilus edulis that was precipitated during a constant-temperature culturing experiment. Elevated Mg/Ca, Sr/Ca and Mn/Ca ratios were found to be associated with the deposition of elaborate shell features, i.e. a shell surface stria in P. maximus and surface shell disturbance marks in both species, the latter a common occurrence in bivalve shells. In both species the observed small-scale elemental heterogeneity most likely was not controlled by variable transport of ions to the extra-pallial fluid, but by factors such as the influence of shell organic content and/or crystal size and orientation, the latter reflecting conditions at the shell crystal-solution interface. In the mid and innermost regions of the P. maximus shell the lack of significant small-scale variation of Mg/Ca ratios, which is consistent with growth at constant temperature, suggest a potential application as a palaeotemperature proxy. Cross-growth band element/Ca ratio profiles in the interior of bivalve shells may provide more promising palaeo-environmental tools than sampling from the outer region of bivalve shells.

  11. Conversion of fuel hulls to zirconate ion exchangers for stabilization of wastes from the thorium fuel cycle

    International Nuclear Information System (INIS)

    Levine, H.S.

    1978-01-01

    A conceptual reprocessing and waste management scheme for Zircaloy clad ThO 2 fuel was formulated to eliminate problems associated with concurrent dissolution of fuel and cladding in the conventional chop-leach headend step. These problems are avoided by use of a modified headend step to form oxide fuel and cladding process streams. A chlorinating agent then converts the cladding hulls and adhering fuel into volatile and nonvolatile chloride fractions. The former product is processed, by use of the Zircaloy conversion process, to form an inorganic ion exchange material and combined with HLLW from subsequent fuel reprocessing to form a stable and refractory waste form. The nonvolatile chloride fraction would be recovered, processed to remove chloride ions, and recombined with the main oxide fuel process stream for further treatment by use of the Thorex process

  12. Multidimensional elemental analysis with the Sandia nuclear microprobe

    International Nuclear Information System (INIS)

    Doyle, B.L.

    1988-01-01

    It is well known that many of the ion beam analysis techniques such as Rutherford backscattering spectrometry, elastic recoil detection, resonant and nonresonant nuclear reaction analysis can be used to nondestructively obtain concentration depth profiles of elements in solids. When these techniques are combined with the small beam spot capabilities of a scanned nuclear microprobe, sample composition can be determined in up to three dimensions. This paper will review the various procedures used to collect and analyze multidimensional data using the Sandia nuclear microprobe. In addition, examples of how these data are being used in the study of materials will be shown. (author)

  13. Zircon dating of Devonian-Carboniferous rocks from the Bombala area, New South Wales

    International Nuclear Information System (INIS)

    Sircombe, K.N.; McQueen, K.G.

    2000-01-01

    Zircons from two igneous and two sedimentary units in the Bombala area of southeastern New South Wales have been examined by the sensitive high resolution ion microprobe (SHRIMP) to establish a time frame in which to interpret these rocks. Previous studies have correlated these rocks with Late Devonian units of the south coast, solely upon the basis of stratigraphy and lithology as palaeontological evidence was absent. The two igneous units are the Hospital Porphyry and Paradise Porphyry occurring beneath the sedimentary units. Both give a Frasnian age that can be correlated with the Boyd Volcanic Complex. The sedimentary samples are from the basal and upper sections of the Rosemeath Formation, a fluvial 'redbed' consisting of conglomerate, coarse sandstone, and associated red siltstone and mudstone. Detrital zircons from the basal conglomeratic section at Kilbrechin indicate a dominant provenance from local Silurian granites and volcanics and a maximum depositional age that can be correlated with the Frasnian-Famennian Merrimbula Group. However, detrital zircons from the upper coarse sandstone section of the Rosemeath Formation at Endeavour Lookout challenge the positive correlation trend with a lack of Silurian-age grains and a presence of grains ranging from Late Devonian to Early Carboniferous in age. These results imply either that the south coast correlation is not valid for the upper sequences, or that the Merrimbula Group sequences also extend upward into the Carboniferous. The general coarseness of the Rosemeath Formation also suggests a relatively local provenance. No Early Carboniferous source is known in the immediate vicinity suggesting that Early Carboniferous igneous activity in this region of the Lachlan Orogen may have been more extensive than is currently realised. Copyright (1999) Geological Society of Australia

  14. Microprobe analysis in human pathology

    International Nuclear Information System (INIS)

    Baker, D.; Kupke, K.G.; Ingram, P.; Roggli, V.L.; Shelburne, J.D.

    1985-01-01

    This tutorial paper reviews the literature on the application of microprobe analysis to practical problems in diagnostic human pathology. The goal is to allow the reader ready access to the literature on specific clinical problems. Specimen preparation and commonly encountered artifacts are also considered. It is concluded that energy dispersive x-ray microanalysis and back-scattered electron imaging are at present the most generally useful microprobe techniques for clinical work, and are no longer solely research tools. The findings often have diagnostic, therapeutic, and/or legal implications. 332 references

  15. Microprobe analysis of human fibroblasts

    International Nuclear Information System (INIS)

    Allan, G.L.; Zhu, J.; Legge, G.J.F.

    1985-01-01

    The Melbourne Proton Microprobe has been used to study the copper content in human skin fibroblast cells derived from patients with the genetic disease Menkes Syndrome. Both normal and diseased cells have been studied to investigate any elemental differences occurring between the two cell types. This paper details the preparatory techniques necessary for individual cell analysis and presents the elemental information with a new three dimensional contour mapping technique. These maps are used to highlight elemental differences between normal and mutant fibroblasts. The work also confirms the expected copper excess found in the Menkes cell and indicates that the microprobe can be used for rapid identification of a Menkes carrier

  16. Zircon U-Pb age of the Pescadero felsite: A late Cretaceous igneous event in the forearc, west-central California Coast Ranges

    Science.gov (United States)

    Ernst, W.G.; Martens, U.C.; McLaughlin, R.J.; Clark, J.C.; Moore, Diane E.

    2011-01-01

    Weathered felsite is associated with the late Campanian-Maastrichtian Pigeon Point Formation near Pescadero, California. Poorly exposed, its age and correlation are uncertain. Is it part of the Pigeon Point section west of the San Gregorio-Hosgri fault? Does it rest on Nacimiento block basement? Is it dextrally offset from the Oligocene Cambria Felsite, ~185 km to the southeast? Why is a calc-alkaline hypabyssal igneous rock intrusive into the outboard accretionary prism? To address these questions, we analyzed 43 oscillatory-zoned zircon crystals from three incipiently recrystallized pumpellyite ?? prehnite ?? laumontite-bearing Pescadero felsite samples by sensitive high-resolution ion microprobe-reverse geometry (SHRIMPRG) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) techniques. Thirty-three zircons gave late Mesozoic U-Pb ages, with single-grain values ranging from 81 to 167 Ma; ten have pre-Mesozoic, chiefl y Proterozoic ages. A group of the four youngest Pescadero zircons yielded an apparent maximum igneous age of ca. 86-90 Ma. Refl ecting broad age scatter and presence of partly digested sandstone inclusions, we interpret the rest of the zircons (perhaps all) as xenocrysts. Twenty-three zircons were separated and analyzed from two samples of the similar Cambria Felsite, yielding a unimodal 27 Ma U-Pb age. Clearly, the origin of the Upper Oligocene Cambria Felsite is different from that of the Upper Cretaceous Pescadero felsite; these rocks are not correlated, and do not constrain displacement along the San Gregorio-Hosgri fault. Peak ages differ slightly, but relative probability curves for Mesozoic and pre-Mesozoic Pescadero zircons compare well, for example, with abundant U-Pb age data for detrital zircons from Franciscan metaclastic strata ~100 km to the east in the Diablo Range- San Francisco Bay area, San Joaquin Great Valley Group turbidites, Upper Cretaceous Nacimiento block Franciscan strata, and Upper Cretaceous

  17. The 3.5 Ga granulites of the Bug polymetamorphic complex, Ukraine (U-Pb SHRIMP-II zircon data)

    Science.gov (United States)

    Lobach-Zhuchenko, Svetlana; Kaulina, Tatiana; Baltybaev, Shauket; Yurchenko, Anastasija; Balagansky, Victor; Skublov, Sergei; Sukach, Vitaliji

    2014-05-01

    and Cpx). Zircon U-Pb isotopic analysis was carried out using SHRIMP II ion microprobe technique at the Isotopic Centre of VSEGEI, St.-Petersburg. Six transparent grains of the (1) group form a discordia line with Concordia intercepts at 3499+/-33 Ma (and 2638+/-240 Ma (MSWD=2.3). According to internal textures and chemical composition of zircons their formation is associated with granulite metamorphism. The 207 Pb/ 206 Pb data for 11 grains from (3) group are highly variable in age from 3330+/-5 to 2356+/-7 Ma indicating isotopic disturbance. They do not form an isochrone, thus reliable determination of their age is not yet possible. Thus, the oldest granulitic event at 3499 ± 33 Ma has been identified and justified for rocks of the Bug polymetamorphic granulite complex. Recognition of this oldest granulite metamorphism proved possible due to preserved isotopic and geochemical features of zircon. The work was financially supported by program ONZ - 6.

  18. Deciphering igneous and metamorphic events in high-grade rocks of the Wilmington complex, Delaware: Morphology, cathodoluminescence and backscattered electron zoning, and SHRIMP U-Pb geochronology of zircon and monazite

    Science.gov (United States)

    Aleinikoff, J.N.; Schenck, W.S.; Plank, M.O.; Srogi, L.A.; Fanning, C.M.; Kamo, S.L.; Bosbyshell, H.

    2006-01-01

    High-grade rocks of the Wilmington Complex, northern Delaware and adjacent Maryland and Pennsylvania, contain morphologically complex zircons that formed through both igneous and metamorphic processes during the development of an island-arc complex and suturing of the arc to Laurentia. The arc complex has been divided into several members, the protoliths of which include both intrusive and extrusive rocks. Metasedimentary rocks are interlayered with the complex and are believed to be the infrastructure upon which the arc was built. In the Wilmingto n Complex rocks, both igneous and metamorphic zircons occur as elongate and equant forms. Chemical zoning, shown by cathodoluminescence (CL), includes both concentric, oscillatory patterns, indicative of igneous origin, and patchwork and sector patterns, suggestive of metamorphic growth. Metamorphic monazites are chemically homogeneous, or show oscillatory or spotted chemical zoning in backscattered electron images. U-Pb geochronology by sensitive high resolution ion microprobe (SHRIMP) was used to date complexly zoned zircon and monazite. All but one member of the Wilmington Complex crystallized in the Ordovician between ca. 475 and 485 Ma; these rocks were intruded by a suite of gabbro-to-granite plutonic rocks at 434 ?? Ma. Detrital zircons in metavolcanic and metasedimentary units were derived predominantly from 0.9 to 1.4 Ga (Grenvillian) basement, presumably of Laurentian origin. Amphibolite to granulite facies metamorphism of the Wilmington Complex, recorded by ages of metamorphic zircon (428 ?? 4 and 432 ?? 6 Ma) and monazite (429 ?? 2 and 426 ?? 3 Ma), occurred contemporaneously with emplacement of the younger plutonic rocks. On the basis of varying CL zoning patterns and external morphologies, metamorphic zircons formed by different processes (presumably controlled by rock chemistry) at slightly different times and temperatures during prograde metamorphism. In addition, at least three other thermal episodes are

  19. Microprobe channeling analysis of pyrite crystals

    International Nuclear Information System (INIS)

    Jamieson, D.N.; Ryan, C.G.

    1992-01-01

    Nuclear microprobe analysis has provided much useful information about the composition of microscopic inclusions in minerals, mainly through the use of Particle Induced X-ray Emission (PIXE). However this technique, while powerful, does not provide any direct information about the chemical state, in particular the lattice location, of the elements in the mineral. This information is often of crucial importance in understanding the ore genesis. The technique of ion channeling may be used to identify lattice location, but many minerals occur as microscopic crystals. Therefore it is necessary to utilize a nuclear microprobe with the technique of Channeling Contrast Microscopy (CCM). As many minerals contain interesting trace elements, it is necessary to measure both the yield of backscattered particles and the induced x-rays to get a clear picture of the lattice location of the elements in the crystal. CCM with PIXE was used to analyse natural pyrite crystals containing a variety of substitutional and non-substitutional elements and natural pyrite crystals from a gold bearing ore. In the latter case, evidence was obtained for two habits for Au in the 400 μm crystals: one as inclusions of Au rich minerals, the other substituted on the pyrite lattice sites. 31 refs., 3 tabs., 6 figs

  20. Detrital zircon provenance from three turbidite depocenters of the Middle-Upper Triassic Songpan-Ganzi complex, central China: Record of collisional tectonics, erosional exhumation, and sediment production

    Science.gov (United States)

    Weislogel, A.L.; Graham, S.A.; Chang, E.Z.; Wooden, J.L.; Gehrels, G.E.

    2010-01-01

    To test the idea that the voluminous upper Middle to Upper Triassic turbidite strata in the Songpan-Ganzi complex of central China archive a detrital record of Dabie ultrahigh-pressure (UHP) terrane unroofing, we report 2080 single detrital U-Pb zircon ages by sensitive high-resolution ion microprobe-reverse geometry (SHRIMP-RG) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) analysis from 29 eastern Songpan-Ganzi complex sandstone samples. Low (Th/U zircons, consistent with crystallization under UHP conditions, are rare in eastern Songpan-Ganzi complex zircon, and U-Pb ages of low Th/U zircons are incompatible with a Dabie terrane source. An unweighted pair group method with arithmetic mean nearest-neighbor analysis of Kolmogorov-Smirnov two-sample test results reveals that the eastern Songpan-Ganzi complex is not a single contiguous turbidite system but is instead composed of three subsidiary depocenters, each associated with distinct sediment sources. The northeastern depocenter contains zircon ages characterized by Paleozoic and bimodally distributed Precambrian zircon populations, which, together with south-to southeast-directed paleocurrent data, indicate derivation from the retro-side of the Qinling-Dabie (Q-D) collisional orogen wedge. In the central depocenter, the dominantly Paleozoic detrital zircon signature and south-to southwest-oriented paleocurrent indicators reflect a profusion of Paleozoic zircon grains. These data are interpreted to reflect an influx of material derived from erosion of Paleozoic supra-UHP rocks of the Dabie terrane in the eastern Qinling-Dabie orogen, which we speculate may have been enhanced by development of a monsoonal climate. This suggests that erosional unroofing played a significant role in the initial phase of UHP exhumation and likely influenced the petrotectonic and structural evolution of the Qinling-Dabie orogen, as evidenced by compressed Triassic isotherms/grads reported in the Huwan

  1. Role of zircon in tracing crustal growth and recycling

    Science.gov (United States)

    Compston, W.; Williams, I. S.; Armstrong, R. A.; Claoue-Long, J. C.; Kinny, P. D.; Foster, J. J.; Kroener, A.; Pidgeon, R. T.; Myers, J. S.

    Single crystal ion probe ages of zircons is discussed, which allow much better time resolution compared to other geochronological methods, although the technique is not without problems. Rocks from two areas that contain composite zircon populations, including true magmatic zircons as well as a variety of xenocrystic types are described. It is often difficult to distinguish these; xenocrystic zircons, for example, cannot always be identified on the basis of morphology alone. Additional evidence is needed before making age interpretations. Evidence is also presented of zircon growth long after the original time of crystallization, in some cases apparently at temperatures less than 300 C. The spectacular discovery of 4.1 to 4.2 Ga detrital zircons in metaquartzites from the Mount Narryer area of Western Australia is described. Similar zircons with ages as old as 4276 Ma have been found in the nearby Jack Hills area. The source areas or parent lithologies of these zircons have not yet been determined, but the author expects that they may be unrecognized or buried antecedents of the K rich Narryer gneisses. U or Th concentrations of zircon cannot be used to discriminate between felsic and mafic source rocks.

  2. Neoproterozoic igneous complex emplaced along major tectonic boundary in the Kaoko Belt (NW Namibia): ion probe and LA-ICP-MS dating of magmatic and metamorphic zircons

    Czech Academy of Sciences Publication Activity Database

    Konopásek, J.; Košler, J.; Tajčmanová, L.; Ulrich, Stanislav; Kitt, S. L.

    2008-01-01

    Roč. 165, č. 1 (2008), s. 153-166 ISSN 0016-7649 Institutional research plan: CEZ:AV0Z30120515 Keywords : boundary igneous complex * Kaoko Belt * zircon Subject RIV: DB - Geology ; Mineralogy Impact factor: 2.797, year: 2008

  3. Ion-microprobe measurements of Mg, Ca, Ti and Fe isotopic ratios and trace element abundance in hibonite-bearing inclusions in primitive meteorites

    International Nuclear Information System (INIS)

    Fahey, A.J.

    1988-01-01

    This thesis reports the isotopic abundances of Mg, Ca, and Ti and rare earth element (REE) abundances in 19 hibonite-bearing inclusions from primative meteorites. The isotopic ratios of Fe were measured in one of the samples, Lance HH-1. These measurements were made by means of secondary ion mass spectrometry (CAMECA IMS-3f). The novel hardware and software developments that made this work possible are described in detail. The samples were studied in thin section in order to investigate the relationship between the inclusions and their mineralogical environments. Inclusions from a number of different meteorites, specifically, Mighei, Murray, Murchison, Lance, Efremovka, Vigarano, Qingzhen, Dhajala, and Semarkona, were studied. The isotopes of Ca and Ti show large and correlated abundance anomalies in their most neutron-rich isotopes, 48 Ca and 50 Ti. The largest anomalies among the samples studied here are in the Murray inclusion MY-F6, with a 4.6% deficit in 48 Ca and a 5.2% deficit in 50 Ti, and Lance HH-1, with 3.3% and 6.0% deficits in 48 Ca and 50 Ti respectively. Correlated excesses of 48 Ca and 50 Ti, up to 2.4% and 1.4% respectively, are found in some other samples studied here. The fact that there is a correlation of isotopic anomalies in two different elements is clear evidence for a nucleosynthetic origin of these effects. Various possibilities for the origin of these isotopic anomalies are discussed and it is shown that a Cosmic Chemical Memory-like model of the incomplete mixing of dust grains from one or several supernovae is sufficient to explain the data. Magnesium isotopes show excesses of 26 Mg, attributable to the in-situ decay of 26 Al, in 7 of these inclusions

  4. Microprobe PIXE analysis and EDX analysis on the brain of patients with Alzheimer's disease

    International Nuclear Information System (INIS)

    Yumoto, S.; Horino, Y.; Mokuno, Y.; Fujii, K.; Kakimi, S.; Mizutani, T.; Matsushima, H.; Ishikawa, A.

    1996-01-01

    To investigate the cause of Alzheimer's disease (senile dementia of Alzheimer's disease type), we examined aluminium (Al) in the brain (hippocampus) of patients with Alzheimer's disease using heavy ion (5 MeV Si 3+ ) microprobe particle-induced X-ray emission (PIXE) analysis. Heavy ion microprobes (3 MeV Si 2+ ) have several times higher sensitivity for Al detection than 2 MeV proton microprobes. We also examined Al in the brain of these patients by energy dispersive X-ray spectroscopy (EDX). (1) Al was detected in the cell nuclei isolated from the brain of patients with Alzheimer's disease using 5 MeV Si 3+ microprobe PIXE analysis, and EDX analysis. (2) EDX analysis demonstrated high levels of Al in the nucleolus of nerve cells in frozen sections prepared from the brain of these patients. Our results support the theory that Alzheimer's disease is caused by accumulation of Al in the nuclei of brain cells. (author)

  5. 7th international conference on Nuclear microprobe technology and applications

    International Nuclear Information System (INIS)

    2000-01-01

    This colloquium gives an up-to-date report on the continuously advancing applications and development of microbeam technology. It presents abstracts and oral contributions in the following domains: microprobes facilities, analysis techniques, imaging techniques, micro-ion beam modification of materials, microelectronics, applications in Material Sciences in Biology in Medicine in earth and planetary Sciences in environment in art in archaeology, alternative techniques. (A.L.B.)

  6. Resolving the age of Wilson Creek Formation tephras and the Mono Lake excursion using high-resolution SIMS dating of allanite and zircon rims

    Science.gov (United States)

    Vazquez, J. A.; Lidzbarski, M. I.

    2012-12-01

    Sediments of the Wilson Creek Formation surrounding Mono Lake preserve a high-resolution archive of glacial and pluvial responses along the eastern Sierra Nevada due to late Pleistocene climate change. An absolute chronology for the Wilson Creek stratigraphy is critical for correlating the paleoclimate record to other archives in the western U.S. and the North Atlantic region. However, multiple attempts to date the Wilson Creek stratigraphy using carbonates and interbedded rhyolitic tephras yield discordant 14C and 40Ar/39Ar results due to open-system effects, carbon reservoir uncertainties, as well as abundant xenocrysts entrained during eruption. Ion microprobe (SIMS) 238U-230Th dating of the final increments of crystallization recorded by allanite and zircon autocrysts from juvenile pyroclasts yields ages that effectively date eruption of key tephra beds and resolve age uncertainties about the Wilson Creek stratigraphy. To date the final several micrometers of crystal growth, individual allanite and zircon crystals were embedded in soft indium to allow sampling of unpolished rims. Isochron ages derived from rims on coexisting allanite and zircon (± glass) from hand-selected pumiceous pyroclasts delimit the timing of Wilson Creek sedimentation between Ashes 7 and 19 (numbering of Lajoie, 1968) to the interval between ca. 27 to ca. 62 ka. The interiors of individual allanite and zircon crystals sectioned in standard SIMS mounts yield model 238U-230Th ages that are mostly hydrologic responses in the Sierra Nevada and Mono Basin to climate change, with intervals of lake filling and glacial-snowpack melting that are in phase with peaks in spring insolation. Moreover, the results demonstrate that high-spatial resolution SIMS dating of accessory mineral rims is an alternative and promising approach for resolving the depositional ages of silicic tephras containing minerals that crystallized over protracted intervals or that are plagued by incorporation of xenocrysts

  7. High current pulsed positron microprobe

    International Nuclear Information System (INIS)

    Howell, R.H.; Stoeffl, W.; Kumar, A.; Sterne, P.A.; Cowan, T.E.; Hartley, J.

    1997-01-01

    We are developing a low energy, microscopically focused, pulsed positron beam for defect analysis by positron lifetime spectroscopy to provide a new defect analysis capability at the 10 10 e + s -l beam at the Lawrence Livermore National Laboratory electron linac. When completed, the pulsed positron microprobe will enable defect specific, 3-dimensional maps of defect concentrations with sub-micron resolution of defect location. By coupling these data with first principles calculations of defect specific positron lifetimes and positron implantation profiles we will both map the identity and concentration of defect distributions

  8. Peculiar Feldspar And Quartz Inclusions Within Zircons From Anorthosites, North Eastern Desert, Egypt

    Science.gov (United States)

    Eliwa, H. A.; Dawoud, M. I.; Khalaf, I. M.; Negendank, J. F.; Itaya, T.

    2004-12-01

    Zircons from three anorthosite outcrops along Wadi Dib area, north Eastern Desert of Egypt contain abundant and conspicuous inclusions of quartz, feldspar, amphibole and apatite. These anorthosites, as (50-100m thick) layers, represent the top of mafic-ultramafic intrusions exhibiting rhythmic layering visible by reputation of melanocratic and leucocratic layers. Field and microscopic studies exhibit that these anorthosites were affected by the action of residual magmatic solutions associated with the late stage crystallization of the younger granites, which modified their mineralogical composition. They are composed totally of plagioclase with subordinate amount of clinoenstatite, augite, amphibole, biotite, K-feldspar, and quartz. Accessories are magnetite, ilmenite, apatite and zircon. The abundance and the mode of occurrence of K-feldspar, quartz, and biotite with apatite and zircon among the megacrysts suggest their formation is ascribed to the interaction with the residual solutions. The microprobe data exhibit difference between feldspar and amphiboles contained herein zircons and those as anorthosite mineral constituents. The genetic relationship between zircons and their inclusions suggests later growth of zircons than inclusions and most probably at the final stage of rock modification. Zircons are magmatic and found in the interstitial feldspar and quartz among plagioclase megacrysts in aggregates or as individual grains. The microscopic and SEM images investigation exhibit that most zircons are subhedral to euhedral equant and prismatic crystals. Most zircons have same range of crystal morphologies and internal growth structures with predominance of prism /{100/} and pyramid /{101/} and occasionally prism /{110/} and pyramid /{111/}. No evidences for poly-faceted grains, inherited cores or later overgrowths were detected. CL images distinguished zircons with visible core-rim structures and others with regular and continuous growth zones contained herein

  9. Electron Backscatter Diffraction (EBSD) Analysis and U-Pb Geochronology of the Oldest Lunar Zircon: Constraining Early Lunar Differentiation and Dating Impact-Related Deformation

    Science.gov (United States)

    Timms, Nick; Nemchin, Alexander; Grange, Marion; Reddy, Steve; Pidgeon, Bob; Geisler, Thorsten; Meyer, Chuck

    2009-01-01

    The evolution of the early moon was dominated by two processes (i) crystallization of the Lunar Magma Ocean (LMO) and differentiation of potassium-rare earth element-phosphorous-rich residual magma reservoir referred to as KREEP, and (ii) an intense meteorite bombardment referred to as lunar cataclysm . The exact timing of these processes is disputed, and resolution relies on collection and interpretation of precise age data. This study examines the microstructure and geochronology of zircon from lunar impact breccias collected during the Apollo 17 mission. A large zircon clast within lunar breccia 72215,195 shows sector zoning in optical microscopy, cathodoluminescence (CL) imaging and Raman mapping, and indicates that it was a relict fragment of a much larger magmatic grain. Sensitive high resolution ion microprobe (SHRIMP) U-Pb analysis of the zircon shows that U and Th concentration correlate with sector zoning, with darkest CL domains corresponding with high-U and Th (approx.150 and approx.100 ppm respectively), and the brightest-CL sectors containing approx.30-50 ppm U and approx.10-20 ppm Th. This indicates that variations in optical CL and Raman properties correspond to differential accumulation of alpha-radiation damage in each sector. Electron backscatter diffraction (EBSD) mapping shows that the quality of electron backscatter patterns (band contrast) varies with sector zoning, with the poorest quality patterns obtained from high-U and Th, dark-CL zones. EBSD mapping also reveals a deformation microstructure that is cryptic in optical, CL and Raman imaging. Two orthogonal sets of straight discrete and gradational low-angle boundaries accommodate approx.12 misorientation across the grain. The deformation bands are parallel to the crystallographic {a}-planes of the zircon, have misorientation axes parallel to the c-axis, and are geometrically consistent with formation by dislocation creep associated with {010} slip. The deformation bands are unlike curved

  10. SHRIMP-RG U-Pb isotopic systematics of zircon from the Angel Lake orthogneiss, East Humboldt Range, Nevada: Is this really archean crust?

    Science.gov (United States)

    Premo, Wayne R.; Castineiras, Pedro; Wooden, Joseph L.

    2008-01-01

    New SHRIMP-RG (sensitive high-resolution ion microprobe-reverse geometry) data confirm the existence of Archean components within zircon grains of a sample from the orthogneiss of Angel Lake, Nevada, United States, previously interpreted as a nappe of Archean crust. However, the combined evidence strongly suggests that this orthogneiss is a highly deformed, Late Cretaceous monzogranite derived from melting of a sedimentary source dominated by Archean detritus. Zircon grains from the same sample used previously for isotope dilution-thermal ionization mass spectrometry (ID-TIMS) isotopic work were analyzed using the SHRIMP-RG to better define the age and origin of the orthogneiss. Prior to analysis, imaging revealed a morphological variability and intragrain, polyphase nature of the zircon population. The SHRIMP-RG yielded 207Pb/206Pb ages between ca. 2430 and 2580 Ma (a best-fit mean 207Pb/206Pb age of 2531 ± 19 Ma; 95% confidence) from mostly rounded to subrounded zircons and zircon components (cores). In addition, several analyses from rounded to subrounded cores or grains yielded discordant 207Pb/206Pb ages between ca. 1460 and ca. 2170 Ma, consistent with known regional magmatic events. All cores of Proterozoic to latest Archean age were encased within clear, typically low Th/U (206Pb/238U ages between 72 and 91 Ma, consistent with magmatic ages from Lamoille Canyon to the south. An age of ca. 90 Ma is suggested, the younger 206Pb/238U ages resulting from Pb loss. The Cretaceous and Precambrian zircon components also have distinct trace element characteristics, indicating that these age groups are not related to the same igneous source. These results support recent geophysical interpretations and negate the contention that the Archean-Proterozoic boundary extends into the central Great Basin area. They further suggest that the world-class gold deposits along the Carlin Trend are not underlain by Archean cratonal crust, but rather by the Proterozoic Mojave

  11. The Fudan nuclear microprobe set-up and performance

    International Nuclear Information System (INIS)

    Zhong, L.; Zhuang, W.; Shen, H.; Mi, Y.; Wu, Y.; Liu, B.; Yang, M.; Cheng, H.

    2007-01-01

    A new scanning nuclear microprobe has been constructed at the Institute of Modern Physics in Fudan University, to replace the old microbeam system which had been running for more than ten years. The key parts were purchased from Oxford Microbeams Ltd., including triplet quadrupole lens (model OM-150), collimator slits, scanning system, target chamber, and data acquisition system. Ion beams are provided from a NEC 9SDH-2 Tandem accelerator. Three CCD cameras and multiple monitors were installed to assist beam adjust. The design of beam line and beam monitors is described. Beam optics calculations were carried out based on the specific Fudan microprobe system geometry, and the results regarding beam line performance and limitations of the spacial resolution are presented and discussed here. A comparison with experimental results is given as well. About 1.5 μm beam spot size could be achieved with a 3 MeV proton beam at a current of around 10 pA. Recently, the new microprobe is applied to obtain information of fly ash particle, algae cell and otoliths

  12. Novel imaging techniques for the nuclear microprobe

    International Nuclear Information System (INIS)

    Saint, A.

    1998-01-01

    Many of the developments of the scanning electron microscope (SEM) have been paralleled during the development of the scanning nuclear microprobe. Secondary electrons were used in the early development of both devices to provide specimen imaging due to the large numbers of secondaries produced per incident charged particle. Other imaging contrast techniques have also been developed on both machines. These include X-ray analysis, scattering contrast, transmission microscopy, channelling induced charge and others. The 'cross-section dependent' imaging techniques such as PIXE, RBS, NRA, etc., rely on the beam current on target for a given resolution. This has prompted research and development of brighter ion sources to maintain probe resolution at high beam current. Higher beam current bring problems with beam damage to the specimen. Low beam current techniques however rely on high countrate data collection systems, but this is only for spectroscopy. To produce an image we can increase beam currents to produce live-time images for specimen manipulation and observation. The work presented here will focus on some developments in live-time imaging with a nuclear micro probe that have taken place recently at the School of Physics, Microanalytical Research Centre (MARC), University of Melbourne

  13. ALKALI FUSION OF ROSETTA ZIRCON

    International Nuclear Information System (INIS)

    DAHER, A.

    2008-01-01

    The decomposition of Rosetta zircon by fusion with different types of alkalis has been investigated. These alkalis include sodium hydroxide, potassium hydroxide and eutectic mixture of both. The influences of the reaction temperature, zircon to alkalis ratio, fusion time and the stirring of the reactant on the fusion reaction have been evaluated. The obtained results favour the decomposition of zircon with the eutectic alkalis mixture by a decomposition efficiency of 96% obtained at 500 0 C after one hour

  14. Oxygen diffusion in zircon

    Science.gov (United States)

    Watson, E. B.; Cherniak, D. J.

    1997-05-01

    Oxygen diffusion in natural, non-metamict zircon was characterized under both dry and water-present conditions at temperatures ranging from 765°C to 1500°C. Dry experiments were performed at atmospheric pressure by encapsulating polished zircon samples with a fine powder of 18O-enriched quartz and annealing the sealed capsules in air. Hydrothermal runs were conducted in cold-seal pressure vessels (7-70 MPa) or a piston cylinder apparatus (400-1000 MPa) on zircon samples encapsulated with both 18O-enriched quartz and 18O water. Diffusive-uptake profiles of 18O were measured in all samples with a particle accelerator, using the 18O(p, α) 15N reaction. For dry experimental conditions at 1100-1500°C, the resulting oxygen diffusivities (24 in all) are well described by: D dry (m 2/s) = 1.33 × 10 -4exp(-53920/T) There is no suggestion of diffusive anisotropy. Under wet conditions at 925°C, oxygen diffusion shows little or no dependence upon P H 2O in the range 7-1000 MPa, and is insensitive to total pressure as well. The results of 27 wet experiments at 767-1160°C and 7-1000 MPa can be described a single Arrhenius relationship: D wet (m 2/s) = 5.5 × 10 -12exp(-25280/T) The insensitivity of oxygen diffusion to P H 2O means that applications to geologic problems can be pursued knowing only whether the system of interest was 'wet' (i.e., P H 2O > 7MPa ) or 'dry'. Under dry conditions (presumably rare in the crust), zircons are extremely retentive of their oxygen isotopic signatures, to the extent that δ 18O would be perturbed at the center of a 200 μm zircon only during an extraordinarily hot and protracted event (e.g., 65 Ma at 900°C). Under wet conditions, δ 18O may or may not be retained in the central regions of individual crystals, cores or overgrowth rims, depending upon the specific thermal history of the system.

  15. The new Schonland PIXE microprobe and applications to geological and archaeological samples

    Energy Technology Data Exchange (ETDEWEB)

    Przybylowicz, W J; Watterson, J I.W.; Annegarn, H J; Connell, S H; Fearick, R W; Andeweg, A H; Sellschop, J P.F. [Schonland Research Centre for Nuclear Sciences, Univ. of the Witwatersrand, Johannesburg (South Africa)

    1993-04-01

    The new positive ion microprobe at the Schonland Centre is described and details are given of its configuration, its imaging system and software. In a unique configuration, the microprobe has access to two accelerators, a 6 MV EN tandem and a 2.5 MV single-ended machine. The imaging system uses a CAMAC based system and runs on a personal computer under OS/2. The implementation of PIXE and treatment of thick-target data are presented. Applications discussed are analysis of tin artifacts from the prehistory of metallurgy in South Africa; a diamond-containing rock; carbonado, gold contained in pyrite and cogenetic minerals included in diamond. (orig.).

  16. The new Schonland PIXE microprobe and applications to geological and archaeological samples

    International Nuclear Information System (INIS)

    Przybylowicz, W.J.; Watterson, J.I.W.; Annegarn, H.J.; Connell, S.H.; Fearick, R.W.; Andeweg, A.H.; Sellschop, J.P.F.

    1993-01-01

    The new positive ion microprobe at the Schonland Centre is described and details are given of its configuration, its imaging system and software. In a unique configuration, the microprobe has access to two accelerators, a 6 MV EN tandem and a 2.5 MV single-ended machine. The imaging system uses a CAMAC based system and runs on a personal computer under OS/2. The implementation of PIXE and treatment of thick-target data are presented. Applications discussed are analysis of tin artifacts from the prehistory of metallurgy in South Africa; a diamond-containing rock; carbonado, gold contained in pyrite and cogenetic minerals included in diamond. (orig.)

  17. Realtime control system for microprobe beamline at PLS

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, J.C.; Lee, J.W.; Kim, K.H.; Ko, I.S. [Pohang Accelerator Laboratory, POSTECH, Pohang (Korea)

    1998-11-01

    The microprobe beamline of the Pohang Light Source (PLS) consists of main and second slits, a microprobe system, two ion chambers, a video-microscope, and a Si(Li) detector. These machine components must be controlled remodely through the computer system to make user's experiments precise and speedy. A real-time computer control system was developed to control and monitor these components. A VMEbus computer with an OS-9 real-time operating system was used for the low-level data acquisition and control. VME I/O modules were used for the step motor control and the scalar control. The software has a modular structure for the maximum performance and the easy maintenance. We developed the database, the I/O driver, and the control software. We used PC/Windows 95 for the data logging and the operator interface. Visual C{sup ++} was used for the graphical user interface programming. RS232C was used for the communication between the VME and the PC. (author)

  18. Charge collection control using retrograde well tested by proton microprobe irradiation

    International Nuclear Information System (INIS)

    Sayama, Hirokazu; Takai, Mikio; Kimura, Hiroshi; Ohno, Yoshikazu; Satoh, Shinichi; Sonoda, Kenichirou; Katani, Norihiko.

    1993-01-01

    Soft error reduction by high-energy ion-implanted layers has been investigated by novel evaluation techniques using high-energy proton microprobes. A retrograde well formed by 160 and 700 keV boron ion implantation could completely suppress soft errors induced by the proton microprobes at 400 keV. The proton-induced current revealed the charge collection efficiency for the retrograde well structure. The collected charge for the retrograde well in the soft-error mapping was proved to be lower than the critical charge of the measured DRAMs(dynamic random-access memories). Complementary use of soft-error mapping and ion-induced-current measurement could clarify well structures immune against soft errors. (author)

  19. Microprobe PIXE analysis and EDX analysis on the brain of patients with Alzheimer`s disease

    Energy Technology Data Exchange (ETDEWEB)

    Yumoto, S. [Tokyo Univ. (Japan). Faculty of Medicine; Horino, Y.; Mokuno, Y.; Fujii, K.; Kakimi, S.; Mizutani, T.; Matsushima, H.; Ishikawa, A.

    1996-12-31

    To investigate the cause of Alzheimer`s disease (senile dementia of Alzheimer`s disease type), we examined aluminium (Al) in the brain (hippocampus) of patients with Alzheimer`s disease using heavy ion (5 MeV Si{sup 3+}) microprobe particle-induced X-ray emission (PIXE) analysis. Heavy ion microprobes (3 MeV Si{sup 2+}) have several times higher sensitivity for Al detection than 2 MeV proton microprobes. We also examined Al in the brain of these patients by energy dispersive X-ray spectroscopy (EDX). (1) Al was detected in the cell nuclei isolated from the brain of patients with Alzheimer`s disease using 5 MeV Si{sup 3+} microprobe PIXE analysis, and EDX analysis. (2) EDX analysis demonstrated high levels of Al in the nucleolus of nerve cells in frozen sections prepared from the brain of these patients. Our results support the theory that Alzheimer`s disease is caused by accumulation of Al in the nuclei of brain cells. (author)

  20. Developments of new generation nuclear microprobe systems at the University of Melbourne

    International Nuclear Information System (INIS)

    Rout, B.; Jamieson, D.N.; Hopt, R.; Hearne, S.; Szymaski, R.

    2002-01-01

    Full text: A review of the recent developments in fabricating a new generation nuclear microprobe systems at University of Melbourne, Melbourne, will be presented. These new generation systems present high spatial resolution (less than 1 micrometer) with increasing current density (in excess of 100 pA/micrometer 2 ) of the probing ion beam. Detectors with large solid angles and high brightness of the ion source of the accelerator increase the capabilities of these microprobes many fold. Some of the key ingredients of these microprobes are (i) novel magnetic quadrupole lens quintuplet probe forming system (ii) integrated fast data acquisition system to handle high count rates (excess of 100 KHz) due to increasing current density as well as large detector solid angles up to 4 detector stations. Full dead time corrected and charge normalised maps are also implemented to counter the problems normally associated with such high count rate systems. First version of these systems is presently under operation at CSIRO, Sydney. Another similar system is currently being installed at Dutch Institute for Nuclear and High Energy Physics, Amsterdam, Netherlands. A further optimised version of the CSIRO/MARC quintuplet probe forming systems is currently being fabricated at University of Melbourne. Some of the applications involve microelectronic materials, superconductors and geological samples. We will be presenting exciting results arising out of investigations into these materials. We will be demonstrating ultimate spatial resolution of the new microprobe being fabricated at Melbourne

  1. Zircon/fluid trace element partition coefficients measured by recrystallization of Mud Tank zircon at 1.5 GPa and 800-1000 °C

    Science.gov (United States)

    Ayers, John C.; Peters, Timothy J.

    2018-02-01

    Hydrothermal zircon grains have trace element characteristics such as low Th/U, high U, and high rare earth element (REE) concentrations that distinguish them from magmatic, metamorphic, and altered zircon grains, but it is unclear whether these characteristics result from distinctive fluid compositions or zircon/fluid fractionation effects. New experiments aimed at measuring zircon/fluid trace element partition coefficients Dz/f involved recrystallizing natural Mud Tank zircon with low trace element concentrations in the presence of H2O, 1 m NaOH, or 1 m HCl doped with ∼1000 ppm of rare earth elements (REE), Y, U and Th and ∼500 ppm of Li, B, P, Nb, Ba, Hf, and Ta. Experiments were run for 168 h at 1.5 GPa, 800-1000 °C, and fO2 = NNO in a piston cylinder apparatus using the double capsule method. LA-ICP-MS analysis shows that run product zircon crystals have much higher trace element concentrations than in Mud Tank zircon starting material. Dz/f values were estimated from run product zircon analyses and bulk composition using mass balance. Most elements behave incompatibly, with median Dz/f being highest for Hf = 8 and lowest for B = 0.02. Addition of NaOH or HCl had little influence on Dz/f values. Dz/f for LREE are anomalously high, likely due to contamination of run product zircon with quenched solutes enriched in incompatible elements, so DLREE were estimated using lattice strain theory. Brice curves for +3 ions yield zircon/fluid DLu/DLa of ∼800-5000. A Brice curve fit to +4 ions yielded DCe4+ values. Estimated concentrations of Ce3+ and Ce4+ show that the average Ce4+/Ce3+ in zircon of 27 is much higher than in fluid of 0.02. Th and U show little fractionation, with median DTh/DU = 0.7, indicating that the low Th/U in natural hydrothermal zircon is inherited from the fluid. Natural fluid compositions estimated from measured Dz/f and published compositions of hydrothermal zircon grains from aplite and eclogite reflect the mineralogy of the host rock, e

  2. A new scanning proton microprobe with long focus

    International Nuclear Information System (INIS)

    Zhu Jieqing; Li Minqian; Mao Yu; Chen Hanmin; Gu Yingmei; Yang Changyi; Sheng Kanglong

    1991-01-01

    A new scanning proton microprobe equipped with a long focus Russian magnetic quadruplet is set up. With excellent performances of ion optics, it can be used to do experiments of PIXE, RBS, RFS, NRA and channelling simultaneously within a micron-region. The power supplies for quadruplet and scanning coils are controlled by an IBM-PC computer and a scanning graphical monitor based on an Apple IIe microcomputer provides convenience of searching for an interesting area to scan. The advanced modes of the fast random scan and the event-by-event data collection make it possible to treat the multi-parameter and multi-detector data by means of the strategy of TQSA (Total quantitative scanning analysis). There are three types of graphical display including the innovation of three dimensional contour mapping

  3. Nuclear microprobe analysis of lead profile in crocodile bones

    Energy Technology Data Exchange (ETDEWEB)

    Orlic, I. E-mail: ivo@ansto.gov.au; Siegele, R.; Hammerton, K.; Jeffree, R.A.; Cohen, D.D

    2003-09-01

    Elevated concentrations of lead were found in Australian free ranging saltwater crocodile (Crocodylus porosus) bone and flesh. Lead shots were found as potential source of lead in these animals. ANSTO's heavy ion nuclear microprobe was used to measure the distribution of Pb in a number of bones and osteoderms. The aim was to find out if elevated Pb concentration remains in growth rings and if the concentration is correlated with the blood levels recorded at the time. Results of our study show a very distinct distribution of accumulated Pb in bones and osteoderms as well as good correlation with the level of lead concentration in blood. To investigate influence of ion species on detection limits measurements of the same sample were performed by using 3 MeV protons, 9 MeV He ions and 20 MeV carbon ions. Peak to background ratios, detection limits and the overall 'quality' of obtained spectra are compared and discussed.

  4. Analysis of monazite, zircon, and apatite from the southeastern Piedmont. National uranium resource evaluation program

    International Nuclear Information System (INIS)

    Karfunkel, B.S.; Fay, W.M.; Price, V. Jr.

    1981-12-01

    Two hundred sixty-three monazite, 191 zircon, and 16 apatite grains from 52 stream-sediment locations in the Southeastern Piedmont were analyzed by electron microprobe for one of the following suites of elements: Ca, La, Ce, Pr, Nd, Sm, Eu, Gd, Er, Dy, Y, Th, U, P, and F, or Ca, La, Ce, Fe, Er, Hf, Y, Th, U, P, Zr, Mg, Al, and Si. Monazite samples that had high uranium or thorium content and zircon samples that had high hafnium or iron content from a total of six locations were reanalyzed to confirm the initial results. This report contains a description of sample collection and preparation procedures, analytical methods, tables of analyses, and a statistical summary of analyses

  5. PIXE macro and microprobe techniques in archaeometry

    International Nuclear Information System (INIS)

    Brissaud, I.; Lagarde, G.; Houdayer, A.

    1987-01-01

    PIXE analysis method is applied to archaeometry problems. Advantages and disadvantages are emphasized. Some examples are presented which show the difficulties: especially important heterogeneities of ceramics, old coins and metals restrain from the use of this technique. Other analysis systems, less expensive, like electron microbrobe or x-ray fluorescence spectrometry, are compared with conventional PIXE method. The importance of proton microprobe is explained. (author) 40 refs.; 7 figs.; 5 tabs

  6. Biomedical application of the nuclear microprobe

    International Nuclear Information System (INIS)

    Lindh, U.

    1987-01-01

    The Studsvik Nuclear Microprobe (SMP) has mainly been devoted to applications in the biomedical field. Its ultimate resolution is reached at 2.9x2.9 μm 2 with a proton current of 100 pA. With this performance the SMP has been used in a wide range of disciplines covering environmental hygiene, toxicology, various aspects of internal medicine and trace element physiology. Examples of recent applications in these fields are described. (orig.)

  7. Development of a nuclear microprobe at IGCAR

    International Nuclear Information System (INIS)

    Ramesh, C.; Nair, K.G.M.; Thampi, N.S.; Saha, B.; Mathews, C.K.

    1988-01-01

    A nuclear microprobe is being developed at IGCAR. The system is being built to determine the profiles of light elements, specially carbon in clad and other structural materials of a fast breeder reactor. By scanning a focussed charged particle beam on the sample surface and by detecting the charged particle induced emissions, an elemental map of the surface is obtained. The paper gives the basic design considerations and present status. (author)

  8. Constraints on the timing of Co-Cu ± Au mineralization in the Blackbird district, Idaho, using SHRIMP U-Pb ages of monazite and xenotime plus zircon ages of related Mesoproterozoic orthogneisses and metasedimentary rocks

    Science.gov (United States)

    Aleinikoff, John N.; Slack, John F.; Lund, Karen; Evans, Karl V.; Fanning, C. Mark; Mazdab, Frank K.; Wooden, Joseph L.; Pillers, Renee M.

    2012-01-01

    The Blackbird district, east-central Idaho, contains the largest known Co reserves in the United States. The origin of strata-hosted Co-Cu ± Au mineralization at Blackbird has been a matter of controversy for decades. In order to differentiate among possible genetic models for the deposits, including various combinations of volcanic, sedimentary, magmatic, and metamorphic processes, we used U-Pb geochronology of xenotime, monazite, and zircon to establish time constraints for ore formation. New age data reported here were obtained using sensitive high resolution ion microprobe (SHRIMP) microanalysis of (1) detrital zircons from a sample of Mesoproterozoic siliciclastic metasedimentary country rock in the Blackbird district, (2) igneous zircons from Mesoproterozoic intrusions, and (3) xenotime and monazite from the Merle and Sunshine prospects at Blackbird. Detrital zircon from metasandstone of the biotite phyllite-schist unit has ages mostly in the range of 1900 to 1600 Ma, plus a few Neoarchean and Paleoproterozoic grains. Age data for the six youngest grains form a coherent group at 1409 ± 10 Ma, regarded as the maximum age of deposition of metasedimentary country rocks of the central structural domain. Igneous zircons from nine samples of megacrystic granite, granite augen gneiss, and granodiorite augen gneiss that crop out north and east of the Blackbird district yield ages between 1383 ± 4 and 1359 ± 7 Ma. Emplacement of the Big Deer Creek megacrystic granite (1377 ± 4 Ma), structurally juxtaposed with host rocks in the Late Cretaceous ca. 5 km north of Blackbird, may have been involved in initial deposition of rare earth elements (REE) minerals and, possibly, sulfides. In situ SHRIMP ages of xenotime and monazite in Co-rich samples from the Merle and Sunshine prospects, plus backscattered electron imagery and SHRIMP analyses of trace elements, indicate a complex sequence of Mesoproterozoic and Cretaceous events. On the basis of textural relationships

  9. U-Pb SHRIMP ages of volcanic zircons from the Merrions and Turondale Formations, New South Wales, and the early devonian time-scale: a biostratigraphic and sedimentological assessment

    International Nuclear Information System (INIS)

    Packham, G.H.

    2003-01-01

    U-Pb ages for volcanic zircons from the Lower Devonian Turondale and Merrions Formations initially dated by Jagodzinski and Black (1999) have been recalculated by Compston (2000, 2001). The Turondale, Waterbeach and Merrions Formations are, in ascending stratigraphic order, three of the Lower Devonian deep-water formations of the Hill End Trough. The recent discovery of a Lochkovian conodont fauna of the delta zone in derived limestone blocks from the uppermost beds of the Turondale Formation has established a maximum age for that horizon. The principal lithological assemblages of the formations are volcanic (megaturbidite and lavas), epiclastic turbidites and essentially hemipelagic lithologies. The mean zircon ages, determined by Sensitive High-Resolution Ion MicroProbe (SHRIMP), suggest a long duration for the Merrions Formation, 615 m thick and 91% volcanic, and a very much shorter interval for the upper two-thirds of the Turondale Formation, 360 m thick and 34% volcanic, plus the intervening non-volcanic Waterbeach Formation, 512 m thick. A sedimentological model based on scaled depositional rates for the facies has been used to estimate the relative accumulation rates and durations of the succession from the base of the Turondale Formation to the top of the Merrions Formation The model indicates that the Merrions Formation accumulated in a much shorter time than the interval from the top of the lower Turondale Formation to the base of the Merrions Formation. The analytical uncertainties of the Jagodzinski and Black (1999) zircon ages are large enough to be compatible with the sedimentological model, but the smaller analytical uncertainties calculated by Compston (2000, 2001) fall far from the scaled sedimentological model. Grouping together of the lower Merrions Formation and lower Turondale Formation zircon dates in Compston (2000) for a single mid-Lochkovian age is in conflict with the biostratigraphic and sedimentological evidence available and the derived

  10. Chemical history with a nuclear microprobe

    International Nuclear Information System (INIS)

    Maggiore, C.J.; Benjamin, T.M.; Burnett, D.S.; Hyde, P.J.; Rogers, P.S.Z.; Srinivasan, S.; Tesmer, T.; Woolum, D.S.

    1983-01-01

    A nuclear microprobe cannot give direct information on the chemical state of an element, but the spatial distribution of elements in a specimen is often determined by the chemical history of the sample. Fuel cells and minerals are examples of complex systems whose elemental distributions are determined by past chemical history. The distribution of catalyst in used fuel cell electrodes provides direct information on the chemical stability of dispersed catalysts under operating conditions. The authors have used spatially resolved Rutherford backscattering to measure the migration of platinum and vanadium from intermetallic catalysts and to determine their suitability for use under the extreme operating conditions found in phosphoric acid fuel cells. Geologic materials are complex, heterogeneous samples with small mineral grains. The trace element distribution within the individual mineral grains and between different mineral phases is sensitive to the details of the mineral formation and history. The spatial resolution and sub-100-ppm sensitivity available with a nuclear microprobe open up several new classes of experiments to the geochemist. Geochemistry and electrochemistry are two areas proving particularly fruitful for application of the nuclear microprobe

  11. Direct Chlorination of Zircon Sand

    International Nuclear Information System (INIS)

    Dwiretnani Sudjoko; Budi Sulistyo; Pristi Hartati; Sunardjo

    2002-01-01

    It was investigated the direct chlorination of zircon sand in a unit chlorination equipment. The process was in semi batch. The product gas was scrubbed in aqueous NaOH. It was search the influence of time, ratio of reactant and size of particle sand to the concentration of Zr and Si in the product. From these research it was found that as the times, ratio of reactant increased, the concentration of Zr increased, but the concentration of Si decreased, while as grain size of zircon sand decreased the concentration of Zr decreased, but the concentration of Si increased. (author)

  12. Analysis of biological materials using a nuclear microprobe

    Science.gov (United States)

    Mulware, Stephen Juma

    The use of nuclear microprobe techniques including: Particle induced x-ray emission (PIXE) and Rutherford backscattering spectrometry (RBS) for elemental analysis and quantitative elemental imaging of biological samples is especially useful in biological and biomedical research because of its high sensitivity for physiologically important trace elements or toxic heavy metals. The nuclear microprobe of the Ion Beam Modification and Analysis Laboratory (IBMAL) has been used to study the enhancement in metal uptake of two different plants. The roots of corn (Zea mays) have been analyzed to study the enhancement of iron uptake by adding Fe (II) or Fe(III) of different concentrations to the germinating medium of the seeds. The Fe uptake enhancement effect produced by lacing the germinating medium with carbon nanotubes has also been investigated. The aim of this investigation is to ensure not only high crop yield but also Fe-rich food products especially from calcareous soil which covers 30% of world's agricultural land. The result will help reduce iron deficiency anemia, which has been identified as the leading nutritional disorder especially in developing countries by the World Health Organization. For the second plant, Mexican marigold (Tagetes erecta ), the effect of an arbuscular mycorrhizal fungi (Glomus intraradices ) for the improvement of lead phytoremediation of lead contaminated soil has been investigated. Phytoremediation provides an environmentally safe technique of removing toxic heavy metals (like lead), which can find their way into human food, from lands contaminated by human activities like mining or by natural disasters like earthquakes. The roots of Mexican marigold have been analyzed to study the role of arbuscular mycorrhizal fungi in enhancement of lead uptake from the contaminated rhizosphere.

  13. Quantitative microanalysis with a nuclear microprobe

    International Nuclear Information System (INIS)

    Themner, Klas.

    1989-01-01

    The analytical techniques of paticle induced X-ray emission (PIXE) and Rutherford backscattering (RBS), together with the nuclear microprobe, form a very powerful tool for performing quantitative microanalysis of biological material. Calibration of the X-ray detection system in the microprobe set-up has been performed and the accuracy of the quantitative procedure using RBS for determination of the areal mass density was investigated. The accuracy of the analysis can be affected by alteration in the elemental concentrations during irradiation due to the radiation damage induced by the very intense beams of ionixing radiation. Loss of matrix elements from freeze-dried tissue sections and polymer films have been studied during proton and photon irradiation and the effect on the accuracy discussed. Scanning the beam over an area of the target, with e.g. 32x32 pixels, in order to produce en elemental map, yields a lot of information and, to be able to make an accurate quantitatification, a fast algorithm using descriptions of the different spectral contributions is of need. The production of continuum X-rays by 2.55 MeV protons has been studied and absolute cross-sections for the bremsstrahlung production from thin carbon and some polymer films determined. For the determination of the bremsstrahlung background knowledge of the amounts of the matrix elements is important and a fast program for the evaluation of spectra of proton back- and forward scattering from biological samples has been developed. Quantitative microanalysis with the nuclear microprobe has been performed on brain tissue from rats subjected to different pathological conditions. Increase in calcium levels and decrease in potssium levels for animals subjected to crebral ischaemia and for animals suffering from epileptic seizures were observed coincidentally with or, in some cases before, visible signs of cell necrosis. (author)

  14. Structural evolvement and the capability of resistance to γ-ray irradiation on zircon originating from nyainqentanglha granite

    International Nuclear Information System (INIS)

    Cui Chunlong; Zhang Dong; Kang Houjun; Wang Xiaoli; Zhou Yulin; Yi Facheng; Lu Xirui; Tang Jingyou

    2010-01-01

    In order to investigate the structural evolvement and the capability of resistance to γ-ray irradiation on zircon as mothball waste forms of radionuclide, the zircon crystals (11.01±0.24 M) were studied as investigative object, which were collected from nyainqentanglha granite. All the samples were irradiated using a 60 Co y-ray source with 576 kGy doses. Phases, structures and microstructures of the as-gained samples before and after y-ray irradiation were characterized by means of a multi-functional microscope, cathodoluminescence (CL), backscattered electron microprobe (BEM), X-ray diffraction (XRD), Raman spectroscopy (Raman), infrared spectroscopy (IR) and scanning electron microscopy (SEM), and so on. Moreover, the geological backgrounds and chemical compositions of zircons originating from natural rocks were analyzed as well. The results indicated that the as-gained crystals came from magmatic rock which undergone near 11 million years geological evolvement and still contain UO 2 and ThO 2 with the contents of 0.5729 wt%. The alteration of 10 -3 nm magnitude in the crystal cell parameters was measured (of the standard XRD card of zircon). The irradiation on the crystalline samples using γ-ray induced to the alteration of 10 -4 nm magnitude for their crystal cell parameters. The conclusion shows that zircon crystals with a certain amount of UO 2 and ThO 2 have better structural stability for the y-ray irradiation. (authors)

  15. An RF ion source based primary ion gun for secondary ion mass spectroscopy

    International Nuclear Information System (INIS)

    Menon, Ranjini; Nabhiraj, P.Y.; Bhandari, R.K.

    2011-01-01

    In this article we present the design, development and characterization of an RF plasma based ion gun as a primary ion gun for SIMS application. RF ion sources, in particular Inductively Coupled Plasma (ICP) ion sources are superior compared to LMIS and duoplasmtron ion sources since they are filamentless, can produce ions of gaseous elements. At the same time, ICP ion sources offer high angular current density which is an important factor in producing high current in small spot size on the target. These high current microprobes improve the signal to noise ratio by three orders as compared to low current ion sources such as LMIS. In addition, the high current microprobes have higher surface and depth profiling speeds. In this article we describe a simple ion source in its very basic form, two lens optical column and characteristics of microprobe

  16. Electron microprobe analysis of tantalum--nitride thin films

    International Nuclear Information System (INIS)

    Stoltz, D.L.; Starkey, J.P.

    1979-06-01

    Quantitative chemical analysis of 500- and 2000-angstrom tantalum--nitride films on glass substrates has been accomplished using an electron microprobe x-ray analyzer. In order to achieve this analysis, modifications to the microprobe were necessary. A description of the calibration procedure, the method of analysis, and the quantitative results are discussed

  17. In situ detrital zircon (U-Th)/He thermochronology

    Science.gov (United States)

    Tripathy, A.; Monteleone, B. D.; van Soest, M. C.; Hodges, K.; Hourigan, J. K.

    2010-12-01

    Detrital studies of both sand and rock are relevant to many problems, ranging from the climate and tectonics feedback debate to the long-term record of orogenic evolution. When applying the conventional (U-Th)/He technique to such studies, two important issues arise. Often, only euhedral grains are permissible for analysis in order to make simple geometric corrections for α-recoil. In detrital samples, this is problematic because euhedral grains can be scarce due to mechanical abrasion during transport, and potentially introduce bias in favour of more proximally sourced grains. Second, inherent to detrital studies is the need to date many grains (>100) per sample to ensure a representative sampling of the sediment source region, thus making robust conventional detrital studies both expensive and time-consuming. UV laser microprobes can improve this by permitting careful targeting of the grain interior away from the α-ejection zone, rendering the α-recoil correction unnecessary, thus eliminating bias toward euhedral grains. In the Noble Gas, Geochemistry, and Geochronology Laboratory at ASU, apatite and zircon have been successfully dated using in situ methods. For this study, the conventional and in situ techniques are compared by dating zircons from a modern river sand that drains a small catchment in the Mesozoic-Cenozoic Ladakh Batholith in NW India. This sample has a simple provenance, which allows us to demonstrate the robustness of the in situ method. Moreover, different microbeam techniques will be explored to establish the most efficient approach to obtain accurate and precise U-Th concentrations using synrock, which is our powdered, homogenized, and reconstituted zircon-rock standard. Without this, such in situ U-Th data would be difficult to obtain. 117 zircons were dated using the conventional (U-Th)/He method, revealing dates ranging from 9.70±0.35 to 106.6±3.5 Ma (2σ) with the major mode at 26 Ma. For comparison, 44 grains were dated using the in

  18. Radioactivity in the zircon industry

    International Nuclear Information System (INIS)

    Selby, J.H.

    2002-01-01

    In a presentation from the Zircon Industry, it was shown that zircon sand contains significant concentrations of uranium, 3,500 to 4,500 Bq/kg, and thorium, 400 to 600 Bq/kg. Deposits mainly occur in South Africa, Australia, India and the USA. The mining is done by dredging or by just shoveling the sand onto trucks. The separation could be done by dry or wet concentration. Also the milling could be by dry or wet processes. The dry process has the highest risk of dust generation. The maximum potential annual dose for the milling process has been assessed to be about 5mSv. Measurements from South Africa and Australia indicate lower doses, 0.2 to 1 mSv/y

  19. New electron microprobe for radioactive materials

    International Nuclear Information System (INIS)

    Perrot, M.; Geoffroy, G.; Trotabas, M.

    1989-01-01

    The latest model of CAMECA microprobe SX 50R has just been set up in the high activity laboratory of the Centre d'Etudes Nucleaires de SACLAY. It has been especially designed for the examination of nuclear fuel and irradiated materials. The spectrometers are protected from the radioactivity by an armour plate and the entire equipment has been installed into a special cell in order to protect the operators. The special sample holder allows to examine specimens as large as 80 mm in diameter. One of the interesting uses concerns the quantitative determination of the oxygen content in zircaloy oxidized by steam at high temperature. This analysis was made possible by using the new type of crystals (multilayer)

  20. The new scanning nuclear microprobe in Uppsala

    International Nuclear Information System (INIS)

    Sunde, T.; Nystroem, J.; Lindh, U.

    1991-01-01

    During 1989/90 a scanning microprobe, developed for 2-4 MeV protons and submicron resolution, is being installed at the EN-tandem accelerator at the The Svedberg Laboratory, Uppsala University, Sweden. The probe-forming units (object diaphragm, aperture diaphragm and triplet of spark-eroded quadrupoles), the scanning unit of current-controlled ferrite cores and a current digitizer are of Oxford design. The other parts are commercial products or are constructed by ourselves. The latter includes the equipment for optical alignment by interference, a feedback-controlled magnetic beam steerer and stabiliser, a fast beam deflector, specially designed mechanical vibration reducers and dedicated AT expansion cards for scanning control and data acquisition. (orig.)

  1. Detrital Zircons From the Jack Hills and Mount Narryer, Western Australia: Geochronological, Morphological, and Geochemical Evidence for Diverse >4000 Ma Source Rocks

    Science.gov (United States)

    Crowley, J. L.; Myers, J. S.; Sylvester, P. J.; Cox, R. A.

    2004-05-01

    Detrital zircons from all major clastic units in the Jack Hills and Mount Narryer metasedimentary belts, Western Australia, were analyzed for morphology, internal zoning, inclusion mineralogy, age, and trace element concentrations (latter two obtained by laser-ablation microprobe ICPMS). The results show that zircons were derived from a wide diversity of rocks, including previously described, >4000 Ma grains that are older than any known terrestrial rocks. In three metaconglomerate samples from the western Jack Hills, 4200-3800 Ma zircons ("old grains") comprise 14% of the population, 3800-3600 Ma grains form only 2%, and 3550-3250 Ma zircons ("young grains") are dominant with a significant peak at 3380 Ma. Old and young grains are interpreted as being from similar rock types because they are indistinguishable in trace element concentrations, size (several hundred microns), morphology (subequant, typically fragmented), internal zoning (typically both oscillatory and sector), and U concentration (50-200 ppm). Many of these properties suggest an intermediate plutonic source, whereas an evolved granitic source was previously interpreted from rare-earth element and oxygen isotope data. Detrital zircons in quartzites and metaconglomerates at Mount Narryer differ significantly from zircons from the western Jack Hills. Old grains comprise only 3% (most of which are 4200-4100 Ma), 3800-3600 Ma zircons form 31%, and there are peaks at 3650, 3600, and 3500 Ma. Old and young grains have similar properties that suggest granitic sources, such as elongate prismatic morphology, oscillatory zoning, high U concentrations (100-600 ppm), and xenotime and monazite inclusions. Trace element concentrations are broadly similar to those in Jack Hills zircons, with notable exceptions being generally higher U, smaller Ce and Eu anomalies, and lower Nb/Ta. It is considered unlikely that Jack Hills zircons were derived from granitic gneisses that surround the metasedimentary belts because

  2. Fission track dating of zircon: a multichronometer

    International Nuclear Information System (INIS)

    Carpena, J.

    1992-01-01

    Scattering in Fission Track ages of zircons of a single rock is possible when they present morphological and geochemical variations, if the greatest care is not taken in the choice of the etching conditions and the counting of tracks. The Fission Track study of two heterogeneous populations of zircons from the Mont Blanc granite and from the Gran Paradiso gneisses allows to show that zircon may work as a multichronometer

  3. A photomultiplier-based secondary electron imaging system for a nuclear microprobe

    International Nuclear Information System (INIS)

    Alves, L.C.; Breese, M.B.H.; Silva, M.F. da; Soares, J.C.

    2002-01-01

    The ability to define, or recognise particular regions of interest or surface features is vital to the analysis and interpretation of spatially-resolved images collected with a nuclear microprobe. However, good topographic image contrast is difficult to accomplish using PIXE or RBS images due to their inherent insensitivity to topography, lack of elemental variation or poor statistics. Topographic image contrast is commonly obtained in scanning electron microscopy (SEM) by detecting a large flux of secondary electrons produced by the focused keV electron beam. Similar systems have not been widely used on nuclear microprobes due to ion beam intensity fluctuations, which limit the minimum resolvable contrast and present a major limitation for this technique. This paper describes a secondary electron imaging system which has been developed on the Lisbon microprobe. It is based on a scintillator, a photomultiplier operated in a pulsed mode, a pulse shaping electronic chain and ADC, and requires no changes to the existing data acquisition system. Examples of the images obtained from materials such as patterned SiGe wafers and hydrogen-implanted silicon are given, and compared with SEM or optical images

  4. Structural and electrical characterisation of semiconductor materials using a nuclear microprobe

    International Nuclear Information System (INIS)

    Jamieson, D.N.

    1998-01-01

    The domain of high-resolution imaging techniques (sub-micron) traditionally belongs to low-energy ion beams (ke V ion microprobe), electrons (transmission or scanning electron microscopy), light (near field microscopy), or all variants of scanning probe microscopies. Now, nuclear techniques of analysis, with a nuclear microprobe, have entered this domain, bringing a range of unique techniques for making images. In addition to-conventional techniques like Rutherford (and non-Rutherford) backscattering spectrometry and particle induced x-ray emission for structural characterisation, new ion beam analysis techniques have been developed for electrical characterisation as well. Foremost of these new techniques is ion beam induced charge (IBIC) which has seen an explosion of applications in the last five years to the study of charge transport properties of a variety of materials including polycrystalline diamond and silicon. An additional novel technique is ionoluminescence, which may be used to image various electronic properties of the material. Presented here are some examples of these imaging techniques in a variety of semiconductor materials. In all these examples, the specimens display structural inhomogeneities on the scale of 10 micrometres, making it essential to employ a focused beam. (author)

  5. Structural and electrical characterisation of semiconductor materials using a nuclear microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Jamieson, D.N. [Melbourne Univ., Parkville, VIC (Australia). School of Physics, Microanalytical Centre

    1998-06-01

    The domain of high-resolution imaging techniques (sub-micron) traditionally belongs to low-energy ion beams (ke V ion microprobe), electrons (transmission or scanning electron microscopy), light (near field microscopy), or all variants of scanning probe microscopies. Now, nuclear techniques of analysis, with a nuclear microprobe, have entered this domain, bringing a range of unique techniques for making images. In addition to-conventional techniques like Rutherford (and non-Rutherford) backscattering spectrometry and particle induced x-ray emission for structural characterisation, new ion beam analysis techniques have been developed for electrical characterisation as well. Foremost of these new techniques is ion beam induced charge (IBIC) which has seen an explosion of applications in the last five years to the study of charge transport properties of a variety of materials including polycrystalline diamond and silicon. An additional novel technique is ionoluminescence, which may be used to image various electronic properties of the material. Presented here are some examples of these imaging techniques in a variety of semiconductor materials. In all these examples, the specimens display structural inhomogeneities on the scale of 10 micrometres, making it essential to employ a focused beam. (author). Extended abstract. 18 refs. 4 figs.

  6. Nuclear scanning microprobe: state of the art, applications and progress trends

    International Nuclear Information System (INIS)

    Ponomarev, A.G.

    2011-01-01

    The physical principles of nuclear scanning microprobe are considered. The analysis of state of the art of the microprobe setup from point of view of its spatial resolution and sensitivity of microanalysis techniques is given. The regions of nuclear microprobe applications are reviewed. The ways of spatial resolution and data acquisition system improvement under consideration of microprobe setup progress trends are considered. (authors)

  7. U-Pb zircon in situ dating with LA-MC-ICP-MS using a mixed detector configuration

    Energy Technology Data Exchange (ETDEWEB)

    Chemale Junior, Farid, E-mail: fchemale@unb.br [Universidade de Brasilia (UnB), DF (Brazil). Inst. de Geociencias; Kawashita, Koji; Dussin, Ivo A. [Universidade de Sao Paulo (USP), SP (Brazil). Centro de Pesquisas Geocronologicas; Avila, Janaina N. [Australian National University, Canberra, (Australia). Research School of Earth Sciences; Justino, Dayvisson; Bertotti, Anelise [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Curso de Pos-Graduacao em Geociencias

    2012-06-15

    The LA-MC-ICP-MS method applied to U-Pb in situ dating is still rapidly evolving due to improvements in both lasers and ICP-MS. To test the validity and reproducibility of the method, 5 different zircon samples, including the standard Temora-2, ranging in age between 2.2 Ga and 246 Ma, were dated using both LA-MC-ICP-MS and SHRIMP. The selected zircons were dated by SHRIMP and, after gentle polishing, the laser spot was driven to the same site or on the same zircon phase with a 213 nm laser microprobe coupled to a multi-collector mixed system. The data were collected with a routine spot size of 25 {mu}m and, in some cases, of 15 and 40 {mu}m. A careful cross-calibration using a diluted U-Th-Pb solution to calculate the Faraday reading to counting rate conversion factors and the highly suitable GJ-1 standard zircon for external calibrations were of paramount importance for obtaining reliable results. All age results were concordant within the experimental errors. The assigned age errors using the LA-MC-ICP-MS technique were, in most cases, higher than those obtained by SHRIMP, but if we are not faced with a high resolution stratigraphy, the laser technique has certain advantages. (author)

  8. Zircon's Archean of the Ural

    International Nuclear Information System (INIS)

    Krasnobaev, A.A.; Cherednichenko, N.V.

    2005-01-01

    The age of zircons from metamorphic rocks of the Taratashsky complex located on the Western slope of the South Urals was determined by the methods of U-Pb isotope dating. The age values obtained suggest a two-stage model of the complex evolution at early stages of its existence. The age of 2913±133 mln. years identifies the age of granulite metamorphism, while the age 2127±65 mln. years indicates the period of the most intensive transformations of the rocks within the complex, which were accompanied by occurrence of high-temperature diaphthorites [ru

  9. Soft mode of lead zirconate

    International Nuclear Information System (INIS)

    Pan'ko, G.F.; Prisedskij, V.V.; Klimov, V.V.

    1983-01-01

    Anisotropic diffusional scattering of electrons on PbZrO 3 crystal in the temperature range of phase transition has been recorded. As a result of its analysis it has been established that in lead zirconate the rotational vibrational mode G 25 plays the role of soft mode. The experiment is carried out using PbZrO 3 monocrystals in translucent electron microscope EhM-200, operating in the regime of microdiffraction at accelerating voltage of 150 kV and beam current 50 μA; sample preparation is realized using the method of shearing and fragmentation

  10. Elemental microanalysis of botanical specimens using the Melbourne Proton Microprobe

    International Nuclear Information System (INIS)

    Mazzolini, A.P.J.; Legge, G.J.F.

    1978-01-01

    A proton microprobe has been used to obtain the distribution of elements of various botanical specimens. This paper presents preliminary results obtained by the irradiation of certain organs of the wheat plant

  11. Subgroup report on hard x-ray microprobes

    International Nuclear Information System (INIS)

    Ice, G.E.; Barbee, T.; Bionta, R.; Howells, M.; Thompson, A.C.; Yun, W.

    1994-01-01

    The increasing availability of synchrotron x-ray sources has stimulated the development of advanced hard x-ray (E≥5 keV) microprobes. New x-ray optics have been demonstrated which show promise for achieving intense submicron hard x-ray probes. These probes will be used for extraordinary elemental detection by x-ray fluorescence/absorption and for microdiffraction to identify phase and strain. The inherent elemental and crystallographic sensitivity of an x-ray microprobe and its inherently nondestructive and penetrating nature makes the development of an advanced hard x-ray microprobe an important national goal. In this workshop state-of-the-art hard x-ray microprobe optics were described and future directions were discussed. Gene Ice, Oak Ridge National Laboratory (ORNL), presented an overview of the current status of hard x-ray microprobe optics and described the use of crystal spectrometers to improve minimum detectable limits in fluorescent microprobe experiments. Al Thompson, Lawrence Berkeley Laboratory (LBL), described work at the Center for X-ray Optics to develop a hard x-ray microprobe based on Kirkpatrick-Baez (KB) optics. Al Thompson also showed the results of some experimental measurements with their KB optics. Malcolm Howells presented a method for bending elliptical mirrors and Troy Barbee commented on the use of graded d spacings to achieve highest efficiency in KB multilayer microfocusing. Richard Bionta, Lawrence Livermore National Laboratory (LLNL), described the development of the first hard x-ray zone plates and future promise of so called open-quotes jelly rollclose quotes or sputter slice zone plates. Wenbing Yun, Argonne National Laboratory (ANL), described characterization of jelly roll and lithographically produced zone plates and described the application of zone plates to focus extremely narrow bandwidths by nuclear resonance. This report summarizes the presentations of the workshop subgroup on hard x-ray microprobes

  12. The new nuclear microprobe at Livermore

    International Nuclear Information System (INIS)

    Roberts, M.L.; Bench, G.S.; Heikkinen, D.W.; Morse, D.H.; Bach, P.R.; Pontau, A.E.

    1994-10-01

    Lawrence Livermore National Laboratory (LLNL) and Sandia National Laboratories/California have jointly constructed a new nuclear microprobe beamline. This beamline is located on the LLNL 10 MV tandem accelerator and can be used for multidisciplinary research using PIXE, PIGE, energy loss tomography, or IBS techniques. Distinctive features of the beamline include incorporation of magnet power supplies into the accelerator control system, computer controlled object and image slits, automated target positioning to sub-micron resolution, and video optics for beam positioning and observation. Mitigation of vibrations was accomplished with vibration isolators and a rigid beamline design while integral beamline shielding was used to shield from stray magnetic fields. Available detectors include a wavelength dispersive X-ray spectrometer, a High-Purity Germanium detector (HPGe), a Lithium-Drifted Silicon X-Ray detector (SiLi), and solid state surface barrier detectors. Along with beamline performance, results from recent measurements on determination of trace impurities in an International Thermonuclear Experimental Reactor (ITER) super conducting wire strand, determination of Ca/Sr ratios in seashells, and determination of minor and trace element concentrations in sperm cells are presented

  13. The INS nuclear microprobe and its application

    International Nuclear Information System (INIS)

    Coote, G.E.

    1986-01-01

    The nuclear microprobe directs a well-focused beam of high-energy protons or deuterons at a solid specimen inside a vacuum chamber. Atomic and nuclear reactions are induced in those elements in a layer about 20 micro m thick, leading to the emission of characteristic x-rays, gamma rays, and charged particles as well as Rutherford scattering of the incident beam. These radiations impinge on several detectors near the specimen (NaI, Ge(Li), Si(Li) and Si surface barrier). Using proton-excited x-rays all elements above Na may be detected with sensitivities 10 or 100 times that of the electron probe, while elements which can be estimated from their gamma rays include C, N, O, F, Na and Al. In most of our projects the distribution of a trace or minor element (e.g. F, N) is compared to that of a major element (e.g. Ca or Fe). Recent areas of application include archaeometry (diffusion profiles of F in bones and teeth; depth profiles of sodium in obsidian), geology (F concentrations in mineral grains; studies of the Cretaceous-Tertiary boundary), metallurgy (C, O, N in steel and in welds; S, O, C in corrosion layers), fisheries management (Zn, Sr in otoliths; F in dogfish fin spines and vertebrae), biology (Fe, Sr, N in egg shells; trace elements in human hair), and dental research

  14. Deep Space 2: The Mars Microprobe Mission

    Science.gov (United States)

    Smrekar, Suzanne; Catling, David; Lorenz, Ralph; Magalhães, Julio; Moersch, Jeffrey; Morgan, Paul; Murray, Bruce; Presley-Holloway, Marsha; Yen, Albert; Zent, Aaron; Blaney, Diana

    The Mars Microprobe Mission will be the second of the New Millennium Program's technology development missions to planetary bodies. The mission consists of two penetrators that weigh 2.4 kg each and are being carried as a piggyback payload on the Mars Polar Lander cruise ring. The spacecraft arrive at Mars on December 3, 1999. The two identical penetrators will impact the surface at ~190 m/s and penetrate up to 0.6 m. They will land within 1 to 10 km of each other and ~50 km from the Polar Lander on the south polar layered terrain. The primary objective of the mission is to demonstrate technologies that will enable future science missions and, in particular, network science missions. A secondary goal is to acquire science data. A subsurface evolved water experiment and a thermal conductivity experiment will estimate the water content and thermal properties of the regolith. The atmospheric density, pressure, and temperature will be derived using descent deceleration data. Impact accelerometer data will be used to determine the depth of penetration, the hardness of the regolith, and the presence or absence of 10 cm scale layers.

  15. Proton microprobe analysis of pancreatic. beta. cells

    Energy Technology Data Exchange (ETDEWEB)

    Lindh, U [Uppsala Univ. (Sweden). Gustaf Werner Inst.; Juntti-Berggren, L; Berggren, P O; Hellman, B [Uppsala Univ. (Sweden)

    1985-01-01

    Freeze-dried pancreas sections from obese hyperglycemic mice were subjected to proton bombardment and the elemental contents in the ..beta.. cells and the exocrine part were obtained from the characteristic X-rays emitted. Quantitative data were provided for 18 different elements. The mole ratio between K and Na exceeded 10, implying that neither the sample preparation nor the irradiation had induced significant diffuse changes. With the demonstration of this high K/Na ratio it seems likely that also the ..beta.. cells are equipped with an efficient Na/sup +//K/sup +/ pump. The ..beta.. cells contained about 70 mmoles Cl per litre cell water. Observed amounts of Ca and Mg were equivalent to those previously recorded by electrothermal atomic absorption spectroscopy. The significant role of Zn for the storage of insulin was emphasized by the demonstration of 3 times as much of this element in the ..beta.. cells as compared with the exocrine pancreas. In addition, the sensitivity of the proton microprobe enabled measurements of various trace elements such as Rb, Cr, Cu, Al and Pb not previously demonstrated in the pancreatic ..beta.. cells.

  16. Enthalpy of formation of zircon

    International Nuclear Information System (INIS)

    Ellison, A.J.G.; Navrotsky, A.

    1992-01-01

    Using high-temperature solution calorimetry in molt 2PbO · B 2 O 3 , the enthalpy of reaction of the formation of zircon, ZrSiO 4 , from its constituent oxides has been determined: Δ 4 H 977 (ZrSiO 4 ) = -27.9 (±1.9) kJ/mol. With previously reported data for the heat contents of ZrO 2 SiO 2 and ZrSiO 4 and standard-state enthalpies of formation of ZrO 2 and SiO 2 , we obtain Δ f H 298 degrees. (ZrSiO 4 ) = -2034.2 (±3.1) kJ/mol and Δ t G 298 degrees (ZrSiO 4 ) = -1919.8 kJ/mol. The free energy value is in excellent agreement with a range previously estimated from solid-state reaction equilibria. At higher temperature also the data are in close agreement with existing data, though the data sets diverge somewhat with increasing T. In this paper the limitations of the data for predicting the breakdown temperature of zircon into its constituent oxides are discussed

  17. Cs+ ion source for secondary ion mass spectrometry

    International Nuclear Information System (INIS)

    Bentz, B.L.; Weiss, H.; Liebl, H.

    1981-12-01

    Various types of cesium ionization sources currently used in secondary ion mass spectrometry are briefly reviewed, followed by a description of the design and performance of a novel, thermal surface ionization Cs + source developed in this laboratory. The source was evaluated for secondary ion mass spectrometry applications using the COALA ion microprobe mass analyzer. (orig.)

  18. U-Pb ages and geochemistry of zircon from Proterozoic plutons of the Sawatch and Mosquito ranges, Colorado, U.S.A.: Implications for crustal growth of the central Colorado province

    Science.gov (United States)

    Moscati, Richard J.; Premo, Wayne R.; Dewitt, Ed; Wooden, Joseph L.

    2017-01-01

    A broad study of zircons from plutonic rocks of the Sawatch and Mosquito ranges of west-central Colorado (U.S.A.) was undertaken to significantly refine the magmatic chronology and chemistry of this under-studied region of the Colorado province. This region was chosen because it lies just to the north of the suspected arc-related Gunnison-Salida volcano-plutonic terrane, which has been the subject of many recent investigations—and whose origin is still debated. Our new results provide important insights into the processes active during Proterozoic crustal evolution in this region, and they have important ramifications for broader-scope crustal evolution models for southwestern North America.Twenty-four new U-Pb ages and sequentially acquired rare-earth element (REE), U, Th, and Hf contents of zircon have been determined using the sensitive high-resolution ion microprobe-reverse geometry (SHRIMP-RG). These zircon geochemistry data, in conjunction with whole-rock major- and trace-element data, provide important insights into zircon crystallization and melt fractionation, and they help to further constrain the tectonic environment of magma generation.Our detailed zircon and whole-rock data support the following three interpretations:(1) The Roosevelt Granite in the southern Sawatch Range was the oldest rock dated at 1,766 ± 7 Ma, and it intruded various metavolcanic and metasedimentary rocks. Geochemistry of both whole-rock and zircon supports the contention that this granite was produced in a magmatic arc environment and, therefore, is likely an extension of the older Dubois Greenstone Belt of the Gunnison Igneous Complex (GIC) and the Needle Mountains (1,770–1,755 Ma). Rocks of the younger Cochetopa succession of the GIC, the Salida Greenstone Belt, and the Sangre de Cristo Mountains (1,740–1,725 Ma) were not found in the Sawatch and Mosquito ranges. This observation strongly suggests that the northern edge of the Gunnison-Salida arc terrane underlies the

  19. Inflight dissociation of zircon in air plasma

    Energy Technology Data Exchange (ETDEWEB)

    Yugeswaran, S; Selvarajan, V [Bharathiar University, Coimbatore 641046 (India); Ananthapadmanabhan, P V; Thiyagarajan, T K [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai - 400 085 (India); Nair, Janardhanan [Ion Arc Technologies Pvt Ltd, Coimbatore (India)

    2010-02-01

    Thermal dissociation of zircon can be conveniently carried out in a plasma reactor, which is characterized by high temperature, high energy density and high quench rate. Zirconia is recovered from this partially dissociated zircon by alkali leaching. Dissociation of zircon has been conventionally carried out in argon gas, which is expensive. The present paper reports experimental results on thermal dissociation of zircon in air plasma medium. Process simulation for 'inflight' dissociation of zircon in air plasma medium is also presented. The experimental system consists of a central hollow graphite electrode, which acts as the cathode and a graphite anode. The material to be processed is fed centrally through the cathode. The unique feature of the system is that it uses air as the working gas to generate the thermal plasma. The system has been used to study in-flight dissociation of zircon in the thermal plasma jet. Dissociation was carried out over 10-25 kW power range. Results of the study indicate that complete dissociation of zircon to ZrO{sub 2} and silica could be accomplished at 25 kW in air plasma.

  20. Inflight dissociation of zircon in air plasma

    International Nuclear Information System (INIS)

    Yugeswaran, S; Selvarajan, V; Ananthapadmanabhan, P V; Thiyagarajan, T K; Nair, Janardhanan

    2010-01-01

    Thermal dissociation of zircon can be conveniently carried out in a plasma reactor, which is characterized by high temperature, high energy density and high quench rate. Zirconia is recovered from this partially dissociated zircon by alkali leaching. Dissociation of zircon has been conventionally carried out in argon gas, which is expensive. The present paper reports experimental results on thermal dissociation of zircon in air plasma medium. Process simulation for 'inflight' dissociation of zircon in air plasma medium is also presented. The experimental system consists of a central hollow graphite electrode, which acts as the cathode and a graphite anode. The material to be processed is fed centrally through the cathode. The unique feature of the system is that it uses air as the working gas to generate the thermal plasma. The system has been used to study in-flight dissociation of zircon in the thermal plasma jet. Dissociation was carried out over 10-25 kW power range. Results of the study indicate that complete dissociation of zircon to ZrO 2 and silica could be accomplished at 25 kW in air plasma.

  1. Environmental applications of the LANL nuclear microprobe

    International Nuclear Information System (INIS)

    Hickmott, D.D.; Herrin, J.M.; Abell, R.; George, M.; Gauerke, E.R.; Denniston, R.F.

    1997-01-01

    The LANL nuclear microprobe has been used to study the distributions of trace elements (TE) of environmental interest including: (1) metals in coal and fly ash, (2) Pb in the Bandelier Tuff (BT), (3) Ba in tree rings, (4) Mn, Fe, Sr and Y in Yucca Mountain calcites. Micro-PIXE (MP) analyses with 5-10 micrometer spatial resolution provide constraints on processes that redistribute contaminants in the environment, and hence may help answer environmental problems where fine-scale chemical records are important. MP analyses of particulates in coal and ash show that pyrite contains As, Se, Hg and Pb; macerals contain Cr, halogens and S; cenospheres contain As, Se and Ni; and hematite ash contains Ni and As. Understanding these elemental modes of occurrence allows prediction of metal behavior in boilers and may enhance compliance with the Clean Air Act Amendments. Fine-grained high-Pb minerals were identified using SEM and MP analyses of BT minerals. These minerals were from samples associated with deep-groundwater wells containing Pb at levels greater than regulatory limits. Pb is concentrated in Pb minerals (e.g. cerussite), smectite, and hematite formed during low-T alteration of tuff. Understanding mineralogic speciation of metals may provide insights into sources of groundwater pollution. Tree rings from ponderosa pines that grew in a Ba-contaminated drainage were analyzed using MP. Ba concentrations are typically higher in rings that formed after operations discharging Ba to the environment began. Such tree-ring analyses may ultimately provide information on rates of contaminant migration in the environment. TE in zoned calcites from Yucca Mountain were analyzed by MP. Calcites from the saturated zone (SZ) have distinct chemical signatures (high Fe, Mn and low Y). No calcites in the unsaturated zone with SZ chemical signatures were found using MP

  2. Beneficiation of low grade zircon concentrate

    International Nuclear Information System (INIS)

    Rehim, A.A.

    1976-01-01

    The zircon concentrate obtained from black sands, contains considerable amount of rutile and some ilmenite. It is necessary to separate these minerals before the metallurgical processing of zircon, as otherwise the zirconium products obtained will be contaminated with large amount of titanium. The present work explores the possibility of purification of zircon from rutile and other minerals by flotation. Effective separation can be obtained by selective flotation using oleic acid and liquid glass in alkaline medium or sodium silicon fluoride in weak acidic medium. (author)

  3. Refractory Materials of Zirconate. Part 2: Synthesis and some properties of strontium, zirconate, calcium zirconate and barium zirconate

    Science.gov (United States)

    Okubo, Tsutomo; Yonemochi, Osamu; Nakamura, Kazuo; Maeda, Minoru

    1988-01-01

    Chemical compounds SrZrO3, CaZrO3, and BaZrO3 were synthesized by solid reaction and arc fusion, and their properties examined. Results were as follows: (1) in the synthesis of CaZrO3 by solid reaction, ZrO2 solid solution with cubic form was produced, which then changed into CaZrO3; (2) the BaZrO3 was a cubic form and did not show any transformation, while SrZrO3 and CaZrO3 with an orthorhombic form transformed to a cubic form at high temperature; and (3) the solubility of BaZrO3 in acid and its vaporization rate at a high temperature were greater than those of zirconates.

  4. On the valency state of radiogenic lead in zircon and its consequences

    DEFF Research Database (Denmark)

    Kramers, J.; Frei, Robert; Newville, M.

    2009-01-01

    nucleus comes to rest. Further, a zircon grain, being small, should remain highly oxidizing in its interior by the constant loss of ß-particles, maintaining the 4+ state of radiogenic Pb. From its effective ion radius, similar to that of Zr4+, and its charge, Pb4+ has to be compatible in the zircon...... not resemble that of PbO2. The arguments why radiogenic Pb should be tetravalent are based on analogies with studies relating to the tetravalent state of 234Th and the hexavalent state of 234U, which show that a-recoil in silicates generates a strongly oxidizing environment at the site where the recoiling......-recoil damaged sites could be leached out by any electrolyte solution that reduces it to the divalent state, making it both incompatible and soluble. Thus, discordia can be generated in weathering. The curious observation that discordant Archaean zircon suites generally define trends to lower intercepts at up...

  5. U-Pb dating by zircon dissolution method using chemical abrasion

    Energy Technology Data Exchange (ETDEWEB)

    Takehara, Lucy, E-mail: lucytakehara@gmail.com.br [Servico Geologico do Brasil (CPRM), Brasilia, DF (Brazil); Chemale Junior, Farid [Universidade de Brasilia (UnB), Brasilia, DF (Brazil). Inst. de Geociencias. Lab. de Geocronologia; Hartmann, Leo A. [Universidade Federal do Rio Grande do Sul (UFRS), Porto Alegre, RS (Brazil). Inst. de Geociencias; Dussin, Ivo A.; Kawashita, Koji [Universidade de Sao Paulo (USP), SP, (Brazil). Centro de Pesquisa Geocronologicas

    2012-06-15

    Chemical abrasion was carried out on zircons grains of the Temora II standard for U-Pb dating prior to analyses using in situ Laser Ablation-Multi Collector Ion Coupled Plasma Mass Spectrometer (LA-ICPMS) followed by the Isotope Dissolution Thermal Ionization Mass Spectrometer (ID-TIMS) method. The proposed methodology was herein applied in order to reduce primarily the effects of secondary Pb loss, the presence of common lead and/or silicate impurities. Nine Temora II zircon grains were analyzed by the laser ablation method yielding an age of 418.3 +- 4.3 Ma. Zircon grains of a same population were separated for chemical abrasion before dissolution and mass spectrometry analyses. Six fractions of them were separated for isotope dissolution using {sup 235}U-{sup 205}Pb mixed spike after we have checked and assured the laboratory conditions of low blank values for total Pb of less than 2 pg/g. The obtained U-Pb zircon age by the ID-TIMS method was 415.7 +- 1.8 Ma (error 0.43 %) based on four successful determinations. The results are consistent with the published ages for the Temora diorite (Temora I - 416.75 +- 1.3 Ma; Temora II - 416.78 +- 0.33 Ma) and established as 416 +- 0.33 Ma. The technique is thus recommended for high precision U-Pb zircon analyses (error < 1 %), mainly for high resolution stratigraphic studies of Phanerozoic sequences. (author)

  6. Quantitative analysis method for niobium in lead zirconate titanate

    International Nuclear Information System (INIS)

    Hara, Hideo; Hashimoto, Toshio

    1986-01-01

    Lead zirconate titanate (PZT) is a strong dielectric ceramic having piezoelectric and pyroelectric properties, and is used most as a piezoelectric material. Also it is a main component of lead lanthanum zirconate titanate (PLZT), which is a typical electrical-optical conversion element. Since these have been developed, the various electronic parts utilizing the piezoelectric characteristics have been put in practical use. The characteristics can be set up by changing the composition of PZT and the kinds and amount of additives. Among the additives, niobium has the action to make metallic ion vacancy in crystals, and by the formation of this vacancy, to ease the movement of domain walls in crystal grains, and to increase resistivity. Accordingly, it is necessary to accurately determine the niobium content for the research and development, quality control and process control. The quantitative analysis methods for niobium used so far have respective demerits, therefore, the authors examined the quantitative analysis of niobium in PZT by using an inductively coupled plasma emission spectro-analysis apparatus which has remarkably developed recently. As the result, the method of dissolving a specimen with hydrochloric acid and hydrofluoric acid, and masking unstable lead with ethylene diamine tetraacetic acid 2 sodium and fluoride ions with boric acid was established. The apparatus, reagents, the experiment and the results are reported. (Kako, I.)

  7. Early works on the nuclear microprobe for microelectronics irradiation tests at the CEICI (Sevilla, Spain)

    International Nuclear Information System (INIS)

    Palomo, F.R.; Morilla, Y.; Mogollon, J.M.; Garcia-Lopez, J.; Labrador, J.A.; Aguirre, M.A.

    2011-01-01

    Particle radiation effects are a fundamental problem in the use of numerous electronic devices for space applications, which is aggravated with the technology shrinking towards smaller and smaller scales. The suitability of low-energy accelerators for irradiation testing is being considered nowadays. Moreover, the possibility to use a nuclear microprobe, with a lateral resolution of a few microns, allows us to evaluate the behavior under ion irradiation of specific elements in an electronic device. The CEICI is the new CEnter for Integrated Circuits Irradiation tests, created into the facilities at the Centro Nacional de Aceleradores (CNA) in Sevilla-Spain. We have verified that our 3 MV Tandem accelerator, typically used for ion beam characterization of materials, is also a valuable tool to perform irradiation experiments in the low LET (Linear Energy Transfer) region.

  8. Proton microprobe analysis of zinc in skeletal tissues

    Science.gov (United States)

    Doty, S. B.; Jones, K. W.; Kraner, H. W.; Shroy, R. E.; Hanson, A. L.

    1981-03-01

    A proton microprobe with windowless exit port has been used to study zinc distributions in various types of skeletal tissues. The use of an external beam facilitated positioning of the targets for examination of particular points of interest. The proton microprobe is uniquely suited to this work since it combines high sensitivity for zinc determination in thick samples with good spatial resolution. Our measurements on rat and rabbit Achilles tendon showed a significant increase in zinc concentrations as the beam moved from the unmineralized collagen into the mineralized attachment site. Cartilage gave a similar result, with calcified cartilage having a greater zinc level than the articular surface on unmineralized epiphyseal cartilage.

  9. The CEA nuclear microprobe. Description, possibilities, application examples

    International Nuclear Information System (INIS)

    Engelmann, C.; Bardy, J.

    1986-05-01

    The nuclear microprobe installed on one of the beam lines of a 4 MV Van de Graaff located in the Research Center of Bruyeres-le-Chatel is described. The various possibilities, particularly the imaging system, and the performances of the instrument are exposed. Two typical application examples concerning, the first, the determination of the deuterium and tritium in glass microballons, the second, the detection and the localization of carbon and oxygen in the superficial layer of lithium hydride pellets, are given. Preliminary results of some other application examples are also presented. The advantages of the nuclear microprobe over the other ponctual analysis techniques are emphasized. 7 refs, 19 figs [fr

  10. The remote control of nuclear microprobes over the Internet

    International Nuclear Information System (INIS)

    Churms, C.L.; Prozesky, V.M.; Springhorn, K.A.

    1999-01-01

    Whereas the concept of remote control is not new, the required equipment and data link have typically been costly and specialized. With the growing availability of reliable Internet connection, it has however become possible and increasingly attractive to be able to control complex equipment remotely over the Internet. Some methods of Internet Remote control are discussed, bearing in mind the specific needs of nuclear microprobe control. One such system has been implemented at the NAC nuclear microprobe, and even though improvements are envisaged, it is already functioning satisfactorily

  11. Extraterrestrial materials examined by mean of nuclear microprobe

    Science.gov (United States)

    Khodja, H.; Smith, T.; Engrand, C.; Herzog, G.; Raepsaet, C.

    2013-07-01

    Comet fragments, micrometeorites, and Interplanetary Dust Particles (IDPs) are small objects (purpose, we need instruments and methods that provide both microanalysis and detailed imaging. In these respects, the nuclear microprobe offers many potential advantages: (i) the spatial resolution, ∼1 μm is well-matched to the typical object dimensions, (ii) with some reservations, it is non-destructive when carefully conducted, (iii) it is quantitative, and especially sensitive for light elements. At the Saclay nuclear microprobe, we have been performing analyses of extraterrestrial objects for many years. We review some of these studies, emphasizing the specific requirements for successful analyses. We also discuss the potential pitfalls that may be encountered.

  12. Proton microprobe analysis of zinc in skeletal tissues

    International Nuclear Information System (INIS)

    Doty, S.B.; Jones, K.W.; Kraner, H.W.; Shroy, R.E.; Hanson, A.L.

    1980-06-01

    A proton microprobe with windowless exit port was used to study zinc distributions in various types of skeletal tissues. The use of an external beam facilitated positioning of the targets for examination of particular points of interest. The proton microprobe is uniquely suited to this work since it combines high sensitivity for zinc determinations in thick samples with good spatial resolution. Measurements on rat and rabbit Achilles tendon showed a significant increase in zinc concentrations as the beam moved from the unmineralized collagen into the mineralized attachment site. Cartilage gave a similar result, with calcified cartilage having a greater zinc level than the articular surface on unmineralized epiphyseal cartilage

  13. Synchrotron radiation XRF microprobe study of human bone tumor slice

    International Nuclear Information System (INIS)

    Huang Yuying; Zhao Limin; Wang Zhouguang; Shao Hanru; Li Guangcheng; Wu Yingrong; He Wei; Lu Jianxin; He Rongguo

    1999-01-01

    The experimental apparatus of X-ray fluorescence (XRF) microprobe analysis at Beijing Synchrotron Radiation Facility (BSRF) is described. Using the bovine liver as the standard reference, the minimum detection limit (MDL) of trace element was measured to determine the capability of biological sample analysis by synchrotron radiation XRF microprobe. The relative change of the content of the major or trace element in the normal and tumor part of human bone tissue slice was investigated. The experimental result relation to the clinical medicine was also discussed. (author)

  14. Tracking magmatic processes through Zr/Hf ratios in rocks and Hf and Ti zoning in zircons: An example from the Spirit Mountain batholith, Nevada

    Science.gov (United States)

    Lowery, Claiborne L.E.; Miller, C.F.; Walker, B.A.; Wooden, J.L.; Mazdab, F.K.; Bea, F.

    2006-01-01

    Zirconium and Hf are nearly identical geochemically, and therefore most of the crust maintains near-chondritic Zr/Hf ratios of ???35-40. By contrast, many high-silica rhyolites and granites have anomalously low Zr/Hf (15-30). As zircon is the primary reservoir for both Zr and Hf and preferentially incorporates Zr, crystallization of zircon controls Zr/ Hf, imprinting low Zr/Hf on coexisting melt. Thus, low Zr/Hf is a unique fingerprint of effective magmatic fractionation in the crust. Age and compositional zonation in zircons themselves provide a record of the thermal and compositional histories of magmatic systems. High Hf (low Zr/ Hf) in zircon zones demonstrates growth from fractionated melt, and Ti provides an estimate of temperature of crystallization (TTiZ) (Watson and Harrison, 2005). Whole-rock Zr/Hf and zircon zonation in the Spirit Mountain batholith, Nevada, document repeated fractionation and thermal fluctuations. Ratios of Zr/Hf are ???30-40 for cumulates and 18-30 for high-SiO2 granites. In zircons, Hf (and U) are inversely correlated with Ti, and concentrations indicate large fluctuations in melt composition and TTiZ (>100??C) for individual zircons. Such variations are consistent with field relations and ion-probe zircon geochronology that indicate a >1 million year history of repeated replenishment, fractionation, and extraction of melt from crystal mush to form the low Zr/Hf high-SiO2 zone. ?? 2006 The Mineralogical Society.

  15. Influence of gadolinium concentration on the EMR spectrum of Gd{sup 3+} in zircon

    Energy Technology Data Exchange (ETDEWEB)

    Biasi, R.S. de, E-mail: rsbiasi@ime.eb.b [Secao de Engenharia Mecanica e de Materiais, Instituto Militar de Engenharia, 22290-270 Rio de Janeiro, RJ (Brazil); Grillo, M.L.N., E-mail: mluciag@uerj.b [Instituto de Fisica, Universidade do Estado do Rio de Janeiro, 20550-013 Rio de Janeiro, RJ (Brazil)

    2009-11-01

    Electron magnetic resonance (EMR) spectra of gadolinium-doped zircon (ZrSiO{sub 4}) powders have been studied at room temperature for gadolinium concentrations between 0.20 and 1.0 mol%. The results suggest that Gd{sup 3+} ions occupy substitutional sites in the zircon lattice, that the electron magnetic resonance linewidth increases with increasing gadolinium concentration and that the range of the exchange interaction between Gd{sup 3+} ions is about 1.17 nm, larger than that of the same ion in other host lattices, such as ceria (CeO{sub 2}), strontium oxide (SrO) and calcium oxide (CaO). The fact that the electron magnetic resonance linewidth of the Gd{sup 3+} ion in polycrystalline zircon increases, regularly and predictably, with Gd concentration, shows that the Gd{sup 3+} ion can be used as a probe to study, rapidly and non-destructively, the crystallinity and degradation of ZrSiO{sub 4}.

  16. An SU-8-based microprobe with a nanostructured surface enhances neuronal cell attachment and growth

    Science.gov (United States)

    Kim, Eunhee; Kim, Jin-Young; Choi, Hongsoo

    2017-12-01

    Microprobes are used to repair neuronal injury by recording electrical signals from neuronal cells around the surface of the device. Following implantation into the brain, the immune response results in formation of scar tissue around the microprobe. However, neurons must be in close proximity to the microprobe to enable signal recording. A common reason for failure of microprobes is impaired signal recording due to scar tissue, which is not related to the microprobe itself. Therefore, the device-cell interface must be improved to increase the number of neurons in contact with the surface. In this study, we developed nanostructured SU-8 microprobes to support neuronal growth. Nanostructures of 200 nm diameter and depth were applied to the surface of microprobes, and the attachment and neurite outgrowth of PC12 cells on the microprobes were evaluated. Neuronal attachment and neurite outgrowth on the nanostructured microprobes were significantly greater than those on non-nanostructured microprobes. The enhanced neuronal attachment and neurite outgrowth on the nanostructured microprobes occurred in the absence of an adhesive coating, such as poly- l-lysine, and so may be useful for implantable devices for long-term use. Therefore, nanostructured microprobes can be implanted without adhesive coating, which can cause problems in vivo over the long term.

  17. The French AEC nuclear microprobe: description and first application examples

    International Nuclear Information System (INIS)

    Engelmann, C.; Bardy, J.

    1983-05-01

    The major components of the microprobe are briefly described. The performances and the varying possibilities authorized by the instrument are given. Some application examples concerning especially the determination of concentration profiles in an aqueous leached glass and the distribution of deuterium in a graphite sample exposed to plasma in a Tokamak device are presented

  18. Elemental composition of paint cross sections by nuclear microprobe analysis

    International Nuclear Information System (INIS)

    Nens, B.; Trocellier, P.; Engelmann, C.; Lahanier, C.

    1982-09-01

    Physico-chemical characterization of pigments used in artistic painting give precious indications on age of paintings and sometimes on geographical origin of ores. After recalling the principle of protons microprobe, first results obtained by microanalysis of painting cross sections for non destructive microanalysis of impurities in white lead are given [fr

  19. Detrital Zircons Split Sibumasu in East Gondwana

    Science.gov (United States)

    Zhang, X.; Chung, S. L.

    2017-12-01

    It is widely accepted that Sibumasu developed as a united terrane and originated from NW Australian margin in East Gondwana. Here we report new detrital zircon U-Pb-Hf isotopic data from Sumatra that, in combination with literature data, challenge and refute the above long-held view. In particular, the East and West Sumatra terranes share nearly identical Precambrian to Paleozoic detrital zircon age distributions and Hf isotopes, indicating a common provenance/origin for them. The Sumatra detrital zircons exhibit a prominent population of ca. 1170-1070 Ma, indistinguishable from those of the Lhasa and West Burma terranes, with detritus most probably sourcing from western Australia. By contrast, Sibuma (Sibumasu excluding Sumatra) detrital zircons display a prevailing population of ca. 980-935 Ma, strongly resembling those of the western Qiangtang terrane, with detrital materials most likely derived from Greater India and Himalayas. Such markedly distinct detrital zircon age profiles between Sumatra and Sibuma require disparate sources/origin for them, provoking disintegration of the widely-adopted, but outdated, term Sibumasu and thus inviting a new configuration of East Gondwana in the early Paleozoic, with Sumatra and West Burma lying outboard the Lhasa terrane in the NW Australian margin and Sibuma situated in the northern Greater Indian margin. More future investigations are needed to establish the precise rifting and drifting histories of Sumatra and Sibuma, as two separated terranes, during the breakup of Gondwana.

  20. Constraints on the timing of multiple thermal events and re-equilibration recorded by high-U zircon and xenotime: Case study of pegmatite from Piława Górna (Góry Sowie Block, SW Poland)

    Science.gov (United States)

    Budzyń, Bartosz; Sláma, Jiří; Kozub-Budzyń, Gabriela A.; Konečný, Patrik; Holický, Ivan; Rzepa, Grzegorz; Jastrzębski, Mirosław

    2018-06-01

    The application of zircon and xenotime geochronometers requires knowledge of their potential and limitations related to possible disturbance of the age record. The alteration of the intergrown zircon and xenotime in pegmatite from the Góry Sowie Block (SW Poland) was studied using the electron microprobe analysis, X-ray WDS compositional mapping, micro-Raman analysis, and LA-ICP-MS U-Pb dating of zircon and xenotime, as well as the U-Th-total Pb dating of uraninite. These microanalytical techniques were applied to understand the formation mechanisms of the secondary textures related to post-magmatic processes in the zircon and xenotime intergrowth, and to constrain their timing. Textural and compositional features combined with U-Pb data indicate that the pegmatite-related crystallization of the zircon and xenotime intergrowth occurred ca. 2.09 Ga (2086 ± 35 Ma for zircon and 2093 ± 52 Ma for xenotime), followed by the re-equilibration of zircon and xenotime ca. 370 Ma (373 ± 18 Ma and 368 ± 6 Ma, respectively) during the formation of the younger pegmatite. The zircon and xenotime were most likely derived from Precambrian basement rocks and emplaced in the pegmatite as a restite. The zircon preserved textures related to diffusion-reaction processes that affected its high-U core (up to ca. 9.6 wt% UO2), which underwent further metamictization and amorphization due to self-radiation damage. The zircon rim and xenotime were affected by coupled dissolution-reprecipitation processes that resulted in patchy zoning, age disturbance and sponge-like textures. Xenotime was also partially replaced by fluorapatite or hingganite-(Y) and Y-enriched allanite-(Ce). The termination of the low-temperature alteration was constrained by the U-Th-total Pb age of the uraninite inclusions that crystallized in zircon at 281 ± 2 Ma, which is consistent with the age of 278 ± 15 Ma obtained from the youngest cluster of U-Pb ages in the re-equilibrated high-U zircon domains. This study

  1. Fission track dating of kimberlitic zircons

    International Nuclear Information System (INIS)

    Haggerty, S.E.

    1983-01-01

    The only reliable method for dating kimberlites at present is the lengthy and specialized hydrothermal procedure that extracts 206 Pb and 238 U from low-uranium zircons. This paper describes a second successful method by fission track dating of large single-crystal zircons, 1.0-1.5 cm in dimension. The use of large crystals overcomes the limitations imposed in conventional fission track analysis which utilizes crushed fragments. Low track densities, optical track dispersion, and the random orientation of polished surfaces in the etch and irradiation cycle are effectively overcome. Fission track ages of zircons from five African kimberlites are reported, from the Kimberley Pool (90.0 +- 6.5 m.y.), Orapa (87.4 +- 5.7 and 92.4 +- 6.1 m.y.), Nzega (51.1 +- 3.8 m.y.), Koffiefontein (90.9 +- 8.2 m.y.), and Val do Queve (133.4 +- 11.5 m.y.). In addition we report the first radiometric ages (707.9 +- 59.6 and 705.5 +- 61.0 m.y.) of crustal zircons from kimberlites in northwest Liberia. The fission track ages agree well with earlier age estimates. Most of the zircons examined in this study are zoned with respect to uranium but linear correlations are established (by regression analysis) between zones of variable uranium content, and within zones of constant uranium content (by analysis of variance). Concordance between the fission track method and the U/Pb technique is established and we concluded that track fading from thermal annealing has not taken place. Kimberlitic zircons dated in this study, therefore, record the time of eruption. (orig.)

  2. Decoding a protracted zircon geochronological record in ultrahigh temperature granulite, and persistence of partial melting in the crust, Rogaland, Norway

    Science.gov (United States)

    Laurent, Antonin T.; Bingen, Bernard; Duchene, Stephanie; Whitehouse, Martin J.; Seydoux-Guillaume, Anne-magali; Bosse, Valerie

    2018-04-01

    This contribution evaluates the relation between protracted zircon geochronological signal and protracted crustal melting in the course of polyphase high to ultrahigh temperature (UHT; T > 900 °C) granulite facies metamorphism. New U-Pb, oxygen isotope, trace element, ion imaging and cathodoluminescence (CL) imaging data in zircon are reported from five samples from Rogaland, South Norway. The data reveal that the spread of apparent age captured by zircon, between 1040 and 930 Ma, results both from open-system growth and closed-system post-crystallization disturbance. Post-crystallization disturbance is evidenced by inverse age zoning induced by solid-state recrystallization of metamict cores that received an alpha dose above 35 × 1017 α g-1. Zircon neocrystallization is documented by CL-dark domains displaying O isotope open-system behaviour. In UHT samples, O isotopic ratios are homogenous (δ18O = 8.91 ± 0.08‰), pointing to high-temperature diffusion. Scanning ion imaging of these CL-dark domains did not reveal unsupported radiogenic Pb. The continuous geochronological signal retrieved from the CL-dark zircon in UHT samples is similar to that of monazite for the two recognized metamorphic phases (M1: 1040-990 Ma; M2: 940-930 Ma). A specific zircon-forming event is identified in the orthopyroxene and UHT zone with a probability peak at ca. 975 Ma, lasting until ca. 955 Ma. Coupling U-Pb geochronology and Ti-in-zircon thermometry provides firm evidence of protracted melting lasting up to 110 My (1040-930 Ma) in the UHT zone, 85 My (ca. 1040-955 Ma) in the orthopyroxene zone and some 40 My (ca. 1040-1000 Ma) in the regional basement. These results demonstrate the persistence of melt over long timescales in the crust, punctuated by two UHT incursions.

  3. Laser microprobe mass spectrometry: Potential and limitations for inorganic and organic micro-analysis. Pt. 1

    International Nuclear Information System (INIS)

    Vaeck, I. van; Gijbels, R.

    1990-01-01

    Laser microprobe mass spectrometry (LMMS) employs a highly focused UV laser beam to ionise a microvolume in the order of 1 μm 3 . The ions produced are then mass-separated in a time-of-flight (TOF) or a Fourier Transform (FT) mass spectrometer. TOF LMMS allows element localisation, detailed speciation of inorganic substances and structural information of organic molecules. Quantitation is difficult. This paper focuses on instrumental aspects and inorganic analysis. Organic applications are treated in part II of this series. Selected examples illustrate that TOF LMMS is a valuable tool for the qualitative characterisation of micro-samples. Also, the applicability to the analysis with high spatial resolution is shown. The current technology and the prospects from the recent FTMS development are discussed. (orig.)

  4. Laser microprobe mass spectrometry: Potential and limitations for inorganic and organic micro-analysis. Pt. 2

    International Nuclear Information System (INIS)

    Vaeck, I. van; Gijbels, R.

    1990-01-01

    Laser microprobe mass spectrometry (LMMS) employs a highly focused UV laser beam to ionise a microvolume in the order of 1 μm 3 . The produced ions are then mass-separated in a time-of-flight (TOF) or a Fourier Transform (FT) mass spectrometer. The technique allows element localisation, detailed speciation of inorganic substances and structural information of organic molecules. Inorganic applications are treated in the preceding part. This paper will focus on the organic aspects. Selected examples illustrate that TOF LMMS can achieve structural characterisation of molecules, untractable by conventional mass spectrometric techniques. Applicability to the analysis with high spatial resolution is shown and the need for surface availability of organic target molecules is discussed. The recently developed FT LMMS may fulfil the need for better mass resolution. However, the comparability of FT LMMS results with TOF LMMS data is not yet obvious. (orig.)

  5. Nuclear microprobe analysis of muscle biopsies: Applications in pathology and clinic

    International Nuclear Information System (INIS)

    Moretto, Ph.; Coquet, M.; Gherardi, R.K.; Stoedzel, P.

    2000-01-01

    The nuclear microprobe analysis of muscle biopsy sections has been recently applied to investigate different muscle disorders. This technique, employed as a complementary examination in the frame of pathological studies, permitted to confirm the diagnosis for a first pathology and to elucidate the cause of a second. In skeletal muscles of a young patient suffering from a slow progressive myopathy, calcium accumulations have been demonstrated in histologically abnormal fibers. These findings have been compared to histopathological characteristics previously described. On the other hand, we have evaluated muscle sections from two patients who presented symptoms of an inflammatory myopathy, a rare pathology that recently emerged in France. The chemical analyses permitted us to highlight local aluminium infiltration in muscles. The hypothesis of an unusual reaction to intramuscular aluminium accumulation has been advanced. These studies demonstrate the capability for ion beam microanalytical techniques to address acute problems in pathology

  6. Extraction of zirconium from zircon (A new process)

    International Nuclear Information System (INIS)

    Shahid, K.A.; Saeed, D.; Jan, S.; Masood, A.; Akhtar, J.

    1985-10-01

    A new process has been used for the extraction of zirconium from zircon. Caustic fritting was done in the presence of magnesium hydroxide carbonate and magnesium oxide. These additives decrease the amount of nitric acid soluble silica less than 1000 ppm. Caustic fritting without any additions results in some nitric acid soluble silica, which is removed by dehydration with concentrated sulphuric acid. The present process eliminates the sulphuric acid dissolution and subsequent precipitation with ammonia which involves difficulty in washing of sulphate ions from the geletinous hydroxide cake and hence makes the direct nitric acid dissolution an attractive option. The effect of excess magnesium was studied and extraction does not seem to be effected by excess magnesium. How the reaction proceeds is not exactly understood but a probable mechanism has been postulated. (authors)

  7. Characterization of semiconductor and frontier materials by nuclear microprobe technology

    International Nuclear Information System (INIS)

    Zhu Jieqing; Li Xiaolin; Yang Changyi; Lu Rongrong; Wang Jiqing; Guo Panlin

    2002-01-01

    The nuclear microprobe technology is used to characterize the properties of semiconductor and other frontier materials at the stages of their synthesis, modification, integration and application. On the basis of the beam current being used, the analytical nuclear microprobe techniques being used in this project can be divided into two categories: high beam current (PIXE, RBS, PEB) or low beam current (IBIC, STIM) techniques. The material properties measured are the thickness and composition of a composite surface on a SiC ceramic, the sputtering-induced surface segregation and depth profile change in a Ag-Cu binary alloy, the irradiation effects on the CCE of CVD diamond, the CCE profile at a polycrystalline CVD diamond film and a GaAs diode at different voltage biases and finally, the characterization of individual sample on an integrated material chip. (author)

  8. Installation and performance of the Budapest-Hamburg proton microprobe

    International Nuclear Information System (INIS)

    Kovacs, I.; Kocsonya, A.; Kostka, P.; Szokefalvi-Nagy, Z.; Schrang, K.; Krueger, A.; Niecke, M.

    2005-01-01

    A new scanning proton microprobe has been installed at the 5 MV Van de Graaff accelerator of the KFKI Research Institute for Particle and Nuclear Physics. It is the energy-upgraded version of the Hamburg proton microprobe dismantled in 2001. The probe forming system includes a pair of focusing quadrupoles and an additional quadrupole pair in front of it, which is applied to increase the proton beam divergence. The average probe size at 2.5 MeV proton energy is 2.2 μm x 1.1 μm. The test results on stability and the preliminary experiments on cement corrosion and fish otoliths are also presented

  9. Development of a nuclear microprobe and its application to neurobiology

    International Nuclear Information System (INIS)

    Tapper, Staffan.

    1989-01-01

    A nuclear microprobe has been developed at the Pelletron accelerator in Lund. The design of the achromatic beam focusing system as well as of the beam scanning system is described. The focusing system consists of three magnetic- and three electrostatic quadrupole lenses together forming an chromatic quadrupole triplet with symmetric focusing properties. The beam quality from the accelerator has been improved by use of ultrathin stripper foils. The nuclear microprobe set-up has been applied to investigation of brain tissue specimens. The elemantal disorder following epileptic seizures has been studied by micro-PIXE analysis. A combination of macro- and micro-PIXE analysis have been utilized in an investigaiton of elemental differences between normal human brain and human brain tumours. In the context of the quantification procedure in micro-PIXE analysis, callibration and X-ray detector response function are discussed. (author)

  10. Geochemical fingerprints and pebbles zircon geochronology

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 125; Issue 7. Geochemical fingerprints and pebbles zircon geochronology: Implications for the provenance and tectonic setting of Lower Cretaceous sediments in the Zhucheng Basin (Jiaodong peninsula, North China). Jin-Long Ni Jun-Lai Liu Xiao-Ling Tang ...

  11. Going back in time with zircon

    International Nuclear Information System (INIS)

    Burger, A.; Faurie, J.

    1978-01-01

    Uranium-lead age dating, with zircon as the agent is the most recent advance in exploring rocks and minerals to define their stratigraphic sequence. The authors believe it will have a tremendous effect on the accurate mapping of the earth's mineral resources, including those of Antartica; indeed, even of the moon

  12. Electrophoretic growth of lead zirconate titanate nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Limmer, S.J.; Seraji, S.; Forbess, M.J.; Wu Yun; Chou, T.P.; Nguyen, C.; Cao Guozhong [Washington Univ., Seattle, WA (United States). Dept. of Materials Science and Engineering

    2001-08-16

    Nanorods of lead zirconate titanate (PZT)-a ferro- and piezoelectric material-up to 10 {mu}m in length and 70 to 150 nm in diameter are produced by sol-gel electrophoresis of PZT in a track-etched polycarbonate membrane, which is used as a template. (orig.)

  13. Raman microprobe study of heat-treated pitches

    Energy Technology Data Exchange (ETDEWEB)

    Cottinet, D.; Couderc, P.; Saint Romain, J.L.; Dhamelincourt, P.

    1988-01-01

    A series of heat-treated pitches from the same coal-tar precursor is investigated by means of a Raman microprobe. Separated Raman spectra are obtained for the isotropic phase and the mesophase. The evolutions observed are characteristic of the structural rearrangement change in the two phases. They correlate well with the observations reported in literature and obtained by using different methods of structural investigations.

  14. Design considerations for an x-ray microprobe

    International Nuclear Information System (INIS)

    Howells, M.R.; Hastings, J.B.

    1982-01-01

    The optical design of a fluorescent microprobe covering the x-ray region from 2 to 16 keV is considered for the NSLS x-ray ring. The limit on detectability is from total flux (photons/μm 2 ) and several design choices are considered to match the optical system to the storage ring to maximize throughput. The tradeoffs in image quality and energy resolution of these designs have been considered and within these constraints two firm proposals are presented

  15. A study of VMS ore deposits by the proton microprobe

    International Nuclear Information System (INIS)

    Huston, D.L.; Large, R.R.; Bottril, R.S.; Sie, S.H.; Ryan, C.G.

    1991-01-01

    As part of studies into the mineralogical distribution of gold in volcanogenic massive sulfide (VMS) ore deposits PIXE analysis by the proton microprobe has been used to determine the gold content of pyrite and arsenopyrite from the Rosebery, Mt. Chalmers and Mt. Lyell deposits. In addition, the concentrations of Co, Ni, Cu, Zn, As, Sr, Y, Zr, Mo, Ag, Sb, Te, Au, Tl, Pb and Bi were also determined. 4 refs., 1 tab

  16. The nuclear microprobe of the CENBG: the choices

    International Nuclear Information System (INIS)

    Llabador, Y.

    1987-04-01

    A microbeam line with a spatial resolution of the micrometer order has been set on the Van de Graaf of the Bordeaux-Gradignan nuclear center. This report presents the different stages of the microprobe design: the experimental device which has been chosen, the reason of the different choices, the traps to keep out of during the construction (for instance, the accuracy of the mechanical standards) [fr

  17. Depth Probing Soft X-ray Microprobe (DPSXRM) for High Resolution Probing of Earth's Microstructural Samples

    Science.gov (United States)

    Dikedi, P. N.

    2015-12-01

    The Cambrian explosion; occurrence of landslides in very dry weather conditions; rockslides; dead, shriveled-up and crumbled leaves possessing fossil records with the semblance of well preserved, flat leaves; abundance of trilobite tracks in lower and higher rock layers; and sailing stones are enigmas demanding demystifications. These enigmas could be elucidated when data on soil structure, texture and strength are provided by some device with submicrometre accuracy; for these and other reasons, the design of a Depth Probing Soft X-ray Microprobe (DPSXRM), is being proposed; it is expected to deliver soft X-rays, at spatial resolution, ϛ≥600nm and to probe at the depth of 0.5m in 17s. The microprobe is portable compared to a synchrotron radiation facility (Diamond Light Source has land size of 43,300m2); spatial resolution,ϛ , of the DPSXRM surpasses those of the X-ray Fluorescence microanalysis (10µm), electron microprobe (1-3µm) and ion microprobe (5->30µm); the DPSXRM has allowance for multiple targets. Vanadium and Manganese membranes are proposed owing to respective 4.952KeV VKα1 and 5.899KeV MnKα1 X-rays emitted, which best suits micro-probing of Earth's microstructural samples. Compound systems like the Kirk-Patrick and Baez and Wolter optics, aspheric mirrors like elliptical and parabolic optics, small apertures and Abbe sine condition are employed to reduce or remove astigmatism, obliquity, comatic and spherical aberrations—leading to good image quality. Results show that 5.899KeV MnKα1 and 4.952KeV VKα1 soft X-rays will travel a distance of 2.75mm to form circular patches of radii 2.2mm and 2.95mm respectively. Zone plate with nth zone radius of 1.5mm must be positioned 1.5mm and 2mm from the electron gun if circular patches must be formed from 4.952KeV VKα1 and 5.899KeV MnKα1 soft X-rays respectively. The focal lengths of 0.25μm≤ƒ≤1.50μm and 0.04μm≤ƒ≤0.2μm covered by 4.952KeV VKα1 and 5.899KeV Mn Kα1 soft X-Rays, will

  18. Simultaneous determinations of U-Pb age and REE abundances for zircons using AfF excimer laser ablation-ICPMS

    International Nuclear Information System (INIS)

    Iizuka, Tsuyoshi; Hirata, Takafumi

    2004-01-01

    Using a laser-ablation-inductively coupled plasma mass spectrometer (LA-ICPMS), U-Pb age and rare earth element (REE) abundances have been determined simultaneously from a single 20 μm ablation pit of zircon. The laser ablation system utilizing 193 nm wave-length ArF excimer laser produces stable and reproducible signal intensities resulted in good precisions on measurements of element concentrations and isotopic ratios. Because of the higher energy density of the deep ultra-violet laser beam, ablation fractionation between Pb and U were reduced even with the prolonged ablation, and thus accuracy of Pb-U age was improved significantly. A chicane-type ion lens system was applied to a quadrupole-based ICPMS instrument. With the chicane ion lens, higher elemental sensitivity (4 times or light mass range and 3 times for mid to heavy mass range) and lower white background ( 238 U- 206 Pb ages for Nancy standard zircon (Nancy 91500), SHRIMP calibration standard zircon (SL13) and Antarctic zircon (PMA7) obtained in this study were 1064 ± 24 Ma, 569 ± 78 Ma and 2438 ± 101 Ma (2-sigma), respectively. Relative age differences from previous reports were 0.2%, 0.4% and 3.2% respectively, demonstrative of high reliability of the method. The REE abundances in zircon samples were calibrated using a NIST 610 glass standard reference material. The resulting REE abundance data for zircons (Nancy 91500 and SL13) show good agreement with those for literature values within the analytical precision of ∼20%. The matrix effect that may occur between the synthetic glass standard and zircon crystals is obviously smaller than the precision and thus negligible for this precision levels. The data presented here demonstrate clearly that the combination of ArF excimer laser an ICPMS equipped with the chicane ion lens has a potential to become a significant tool for zircon geochemistry. (author)

  19. Sulfur in zircons: A new window into melt chemistry

    Science.gov (United States)

    Tang, H.; Bell, E. A.; Boehnke, P.; Barboni, M.; Harrison, T. M.

    2017-12-01

    The abundance and isotopic composition of sulfur are important tools for exploring the photochemistry of the atmosphere, the thermal history of mantle and igneous rocks, and ancient metabolic processes on the early Earth. Because the oldest terrestrial samples are zircons, we developed a new in-situ procedure to analyze the sulfur content of zircons using the CAMECA ims 1290 at UCLA. We analyzed zircons from three metaluminous/I-type granites (reduced and oxidized Peninsular range and Elba), which exhibit low sulfur abundance with the average of 0.5ppm, and one peraluminous/S-type zircon (Strathbogie Range), which shows an elevated sulfur level with the average of 1.5ppm. Additionally, we found that sulfur content ranges between 0.4 and 2.3 ppm in young volcanic zircons (St. Lucia). Our analyses of zircons from the Jack Hills, Western Australia, whose ages range between 3.4 and 4.1 Ga, show a variety of sulfur contents. Three out of the ten zircons are consistent with the sulfur contents of S-type zircons; the rest have low sulfur contents, which are similar to those of I-type zircons. The high sulfur content in some of these Jack Hills zircons can be interpreted as indicating their origin in either a S-type granite or a volcanic reservoir. We favor the former interpretation since the Ti-in-zircon temperatures of our Jack Hills zircons is lower than those of volcanic zircons. Future work will be undertaken to develop a systematic understanding of the relationship between melt volatile content, melt chemistry, and zircon sulfur content.

  20. Quantification of the distribution of hydrogen by nuclear microprobe at the Laboratory Pierre Sue in the width of zirconium alloy fuel clad of PWR reactors

    International Nuclear Information System (INIS)

    Raepsaet, C.; Bossis, Ph.; Hamon, D.; Bechade, J.L.; Brachet, J.C.

    2007-01-01

    Among the analysis techniques by ions beams, the micro ERDA (Elastic Detection Analysis) is an interesting technique which allows the quantitative distribution of the hydrogen in materials. In particular, this analysis has been used for hydride zirconium alloys, with the nuclear microprobe of the Laboratory Pierre Sue. This probe allows the characterization of radioactive materials. The technique principles are recalled and then two examples are provided to illustrate the fuel clad behavior in PWR reactors. (A.L.B.)

  1. 7th international conference on Nuclear microprobe technology and applications; 7. conference internationale sur la technologie et les applications des microsondes nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-07-01

    This colloquium gives an up-to-date report on the continuously advancing applications and development of microbeam technology. It presents abstracts and oral contributions in the following domains: microprobes facilities, analysis techniques, imaging techniques, micro-ion beam modification of materials, microelectronics, applications in Material Sciences in Biology in Medicine in earth and planetary Sciences in environment in art in archaeology, alternative techniques. (A.L.B.)

  2. Other applications of ion microbeams

    International Nuclear Information System (INIS)

    Cookson, J.A.

    1987-01-01

    The paper concerns the analytical and non-analytical applications of ion microbeams. The analytical applications considered include:-fusion research, environmental studies, ion implantations and criminology, and each is briefly discussed. Non-analytical applications in which nuclear microprobes have been used include:-thickness and uniformity measurements, energy loss radiography, channelling contrast, tomography, topography, ion implantation, and detector testing, and these are also discussed. (UK)

  3. Characterization of PE-g-HEMA films prepared by gamma irradiation through nuclear microprobe techniques

    International Nuclear Information System (INIS)

    Ferreira, L.M.; Rodrigues, P.A.; Falcao, A.N.; Leal, J.P.

    2011-01-01

    Complete text of publication follows. The functional success of a copolymer as biomaterial depends fundamentally on their mechanical properties (stemming from the material matrix) and on the characteristics of its surface. For biomedical applications, among all the other important properties, the biocompatibility of the surface acquires extreme importance and can dictate its rejection. One of the issues regarding biocompatibility is cytotoxicity which strongly depends on the contamination level at surface. Ion beam analysis techniques associated to Nuclear Microprobe (PIXE, RBS and STIM) allows a rigorous and precise analysis of the concentration (ppm) and distribution of elements contamination, and may also provide information on its near-surface structure. In this work PE-g-HEMA films with different grafting yields were prepared by mutual gamma irradiation at a 60 Co source and were analyzed through nuclear microprobe. Data collected allowed the qualitative and quantitative evaluation of contaminants distribution observed in the different samples as well as the clarification of some processes occurred during the copolymerization reaction. Qualitative analysis showed a random and no homogeneous distribution of the contaminant elements, independent of the grafting degree, suggesting the existence of several sources of contamination at different stages of their preparation. Results also suggest that this 'phased' contamination occurs simultaneously with mechanisms of agglomeration/entrapment of impurities during the gamma induced copolymerization reaction. Moreover, quantitative data showed that all contaminants found in the copolymeric films are natural contaminants of their reagents of preparation, although at concentrations without toxicological hazard, which points to a low cytotoxic potential. The combined analysis of these data with data from SEM and AFM allowed a better understanding of the surface structure and other properties already observed in these

  4. Trans-Regional technologies and the Lapita problem: characterisation of volcanic glass inclusions by electron microprobe

    International Nuclear Information System (INIS)

    Grave, P.; Nockolds, C.; White, P.

    1997-01-01

    Full text: Analysis of pre-modern pottery of the Pacific has long attempted to formulate measures independent of style for constructing archaeologically meaningful groups. However, the variable character of fabrics and the longevity of production (Lapita and post-Lapita wares from 3000 years ago to the present) have tended to obscure differences due to changes in production practices and resources through time and differences relating to the exchange of ceramics between islands or regions. In this poster we outline a preliminary study that employs an economical and robust technique to distinguish both within- and between-region groups. This is achieved with electron microprobe analysis of small volcanic glass fragments present in wares tempered with volcanic sands, and interpretation based on Principal Components Analysis. The method builds on the chemical groupings for glass from different volcanic complexes in the Pacific established through high energy ion beam (PIXE-PIGME) analysis. The purpose of this study is to characterise a selection of samples of pottery from the Duke of York's peninsula using electron microprobe analysis of very small glass fragments in the sections that ranged in size from around 0.05 mm to 1 mm.. The study involved the identification and elemental characterisation of individual fragments of glass in a section. Principal Component Analysis was used to identify structure latent in the dataset. The results of the study show that clear characterisation is possible to enable the wider application of the technique to Lapita and post Lapita ceramics produced originating in volcanic areas of the Pacific

  5. Laser-Assisted Atom Probe Tomography of Deformed Minerals: A Zircon Case Study.

    Science.gov (United States)

    La Fontaine, Alexandre; Piazolo, Sandra; Trimby, Patrick; Yang, Limei; Cairney, Julie M

    2017-04-01

    The application of atom probe tomography to the study of minerals is a rapidly growing area. Picosecond-pulsed, ultraviolet laser (UV-355 nm) assisted atom probe tomography has been used to analyze trace element mobility within dislocations and low-angle boundaries in plastically deformed specimens of the nonconductive mineral zircon (ZrSiO4), a key material to date the earth's geological events. Here we discuss important experimental aspects inherent in the atom probe tomography investigation of this important mineral, providing insights into the challenges in atom probe tomography characterization of minerals as a whole. We studied the influence of atom probe tomography analysis parameters on features of the mass spectra, such as the thermal tail, as well as the overall data quality. Three zircon samples with different uranium and lead content were analyzed, and particular attention was paid to ion identification in the mass spectra and detection limits of the key trace elements, lead and uranium. We also discuss the correlative use of electron backscattered diffraction in a scanning electron microscope to map the deformation in the zircon grains, and the combined use of transmission Kikuchi diffraction and focused ion beam sample preparation to assist preparation of the final atom probe tip.

  6. Zirconium oxide obtainment from brazilian zircon concentrate

    International Nuclear Information System (INIS)

    Ribeiro, S.; Martins, A.H.

    1991-01-01

    This work presents the experimental results of studies about alkaline melting, acid leaching and sulfation steps for obtention of zirconium oxide and partially stabilized zirconia by yttrium and rare-earth coprecipitation in chlorine medium, starting from the brazilian zircon concentrate. Using statistical methods of factorial design and the Packett-Burman approach, the results are discussed and the optimal conditions of the production steps were determined. (author)

  7. A tunable x-ray microprobe using synchrotron radiation

    International Nuclear Information System (INIS)

    Wu, Y.; Thompson, A.C.; Underwood, J.H.; Giauque, R.D.; Chapman, K.; Rivers, M.L.; Jones, K.W.

    1989-08-01

    We describe an x-ray microprobe using multilayer mirrors. Previously, we had demonstrated a Kirkpatrick-Baez type focusing system working at both 8 and 10 keV and successfully applied it to a variety of applications, including the determination of elemental contents in fluid inclusions. In this paper, we show that the usable excitation energy for this microprobe is not restricted to between 8 and 10 keV, and furthermore, it can be simply tuned in operation. A 10-keV x-ray fluorescence microprobe can be used to measure the concentration of the elements form potassium (Z = 19) to zinc (Z = 30) using K x-ray lines, and from cadmium (Z = 48) to erbium (Z = 68) using L x-ray lines. There are a number of geologically important elements in the gap between gallium (Z = 31) and silver(Z = 47) and also with Z > 68. In order to cover this range, a higher excitation energy is required. On the other hand, for samples that contain major elements with absorption edges lower than the excitation energy, it would be hard to detect other mirror elements because of the strong signal from the major elements and the background they produce. In this case, a tunable x-ray source can be used to avoid the excitation of the major elements. We demonstrate that, with the existing setup, it is possible to tune the excitation energy from 6 keV to 14 keV, in this range, the intensity does not decrease by more than one order of magnitude. As an illustration, a geological sample was examined by using two different excitation energy range as well as the possibility of improving the intensity. 11 refs., 5 figs

  8. Thermoluminescence of zircon: a kinetic model

    CERN Document Server

    Turkin, A A; Vainshtein, D I; Hartog, H W D

    2003-01-01

    The mineral zircon, ZrSiO sub 4 , belongs to a class of promising materials for geochronometry by means of thermoluminescence (TL) dating. The development of a reliable and reproducible method for TL dating with zircon requires detailed knowledge of the processes taking place during exposure to ionizing radiation, long-term storage, annealing at moderate temperatures and heating at a constant rate (TL measurements). To understand these processes one needs a kinetic model of TL. This paper is devoted to the construction of such a model. The goal is to study the qualitative behaviour of the system and to determine the parameters and processes controlling TL phenomena of zircon. The model considers the following processes: (i) Filling of electron and hole traps at the excitation stage as a function of the dose rate and the dose for both (low dose rate) natural and (high dose rate) laboratory irradiation. (ii) Time dependence of TL fading in samples irradiated under laboratory conditions. (iii) Short time anneali...

  9. Proton microprobe analysis of zinc in skeletal tissues

    International Nuclear Information System (INIS)

    Doty, S.B.; Jones, K.W.; Kraner, H.W.; Shroy, R.E.; Hanson, A.L.

    1981-01-01

    A proton microprobe with windowless exit port has been used to study zinc distributions in various types of skeletal tissues. The use of an external beam facilitated positioning of the targets for examination of particular points of interest. The proton micorprobe is uniquely suited to this work since it combines high sensitivity for zinc determinations in thick samples with good spatial resolution. Our measurements on rat and rabbit Achilles tendon showed a significant increase in zinc concentrations as the beam moved from the unmineralized collagen into the mineralized attachment site. Cartilage gave a similar result, with calcified cartilage having a greater zinc level than the articular surface on unmineralized epiphyseal cartilage. (orig.)

  10. X-ray microprobe for the microcharacterization of materials

    International Nuclear Information System (INIS)

    Sparks, C.J.; Ice, G.E.

    1988-01-01

    The unique properties of x rays offer many advantages over those of electrons and other charged particles for the microcharacterization of materials. X rays are more efficient in exciting characteristic x-ray fluorescence and produce higher fluorescent signal-to-background ratios than obtained with electrons. Such x-ray microprobes will also produce unprecedentedly low levels of detection in diffraction, EXAFS, Auger, and photoelectron spectroscopies for structural and chemical characterization and elemental identification. These major improvements in microcharacterization capabilities will have wide-ranging ramifications not only in materials science but also in physics, chemistry, geochemistry, biology, and medicine. 24 refs., 6 figs., 2 tabs

  11. X-ray Microprobe for Fluorescence and Diffraction Analysis

    International Nuclear Information System (INIS)

    Ice, G.E.

    2005-01-01

    X-ray diffraction (see unit 1.1) and x-ray excited fluorescence analysis are powerful techniques for the nondestructive measurement of crystal structure and chemical composition. X-ray fluorescence analysis is inherently nondestructive with orders of magnitude lower power deposited for the same detectable limit as with fluorescence excited by charged particle probes (Sparks, 1980). X-ray diffraction analysis is sensitive to crystal structure with orders-of-magnitude greater sensitivity to crystallographic strain than electron probes (Rebonato, et al. 1989). When a small-area x-ray microbeam is used as the probe, chemical composition (Z>14), crystal structure, crystalline texture, and crystalline strain distributions can be determined. These distributions can be studied both at the surface of the sample and deep within the sample (Fig. 1). Current state-of-the-art can achieve an ∼1 mm-D x-ray microprobe and an ∼0.1 mm-D x-ray microprobe has been demonstrated (Bilderback, et al., 1994). Despite their great chemical and crystallographic sensitivities, x-ray microprobe techniques have until recently been restricted by inefficient x-ray focusing optics and weak x-ray sources; x-ray microbeam analysis was largely superseded by electron techniques in the 50's. However, interest in x-ray microprobe techniques has now been revived (Howells, et al., 1983; Ice and Sparks, 1984; Chevallier, et al., 1997; Riekel 1992; Thompson, el al., 1992; and Making and Using... 1997) by the development of efficient x-ray focusing optics and ultra-high intensity synchrotron x-ray sources (Buras and Tazzari, 1984; Shenoy, et al., 1988). These advances have increased the achievable microbeam flux by more than 11 orders of magnitude (Fig. 2) (Ice, 1997); the flux in a tunable 1 mm-D beam on a 'so called' 3rd-generation synchrotron source such as the APS can exceed the flux in a fixed-energy mm2 beam on a conventional source. These advances make x-ray microfluorescence and x

  12. Enhancements to the analytical facilities at the GNS proton microprobe

    International Nuclear Information System (INIS)

    Barry, B.J.; Markwitz, A.; Kennedy, V.J.; Trompetter, W.J.

    2005-01-01

    In recent years a number of detection systems have been added to the proton microprobe facility at GNS Science. Particular additions have been a large area HPGe detector and a system for scanning transmission imaging microscopy. The HPGe detector has improved detection sensitivity, particularly for higher energy K x-rays where energy resolution is of lesser importance. The scanning microscopy system has enabled mapping of areal densities in biological samples to give accurate elemental maps. Examples are given of these applications. (author). 22 refs., 7 figs

  13. Operation and acquisition automation of a nuclear microprobe

    International Nuclear Information System (INIS)

    Simond, Isabelle

    1990-01-01

    The purpose of this work was to design the hardware and the software parts of data acquisition and its graphical analyses of a nuclear microprobe. Our realisation was built from a microprocessor 68020 and specialized co-processors on a VME bus. The more important demand was the amount of time required to collect the data and to perform the graphical analyses during the acquisition. To overcome this problem, we adapted a real time operating system and its kernel to our need, and built special graphical processes. (author) [fr

  14. Cryosystem for cathodoluminescence investigations by means of electron microprobe analysis

    International Nuclear Information System (INIS)

    Schreiber, J.

    1982-01-01

    A cryosystem is presented which has been designed as auxiliary equipment for electron beam microprobes used in cathodoluminescence studies. The sample holder temperature is adjustable down to 66 K with an accuracy of 0.5 K. Finally, experimental results (transmission spectra and cathodoluminescence spectra of N-doped GaP epitaxial layers at 80 K; changes in microscopic cathodoluminescence distribution at small angle grain boundaries at the (0001) plane of CdS during temperature decrease from 300 to 80 K) obtained by means of the described measuring equipment are given for illustration

  15. Mid-1970's imbalance in zircon supply and demand

    International Nuclear Information System (INIS)

    Van Gordon, D.V.; Collins, R.E.

    1975-01-01

    Mining and the historical development of the zircon market are briefly reviewed. Causes of the fluctuations in the zircon demand and supply and in the price are discussed. Possible adjustments (such as substitution of other materials in the steel foundry) are listed. Future uses of zircon will probably be limited to those which can justify high prices and those for which there are no substitutes. (DLC)

  16. Stability of Zircon and Its Isotopic Ratios in High-Temperature Fluids: Long-Term (4 months Isotope Exchange Experiment at 850°C and 50 MPa

    Directory of Open Access Journals (Sweden)

    Ilya N. Bindeman

    2018-05-01

    Full Text Available Stability of zircon in hydrothermal fluids and vanishingly slow rates of diffusion identify zircon as a reliable recorder of its formation conditions in recent and ancient rocks. Debate, however, persists on how rapidly oxygen and key trace elements (e.g., Li, B, Pb diffuse when zircon is exposed to silicate melt or hot aqueous fluids. Here, we report results of a nano- to micrometer-scale investigation of isotopic exchange using natural zircon from Mesa Falls Tuff (Yellowstone treated with quartz-saturated, isotopically (18O, D, 7Li, and 11B labeled water with a nominal δ18O value of +450%0 over 4 months at 850°C and 50 MPa. Frontside (crystal rim inwards δ18O depth profiling of zircon by magnetic sector SIMS shows initially high but decreasing 18O/16O over a ~130 nm non-Fickian profile, with a decay length comparable to the signal from surficial Au coating deposited onto zircon. In contrast, backside (crystal interior outwards depth profiling on a 2-3 μm thick wafer cut and thinned from treated zircon by focused ion beam (FIB milling lacks any significant increase in 18O/16O during penetration of the original surface layer. Near-surface time-of-flight (TOF-SIMS frontside profiles of uncoated zircon from 4-month and 1-day-long experiments as well as untreated zircons display similar enrichments of 18O over a distance of ~20 nm. All frontside 18O profiles are here interpreted as transient surface signals from nm-thick surface enrichment or contamination unrelated to diffusion. Likewise, frontside depth profiling of H, Li, and B isotopes are similar for long- and short-duration experiments. Additionally, surface U-Pb dating of zircon from the 4-month experiment returned U-Pb ages by depth profiling with ~1 μm penetration that were identical to untreated samples. Frontside and backside depth-profiling thus demonstrate that diffusive 18O enrichment in the presence of H2O is much slower than predicted from experiments in Watson and Cherniak

  17. A study of a production process for hafnium-free zirconium from zircon

    International Nuclear Information System (INIS)

    Ratanalert, N.

    1985-01-01

    The purpose of this experiment was to extract and purify the zirconium from zircon. The effects of time of extraction and stripping of zirconium, concentration of feed solution, concentration of hydrochloric acid in stripping process, equilibrium curve of extraction of zirconium and hafnium and equilibrium curve of stripping zirconium or scrubbing hafnium were studied from standard zirconium and hafnium. The results, subsequently were applied to the extraction procedures for zirconium from zircon. Minus 100 mesh zircon was fused with sodium hydroxide in the ratio of 1 : 6 at 700 degree C for l hour. After fusion the zirconate was leached with water and dissolved in hot concentrated hydrochloric acid. Zirconyl chloride octahydrate crystallized out when the solution was cooled. An agueons solution of zirconyl chloride was used as the feed to the hexone - thiocyanate solvent extraction process. This was prepared by dissolving zirconyl chloride octahydrate crystal in waster. This zirconium feed solution in 1 M HCl and 1 M N H 4 CNS was extracted with 2.7 m N H 4 CNS in hexone and then stripped with 3.6 M HCl the aqueous phase was got rid of thiocyanate ion by extracting with pure hexone, then the zirconium in aqueous phase was precipitated with sulfuric acid and ammonium hydroxide at pH 1.8 - 2.0 and zirconium oxide was obtained by ignition at 700 degree C. The process could be modified to improve the purity of zirconium by using cation exchange resin to get rid of thiocyanate ion after solvent extraction process

  18. Thermal diffusivity of samarium-gadolinium zirconate solid solutions

    International Nuclear Information System (INIS)

    Pan, W.; Wan, C.L.; Xu, Q.; Wang, J.D.; Qu, Z.X.

    2007-01-01

    We synthesized samarium-gadolinium zirconate solid solutions and determined their thermal diffusivities, Young's moduli and thermal expansion coefficients, which are very important for their application in thermal barrier coatings. Samarium-gadolinium zirconate solid solutions have extremely low thermal diffusivity between 20 and 600 deg. C. The solid solutions have lower Young's moduli and higher thermal expansion coefficients than those of pure samarium and gadolinium zirconates. This combination of characteristics is promising for the application of samarium and gadolinium zirconates in gas turbines. The mechanism of phonon scattering by point defects is discussed

  19. Influence of some additions on zircon synthesis and its properties

    International Nuclear Information System (INIS)

    Goryacheva, Z.E.; Poplevina, O.G.; Suvorov, S.A.; Toropov, A.N.

    1978-01-01

    Kinetics of zircon synthesis from pure ZrO 2 and SiO 2 is studied in the presence of additions of magnesium, calcium and rare earth oxides. The addition introduction accelerates zircon formation, its yield reaching 97% at 1600 deg C. Constants of zircon formation reaction rate are determined in the presence of additions of various oxides. It is shown that synthetic zircon surpasses the natural one in tensile and density properties at similar thermostability. It is stable to the effect of molten alkaline borosilicate glass and does not polute it

  20. Annealing effects on cathodoluminescence of zircon

    Science.gov (United States)

    Tsuchiya, Y.; Nishido, H.; Noumi, Y.

    2011-12-01

    U-Pb zircon dating (e. g., SHRIMP) is an important tool to interpret a history of the minerals at a micrometer-scale, where cathodoluminescence (CL) imaging allows us to recognize internal zones and domains with different chemical compositions and structural disorder at high spatial resolution. The CL of zircon is attributed by various types of emission centers, which are extrinsic ones such as REE impurities and intrinsic ones such as structural defects. Metamictization resulted from radiation damage to the lattice by alpha particles from the decay of U and Th mostly causes an effect on the CL features of zircon as a defect center. However, slightly radiation-damaged zircon, which is almost nondetectable by XRD, has not been characterized using CL method. In this study, annealing effects on CL of zircon has been investigated to clarify a recovery process of the damaged lattice at low radiation dose. A single crystal of zircon from Malawi was selected for CL measurements. It contains HfO2: 2.30 w.t %, U: 241 ppm and Th: 177 ppm. Two plate samples perpendicular to c and a axes were prepared for annealing experiments during 12 hours from room temperature to 1400 degree C. Color CL images were captured using a cold-cathode microscope (Luminoscope: Nuclide ELM-3R). CL spectral measurements were conducted using an SEM (JEOL: JSM-5410) combined with a grating monochromator (Oxford: Mono CL2) to measure CL spectra ranging from 300 to 800 nm in 1 nm steps with a temperature controlled stage. The dispersed CL was collected by a photoncounting method using a photomultiplier tube (Hamamatsu: R2228) and converted to digital data. All CL spectra were corrected for the total instrumental response. Spectral analysis reveals an anisotropy of the CL emission bands related to intrinsic defect center in blue region, radiation-induced defect center from 500 to 700 nm, and trivalent Dy impurity center at 480 and 580 nm, but their relative intensities are almost constant. CL on the

  1. Response of zircon to electron and Ne+ irradiation

    International Nuclear Information System (INIS)

    Devanathan, R.; Weber, W.J.; Boatner, L.A.

    1997-01-01

    Zircon (ZrSiO 4 ) is an actinide host phase in vitreous ceramic nuclear waste forms and a potential host phase for the disposition of excess weapons plutonium. In the present work, the effects of 800 and 900 keV electron and 1 MeV Ne + irradiations on the structure of single crystals of ZrSiO 4 have been investigated. The microstructural evolution during the irradiations was studied in situ using a high-voltage electron microscope interfaced to an ion accelerator at Argonne National Laboratory. The results indicate that electron irradiation at 15 K cannot amorphize ZrSiO 4 even at fluences an order of magnitude higher than that required for amorphization by 1.5 MeV Kr + ions. However, the material is readily amorphized by 1 MeV Ne + irradiation at 15 K. The temperature dependence of this amorphization is discussed in light of previous studies of radiation damage in ZrSiO 4

  2. Microprobe analysis of teeth by synchrotron radiation: environmental contamination

    International Nuclear Information System (INIS)

    Pinheiro, T.; Carvalho, M.L.; Casaca, C.; Barreiros, M.A.; Cunha, A.S.; Chevallier, P.

    1999-01-01

    An X-ray fluorescence set-up with microprobe capabilities, installed at the Laboratoire pour l'Utilisation du Rayonnement Electromagnetique (LURE) synchrotron (France) was used for elemental determination in teeth. To evaluate the influence of living habits in dental elemental composition nine teeth collected post-mortem were analysed, five from a miner and four from a fisherman. All teeth from the fisherman were healthy. From the miner some teeth were carious and one of them was filled with metallic amalgam. Teeth were sliced under the vertical plane and each slice was scanned from the root to the enamel for elemental profile determination. The synchrotron microprobe resolution was of 100 μm and incident photons of 18 keV energy were used. The elemental concentration values found suggest heterogeneity of the teeth material. Moreover, the distinct profiles for Mn, Sr, Br and Pb were found when teeth from the miner and from the fisherman are compared which can be associated with dietary habits and environmental influence. Higher concentrations of Mn and Sr were found for the fisherman teeth. In addition, Br was only observed in this group of teeth. Pb levels are higher for the miner teeth in particular for dentine regions. The influence of amalgam, such as, increase of Zn and Hg contents in the teeth material, is only noticed for the immediate surroundings of the treated cavity

  3. Stained glasses under the nuclear microprobe: A window into history

    Energy Technology Data Exchange (ETDEWEB)

    Vilarigues, M. [Dep. de Conservacao e Restauro and R and D Unit Vidro e da Ceramica Para as Artes, FCT-UNL, Quinta da Torre, 2829-516 Caparica (Portugal)], E-mail: mgv@fct.unl.pt; Fernandes, P. [Dep. de Conservacao e Restauro and R and D Unit Vidro e da Ceramica Para as Artes, FCT-UNL, Quinta da Torre, 2829-516 Caparica (Portugal); Alves, L.C.; Silva, R.C. da [Dep. Fisica, LFI, ITN, E.N.10, 2686-953 Sacavem (Portugal)

    2009-06-15

    Stained glass fragments from the 15th, 16th and 20th centuries, belonging to Mosteiro de Santa Maria da Vitoria, Batalha (Portugal), were characterised non-destructively in a nuclear microprobe. The work aimed at finding the composition of the glasses and glass paintings and relating these with the corresponding production periods. The elemental compositions of the glass fragments were obtained by means of scanning micro-beam Particle Induced X-ray Emission ({mu}-PIXE) spectrometry in selected cross-sections. These were complemented by micro X-Ray fluorescence spectrometry. Characterisation of colour was performed by optical absorption spectroscopy in the UV-vis range, while the corrosion products were identified by optical microscopy and {mu}-FTIR (Fourier Transform Infra Red) spectroscopy in combination with the data generated by {mu}-PIXE. Nuclear microprobe analysis allowed unveiling the compositions and structures, in particular of glass paintings and corrosion products. While it is not surprising that Fe, Cu and Pb were the main elements identified in the grisaille paintings of all studied periods, as well as Ag and Cu found in the glasses decorated with yellow silver painting, their distribution gave important clues on the materials and techniques used to manufacture these stained glasses. Furthermore, it allowed establishing a definite relation between the compositions found and the periods of production, with the added bonus of correctly reassigning the manufacturing period of some samples.

  4. Elemental and Isotopic Tomography at Single-Atom-Scale in 4.0 and 2.4 Ga Zircons

    Science.gov (United States)

    Valley, J. W.; Reinhard, D. A.; Snoeyenbos, D.; Lawrence, D.; Martin, I.; Kelly, T. F.; Ushikubo, T.; Strickland, A.; Cavosie, A. J.

    2012-12-01

    Atom probe tomography can determine identity (mass/charge ratio) and 3-D position of individual atoms in minerals such as zircon. These data provide unique information for understanding the thermal history and mechanisms of mineral reaction and exchange, including radiation damage. Nine needle-shaped specimens ~100 nm in diameter (at the apex) were sampled from 2 zircons by FIB and analyzed with a local-electrode atom probe (LEAP), CAMECA LEAP 4000X HR. The LEAP uses pulsed-laser heating to field evaporate the tip of a zircon needle and accelerates the ions into a position-sensitive TOF-MS. With due care for complex isobaric interferences (molecules, multiple ionizations) and background correction, it is possible to individually identify up to 10E8 atoms/needle (36% detection efficiency) by mass/charge (MRP ~ 1000@ m/n=16Da) and position (X-Y-Z coordinates on 0.2 nm scale) (Kelly & Larson 2012). The 3-D distribution of Pb and Y differ at atom-scale in the 2 zircons. Zircon #1 (4007 Ma, Jack Hills, W. Australia, Cavosie 2005, Ushikubo et al. 2008, Bouvier et al. 2011) is homogeneous in Pb and Y. In contrast, incompatible elements, including Pb and Y, are concentrated in equant 5-10 nm dia. domains, spaced ~50 nm apart in zircon #2 (2438 Ma, Albion-Raft R-Grouse Ck core complex, Utah, Strickland et al. 2011). U is homogeneously distributed in both zircons. The analyzed domains suffered 4-8 x 10E15 α-decay events/mg due to U and Th decay and yet both zircons yield >97% concordant U-Pb ages by SIMS, suggesting annealing of radiation damage during the life of the zircons. The 207-Pb/206-Pb ratios for these nm-scale domains, as measured by LEAP, average 0.17 for the 2.4 Ga Zrc2 (3 needles) and 0.43 for the 4.0 Ga Zrc1 (5 needles). These ratios are less precise (±40% 2σ) due to ultra-small sample size, but are in excellent agreement with values measured by SIMS, 0.1684 and 0.4269, respectively. Thus Pb in both zircons is radiogenic. The Pb-Y-rich domains and lack of

  5. General theory of three-dimensional radiance measurements with optical microprobes RID A-1977-2009

    DEFF Research Database (Denmark)

    FukshanskyKazarinova, N.; Fukshansky, L.; Kuhl, M.

    1997-01-01

    Measurements of the radiance distribution and fluence rate within turbid samples with fiber-optic radiance microprobes contain a large variable instrumental error caused by the nonuniform directional sensitivity of the microprobes. A general theory of three-dimensional radiance measurements...

  6. Ultra High Spatial Resolution Ion Imaging with a NanoSIMS Ion Microprobe: Applications to Astrobiology

    OpenAIRE

    伊藤, 元雄; Ito, Motoo

    2013-01-01

    会議情報: 国際アストロバイオロジーワークショップ2013(第6回日本アストロバイオロジーネットワーク年次研究会)(2013年11月28日-30日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)), 相模原市, 神奈川県

  7. Testing the reliability of information extracted from ancient zircon

    Science.gov (United States)

    Kielman, Ross; Whitehouse, Martin; Nemchin, Alexander

    2015-04-01

    Studies combining zircon U-Pb chronology, trace element distribution as well as O and Hf isotope systematics are a powerful way to gain understanding of the processes shaping Earth's evolution, especially in detrital populations where constraints from the original host are missing. Such studies of the Hadean detrital zircon population abundant in sedimentary rocks in Western Australia have involved analysis of an unusually large number of individual grains, but also highlighted potential problems with the approach, only apparent when multiple analyses are obtained from individual grains. A common feature of the Hadean as well as many early Archaean zircon populations is their apparent inhomogeneity, which reduces confidence in conclusions based on studies combining chemistry and isotopic characteristics of zircon. In order to test the reliability of information extracted from early Earth zircon, we report results from one of the first in-depth multi-method study of zircon from a relatively simple early Archean magmatic rock, used as an analogue to ancient detrital zircon. The approach involves making multiple SIMS analyses in individual grains in order to be comparable to the most advanced studies of detrital zircon populations. The investigated sample is a relatively undeformed, non-migmatitic ca. 3.8 Ga tonalite collected a few kms south of the Isua Greenstone Belt, southwest Greenland. Extracted zircon grains can be combined into three different groups based on the behavior of their U-Pb systems: (i) grains that show internally consistent and concordant ages and define an average age of 3805±15 Ma, taken to be the age of the rock, (ii) grains that are distributed close to the concordia line, but with significant variability between multiple analyses, suggesting an ancient Pb loss and (iii) grains that have multiple analyses distributed along a discordia pointing towards a zero intercept, indicating geologically recent Pb-loss. This overall behavior has

  8. (De)coupled zircon metamictization, radiation damage, and He diffusivity

    Science.gov (United States)

    Ault, A. K.; Guenthner, W.; Reiners, P. W.; Moser, A. C.; Miller, G. H.; Refsnider, K. A.

    2017-12-01

    We develop and apply a new protocol for targeting crystals for the zircon (U-Th)/He (He) thermochronometry to maximize effective U (eU) and corresponding closure temperature variability to develop zircon He date-eU correlations observed in some datasets. Our approach exploits visual proxies for radiation damage accumulation (metamictization) during zircon selection. We show that by purposefully targeting a spectrum of zircon textures from pristine to metamict grains, it is possible to generate broad eU variation in suites of zircon from a single sample and zircon He date-eU-metamictization trends that can be exploited to resolve increasingly complex thermal histories. We present plane light photographs, eU concentration, and zircon He results from 59 individual zircons from nine crystalline rock samples. Six of the nine samples come from exposed Proterozoic granitoids on SE Baffin Island, Canada; Boulder Creek, CO; Sandia Mountains, NM; and Mecca Hills, CA. We report data from three Archean Baffin samples to compare with the Proterozoic Baffin sample date-eU-metamictization trend. In each Proterozoic sample, target zircons display a spectrum of metamictization from pristine, transparent crystals to purple-brown, translucent grains. Progressive loss of transparency and increase in discoloration consistently corresponds to an increase in eU in all samples. Individual zircon eU varies from 89-1885 ppm and, within each sample, the total eU spread is 538 ppm to 1374 ppm. For any given eU value, the Archean zircon appear comparatively more metamict than the Proterozoic Baffin grains and samples collectively define a 1681 ppm range in eU, with more restrictive intrasample eU spreads (199-1120 ppm). Proterozoic samples from Baffin, Sandia, and Front Range yield negative zircon He date-eU correlations with intrasample date ranges of 90-783 Ma. Increasing eU and younger dates correspond with increasing metamictization. In contrast, all three Proterozoic Mecca Hills samples

  9. Silica-calcium zirconate nanocomposite, studying its thermal

    Indian Academy of Sciences (India)

    Silica–calcium zirconate nanocomposite was prepared in a two-step procedure. First, nanocalcium zirconate was synthesized by the modified sol–gel method; then, silica was added to the prepared sol and the resulting product was calcined at 700–1000° C. Dilatometric measurements were performed to determine the ...

  10. Natural radioactivity and radon specific exhalation rate of zircon sands

    International Nuclear Information System (INIS)

    Righi, S.; Verita, S.; Bruzzi, L.; Albertazzi, A.

    2006-01-01

    The study focuses on the radon emanation from zircon sands and their derivatives, which are widely used in many sectors of industry. In particular, the results obtained by experimental measurements on samples of zircon sands and zircon flours commonly used in Italian ceramic industries are reported. Zircon sands contain a significant concentration of natural radioactivity because Th and U may substitute zirconium in the zircon crystal lattice. The relevant routes of exposure of workers to T.E.N.O.R.M. from zircon materials are external radiation and internal exposure, either by inhalation of aerosols in dusty working conditions or by inhalation of radon in workplaces. The main objective of this investigation is to provide experimental data able to better calculate the internal exposure of workers due to radon inhalation. Zircon samples were surveyed for natural radioactivity, radon specific exhalation rate and emanation fraction. Measurements of radioactivity concentration were carried out using γ-spectrometry. Methods used for determining radon consisted in determining the 222 Rn activity accumulated in a vessel after a given accumulation build-up time. The average activity concentrations of 238 U and 232 Th in samples result about 2600 and 550 Bq kg-1, respectively; these concentrations are significantly higher than the world average noticed in soils, rocks and Earth crust. The 222 Rn specific exhalation rates result very low probably due to the low porosity of the material and the consequent difficulty for radon to be released from the zircon crystal lattice. (author)

  11. Auto-regenerative thermoluminescence dating using zircon inclusions

    International Nuclear Information System (INIS)

    Templer, R.H.

    1993-01-01

    Fired ceramics containing zircon inclusions have been dated by allowing the zircons to regenerate their own thermoluminescence (TL) signal, hence auto-regenerative TL dating. The technique is conceptually straightforward. One first measures the TL accrued since the last heating of the material. The zircon grains are then stored for six months and the TL signal regenerated through self-irradiation is measured. Since the internal dose-rate for zircon is dominated by the internal component the age of the sample is simply given by the ratio of the natural to auto-regenerated signal times the laboratory storage period. The technique, however, requires the measurement of a very small auto-regenerated signal, which introduces a number of experimental and physical complications. The methods for overcoming these problems and successfully dating zircons by auto-regeneration are described. (Author)

  12. Implementation of ionoluminescence in the AGLAE scanning external microprobe

    International Nuclear Information System (INIS)

    Pichon, L.; Calligaro, T.; Gonzalez, V.; Lemasson, Q.; Moignard, B.; Pacheco, C.

    2015-01-01

    The scope of this work is to present the implementation of an IBIL imaging system in the scanning external microprobe of the AGLAE facility so as to correlate luminescence and composition maps provided by PIXE, RBS and PIGE. The challenging integration of the optical spectrometer, due to incompatibility of acquisition timings and data formats with the other IBA channels has motivated the development of a specific acquisition system. This article details the IBIL setup and explains the technical solutions retained for the coupling of IBIL with IBA techniques in order to produce fast and large IBIL-IBA maps. The IBIL maps stored in the same format as the PIXE, RBS and PIGE ones can be visualised and compared using the dedicated AGLAEmap program or the PyMCA processing package. An example of such a coupled mapping on Mesoamerican jade is presented to emphasise the interest of performing simultaneously IBA and IBIL large mappings

  13. Wireless cardiac action potential transmission with ultrasonically inserted silicon microprobes

    International Nuclear Information System (INIS)

    Shen, C J; Ramkumar, A; Lal, A; Gilmour, R F Jr

    2011-01-01

    This paper reports on the integration of ultrasonically inserted horn-shaped cardiac probes with wireless transmission of 3D cardiac action potential measurement for applications in ex vivo preparations such as monitoring the onset of ventricular fibrillation. Ultrasonically inserted silicon horn probes permit reduced penetration force during insertion, allowing silicon, a brittle material, to penetrate cardiac tissue. The probes also allow recording from multiple sites that are lithographically defined. An application-specific integrated circuit has been designed with a 40 dB amplifying stage and a frequency modulating oscillator at 95 MHz to wirelessly transmit the recorded action potentials. This ultrasonically inserted microprobe wireless system demonstrates the initial results in wireless monitoring of 3D action potential propagation, and the extraction of parameters of interest including the action potential duration and diastolic interval

  14. Nuclear microprobe imaging of gallium nitrate in cancer cells

    Science.gov (United States)

    Ortega, Richard; Suda, Asami; Devès, Guillaume

    2003-09-01

    Gallium nitrate is used in clinical oncology as treatment for hypercalcemia and for cancer that has spread to the bone. Its mechanism of antitumor action has not been fully elucidated yet. The knowledge of the intracellular distribution of anticancer drugs is of particular interest in oncology to better understand their cellular pharmacology. In addition, most metal-based anticancer compounds interact with endogenous trace elements in cells, altering their metabolism. The purpose of this experiment was to examine, by use of nuclear microprobe analysis, the cellular distribution of gallium and endogenous trace elements within cancer cells exposed to gallium nitrate. In a majority of cellular analyses, gallium was found homogeneously distributed in cells following the distribution of carbon. In a smaller number of cells, however, gallium appeared concentrated together with P, Ca and Fe within round structures of about 2-5 μm diameter located in the perinuclear region. These intracellular structures are typical of lysosomial material.

  15. Nuclear microprobe imaging of gallium nitrate in cancer cells

    International Nuclear Information System (INIS)

    Ortega, Richard; Suda, Asami; Deves, Guillaume

    2003-01-01

    Gallium nitrate is used in clinical oncology as treatment for hypercalcemia and for cancer that has spread to the bone. Its mechanism of antitumor action has not been fully elucidated yet. The knowledge of the intracellular distribution of anticancer drugs is of particular interest in oncology to better understand their cellular pharmacology. In addition, most metal-based anticancer compounds interact with endogenous trace elements in cells, altering their metabolism. The purpose of this experiment was to examine, by use of nuclear microprobe analysis, the cellular distribution of gallium and endogenous trace elements within cancer cells exposed to gallium nitrate. In a majority of cellular analyses, gallium was found homogeneously distributed in cells following the distribution of carbon. In a smaller number of cells, however, gallium appeared concentrated together with P, Ca and Fe within round structures of about 2-5 μm diameter located in the perinuclear region. These intracellular structures are typical of lysosomial material

  16. Data acquisition for X ray microprobe. User's manual

    International Nuclear Information System (INIS)

    2002-01-01

    A modified data acquisition software for X ray microprobe was developed by the Physics Group, Instrumentation Unit, IAEA Laboratories at Seibersdorf, with assistance from M. Bogovac, Croatia. The software consists of data acquisition (scanning and calibration), automatic positioning and micro-movement of sample, data reduction and evaluation. The acquisition software was designed in order to support different measurement set-ups which are applied in low-energy nuclear physics. The modification was done in 1999-2000 under the projects Nuclear Spectrometry and Utilization of Particle Accelerators. The manual supersedes the first version entitled Microanalysis Data Acquisition and Control Program published under Computer Manual Series, No. 9 in 1996. The software described in this manual is freely available from the IAEA upon request

  17. Proton microprobe study of tin-polymetallic deposits

    Energy Technology Data Exchange (ETDEWEB)

    Murao, S. [Geological Survey of Japan, Tsukuba, Ibaraki (Japan); Sie, S.H.; Suter, G.F. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), North Ryde, NSW (Australia). Div. of Exploration Geoscience

    1996-12-31

    Tin-polymetallic vein type deposits are a complex mixture of cassiterite and sulfides and they are the main source of technologically important rare metals such as indium and bismuth. Constituent minerals are usually fine grained having wide range of chemical composition and often the elements of interest occur as trace elements not amenable to electron microprobe analysis. PIXE with a proton microprobe can be an effective tool to study such deposits by delineating the distribution of trace elements among carrier minerals. Two representative indium-bearing deposits of tin- polymetallic type, Tosham of India (Cu-ln-Bi-Sn-W-Ag), and Mount Pleasant of Canada (Zn-Cu-In-Bi-Sn-W), were studied to delineate the distribution of medical/high-tech rare metals and to examine the effectiveness of the proton probe analysis of such ore. One of the results of the study indicated that indium and bismuth are present in chalcopyrite in the deposits. In addition to these important rare metals, zinc, copper, arsenic, antimony, selenium, and tin are common in chalcopyrite and pyrite. Arsenopyrite contains nickel, copper, zinc, silver, tin, antimony and bismuth. In chalcopyrite and pyrite, zinc, arsenic, indium, bismuth and lead are richer in Mount Pleasant ore, but silver is higher at Tosham. Also thallium and gold were found only in Tosham pyrite. The Tosham deposit is related to S-type granite, while Mount Pleasant to A-type. It appears that petrographic character of the source magma is one of the factors to determine the trace element distribution in tin-polymetallic deposit. 6 refs., 2 figs.

  18. Proton microprobe study of tin-polymetallic deposits

    Energy Technology Data Exchange (ETDEWEB)

    Murao, S [Geological Survey of Japan, Tsukuba, Ibaraki (Japan); Sie, S H; Suter, G F [Commonwealth Scientific and Industrial Research Organisation (CSIRO), North Ryde, NSW (Australia). Div. of Exploration Geoscience

    1997-12-31

    Tin-polymetallic vein type deposits are a complex mixture of cassiterite and sulfides and they are the main source of technologically important rare metals such as indium and bismuth. Constituent minerals are usually fine grained having wide range of chemical composition and often the elements of interest occur as trace elements not amenable to electron microprobe analysis. PIXE with a proton microprobe can be an effective tool to study such deposits by delineating the distribution of trace elements among carrier minerals. Two representative indium-bearing deposits of tin- polymetallic type, Tosham of India (Cu-ln-Bi-Sn-W-Ag), and Mount Pleasant of Canada (Zn-Cu-In-Bi-Sn-W), were studied to delineate the distribution of medical/high-tech rare metals and to examine the effectiveness of the proton probe analysis of such ore. One of the results of the study indicated that indium and bismuth are present in chalcopyrite in the deposits. In addition to these important rare metals, zinc, copper, arsenic, antimony, selenium, and tin are common in chalcopyrite and pyrite. Arsenopyrite contains nickel, copper, zinc, silver, tin, antimony and bismuth. In chalcopyrite and pyrite, zinc, arsenic, indium, bismuth and lead are richer in Mount Pleasant ore, but silver is higher at Tosham. Also thallium and gold were found only in Tosham pyrite. The Tosham deposit is related to S-type granite, while Mount Pleasant to A-type. It appears that petrographic character of the source magma is one of the factors to determine the trace element distribution in tin-polymetallic deposit. 6 refs., 2 figs.

  19. Milliprobe and microprobe analysis of gold items of ancient jewellery

    International Nuclear Information System (INIS)

    Demortier, G.; Hackens, T.

    It has long been accepted that the presence of cadmium implies a condemnation of the authenticity of an ancient gold object, or at least, of the part of the object where the cadmium is detected. An analysis in Paris of a recently excavated object from Roman times has shown cadmium. Meanwhile, systematic observations were made at L.A.R.N. on objects dating from Hellenistic to Byzantine times with different given origins (objects from a museum and from private collections). By using PIXE with a 3 MeV proton milliprobe (700 μm beam diameter) in a non vacuum geometry, relative amounts of copper, silver, cadmium and gold at the surface of more than 30 gold objects expected to be ancient have been determined. Traces or significant concentrations of cadmium have been detected at several points on or in the neighbourhood of solders on many objects which seem to be from Roman to early Byzantine times. Cadmium concentrations range between 2 to 100 parts per thousand. This range of variations and the relative concentrations of Au, Ag, Cu and Cd at the surface of the objects studied are often different from the figures obtained during analyses of modern soldering alloys. Experiments with the L.A.R.N. proton microprobe (5 μm x 10 μm area) allow a still better topographical resolution and more significative comparison of the relative amounts of the elements of interest in modern soldering alloys and supposedly old solders. The usefulness of the microprobe is demonstrated. (author)

  20. Proton microprobe study of tin-polymetallic deposits

    International Nuclear Information System (INIS)

    Murao, S.; Sie, S.H.; Suter, G.F.

    1996-01-01

    Tin-polymetallic vein type deposits are a complex mixture of cassiterite and sulfides and they are the main source of technologically important rare metals such as indium and bismuth. Constituent minerals are usually fine grained having wide range of chemical composition and often the elements of interest occur as trace elements not amenable to electron microprobe analysis. PIXE with a proton microprobe can be an effective tool to study such deposits by delineating the distribution of trace elements among carrier minerals. Two representative indium-bearing deposits of tin- polymetallic type, Tosham of India (Cu-ln-Bi-Sn-W-Ag), and Mount Pleasant of Canada (Zn-Cu-In-Bi-Sn-W), were studied to delineate the distribution of medical/high-tech rare metals and to examine the effectiveness of the proton probe analysis of such ore. One of the results of the study indicated that indium and bismuth are present in chalcopyrite in the deposits. In addition to these important rare metals, zinc, copper, arsenic, antimony, selenium, and tin are common in chalcopyrite and pyrite. Arsenopyrite contains nickel, copper, zinc, silver, tin, antimony and bismuth. In chalcopyrite and pyrite, zinc, arsenic, indium, bismuth and lead are richer in Mount Pleasant ore, but silver is higher at Tosham. Also thallium and gold were found only in Tosham pyrite. The Tosham deposit is related to S-type granite, while Mount Pleasant to A-type. It appears that petrographic character of the source magma is one of the factors to determine the trace element distribution in tin-polymetallic deposit. 6 refs., 2 figs

  1. Are there impact-formed zircons in the Hadean record?

    Science.gov (United States)

    Wielicki, M. M.; Lu, X.; Bell, E. A.; Schmitt, A. K.; Harrison, T. M.

    2008-12-01

    Detrital Hadean zircons from the Jack Hills, Western Australia, show a remarkable cluster of crystallization temperatures at 680±25°C. This is particularly surprising as a simple model relating rock composition and Zr concentration predicts that a very broad spectrum of crystallization temperatures (ca. 650°C to 1000°C) with a median value of 780°C, would result from impact melting of the Earth's surface. Magmatic fractionation would tend to increase the aforementioned values. Given the predicted high rate of impacts during the Hadean, the absence of such a population in the Jack Hills zircons could signal a profound sampling problem, a hint of a history much different than previously supposed, or our lack of understanding of zircon formation due to impact related processes. We have begun to examine the latter issue by investigating the crystallization temperatures of zircons formed in melt sheets preserved in the geologic record. The Sudbury Igneous Complex, formed at 1850±3 Ma within the second largest impact crater on Earth, includes two igneous units termed the Black and Felsic Norites. Examination of zircons from each by SIMS confirms their crystallization age at 1847.3±2.2 Ma and yields Ti-in-zircon temperatures of 720°C and 750°C, respectively. This is consistent with that predicted from zircon saturation systematics. A statistical test indicates that the combined norite population is distinct from the Hadean temperature distribution. Thus the question arises: where are the Hadean zircons expected to have formed at >780°C via impact processes? Similar analysis is being pursued for zircons from the Vredefort Impact Structure, South Africa, which should provide further information on impact-formed zircon temperature spectra.

  2. New zircon (U-Th)/He and U/Pb eruption age for the Rockland tephra, western USA

    Science.gov (United States)

    Coble, Matthew A.; Burgess, Seth D.; Klemetti, Erik W.

    2017-09-01

    Eruption ages of a number of prominent Quaternary volcanic deposits remain inaccurately and/or imprecisely constrained, despite their importance as regional stratigraphic markers in paleo-environment reconstruction and as evidence of climate-altering eruptions. Accurately dating volcanic deposits presents challenging analytical considerations, including poor radiogenic yield, scarcity of datable minerals, and contamination of crystal populations by magma, eruption, and transport processes. One prominent example is the Rockland tephra, which erupted from the Lassen Volcanic Center in the southern Cascade arc. Despite a range in published eruption ages from 0.40 to 0.63 Ma, the Rockland tephra is extensively used as a marker bed across the western United States. To more accurately and precisely constrain the age of the Rockland tephra-producing eruption, we report U/Pb crystallization dates from the outermost ∼2 μm of zircon crystal faces (surfaces) using secondary ion mass spectrometry (SIMS). Our new weighted mean 238U/206Pb age for Rockland tephra zircon surfaces is 0.598 ± 0.013 Ma (2σ) and MSWD = 1.11 (mean square weighted deviation). As an independent test of the accuracy of this age, we obtained new (U-Th)/He dates from individual zircon grains from the Rockland tephra, which yielded a weighted mean age of 0.599 ± 0.012 Ma (2σ, MSWD = 5.13). We also obtained a (U-Th)/He age of 0.628 ± 0.014 Ma (MSWD = 1.19) for the Lava Creek Tuff member B, which was analyzed as a secondary standard to test the accuracy of the (U-Th)/He technique for Quaternary tephras, and to evaluate assumptions made in the model-age calculation. Concordance of new U/Pb and (U-Th)/He zircon ages reinforces the accuracy of our preferred Rockland tephra eruption age, and confirms that zircon surface dates sample zircon growth up to the time of eruption. We demonstrate the broad applicability of coupled U/Pb zircon-surface and single-grain zircon (U-Th)/He geochronology to accurate

  3. Significance of zircon U-Pb ages from the Pescadero felsite, west-central California coast ranges

    Science.gov (United States)

    McLaughlin, Robert J.; Moore, Diane E.; ,; Martens, UWE C.; Clark, J.C.

    2011-01-01

    Weathered felsite is associated with the late Campanian–Maastrichtian Pigeon Point Formation near Pescadero, California. Poorly exposed, its age and correlation are uncertain. Is it part of the Pigeon Point section west of the San Gregorio–Hosgri fault? Does it rest on Nacimiento block basement? Is it dextrally offset from the Oligocene Cambria Felsite, ∼185 km to the southeast? Why is a calc-alkaline hypabyssal igneous rock intrusive into the outboard accretionary prism? To address these questions, we analyzed 43 oscillatory-zoned zircon crystals from three incipiently recrystallized pumpellyite ± prehnite ± laumontite-bearing Pescadero felsite samples by sensitive high-resolution ion microprobe–reverse geometry (SHRIMP-RG) and laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) techniques. Thirty-three zircons gave late Mesozoic U-Pb ages, with single-grain values ranging from 81 to 167 Ma; ten have pre-Mesozoic, chiefly Proterozoic ages. A group of the four youngest Pescadero zircons yielded an apparent maximum igneous age of ca. 86–90 Ma. Reflecting broad age scatter and presence of partly digested sandstone inclusions, we interpret the rest of the zircons (perhaps all) as xenocrysts. Twenty-three zircons were separated and analyzed from two samples of the similar Cambria Felsite, yielding a unimodal 27 Ma U-Pb age. Clearly, the origin of the Upper Oligocene Cambria Felsite is different from that of the Upper Cretaceous Pescadero felsite; these rocks are not correlated, and do not constrain displacement along the San Gregorio–Hosgri fault. Peak ages differ slightly, but relative probability curves for Mesozoic and pre-Mesozoic Pescadero zircons compare well, for example, with abundant U-Pb age data for detrital zircons from Franciscan metaclastic strata ∼100 km to the east in the Diablo Range–San Francisco Bay area, San Joaquin Great Valley Group turbidites, Upper Cretaceous Nacimiento block Franciscan strata, and Upper

  4. High-precision ID-TIMS zircon U-Pb geochronology using new 1013 Ohm resistors

    Science.gov (United States)

    Von Quadt, A.; Buret, Y.; Large, S.; Peytcheva, I.; Trinquier, A.; Wotzlaw, J. F.

    2015-12-01

    Faraday cups equipped with high gain amplifiers provide a means to measure small ion beams in static mode without the limited linear range of ion counting systems. We tested the application of newly available 1013 Ohm resistors to ID-TIMS zircon U-Pb geochronology using a range of natural and synthetic reference materials. The TritonPlus-RPQ at the Institute of Geochemistry and Petrology, ETH Zurich, is equipped with five new 1013 Ohm resistors and one MasCom secondary electron multiplier, allowing to measure the 202-204-205-206-207-208Pb masses in static mode. U is measured subsequently as U-oxide (265-267-270UO2) during a second step, also in static Faraday mode. The gain calibration of the 1013 Ohm resistors was performed using the procedure of Trinquier (2014), with 144Nd-146Nd being measured using 1011 Ohm resistor and 142-143-145-148-150Nd being measured using 1013 Ohm resitors (Trinquier, 2014; Koornneef et al., 2014). Standard deviations of the noise in all five new 1013 Ohm resistors are lower than 5.0 x 10-6 over a 6 month period, with no shift occurring over this time interval. This new detector set-up was tested by analyzing natural zircon standard materials and synthetic U/Pb solutions (www.earthime.org), ranging in age from ~2 Ma to ~600 Ma. All natural zircon standards were chemically abraded (Mattinson, 2005) and all samples were spiked with the ET2535 tracer solution. U-Pb dates obtained using the static measurement routine are compared to measurements employing dynamic peak jumping routines on the MasCom multiplier. This study illustrates the benefits and current limitations of using high gain amplifiers to measure small ion beams for zircon U-Pb geochronology compared to conventional dynamic ion counting techniques. Mattinson, J.M. (2005) Chemical Geology 220:47-66; Trinquier, A. (2014) Application Note 30281; Koornneef, J. et al (2014) Analytica Chimica Acta 819:49-55.

  5. A study of aluminium-exposed fish using a scanning proton microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Cholewa, M; Legge, G L.F. [Melbourne Univ., Parkville, VIC (Australia). School of Physics; Eeckhaoudt, S; Van Grieken, R [Universitaire Instelling Antwerpen, Antwerp (Belgium)

    1994-12-31

    A major problem has arisen in Europe with the depopulation of fresh water fish in lakes and streams collecting acid rain. The sensitivity to acidification is species specific and appears to be associated with metal levels. The Scanning Proton Microprobe (SPMP) at the Micro Analytical Research Centre of the University of Melbourne was used to study the subcellular distribution of aluminium and other elements in the gills of fish exposed to acidified water with elevated Al-levels. Experiments were performed on thin sections taken from fish exposed to media with different pH and aluminium concentration. Aluminium was found on the surface of the gill lamellae, but also inside the tissue. Bulk analysis of the gills showed much higher concentrations in the aluminium-exposed fish, compared to the control ones, but no information regarding the actual accumulation sites can be inferred. Extensive study of damage done to the sample by intense proton beams during elemental analysis was performed with scanning transmission ion microscopy. 3 refs., 3 figs.

  6. Application of a nuclear microprobe to the study of calcified tissues

    Science.gov (United States)

    Coote, Graeme E.; Vickridge, Ian C.

    1988-03-01

    The mineral fraction of calcified tissue is largely calcium hydroxyapatite (bones and teeth) or calcium carbonate (shells and fish otoliths). Apatite has such a strong affinity for fluoride ions that the F/Ca ratio can vary markedly with position in a bone or tooth, depending on the amount of fluoride present at the time of calcification or partial recrystallization. New biological information can be obtained by introducing extra fluoride into the diet of an animal and using a microprobe later to scan sections of bones or teeth. In suitable burial sites extra fluoride is introduced after death, and the new distribution may have applications in forensic science and archaeology. Fish otoliths are also of interest since a new carbonate layer is formed each day and the distribution of trace elements may record some aspects of the fish's life history. Results from the following studies are presented: fluorine distributions in the teeth of sheep which ingested extra fluoride for known periods; distributions of calcium and fluorine in femurs of rats which drank water high in fluoride for periods from 2 to 15 weeks; calcium and fluorine distributions in artificially-prepared lesions in tooth enamel; diffusion profiles in archaeological human teeth and animal bones; patterns in the strontium/calcium ratio in sectioned otoliths of several species of fish.

  7. A study of aluminium-exposed fish using a scanning proton microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Cholewa, M.; Legge, G.L.F. [Melbourne Univ., Parkville, VIC (Australia). School of Physics; Eeckhaoudt, S.; Van Grieken, R. [Universitaire Instelling Antwerpen, Antwerp (Belgium)

    1993-12-31

    A major problem has arisen in Europe with the depopulation of fresh water fish in lakes and streams collecting acid rain. The sensitivity to acidification is species specific and appears to be associated with metal levels. The Scanning Proton Microprobe (SPMP) at the Micro Analytical Research Centre of the University of Melbourne was used to study the subcellular distribution of aluminium and other elements in the gills of fish exposed to acidified water with elevated Al-levels. Experiments were performed on thin sections taken from fish exposed to media with different pH and aluminium concentration. Aluminium was found on the surface of the gill lamellae, but also inside the tissue. Bulk analysis of the gills showed much higher concentrations in the aluminium-exposed fish, compared to the control ones, but no information regarding the actual accumulation sites can be inferred. Extensive study of damage done to the sample by intense proton beams during elemental analysis was performed with scanning transmission ion microscopy. 3 refs., 3 figs.

  8. A novel ultra-short scanning nuclear microprobe: Design and preliminary results

    International Nuclear Information System (INIS)

    Lebed, S.; Butz, T.; Vogt, J.; Reinert, T.; Spemann, D.; Heitmann, J.; Stachura, Z.; Lekki, J.; Potempa, A.; Styczen, J.; Sulkio-Cleff, B.

    2001-01-01

    The paper describes an optimized scanning nuclear microprobe (MP) with a new ultra-short (total length of 1.85 m) probe forming system based on a divided Russian quadruplet (DRQ) of magnetic quadrupole lenses. Modern electrostatic accelerators have a comparatively high beam brightness of about 10-25 pA/μm 2 /mrad 2 /MeV. This allows the MP proposed to provide a high lateral resolution even with large (1%) parasitic (sextupole and octupole) pole tip field components in all lenses. The features of the design permit the MP operation in the high current and low current modes with a short working distance and inexpensive quadrupole lenses. A new quadrupole doublet design has been developed for the MP. In the present work the calculated features of the new MP are compared with preliminary experimental results obtained with a similar system (total length of 2.3 m) at the INP in Cracow. The new MP is promising for studies of solids or biological samples with high resolutions (0.08-2 μm) in both modes under ambient conditions. A vertical version of the ultra-short MP can be very useful for single ion bombardments of living cells

  9. A study of aluminium-exposed fish using a scanning proton microprobe

    International Nuclear Information System (INIS)

    Cholewa, M.; Legge, G.L.F.

    1993-01-01

    A major problem has arisen in Europe with the depopulation of fresh water fish in lakes and streams collecting acid rain. The sensitivity to acidification is species specific and appears to be associated with metal levels. The Scanning Proton Microprobe (SPMP) at the Micro Analytical Research Centre of the University of Melbourne was used to study the subcellular distribution of aluminium and other elements in the gills of fish exposed to acidified water with elevated Al-levels. Experiments were performed on thin sections taken from fish exposed to media with different pH and aluminium concentration. Aluminium was found on the surface of the gill lamellae, but also inside the tissue. Bulk analysis of the gills showed much higher concentrations in the aluminium-exposed fish, compared to the control ones, but no information regarding the actual accumulation sites can be inferred. Extensive study of damage done to the sample by intense proton beams during elemental analysis was performed with scanning transmission ion microscopy. 3 refs., 3 figs

  10. Ion emission microscope microanalyzer

    International Nuclear Information System (INIS)

    Cherepin, V.T.; Olckovsky, V.L.

    1977-01-01

    In the ion microanalyzer (microprobe) the object is exposed to the bombardment of a highly focused ion beam, the secondary ions emitted from the object being analyzed by means of a mass filter. In order to be able to control the position of an analysis synchronous to the local analysis of an object an ion-optical converter (electron image with a fluorescent screen) is placed behind the aperture diaphragm in the direction of the secondary ion beam. The converter allows to make visible in front of the mass filter a non-split ion image characterizing the surface of the surface investigated. Then a certain section may be selected for performing chemical and isotope analyses. (DG) [de

  11. Pengaruh Temperatur, Waktu, dan Aditif Dalam Pembuatan Zircon Micronized

    Directory of Open Access Journals (Sweden)

    Sajima

    2017-05-01

    Full Text Available Research on temperature, time and additives effects on milling process in micronized-zircon production has been conducted. The production of zircon micronized started from sorting process on mining products then followed by beneficiation, roasting, leaching, dryng and milling processes. The results showed that the optimum conditions of the roasting process was at the temperature of 425 °C, in 25 minutes and using 4% additives. In these conditions, micronized zircon (2 µm obtained as much as 92.10% in10 minutes milling time.

  12. Sorption of uranyl species on zircon and zirconia

    International Nuclear Information System (INIS)

    Lomenech, C.; Drot, R.; Simoni, E.; Ehrhardt, J.J.; Mielczarski, J.

    2002-01-01

    The safety of a long-term storage of radioactive waste in deep geological repositories would be strongly affected by the migration properties of radionuclides through the different barriers to the surface of the earth. Since the main process involved in the retention of radioactive ions is their sorption at the water/ mineral interface, a quantitative description of the sorption reactions is needed. Macroscopic data have for a long time been the only source of information used to propose a modelling of sorption equilibria, although they bring no direct information on the nature of the sorbed species; a microscopic structural investigation of the surface complexes is difficult indeed, because of the small amount of matter sorbed. Thus, in this study, parallel to the macroscopic measurements, different complementary spectroscopic techniques have been used in order to determine the nature of the surface species. As the final purpose of such a study is the simulation of the experimental retention data, the precise structural identification of the sorption equilibria will then be very useful to constrain the data simulation code. In this work, we present the results of both macroscopic and microscopic studies of the sorption of uranyl species on zircon and zirconia. The first part of our macroscopic approach was the surface characterisation of the non-sorbed materials by the determination of the specific areas, of the pH of the isoelectric points, and of the sorption site numbers, while the second part aimed at obtaining the sorption isotherms (percentage of sorption versus pH), which was performed using alpha spectrometry, for different uranyl concentrations, media (NaClO 4 or KNO 3 ) and ionic strengths. The spectroscopic identification of the different surface complexes and sorption sites has been carried out using four different spectroscopies. Whereas tune-resolved laser spectro-fluorimetry gave a direct answer concerning the number of surface species (only for a

  13. Assessment of dye distribution in sensitized solar cells by microprobe techniques

    Energy Technology Data Exchange (ETDEWEB)

    Barreiros, M.A., E-mail: alexandra.barreiros@lneg.pt [Laboratório Nacional de Energia e Geologia, LEN/UES, Estrada do Paço do Lumiar, 22, 1649-038 Lisboa (Portugal); Corregidor, V. [IPFN, Instituto Superior Técnico, Universidade de Lisboa, E.N. 10, 2686-953 Sacavém (Portugal); Alves, L.C. [C2TN, Campus Tecnológico e Nuclear, Instituto Superior Técnico, Universidade de Lisboa, E.N. 10, 2686-953 Sacavém (Portugal); Guimarães, F. [Laboratório Nacional de Energia e Geologia, LGM/UCTM, Rua da Amieira, Apartado 1089, 4466-901 S. Mamede de Infesta (Portugal); Mascarenhas, J.; Torres, E.; Brites, M.J. [Laboratório Nacional de Energia e Geologia, LEN/UES, Estrada do Paço do Lumiar, 22, 1649-038 Lisboa (Portugal)

    2015-04-01

    Dye sensitized solar cells (DSCs) have received considerable attention once this technology offers economic and environmental advantages over conventional photovoltaic (PV) devices. The PV performance of a DSC relies on the characteristics of its photoanode, which typically consists of a nanocrystalline porous TiO{sub 2} film, enabled with a large adsorptive surface area. Dye molecules that capture photons from light during device operation are attached to the film nanoparticles. The effective loading of the dye in the TiO{sub 2} electrode is of paramount relevance for controlling and optimizing solar cell parameters. Relatively few methods are known today for quantitative evaluation of the total dye adsorbed on the film. In this context, microprobe techniques come out as suitable tools to evaluate the dye surface distribution and depth profile in sensitized films. Electron Probe Microanalysis (EPMA) and Ion Beam Analytical (IBA) techniques using a micro-ion beam were used to quantify and to study the distribution of the Ru organometallic dye in TiO{sub 2} films, making use of the different penetration depth and beam sizes of each technique. Different 1D nanostructured TiO{sub 2} films were prepared, morphologically characterized by SEM, sensitized and analyzed by the referred techniques. Dye load evaluation in different TiO{sub 2} films by three different techniques (PIXE, RBS and EPMA/WDS) provided similar results of Ru/Ti mass fraction ratio. Moreover, it was possible to assess dye surface distribution and its depth profile, by means of Ru signal, and to visualize the dye distribution in sample cross-section through X-ray mapping by EPMA/EDS. PIXE maps of Ru and Ti indicated an homogeneous surface distribution. The assessment of Ru depth profile by RBS showed that some films have homogeneous Ru depth distribution while others present different Ru concentration in the top layer (2 μm thickness). These results are consistent with the EPMA/EDS maps obtained.

  14. Transformations to granular zircon revealed: Twinning, reidite, and ZrO2 in shocked zircon from Meteor Crater (Arizona, USA)

    Science.gov (United States)

    Cavosie, Aaron; Timms, Nicholas E.; Erickson, Timmons M.; Hagerty, Justin J.; Hörz, Friedrich

    2016-01-01

    Granular zircon in impact environments has long been recognized but remains poorly understood due to lack of experimental data to identify mechanisms involved in its genesis. Meteor Crater in Arizona (United States) contains abundant evidence of shock metamorphism, including shocked quartz, the high pressure polymorphs coesite and stishovite, diaplectic SiO2 glass, and lechatelierite (fused SiO2). Here we report the presence of granular zircon, a new shocked mineral discovery at Meteor Crater, that preserve critical orientation evidence of specific transformations that occurred during its formation at extreme impact conditions. The zircon grains occur as aggregates of sub-µm neoblasts in highly shocked Coconino Formation Sandstone (CFS) comprised of lechatelierite. Electron backscatter diffraction shows that each grain consists of multiple domains, some with boundaries disoriented by 65°, a known {112} shock-twin orientation. Other domains have crystallographic c-axes in alignment with {110} of neighboring domains, consistent with the former presence of the high pressure ZrSiO4 polymorph reidite. Additionally, nearly all zircon preserve ZrO2 + SiO2, providing evidence of partial dissociation. The genesis of CFS granular zircon started with detrital zircon that experienced shock-twinning and reidite formation from 20 to 30 GPa, ultimately yielding a phase that retained crystallographic memory; this phase subsequently recrystallized to systematically oriented zircon neoblasts, and in some areas partially dissociated to ZrO2. The lechatelierite matrix, experimentally constrained to form at >2000 °C, provided an ultra high-temperature environment for zircon dissociation (~1670 °C) and neoblast formation. The capacity of granular zircon to preserve a cumulative P-T record has not been recognized previously, and provides a new method for retrieving histories of impact-related mineral transformations in the crust at conditions far beyond which most rocks melt.

  15. Examination of Laser Microprobe Vacuum Ultraviolet Ionization Mass Spectrometry with Application to Mapping Mars Returned Samples

    Science.gov (United States)

    Burton, A. S.; Berger, E. L.; Locke, D. R.; Lewis, E. K.; Moore, J. F.

    2018-04-01

    Laser microprobe of surfaces utilizing a two laser setup whereby the desorption laser threshold is lowered below ionization, and the resulting neutral plume is examined using 157nm Vacuum Ultraviolet laser light for mass spec surface mapping.

  16. Laser microprobe for the study of noble gases and nitrogen in single ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    Planetary and Geosciences Division, Physical Research Laboratory, Ahmedabad 380 009, India. ∗e-mail: murty@prl.ernet.in. A laser microprobe capable of analysing nitrogen and noble gases in .... tion properties for light radiation, with some.

  17. Deep PIXE: finding diamonds with the proton microprobe

    International Nuclear Information System (INIS)

    Griffin, W.L.; Ryan, C.G.

    1991-01-01

    Since 1987 the CSIRO Div. of Exploration Geoscience has carried out a program of proton-microprobe (PIXE) analysis aimed at using trace-element data on indicator minerals to discriminate between those from diamondiferous and barren source rocks. The results have provided both important new tools for the exploration industry, and significant new information on the conditions and processes of diamond growth. Cr-pyrope garnet has been used as Ni thermometer while chromites, in partcular their Zn content, has allowed correlation of chromite composition with temperature. The two techniques described provide a significant increase in exploration efficiency, through early recognition and rejection of barren targets and concentration of resources on more promising targets. They also provide direct cost savings in evaluation of ore bodies once they are found. It is estimated that evaluation of a prospect by conventional bulk testing is expensive ($100-500K) and time-consuming; an evaluation by PIXE methods is done quickly for a tiny fraction of that cost. 1 refs., 4 figs

  18. Synchrotron radiation microprobe quantitative analysis method for biomedical specimens

    International Nuclear Information System (INIS)

    Xu Qing; Shao Hanru

    1994-01-01

    Relative changes of trace elemental content in biomedical specimens are obtained easily by means of synchrotron radiation X-ray fluorescence microprobe analysis (SXRFM). However, the accurate assignment of concentration on a g/g basis is difficult. Because it is necessary to know both the trace elemental content and the specimen mass in the irradiated volume simultaneously. the specimen mass is a function of the spatial position and can not be weighed. It is possible to measure the specimen mass indirectly by measuring the intensity of Compton scattered peak for normal XRF analysis using a X-ray tube with Mo anode, if the matrix was consisted of light elements and the specimen was a thin sample. The Compton peak is not presented in fluorescence spectrum for white light SXRFM analysis. The continuous background in the spectrum was resulted from the Compton scattering with a linear polarization X-ray source. Biomedical specimens for SXRFM analysis, for example biological section and human hair, are always a thin sample for high energy X-ray, and they consist of H,C,N and O etc. light elements, which implies a linear relationship between the specimen mass and the Compton scattering background in the high energy region of spectrum. By this way , it is possible to carry out measurement of concentration for SXRFM analysis

  19. Nuclear micro-probe analysis of Arabidopsis thaliana leaves

    International Nuclear Information System (INIS)

    Ager, F.J.; Ynsa, M.D.; Dominguez-Solis, J.R.; Lopez-Martin, M.C.; Gotor, C.; Romero, L.C.

    2003-01-01

    Phytoremediation is a cost-effective plant-based approach for remediation of soils and waters which takes advantage of the remarkable ability of some plants to concentrate elements and compounds from the environment and to metabolize various molecules in their tissues, such as toxic heavy metals and organic pollutants. Nowadays, phytoremediation technology is becoming of paramount importance when environmental decontamination is concerned, due to the emerging knowledge of its physiological and molecular mechanisms and the new biological and engineering strategies designed to optimize and improve it. In addition, the feasibility of using plants for environmental cleanup has been confirmed by many different trials around the world. Arabidopsis thaliana plants can be used for basic studies to improve the technology on phytoremediation. Making use of nuclear microscopy techniques, in this paper we study leaves of wild type and transgenic A. thaliana plants grown in a cadmium-rich environment under different conditions. Micro-PIXE, RBS and SEM analyses, performed on the scanning proton micro-probe at the CNA in Seville (Spain), prove that cadmium is preferentially sequestered in the central region of epidermal trichome and allow comparing the effects of genetic modifications

  20. Reaction of strontium zirconate with refractory borides and carbides

    International Nuclear Information System (INIS)

    Bowker, J.C.; Lane, J.E.

    1990-01-01

    The chemical compatibility of the potential oxide ceramic matrix material, strontium zirconate, and several different potential nonoxide ceramic reinforcement materials was studied by elevated temperature reaction. Results are presented in this paper

  1. A preliminary geochemical study of zircons and monazites from ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    equation of Watson and Harrison (1983) predicts that zircon with Zr-contents ... tion equation of Montel (1993) predicts that the .... and geochemistry of the basalts of Gujarat state (western ... solution kinetics: implications for the thorium and light.

  2. Nuclear microprobe study of heavy metal uptake and transport in aquatic plant species

    International Nuclear Information System (INIS)

    Kertesz, Zs.; Kocsar, I.; Szikszai, Z.; Lakatos, Gy.

    2005-01-01

    Complete text of publication follows. In aquatic ecosystems water contamination by trace metals is one of the main types of pollution that may stress the biotic community. Although some metals are needed as micronutrients for autotrophic organisms, they can have toxic effects at higher concentration. Aquatic plants can take up large quantities of nutrients and metals from the environment, they can live under extreme environmental conditions therefore they are being increasingly used in remediation processes to reduce contamination. Besides the usually applied bulk analytical techniques quantitative micro-PIXE investigation of the macro, micro and trace element distribution within the root can lead to a better understanding of the heavy metal up-take, transport and detoxification mechanisms of the plants and thus helps to select the proper species for the remedial activity, or possibly to increase the efficiency of the remediation. In this work we determined the elemental distributions in root cross sections and along the roots of reed (Phragmaties australis), bulrush (Typha angustifolia) and sea club-rush (Bolboschoemus maritimus) using the Debrecen nuclear microprobe. The plants originate from the dried units of the wastewater sedimentation pond system of the tannery of Kunszentmarton. 1500 m 3 waste water containing lime, sodium-salts, ammonium-salts, chromium-salts, sodium, chlorine and magnesium ions, sulphur and organic material was released to the pond system every day till 1988. The chosen species are the dominant species of the area, composing 85-90% of the green plant covering. This heavily contaminated area has been regularly monitored by the colleagues of the Dept. of Applied Ecology of the Univ. of Debrecen since 1998. They focused their work the potentially toxic heavy metal chromium. In order to conserve the samples in the living state, the roots were frozen in liquid nitrogen. 16-20 μm thick cross sections were made with cryo-microtome, and all the

  3. Extrusion and properties of lead zirconate titanate piezoelectric ceramics

    DEFF Research Database (Denmark)

    Cai, S.; Millar, C.E.; Pedersen, L.

    1997-01-01

    The purpose of this work was to develop a procedure for fabricating electroceramic actuators with good piezoelectric properties. The preparation of lead zirconate titanate (PZT) piezoelectric ceramic rods and tubes by extrusion processing is described. The microstructure of extrudates was investi......The purpose of this work was to develop a procedure for fabricating electroceramic actuators with good piezoelectric properties. The preparation of lead zirconate titanate (PZT) piezoelectric ceramic rods and tubes by extrusion processing is described. The microstructure of extrudates...

  4. NORM exposure to workers at a zircon sand processing factory

    International Nuclear Information System (INIS)

    Andersen, T.; Israelson, C.

    2003-01-01

    The National Institute of Radiation Hygiene (NIRH) has estimated doses to workers at a Danish zircon-processing industry. Calculations of internal doses were made after measuring dust concentrations in the working area and content of radium-226 and thorium-232 in the zircon sand. The total effective dose from internal and external irradiation was calculated to approximately 0,75 mSv/y. (orig.)

  5. Contribution to the study of xenotime and zircon flotation

    International Nuclear Information System (INIS)

    Scorzeli, Isabella Bernstein; Torem, Mauricio Leonardo

    1995-01-01

    Flotation and electrokinetics behaviour have studied with xenotime (YPO 4 ) and zircon (Zr Si O 4 ) from a mixture of grains with 90% xenotime and 10% zircon, produced in cassiterite concentration process. Micro flotation and zeta potential have been also studied, by using oleic acid P.A. and DP1-6256 as collectors, and sodium metasillicate and Procol DA911 as modifier agents

  6. Development of a gas-phase field ionization ion source

    International Nuclear Information System (INIS)

    Allan, G.L.; Legge, G.J.F.

    1983-01-01

    A field ionization ion source has been developed to investigate the suitability of using such a source with the Melbourne Proton Microprobe. Operating parameters have been measured, and the source has been found to be brighter than the radiofrequency ion source presently used in the Melbourne 5U Pelletron Accelerator. Improvements to the source geometry to increase the current output are planned

  7. Oxidation state of uranium in metamict and annealed zircon: near-infrared spectroscopic quantitative analysis

    CERN Document Server

    Zhang Ming; Ewing, R C

    2003-01-01

    Radiation and thermally induced changes in the oxidation state of uranium in metamict zircon have been systematically analysed, for the first time, using polarized near-infrared spectroscopy. The results showed that in damaged zircon U ions in crystalline domains exhibited relatively sharp, anisotropic signals from tetravalent and pentavalent U ions in crystalline domains (U sub c sub r sub y sub s sub t sub a sub l sup 4 sup + and U sub c sub r sub y sub s sub t sub a sub l sup 5 sup +). The linewidths and peak positions of the 4834 cm sup - sup 1 band (U sub c sub r sub y sub s sub t sub a sub l sup 4 sup + , E || c) and the 6668 cm sup - sup 1 band (U sub c sub r sub y sub s sub t sub a sub l sup 5 sup + , E perp. c) are a non-linear function of the self-radiation dose. They reach nearly constant values at doses greater than approx 3.5 x 10 sup 1 sup 8 alpha-events g sup - sup 1. Quantitative analysis of U sub c sub r sub y sub s sub t sub a sub l sup 4 sup + and U sub c sub r sub y sub s sub t sub a sub l...

  8. TRANSMISSION ION CHANNELING IMAGES OF CRYSTAL DEFECTS

    NARCIS (Netherlands)

    KING, PJC; BREESE, MBH; WILSHAW, PR; SMULDERS, PJM; GRIME, GW

    This paper demonstrates how images of crystal defects can be produced using ion channeling. A focused, scanned beam of MeV protons from the University of Oxford Nuclear Microprobe has been used. With the beam aligned with a channeling direction of the crystal, protons transmitted through the thinned

  9. Spectroscopic determination of optimal hydration time of zircon surface

    Energy Technology Data Exchange (ETDEWEB)

    Ordonez R, E. [ININ, Departamento de Quimica, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Garcia R, G. [Instituto Tecnologico de Toluca, Division de Estudios del Posgrado, Av. Tecnologico s/n, Ex-Rancho La Virgen, 52140 Metepec, Estado de Mexico (Mexico); Garcia G, N., E-mail: eduardo.ordonez@inin.gob.m [Universidad Autonoma del Estado de Mexico, Facultad de Quimica, Av. Colon y Av. Tollocan, 50180 Toluca, Estado de Mexico (Mexico)

    2010-07-01

    When a mineral surface is immersed in an aqueous solution, it develops and electric charge produced by the amphoteric dissociation of hydroxyl groups created by the hydration of the solid surface. This is one influential surface property. The complete hydration process takes a time which is specific for each mineral species. The knowledge of the aqueous solution contact time for complete surface hydration is mandatory for further surface phenomena studies. This study deals with the optimal hydration time of the raw zircon (ZrSiO{sub 4}) surface comparing the classical potentiometric titrations with a fluorescence spectroscopy technique. The latter is easy and rea liable as it demands only one sample batch to determine the optimal time to ensure a total hydration of the zircon surface. The analytical results of neutron activation analysis showed the presence of trace quantities of Dy{sup 3+}, Eu{sup 3+} and Er{sup 3} in the bulk of zircon. The Dy{sup 3+} is structured in the zircon crystalline lattice and undergoes the same chemical reactions as zircon. Furthermore, the Dy{sup 3+} has a good fluorescent response whose intensity is enhanced by hydration molecules. The results show that, according to the potentiometric analysis, the hydration process for each batch (at least 8 sample batches) takes around 2 h, while the spectrometric method indicates only 5 minutes from only one batch. Both methods showed that the zircon surface have a 16 h optimal hydration time. (Author)

  10. Spectroscopic determination of optimal hydration time of zircon surface

    International Nuclear Information System (INIS)

    Ordonez R, E.; Garcia R, G.; Garcia G, N.

    2010-01-01

    When a mineral surface is immersed in an aqueous solution, it develops and electric charge produced by the amphoteric dissociation of hydroxyl groups created by the hydration of the solid surface. This is one influential surface property. The complete hydration process takes a time which is specific for each mineral species. The knowledge of the aqueous solution contact time for complete surface hydration is mandatory for further surface phenomena studies. This study deals with the optimal hydration time of the raw zircon (ZrSiO 4 ) surface comparing the classical potentiometric titrations with a fluorescence spectroscopy technique. The latter is easy and rea liable as it demands only one sample batch to determine the optimal time to ensure a total hydration of the zircon surface. The analytical results of neutron activation analysis showed the presence of trace quantities of Dy 3+ , Eu 3+ and Er 3 in the bulk of zircon. The Dy 3+ is structured in the zircon crystalline lattice and undergoes the same chemical reactions as zircon. Furthermore, the Dy 3+ has a good fluorescent response whose intensity is enhanced by hydration molecules. The results show that, according to the potentiometric analysis, the hydration process for each batch (at least 8 sample batches) takes around 2 h, while the spectrometric method indicates only 5 minutes from only one batch. Both methods showed that the zircon surface have a 16 h optimal hydration time. (Author)

  11. Gold in Accessory Zircon (the Kozhim Massif, Subpolar Urals)

    Science.gov (United States)

    Denisova, Yuliya; Pystin, Aleksandr

    2017-12-01

    The crystals of zircon due to their resistance to external impact of various processes can reveal information about the environment of their formation and the inclusions observed of them. Zircon contains different mineral inclusions: biotite, plagioclase, quartz, apatite, etc. However, there is no information about gold inclusions in the zircons from granites of the Sudpolar Urals. The study results of the inclusions of gold in accessory zircon of the Kozhim granitic massif are presented in this paper. The studied mineral is a dark-brown translucent short-prismatic crystal containing the inclusion of gold and the allocations of quartz. According to studies, the inclusion of gold formed during the growth of zircon and it is the gold covered with a thin film of oxide gold. It was confirmed that the crystallization of the studied zircon occurred at a temperature of 800°C and above on the stage of formation of granites of Kozhim massif. The assumption is made about the additional temperature in the course of which was caused by decreasing of temperature up to 700° C and below during postmagmatic stage.

  12. Acoustic response of piezoelectric lead-zirconate-titanate to a 400MeV/n xenon beam

    CERN Document Server

    Miyachi, T; Ito, H

    2003-01-01

    Characteristics of lead-zirconate-titanate (PZT) elements were studied by directly irradiating them with a 400 MeV/n Xe beam. The elements were sensitive to 10 sup 4 Xe ions and their output amplitudes were proportional to the beam intensity. An ensemble of those output amplitudes displayed a Bragg-curve-like response towards the range of 400 MeV/n Xe ion. We discuss the potential of PZT elements as a radiation detector and their application to high-intensity and high-energy detectors. (author)

  13. Kinetic energy distributions of ions after surface collisions

    International Nuclear Information System (INIS)

    Short, R.T.; Todd, P.J.; Grimm, C.C.

    1991-01-01

    As a part of the development of an organic ion microprobe, to be used for imaging of particular organic compounds in biological tissue, various methods of quadrupole-based tandem mass spectroscopy (MS/MS) have been investigated. High transmission efficiency is essential for the success of the organic ion microprobe, due to expected low analyte concentrations in biological tissue and the potential for sample damage from prolonged exposure to the primary ion beam. MS/MS is necessary for organic ion imaging because of the complex nature of the biological matrices. The goal of these studies of was to optimize the efficiency of daughter ion production and transmission by first determining daughter ion properties and then designing ion optics based on those properties. The properties of main interest are daughter ion kinetic energy and angular distribution. 1 fig

  14. Ion beam induced luminescence characterisation of CVD diamond films

    Energy Technology Data Exchange (ETDEWEB)

    Bettiol, A A; Gonon, P; Jamieson, D N [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1997-12-31

    The characterisation of the band structure properties of materials and devices by ion microprobe techniques has been made possible at the Melbourne MeV ion microprobe facility with the development of Ion Beam Induced Luminescence (IBIL). A number of diamond films grown by Microwave Plasma Chemical Vapour Deposition (MPCVD) on silicon substrates are analysed. A preliminary study of the luminescence properties of these samples has revealed information not previously obtainable via traditional microprobe techniques. The optical effects of incorporating dopants during the deposition process is determined using IBIL. The presence of trace element impurities introduced during growth is examined by Particle Induced X-ray Emission (PIXE), and a measurement of the film thickness is made using Rutherford Backscattering Spectrometry (RBS). 7 refs., 2 figs.

  15. Ion beam induced luminescence characterisation of CVD diamond films

    Energy Technology Data Exchange (ETDEWEB)

    Bettiol, A.A.; Gonon, P.; Jamieson, D.N. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1996-12-31

    The characterisation of the band structure properties of materials and devices by ion microprobe techniques has been made possible at the Melbourne MeV ion microprobe facility with the development of Ion Beam Induced Luminescence (IBIL). A number of diamond films grown by Microwave Plasma Chemical Vapour Deposition (MPCVD) on silicon substrates are analysed. A preliminary study of the luminescence properties of these samples has revealed information not previously obtainable via traditional microprobe techniques. The optical effects of incorporating dopants during the deposition process is determined using IBIL. The presence of trace element impurities introduced during growth is examined by Particle Induced X-ray Emission (PIXE), and a measurement of the film thickness is made using Rutherford Backscattering Spectrometry (RBS). 7 refs., 2 figs.

  16. Research on output signal of piezoelectric lead zirconate titanate detector using Monte Carlo method

    Energy Technology Data Exchange (ETDEWEB)

    Takechi, Seiji, E-mail: takechi@elec.eng.osaka-cu.ac.jp [Graduate School of Engineering, Osaka City University, Osaka 558-8585 (Japan); Mitsuhashi, Tomoaki; Miura, Yoshinori [Graduate School of Engineering, Osaka City University, Osaka 558-8585 (Japan); Miyachi, Takashi; Kobayashi, Masanori; Okudaira, Osamu [Planetary Exploration Research Center, Chiba Institute of Technology, Narashino, Chiba 275-0016 (Japan); Shibata, Hiromi [The Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047 (Japan); Fujii, Masayuki [Famscience Co., Ltd., Tsukubamirai, Ibaraki 300-2435 (Japan); Okada, Nagaya [Honda Electronics Co., Ltd., Toyohashi, Aichi 441-3193 (Japan); Murakami, Takeshi; Uchihori, Yukio [National Institute of Radiological Sciences, Chiba 263-8555 (Japan)

    2017-06-21

    The response of a radiation detector fabricated from piezoelectric lead zirconate titanate (PZT) was studied. The response signal due to a single 400 MeV/n xenon (Xe) ion was assumed to have a simple form that was composed of two variables, the amplitude and time constant. These variables were estimated by comparing two output waveforms obtained from a computer simulation and an experiment on Xe beam irradiation. Their values appeared to be dependent on the beam intensity. - Highlights: • The performance of PZT detector was studied by irradiation of a 400 MeV/n Xe beam. • Monte Carlo simulation was used to examine the formation process of the output. • The response signal due to a single Xe ion was assumed to have a simple form. • The form was composed of two variables, the amplitude and time constant. • These variables appeared to be dependent on the beam intensity.

  17. Carbon Dioxide Adsorption by Calcium Zirconate at Higher Temperature

    Directory of Open Access Journals (Sweden)

    K. B. Kale

    2012-12-01

    Full Text Available The CO2 adsorption by calcium zirconate was explored at pre- and post- combustion temperature condition. The several samples of the calcium zirconate were prepared by different methods such as sol-gel, solid-solid fusion, template and micro-emulsion. The samples of the calcium zirconate were characterized by measurement of surface area, alkalinity/acidity, and recording the XRD patterns and SEM images. The CO2 adsorptions by samples of the calcium zirconate were studied in the temperature range 100 to 850 oC and the CO2 adsorptions were observed in the ranges of 6.88 to 40.6 wt % at 600 0C and 8 to 16.82 wt% at in between the temperatures 200 to 300 oC. The effect of Ca/Zr mol ratio in the samples of the calcium zirconate on the CO2 adsorption and alkalinity were discussed. The adsorbed moisture by the samples of the calcium zirconate was found to be useful for the CO2 adsorption. The promoted the samples of the calcium zirconate by K+, Na+, Rb+, Cs+, Ag+ and La3+ showed the increased CO2 adsorption. The exposure time of CO2 on the samples of the calcium zirconate showed the increased CO2 adsorption. The samples of the calcium zirconate were found to be regenerable and reusable several times for the adsorption of CO2 for at the post- and pre-combustion temperature condition. Copyright © 2012 by BCREC Undip. All rights reservedReceived: 23rd June 2012, Revised: 28th August 2012, Accepted: 30th August 2012[How to Cite: K. B. Kale, R. Y. Raskar, V. H. Rane and A. G.  Gaikwad (2012. Carbon Dioxide Adsorption by Calcium Zirconate at Higher Temperature. Bulletin of Chemical Reaction Engineering & Catalysis, 7 (2: 124-136. doi:10.9767/bcrec.7.2.3686.124-136] [How to Link / DOI: http://dx.doi.org/10.9767/bcrec.7.2.3686.124-136 ] | View in 

  18. The LLNL Multi-User Tandem Laboratory PIXE microprobe

    International Nuclear Information System (INIS)

    Heikkinen, D.W.; Bench, G.S.; Antolak, A.J.; Morse, D.H.; Pontau, A.E.

    1992-01-01

    We have recently completed the construction of a new ion beamline primarily for particle-induced x-ray emission (PIXE) analysis. This will supplement our current ion microtomography (IMT) material characterization capabilities using accelerator microanalysis. In this paper we describe the PIXE beamline and give some results that characterize the system. We also report the results of some initial experiments

  19. Fracture mechanisms in lead zirconate titanate ceramics

    International Nuclear Information System (INIS)

    Freiman, S.W.; Chuck, L.; Mecholsky, J.J.; Shelleman, D.L.

    1986-01-01

    Lead Zirconate Titanate (PZT) ceramics can be formed over a wide range of PbTiO 3 /PbZrO 3 ratios and exist in a number of crystal structures. This study involved the use of various fracture mechanics techniques to determine critical fracture toughness, K /SUB IC/ , as a function of composition, microstructure, temperature, and electrical and thermal history. The results of these experiments indicate that variations in K /SUB IC/ are related to phase transformations in the material as well as to other toughening mechanisms such as twinning and microcracking. In addition, the strength and fracture toughness of selected PZT ceramics were determined using specimens in which a crack was introduced by a Vicker's hardness indentor. The variation of K /SUB IC/ with composition and microstructure was related to the extent of twin-crack interaction. Comparison of the plot of strength as a function of indentation load with that predicted from indentation fracture models indicates the presence of internal stresses which contribute to failure. The magnitude of these internal stresses has been correlated with electrical properties of the ceramic. Fractographic analysis was used to determine the magnitude of internal stresses in specimens failing from ''natural flaws.''

  20. On the identification of carbonaceous aerosols via 14C accelerator mass spectrometry, and laser microprobe mass spectrometry

    International Nuclear Information System (INIS)

    Currie, L.A.; Fletcher, R.A.; Klouda, G.A.

    1987-01-01

    Carbon isotopic measurements ( 12 C, 14 C), derived from chemical measurements of total carbon plus AMS measurements of 14 C/ 12 C have become an accepted means for estimating fossil and contemporary carbon source contributions to atmospheric carbon. Because of the limited sensitivity of these techniques, however, such measurements are restricted to 'bulk' samples comprising at least 10-100 μg of carbon. Laser microprobe mass spectrometry (LMMS) offers an important complementary opportunity to investigate the chemical nature of individual particles as small as 0.1 μm in diameter. Although there is little hope to measure 14 C/ 12 C in such small samples, the compositional and structural information available with the laser microprobe is of interest for possible source discrimination. Also, the analysis of individual particles, which may reflect individual sources, yields significant potential increases in spatial, temporal and source resolution, in comparison to bulk sample analysis. Results of our exploratory investigation of known sources of carbonaceous particles, using LMMS, are presented. By applying multivariate techniques to laser mass spectra of soot from the combustion of heptane and wood, we found striking differences in the alkali metals (notably potassium) in the positive ion mass spectra. For ambient particles, 14 C has proved to be a crucial adjunct for the development and validation of the LMMS approach to single particle source assignment via carbon cluster pattern recognition. The combined techniques offer great promise for objective modeling (number and types of carbon sources) and for extension of the dichotomous carbon apportionment (fossil, contemporary) to subclasses such as soot from wood and agricultural burning, and that from coal and petroleum combustion. (orig.)

  1. San Francisco Estuary Striped Bass Migration History Determined by Electron-microprobe Analysis of Otolith Sr/Ca Ratio

    Energy Technology Data Exchange (ETDEWEB)

    Ostrach, D J; Phillis, C C; Weber, P K; Ingram, B L; Zinkl, J G

    2004-09-17

    Habitat use has been shown to be an important factor in the bioaccumulation of contaminants in striped bass. This study examines migration in striped bass as part of a larger study investigating bioaccumulation and maternal transfer of xenobiotics to progeny in the San Francisco Estuary system. Habitat use, residence time and spawning migration over the life of females (n = 23) was studied. Female striped bass were collected between Knights Landing and Colusa on the Sacramento River during the spawning runs of 1999 and 2001. Otoliths were removed, processed and aged via otolith microstructure. Subsequently, otoliths were analyzed for strontium/calcium (Sr/Ca) ratio using an electron-microprobe to measure salinity exposure and to distinguish freshwater, estuary, and marine habitat use. Salinity exposure during the last year before capture was examined more closely for comparison of habitat use by the maternal parent to contaminant burden transferred to progeny. Results were selectively confirmed by ion microprobe analyses for habitat use. The Sr/Ca data demonstrate a wide range of migratory patterns. Age of initial ocean entry differs among individuals before returning to freshwater, presumably to spawn. Some fish reside in freshwater year-round, while others return to more saline habitats and make periodic migrations to freshwater. Frequency of habitat shifts and residence times differs among fish, as well as over the lifetime of individual fish. While at least one fish spent its final year in freshwater, the majority of spawning fish spent their final year in elevated salinity. However, not all fish migrated to freshwater to spawn in the previous year. Results from this investigation concerning migration history in striped bass can be combined with contaminant and histological developmental analyses to better understand the bioaccumulation of contaminants and the subsequent effects they and habitat use have on fish populations in the San Francisco Estuary system.

  2. Fabrication of zircon for disposition of weapons plutonium

    International Nuclear Information System (INIS)

    Kim, K.C.; Huang, J.Y.; Serrano, P.L.

    1997-01-01

    This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). In an effort to address the problems of long term storage and nuclear waste minimization, zircon has been proposed as a host medium for plutonium and other actinides recovered from dismantled nuclear weapons. The objective of this work is to investigate the feasibility of large scale fabrication of Pu-bearing zircon. Since PuO 2 is thermodynamically less stable than ZrO 2 , it is expected that the process parameters determined for synthesizing ZrSiO 4 (zircon) would be applicable to those for PuSiO 4 (Pu-zircon). Furthermore, since the foremost concern in plutonium processing is the potential for contamination release, this work emphasizes the development of process parameters, using zircon first, to anticipate potential material problems in the containment system for reaction mixtures during processing. Stoichiometric mixtures of ZrO 2 and SiO 2 , in hundred-gram batches, have been subjected to hot isostatic pressing (HIP) at temperatures near 1,500 C and pressures approximately 10,000 psi. The product materials have been analyzed by x-ray powder diffraction, and are found to consist of zircon after approximately two hours of reaction time. From this work, it is clear that the fabrication of large quantities of Pu-zircon is feasible. The most notable result of this work is evidence for the existence of container problems. This result, in turn, suggests potential solutions to these problems. Experiments with the quartz inner container, the glass sealant, a sacrificial metal barrier, and a metal outer container are being investigated to mitigate these potential hazards

  3. Crystallization process of zircon and fergusonite during hydrothermal alteration in Nechalacho REE deposit, Thor Lake, Canada

    Science.gov (United States)

    Hoshino, M.; Watanabe, Y.; Murakami, H.; Kon, Y.; Tsunematsu, M.

    2012-04-01

    The core samples of two drill holes, which penetrate sub-horizontal mineralized horizons at Nechalacho REE deposit in the Proterozoic Thor Lake syenite, Canada, were studied in order to clarify magmatic and hydrothermal processes that enriched HFSE (e.g. Zr, Nb, Y and REE). Zircon is the most common REE minerals in Nechalacho REE deposit. The zircon is divided into five types as follows: Type-1 zircon occurs as single grain in phlogopite and the chondrite-normalized REE pattern is characterized by a steeply-rising slope from the LREE to the HREE with a positive Ce-anomaly and negative Eu-anomaly. This chemical characteristic is similar to that of igneous zircon. Type-2 zircon consists of HREE-rich magmatic porous core and LREE-Nb-F-rich hydrothermal rim. This type zircon is mostly included in phlogopite and fluorite, and occasionally in microcline. Type-3 zircon is characterized by euhedral to anhedral crystal, occurring in a complex intergrowth with REE fluorocarbonates. Type-3 zircons have high contents of REE, Nb and fluorine. Type-4 zircon consists of porous-core and -rim zones, but their chemical compositions are similar to each other. This type zircon is a subhedral crystal rimmed by fergusonite. Type-5 zircon is characterized by smaller, porous and subhedral to anhedral crystals. The interstices between small zircons are filled by fergusonite. Type-4 and -5 zircons show low REE and Nb contents. Occurrences of these five types of zircon are different according to the depth and degree of the alteration by hydrothermal solutions rich in F- and CO3 of the two drill holes, which permit a model for evolution of the zircon crystallization in Nechalacho REE deposit as follows: (1) type-1 (single magmatic zircon) is formed in miaskitic syenite. (2) LREE-Nb-F-rich hydrothermal zircon formed around HREE-rich magmatic zircon (type-2 zircon); (3) type-3 zircon crystallized thorough F and CO3-rich hydrothermal alteration of type-2 zircon which formed the complex

  4. Zircon crytallization and recycling in the magma chamber of the rhyolitic Kos Plateau Tuff (Aegean arc)

    Science.gov (United States)

    Bachman, O.; Charlier, B.L.A.; Lowenstern, J. B.

    2007-01-01

    In contrast to most large-volume silicic magmas in continental arcs, which are thought to evolve as open systems with significant assimilation of preexisting crust, the Kos Plateau Miff magma formed dominantly by crystal fractionation of mafic parents. Deposits from this ??? 60 km3 pyroclastic eruption (the largest known in the Aegean arc) lack xenocrystic zircons [secondary ion mass spectrometry (SIMS) U-Pb ages on zircon cores never older than 500 ka] and display Sr-Nd whole-rock isotopic ratios within the range of European mantle in an area with exposed Paleozoic and Tertiary continental crust; this evidence implies a nearly closed-system chemical differentiation. Consequently, the age range provided by zircon SIMS U-Th-Pb dating is a reliable indicator of the duration of assembly and longevity of the silicic magma body above its solidus. The age distribution from 160 ka (age of eruption by sanidine 40Ar/39Ar dating; Smith et al., 1996) to ca. 500 ka combined with textural characteristics (high crystal content, corrosion of most anhydrous phenocrysts, but stability of hydrous phases) suggest (1) a protracted residence in the crust as a crystal mush and (2) rejuvenation (reduced crystallization and even partial resorption of minerals) prior to eruption probably induced by new influx of heat (and volatiles). This extended evolution chemically isolated from the surrounding crust is a likely consequence of the regional geodynamics because the thinned Aegean microplate acts as a refractory container for magmas in the dying Aegean subduction zone (continent-continent subduction). ?? 2007 Geological Society of America.

  5. Zircon crystallization and recycling in the magma chamber of the rhyolitic Kos Plateau Tuff (Aegean arc)

    Science.gov (United States)

    Bachman, O.; Charlier, B.L.A.; Lowenstern, J. B.

    2007-01-01

    In contrast to most large-volume silicic magmas in continental arcs, which are thought to evolve as open systems with significant assimilation of preexisting crust, the Kos Plateau Tuff magma formed dominantly by crystal fractionation of mafic parents. Deposits from this ~60 km3 pyroclastic eruption (the largest known in the Aegean arc) lack xenocrystic zircons [secondary ion mass spectrometry (SIMS) U-Pb ages on zircon cores never older than 500 ka] and display Sr-Nd whole-rock isotopic ratios within the range of European mantle in an area with exposed Paleozoic and Tertiary continental crust; this evidence implies a nearly closed-system chemical differentiation. Consequently, the age range provided by zircon SIMS U-Th-Pb dating is a reliable indicator of the duration of assembly and longevity of the silicic magma body above its solidus. The age distribution from 160 ka (age of eruption by sanidine 40Ar/39Ar dating; Smith et al., 1996) to ca. 500 ka combined with textural characteristics (high crystal content, corrosion of most anhydrous phenocrysts, but stability of hydrous phases) suggest (1) a protracted residence in the crust as a crystal mush and (2) rejuvenation (reduced crystallization and even partial resorption of minerals) prior to eruption probably induced by new influx of heat (and volatiles). This extended evolution chemically isolated from the surrounding crust is a likely consequence of the regional geodynamics because the thinned Aegean microplate acts as a refractory container for magmas in the dying Aegean subduction zone (continent-continent subduction).

  6. High-voltage scanning ion microscope: Beam optics and design

    Energy Technology Data Exchange (ETDEWEB)

    Magilin, D., E-mail: dmitrymagilin@gmail.com; Ponomarev, A.; Rebrov, V.; Ponomarov, A.

    2015-05-01

    This article is devoted to the conceptual design of a compact high-voltage scanning ion microscope (HVSIM). In an HVSIM design, the ion optical system is based on a high-brightness ion source. Specifically, the ion optical system is divided into two components: an ion injector and a probe-forming system (PFS) that consists of an accelerating tube and a multiplet of quadrupole lenses. The crossover is formed and controlled by the injector, which acts as an object collimator, and is focused on the image plane by the PFS. The ion microprobe has a size of 0.1 μm and an energy of 2 MeV. When the influence of the chromatic and third-order aberrations is theoretically taken into account, the HVSIM forms an ion microprobe.

  7. Twinning in Zircon: Not a High-Pressure Phenomenon

    Science.gov (United States)

    Jones, G. A.; Moser, D.; Shieh, S. R.; Barker, I.

    2017-12-01

    Microtwins in zircon are commonly found in shocked terrestrial and extraterrestrial samples and are potentially important for shock history and crater reconstruction. Twinning is easily observed with both the optical microscope and variety of electron beam techniques. Twinning as a deformation mechanism is consistent with the high strain rates generated during impact. No constitutive relationships, or even general limits on the physical conditions required for twinning in zircon are known, however. Present speculation on the critical quantity for twin formation, i.e. 10s of GPa of shock pressure (Moser et al. 2011, Timms et al., 2012), has no basis in the underlying mechanisms of twin nucleation, which are related to the motion of dislocations. This erroneous value is due to conflation of twinning sensu stricto with a phase transformation to reidite. Reidite occurs as twin-like lamellae occupying the {112} planes which are thought to be a mirror plane for twinning. We review the crystallographic theory of twinning in zircon. We then evaulate several theories on the nucleation of twins along with their necessary stresses involved. Our aim is to show that shock microtwins in zircon can be a `low pressure' shock phenomenon. This 'low pressure' hypothesis is supported by natural samples. These zircons are from the lower crust nearly 80 km from the centre of the Vredefort impact structure—the most distal zircon shock microstructures yet found in the lithosphere. Twins are present in 10% of the zircon grains greater than 50 µm in diameter. As an extensive, 'low pressure' phenomenon, twins are an easily recognized and potentially widespread record of Earth's impact history.Moser, D.E., Cupelli, C. L., Barker, I., Flowers, R. M., Mowman, J. R., Wooden, J. and Hart, R. (2011) New zircon shock phenomena and their use for dating and […] analysis of the Vredefort dome, Canadian Journal of Earth Sciences 48(2), 117-139.Timms, N.E., Reddy, S. M., Healy, D., Nemchin, A. A

  8. U-Th-Pb systematics in zircon and titanite

    International Nuclear Information System (INIS)

    Zartman, R.E.; Kwak, L.M.

    1990-01-01

    U-Th-Pb isotopic analyses of zircon and titanite were made for two core samples of granite from borehole ATK-1 drilled into the Eye-Dashwa Lakes pluton. One of the samples from near the bottom of the hole (990.97 to 996.78 m) yielded zircon and titanite that were slightly to severely disturbed isotopically. Eight fractions of zircon give an upper concordia intercept age of 2625 ± 16 Ma (MSWD = 34), which, based on an evaluation of the more concordant data points and on other geochronological results, is interpreted as being slightly too young. The time of crystallization is probably better approximated by the 207 Pb/ 206 Pb age of 2665 Ma determined on a slightly (∼8 percent) discordant titanite. The other sample from near the surface (3.85 to 9.61 m) generally revealed even more severely disturbed isotopic systematics for both zircon and titanite. The complex nature of the disturbances probably resulted from the penetration of meteoritic water into rock already modified by post-crystallization hydrothermal alteration. Nuclide migration occurred in both minerals -- during the Middle or Late Proterozoic for the zircon and during the modern weathering cycle for the titanite. Material balance calculations are used to demonstrate a recent relative gain of radiogenic Pb and/or loss of Th and U from the freshest-looking, least-altered titanite by exchange with altered, leucoxenite-bearing titanite

  9. Comment on "Zircon U-Th-Pb dating using LA-ICP-MS: Simultaneous U-Pb and U-Th dating on 0.1 Ma Toya Tephra, Japan" by Hisatoshi Ito

    Science.gov (United States)

    Guillong, M.; Schmitt, A. K.; Bachmann, O.

    2015-04-01

    Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) of eight zircon reference materials and synthetic zircon-hafnon end-members indicate that corrections for abundance sensitivity and molecular zirconium sesquioxide ions (Zr2O3+) are critical for reliable determination of 230Th abundances in zircon. Other polyatomic interferences in the mass range 223-233 amu are insignificant. When corrected for abundance sensitivity and interferences, activity ratios of (230Th)/(238U) for the zircon reference materials we used average 1.001 ± 0.010 (1σ error; mean square of weighted deviates MSWD = 1.45; n = 8). This includes the 91500 and Plešovice zircons, which were deemed unsuitable for calibration of (230Th)/(238U) by Ito (2014). Uranium series zircon ages generated by LA-ICP-MS without mitigating (e.g., by high mass resolution) or correcting for abundance sensitivity and molecular interferences on 230Th such as those presented by Ito (2014) are potentially unreliable.

  10. Alpha-decay event damage in zircon

    International Nuclear Information System (INIS)

    Murakami, Takashi; Chakoumakos, B.C.; Ewing, R.C.; Lumpkin, G.R.; Weber, W.J.

    1991-01-01

    Based on density measurements, X-ray diffraction analysis, and high-resolution transmission electron microscopy of a suite of natural zircon samples from Sri Lanka, three stages of damage accumulation may be delineated. Stage 1 ( 15 α-decay events/mg) is characterized by sharp Bragg diffraction maxima with a minor contribution from the diffuse-scattering component. Electron diffraction patterns were sharp. Damage is dominated by the accumulation of isolated point defects, which cause unit-cell expansion and distortion that account for most of the decrease in density. These defects may partially anneal over geologic periods of time. Stage 2 (3 x 10 15 to 8 x 10 15 α-decay events/mg) is characterized by significant decreases in the intensity of the Bragg diffraction maxima, which becomes asymmetric from increased contributions of the diffuse-scattering component. High-resolution transmission electron microscopy indicated that the microstructure consists of distorted crystalline regions and amorphous tracks caused by α-recoil nuclei. With increasing α-decay dose, damaged crystalline regions are converted into aperiodic regions but with no further significant expansion of the unit cell in the remaining crystalline regions. State 3 (> 8 x 10 15 α-decay events/mg) consists of material that is entirely aperiodic as far as can be determined by X-ray or electron diffraction. There was no evidence for the formation of ZrO 2 or SiO 2 as final products during the last stage of metamictization. Based on modeled density changes, aperiodic regions continue to experience a change in structure as they are redamaged

  11. The Effect of Element Substitution on Ti-in-Zircon Geothermometry in Volcanic Zircons from Mount Pinatubo, Philippines

    Science.gov (United States)

    Lee, S. L.; Hattori, K.

    2017-12-01

    Despite the extensive application of the Ti-in-zircon geothermometer, its accuracy in natural systems remains uncertain. In order to investigate the parameters contributing to Ti in zircon, we examined zircons from dacitic eruption products of Mount Pinatubo, Philippines, from the Pliocene (>2.5-2.7 Ma), 35000BP and 1991AD. All samples are unaltered and quenched from magmas at 790-825°C (Fe-Ti-oxide thermometry). Furthermore, the magma conditions of 1991 samples are well characterized: 780°C (cummingtonite rims on hornblende, Fe-Ti-oxide thermometry), 2 kbar pressure, 5.5-6.5 wt.% H2O and fO2 of NNO+1.6. Calculated zircon saturation temperatures are 760, 744 and 738°C (oldest to youngest). Zircon Ti concentrations are low (2.0-8.8 ppm), show positive covariation with U (35.6-639 ppm), Th (18.7-696 ppm), ∑REE (237-1310 ppm) and Y (247-1770 ppm), and negative covariation with Hf (7610-12000 ppm). The Ti-in-zircon geothermometer by Ferry and Watson (2007) yields mean temperatures of 690, 666 and 663°C (oldest to youngest), using TiO2 activity=0.6, SiO2 activity=1 and -40°C pressure correction. Therefore, temperatures calculated using this method are underestimated by >100°C. We suggest that elements in the Zr site impact the substitution of Ti in the Si site of zircon. Ti shows a positive covariation with Zr/Hf (37.0-57.3, r2=0.551). The ionic radius of Hf4+ is smaller than Zr4+, whereas cations like U4+, Th4+, REE3+ and Y3+ are larger. The departure from the ideal crystal configuration is evaluated using the parameter Zr/(Hf-x), whereby x=U4+, Th4+, ∑REE and Y3+. Ti contents are more strongly correlated with the parameter than Zr/Hf (r2=0.559, 0.565, 0.608, 0.616; respectively). This suggests that large cations replacing Zr strain the lattice, reducing the amount of Ti incorporated into zircon. This further suggests that ZrSiO4 activity is less than 1 in natural rocks, resulting in the systematic underestimation of Ti-in-zircon temperatures.

  12. Chemical characterisation of zircon-cadmium sulfoselenide ceramic pigments

    International Nuclear Information System (INIS)

    Gazulla Barreda, M. F.; Rodrigo Edo, M.; Blasco Roca, E.; Orduna Cordero, M.

    2013-01-01

    The present paper addresses the development of a methodology that allows the complete chemical characterisation of zircon cadmium sulfoselenide ceramic pigments including minor and major elements. To develop the methodology, five zircon-cadmium sulfoselenide pigments with different hues were selected, studying the different measurement process steps, from sample preparation to the optimisation of the measurement of the different components of the pigments by spectroscopic techniques (WD-XRF and elemental analysis by combustion and IR detection). The chemical characterisation method developed was validated with synthetic standards prepared from the mixture of certified reference materials and pure oxides because no certified referenced materials of this type of pigments were commercially available. The developed method can be used for a complete chemical characterization of zircon-cadmium sulfoselenide ceramic pigments with a very low uncertainty for all the elements analysed. (Author)

  13. Core Community Specifications for Electron Microprobe Operating Systems: Software, Quality Control, and Data Management Issues

    Science.gov (United States)

    Fournelle, John; Carpenter, Paul

    2006-01-01

    Modem electron microprobe systems have become increasingly sophisticated. These systems utilize either UNIX or PC computer systems for measurement, automation, and data reduction. These systems have undergone major improvements in processing, storage, display, and communications, due to increased capabilities of hardware and software. Instrument specifications are typically utilized at the time of purchase and concentrate on hardware performance. The microanalysis community includes analysts, researchers, software developers, and manufacturers, who could benefit from exchange of ideas and the ultimate development of core community specifications (CCS) for hardware and software components of microprobe instrumentation and operating systems.

  14. Mapping of trace elements with photon microprobes: x-ray fluorescence with focussed synchrotron radiation

    International Nuclear Information System (INIS)

    Hanson, A.L.; Jones, K.W.; Gordon, B.M.; Pounds, J.G.; Rivers, M.L.; Schidlovsky, G.

    1985-04-01

    High energy electron synchrotron storage rings provide copious quantities of polarized photons that make possible the mapping of many trace elements with sensitivities at the parts per billion (ppB) level with spatial resolutions in the micrometer range. The brightness of the x-ray ring of the National Synchrotron Light Source (NSLS), presently being commissioned, will be five orders of magnitude larger than that of the bremsstrahlung spectrum of state-of-the-art rotating anode tubes. We will discuss mapping trace elements with a photon microprobe presently being constructed for use at the NSLS. This microprobe will have micrometer spatial resolution

  15. Proton microprobe analysis of zinc in skeletal tissues. [Proton induced x-ray emission analysis

    Energy Technology Data Exchange (ETDEWEB)

    Doty, S B; Jones, K W; Kraner, H W; Shroy, R E; Hanson, A L

    1980-06-01

    A proton microprobe with windowless exit port was used to study zinc distributions in various types of skeletal tissues. The use of an external beam facilitated positioning of the targets for examination of particular points of interest. The proton microprobe is uniquely suited to this work since it combines high sensitivity for zinc determinations in thick samples with good spatial resolution. Measurements on rat and rabbit Achilles tendon showed a significant increase in zinc concentrations as the beam moved from the unmineralized collagen into the mineralized attachment site. Cartilage gave a similar result, with calcified cartilage having a greater zinc level than the articular surface on unmineralized epiphyseal cartilage.

  16. An x-ray microprobe using focussing optics with a synchrotron radiation source

    International Nuclear Information System (INIS)

    Thompson, A.C.; Underwood, J.H.; Wu, Y.; Giauque, R.D.

    1989-01-01

    An x-ray microprobe can be used to produce maps of the concentration of elements in a sample. Synchrotron radiation provides x-ray beams with enough intensity and collimation to make possible elemental images with femtogram sensitivity. The use of focussing x-ray mirrors made from synthetic multilayers with a synchrotron x-ray beam allows beam spot sizes of less than 10 μm /times/ 10 μm to be produced. Since minimal sample preparation is required and a vacuum environment is not necessary, there will be a wide variety of applications for such microprobes. 8 refs., 6 figs

  17. The PNC/XOR x-ray microprobe station at APS sector 20

    International Nuclear Information System (INIS)

    Heald, S. M.; Cross, J. O.; Brewe, D. L.; Gordon, R. A.

    2007-01-01

    The X-ray microprobe is the most popular experimental setup at the PNC/XOR insertion device beamline located at sector 20 at the Advanced Photon Source. To satisfy user demand and to simplify the setup, we have developed a dedicated station with multiple detection options. This paper will describe the setup in detail and demonstrate the capabilities with some example imaging, micro-XAS and microdiffraction data. In the future, an improved version of the microprobe will be installed on a dedicated undulator. The improvements planned for this station are based on our operational experience and will also be discussed

  18. Polymer SU-8 Based Microprobes for Neural Recording and Drug Delivery

    Science.gov (United States)

    Altuna, Ane; Fernandez, Luis; Berganzo, Javier

    2015-06-01

    This manuscript makes a reflection about SU-8 based microprobes for neural activity recording and drug delivery. By taking advantage of improvements in microfabrication technologies and using polymer SU-8 as the only structural material, we developed several microprobe prototypes aimed to: a) minimize injury in neural tissue, b) obtain high-quality electrical signals and c) deliver drugs at a micrometer precision scale. Dedicated packaging tools have been developed in parallel to fulfill requirements concerning electric and fluidic connections, size and handling. After these advances have been experimentally proven in brain using in vivo preparation, the technological concepts developed during consecutive prototypes are discussed in depth now.

  19. POLYMER SU-8 BASED MICROPROBES FOR NEURAL RECORDING AND DRUG DELIVERY

    Directory of Open Access Journals (Sweden)

    Ane eAltuna

    2015-06-01

    Full Text Available This manuscript makes a reflection about SU-8 based microprobes for neural activity recording and drug delivery. By taking advantage of improvements in microfabrication technologies and using polymer SU-8 as the only structural material, we developed several microprobe prototypes aimed to: a minimize injury in neural tissue, b obtain high-quality electrical signals and c deliver drugs at a micrometer precision scale. Dedicated packaging tools have been developed in parallel to fulfill requirements concerning electric and fluidic connections, size and handling. After these advances have been experimentally proven in brain using in vivo preparation, the technological concepts developed during consecutive prototypes are discussed in depth now.

  20. Theory of equidistant three-dimensional radiance measurements with optical microprobes RID A-1977-2009

    DEFF Research Database (Denmark)

    FukshanskyKazarinova, N.; Fukshansky, L.; Kuhl, Morten

    1996-01-01

    Fiber-optic radiance microprobes, increasingly applied for measurements of internal light fields in living tissues, provide three-dimensional radiance distribution solids and radiant energy fluence rates at different depths of turbid samples. These data are, however, distorted because of an inher...... of application is presented. The limitations of this theory and the prospects for this approach are discussed....... of an inherent feature of optical fibers: nonuniform angular sensitivity. Because of this property a radiance microprobe during a single measurement partly underestimates light from the envisaged direction and partly senses light from other directions. A theory of three-dimensional equidistant radiance...

  1. Combination of synchrotron radiation X-ray microprobe and nuclear microprobe for chromium and chromium oxidation states quantitative mapping in single cells

    International Nuclear Information System (INIS)

    Ortega, Richard; Deves, Guillaume; Fayard, Barbara; Salome, Murielle; Susini, Jean

    2003-01-01

    Hexavalent chromium compounds are established carcinogens but their mechanism of cell transformation has not been elucidated yet. In this study, chromium oxidation state distribution maps in cells exposed to soluble (Na 2 CrO 4 ), or insoluble (PbCrO 4 ), Cr(VI) compounds have been obtained by use of the ESRF ID-21 X-ray microscope. In addition, the quantitative maps of element distributions in cells have been determined using the nuclear microprobe of Bordeaux-Gradignan. Nuclear microprobe quantitative analysis revealed interesting features on chromium, and lead, cellular uptake. It is suggested that cells can enhance PbCrO 4 solubility, resulting in chromium, but not lead uptake. The differential carcinogenic potential of soluble and insoluble Cr(VI) compounds is discussed with regard to chromium intracellular quantitative distribution

  2. Dating of zircons by the fission track method

    International Nuclear Information System (INIS)

    Tenorio Hernandez, L.M.

    1992-01-01

    This work describes the methodology to date zircons by the Fission Track Method. A brief discussion is made of the physical principles of the method, physical properties of zircons and the geochemical properties of uranium. When starting with a hand sample, a mineral separation is required; to do this the following steps are needed: crushing and sieving of the sample, washing and drying, magnetic separation, heavy liquid separation (Bromoform 2.89 g/cm 3 , Diyodomethane = 3.31 g/cm 3 ), and manual separation on a stereoscopic microscope. Once the zircon concentrate is obtained, these are mounted on a FEP teflon mount, then polished and etched on an eutectic mix of 10 g. of KOH + 7.2 g. of NaOH, heated to 210 Centigrade degrees. Afterwards the mounts are prepared for irradiation, sterilizing and putting on top of them an external detector (a thin sheet of muscovite poor in uranium content). The package is then wrapped in plastic and sent to the reactor together with standard zircons of known age (Fish Canyon Tuff: Naeser et.al., 1981), mounted in the same way, plus standard glasses of known uranium content. The package was irradiated in a site known as SIRCA (Rotatory Capsules Irradiation System). Then the package is left to decay for several days, and then the external detectors are etched in a 48% concentrated hydrofluoric acid for 5 minutes. Once the samples are processed through the mentioned steps, spontaneous tracks appear in the zircons and induced tracks appear in the external detectors. On counting the tracks one obtains ρ s (spontaneous track density) and ρ 1 (induced track density). These two parameters together with another one called '#zeta #' (obtained from the standard zircons and glasses), are used to obtain the age of the sample. Zircons from Cerro de Mercado, Durango were dated and the age obtained was 30 ±5 Ma. This date is in agreement with similar results obtained by Fleisher and Naeser (1975) for zircons of the same locality and dated by the

  3. Synthesis, Characterization and Thermal Diffusivity of Holmium and Praseodymium Zirconates

    OpenAIRE

    Stopyra M.; Niemiec D.; Moskal G.

    2016-01-01

    A2B2O7 oxides with pyrochlore or defected fluorite structure are among the most promising candidates for insulation layer material in thermal barrier coatings. The present paper presents the procedure of synthesis of holmium zirconate Ho2Zr2O7 and praseodymium zirconate Pr2Zr2O7 via Polymerized-Complex Method (PCM). Thermal analysis of precursor revealed that after calcination at relatively low temperature (700°C) fine-crystalline, single-phase material is obtained. Thermal diffusivity was me...

  4. At what conditions does zircon grow/dissolve during high-T metamorphism? Relating zircon textures to PT-conditions

    Science.gov (United States)

    Kunz, Barbara E.; Regis, Daniele; Manzotti, Paola; Engi, Martin

    2015-04-01

    A key question in ziconology is when and how zircon grows during metamorphism. To shed light on zircon forming processes and the corresponding PT-conditions during high-T metamorphism a case study was undertaken. The Ivrea Zone (N-Italy) exposes a lower continental crustal section in which a continuous metamorphic field gradient from amphibolite to granulite facies is documented. This field gradient is thought to reflect protracted heating during late Paleozoic times, with a probable high-T peak in the Permian. We present first results from a primarily textural study supported by U-Pb ages, Th/U ratios and Ti-in-Zrn thermometry. Four types of zircon were identified based on their overgrowth proportions and the preservation of detrital cores. Zircon grains were thus classified as Type1 - detrital grains with no overgrowth or very narrow rims (300 Ma) and appears to reflect an early dehydration phase. Rim2b has Permian ages (median 275 Ma), is by far the most common overgrowth type, found in a wide PT-range. Its development appears related to biotite breakdown. Rim3 is texturally indicative of magmatic zircon, occurs only in diatexites. Rim4 is the latest overgrowth and is locally found at all metamorphic grades. Textural features suggest late fluid-related recrystallization of existing zircon. At lowest grade (675±35°C, 6±2 kbar) zircons show type1 only, overgrowths are too thin to clearly identify the rim type. Further upgrade (~700°C, 7 kbar) type1 and type2 dominate. Type2 zircons show rim1, rim2a and occasionally rim4. At the Mu-out isograd (750±50°C, 8.2±1.4 kbar) most zircons are of type2, now with rim2b instead of 2a, in addition to rim1 and rim4. Near and in granulite facies (to 800°C, 8±2 kbar) mostly zircon type2 and type4 are present. While rim1 gets more narrow with increasing metamorphic grade, rim2b grows significantly thicker. Occasionally rim2a and rim4 occur. Close to the Bt-out isograd (~860°C, 9.2±1.7 kbar), mostly type3 and type4 are

  5. Developing Zircon as a Probe of Planetary Impact History

    Science.gov (United States)

    Wielicki, Matthew

    2014-12-01

    The identification of Meteor Crater in Arizona as an extraterrestrial impact by Eugene Shoemaker provided the first evidence of this geologic phenomenon and opened the door to a new field of research that has eventually lead to the identification of over ~150 terrestrial impact structures. Subsequently impacts have been evoked in the formation of the moon, delivery of volatiles and bio-precursors to early Earth, creation of habitats for the earliest life and, in more recent times, major mass extinction events. However, understanding the impact flux to the Earth-Moon system has been complicated by the constant weathering and erosion at Earth's surface and the complex nature of impactite samples such that only a hand full of terrestrial craters have been accurately and precisely dated. Currently 40Ar/39Ar step-heating analysis of impactite samples is commonly used to infer impact ages but can be problematic due to the presence of relic clasts, incomplete 40Ar outgassing or excess 40Ar, and recoil and shock effects. The work presented here attempts to develop zircon geochronology to probe planetary impact histories as an alternative to current methods and provides another tool by which to constrain the bolide flux to the Earth-Moon system. Zircon has become the premier geo-chronometer in earth science and geochemical investigation of Hadean zircon from Western Australia has challenged the long-standing, popular conception that the near-surface Hadean Earth was an uninhabitable and hellish world; Zircons may preserve environmental information regarding their formation and thus provide a rare window into conditions on early Earth. Isotopic and petrologic analyses of these ancient grains have been interpreted to suggest that early Earth was more habitable than previously envisioned, with water oceans, continental crust, and possibly even plate tectonics. The Hadean is also suspected to be a time of major planetary bombardment however identifying impact signatures within

  6. Two-stage model of development of heterogeneous uranium-lead systems in zircon

    International Nuclear Information System (INIS)

    Mel'nikov, N.N.; Zevchenkov, O.A.

    1985-01-01

    Behaviour of isotope systems of multiphase zircons at their two-stage distortion is considered. The results of calculations testify to the fact that linear correlations on the diagram with concordance can be explained including two-stage discovery of U-Pb systems of cogenetic zircons if zircon is considered physically heterogeneous and losing in its different part different ratios of accumulated radiogenic lead. ''Metamorphism ages'' obtained by these two-stage opening zircons are intermediate, and they not have geochronological significance while ''crystallization ages'' remain rather close to real ones. Two-stage opening zircons in some cases can be diagnosed by discordance of their crystal component

  7. Fatigue studies in compensated bulk lead zirconate titanate

    International Nuclear Information System (INIS)

    Verdier, Cyril; Morrison, Finlay D.; Lupascu, Doru C.; Scott, James F.

    2005-01-01

    Impedance analysis studies were carried out on compensated bulk lead zirconate titanate samples. Fatigue is concomitant with the onset of dielectric loss. This is shown to be dominantly due to an irreversibly modified near-surface layer that can be polished off. The highly compensated nature of these samples minimizes the role of oxygen vacancies

  8. Pyroelectricity versus conductivity in soft lead zirconate titanate (PZT) ceramics

    NARCIS (Netherlands)

    Kamel, T.M.; With, de G.

    2007-01-01

    The electrical behavior of modified soft lead zirconate titanate (PZT) ceramics has been studied as a function of temperature at different direct current (dc) electric fields and grain sizes. As ferroelectrics, such as PZT, are highly polarizable materials, poling, depolarization, and electric

  9. Raman study of radiation-damaged zircon under hydrostatic compression

    Science.gov (United States)

    Nasdala, Lutz; Miletich, Ronald; Ruschel, Katja; Váczi, Tamás

    2008-12-01

    Pressure-induced changes of Raman band parameters of four natural, gem-quality zircon samples with different degrees of self-irradiation damage, and synthetic ZrSiO4 without radiation damage, have been studied under hydrostatic compression in a diamond anvil cell up to ~10 GPa. Radiation-damaged zircon shows similar up-shifts of internal SiO4 stretching modes at elevated pressures as non-damaged ZrSiO4. Only minor changes of band-widths were observed in all cases. This makes it possible to estimate the degree of radiation damage from the width of the ν3(SiO4) band of zircon inclusions in situ, almost independent from potential “fossilized pressures” or compressive strain acting on the inclusions. An application is the non-destructive analysis of gemstones such as corundum or spinel: broadened Raman bands are a reliable indicator of self-irradiation damage in zircon inclusions, whose presence allows one to exclude artificial color enhancement by high-temperature treatment of the specimen.

  10. Dielectric Strontium Zirconate Sprayed by a Plasma Torch.

    Czech Academy of Sciences Publication Activity Database

    Ctibor, Pavel; Sedláček, J.; Janata, Marek

    2017-01-01

    Roč. 10, č. 4 (2017), s. 225-230 ISSN 2008-2134 Institutional support: RVO:61389021 Keywords : Plasma spraying * Electrical properties * Strontium Zirconate * Insulators Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass OBOR OECD: Ceramics www.pccc.icrc.ac.ir/Articles/18/1/18/1010/

  11. Round robin: Quantitative lateral resolution of PHI XPS microprobes Quantum 2000/Quantera SXM

    International Nuclear Information System (INIS)

    Scheithauer, Uwe; Kolb, Max; Kip, Gerard A.M.; Naburgh, Emile; Snijders, J.H.M.

    2016-01-01

    Highlights: • The quantitative lateral resolution of 7 PHI XPS microprobes has been estimated in a round robin. • An ellipsoidally shaped quartz crystal monochromatizes the Alkα radiation and refocuses it from the Al anode to the sample surface. • The long tail contributions of the X-ray beam intensity distribution were measured using a new and innovative approach. • This quantitative lateral resolution has a significantly larger value than the nominal X-ray beam diameter. • The quantitative lateral resolution follows a trend in time: The newer the monochromator so much the better the quantitative lateral resolution. - Abstract: The quantitative lateral resolution is a reliable measure for the quality of an XPS microprobe equipped with a focused X-ray beam. It describes the long tail contributions of the X-ray beam intensity distribution. The knowledge of these long tail contributions is essential when judging on the origin of signals of XPS spectra recorded on small-sized features. In this round robin test the quantitative lateral resolution of 7 PHI XPS microprobes has been estimated. As expected, the quantitative lateral resolution has significantly larger values than the nominal X-ray beam diameter. The estimated values of the quantitative lateral resolution follow a trend in time: the newer the monochromator of an XPS microprobe so much the better the quantitative lateral resolution.

  12. Round robin: Quantitative lateral resolution of PHI XPS microprobes Quantum 2000/Quantera SXM

    Energy Technology Data Exchange (ETDEWEB)

    Scheithauer, Uwe, E-mail: scht.uhg@googlemail.com [82008 Unterhaching (Germany); Kolb, Max, E-mail: max.kolb@airbus.com [Airbus Group Innovations, TX2, 81663 Munich (Germany); Kip, Gerard A.M., E-mail: G.A.M.Kip@utwente.nl [Universiteit Twente, MESA+ Nanolab, Postbus 217, 7500AE Enschede (Netherlands); Naburgh, Emile, E-mail: e.p.naburgh@philips.com [Materials Analysis, Philips Innovation Services, High Tech Campus 11, 5656 AE Eindhoven (Netherlands); Snijders, J.H.M., E-mail: j.h.m.snijders@philips.com [Materials Analysis, Philips Innovation Services, High Tech Campus 11, 5656 AE Eindhoven (Netherlands)

    2016-07-15

    Highlights: • The quantitative lateral resolution of 7 PHI XPS microprobes has been estimated in a round robin. • An ellipsoidally shaped quartz crystal monochromatizes the Alkα radiation and refocuses it from the Al anode to the sample surface. • The long tail contributions of the X-ray beam intensity distribution were measured using a new and innovative approach. • This quantitative lateral resolution has a significantly larger value than the nominal X-ray beam diameter. • The quantitative lateral resolution follows a trend in time: The newer the monochromator so much the better the quantitative lateral resolution. - Abstract: The quantitative lateral resolution is a reliable measure for the quality of an XPS microprobe equipped with a focused X-ray beam. It describes the long tail contributions of the X-ray beam intensity distribution. The knowledge of these long tail contributions is essential when judging on the origin of signals of XPS spectra recorded on small-sized features. In this round robin test the quantitative lateral resolution of 7 PHI XPS microprobes has been estimated. As expected, the quantitative lateral resolution has significantly larger values than the nominal X-ray beam diameter. The estimated values of the quantitative lateral resolution follow a trend in time: the newer the monochromator of an XPS microprobe so much the better the quantitative lateral resolution.

  13. Characterization of Alq3 thin films by a near-field microwave microprobe.

    Science.gov (United States)

    Hovsepyan, Artur; Lee, Huneung; Sargsyan, Tigran; Melikyan, Harutyun; Yoon, Youngwoon; Babajanyan, Arsen; Friedman, Barry; Lee, Kiejin

    2008-09-01

    We observed tris-8-hydroxyquinoline aluminum (Alq3) thin films dependence on substrate heating temperatures by using a near-field microwave microprobe (NFMM) and by optical absorption at wavelengths between 200 and 900 nm. The changes of absorption intensity at different substrate heating temperatures are correlated to the changes in the sheet resistance of Alq3 thin films.

  14. Microprobe investigation of brittle segregates in aluminum MIG and TIG welds

    Science.gov (United States)

    Larssen, P. A.; Miller, E. L.

    1968-01-01

    Quantitative microprobe analysis of segregated particles in aluminum MIG /Metal Inert Gas/ and TIG /Tungsten Inert Gas/ welds indicated that there were about ten different kinds of particles, corresponding to ten different intermetallic compounds. Differences between MIG and TIG welds related to the individual cooling rates of these welds.

  15. Evaluation of an x-ray microprobe technique as a possible aid to detect salmonellae

    International Nuclear Information System (INIS)

    Richter, E.R.; Banwart, G.J.

    1982-01-01

    Specific bacterial antigen (Salmonella) increased in phosphorus and sqlfur after reaction with the flukrescain isothiocyanate-tagged anti-Salmonella antibody, while nonspecific antigen (Escherichia coli) did not. X-ray microprobe analysis may be useful in detecting salmonellae or other bacteria by determining increases in the elemental constituents of bacterial cells when reacted with elemental-tagged antibodies

  16. Elemental microanalysis of biological and medical specimens with a scanning proton microprobe

    International Nuclear Information System (INIS)

    Legge, G.J.F.; Mazzolini, A.P.

    1979-01-01

    The scanning proton microprobe is shown to be a sensitive instrument for elemental microanalysis of cells and tissues in biological and medical specimens. The preparation of specimens and their behaviour under irradiation are crucial and the application of quantitative scanning analysis to the monitoring of such problems is illustrated

  17. The evolution of complex type B Allende inclusion - An ion microprobe trace element study

    Science.gov (United States)

    Macpherson, Glenn J.; Crozaz, Ghislaine; Lundberg, Laura L.

    1989-01-01

    Results are presented of a detailed trace-element and isotopic analyses of the constituent phases in each of the major textural parts (mantle, core, and islands) of a Type B refractory inclusion, the USNM 5241 inclusion from Allende, first described by El Goresy et al. (1985). The REE data on 5241 were found to be largely consistent with a model in which the mantle and the core of 5241 formed sequentially out of a single melt by fractional crystallization. The numerical models of REE evolution in the 5241 melt, especially that of Eu, require that a significant mass of spinel-free island material was assimilated into the evolving melt during the last half of the solidification history of 5241. The trace element results pbtained thus strongly support the interpretation of El Goresy et al. (1985) that the spinel-free islands in the 5241 are trapped xenoliths.

  18. Oxygen isotope systematics of chondrules in the Allende CV3 chondrite: High precision ion microprobe studies

    Digital Repository Service at National Institute of Oceanography (India)

    Rudraswami, N.G.; Ushikubo, T.; Nakashima, D.; Kita, N.T.

    grains and some of them were derived from precursors related to refractory inclusions. However, most relict olivine grains show oxygen isotope ratios that overlap with those in homogeneous chondrules. The delta sup(17)O values of four barred olivine...

  19. Uranium and Thorium in zircon sands processed in Northeastern Brazil

    International Nuclear Information System (INIS)

    Hazin, Clovis A.; Farias, Emerson E. G. de

    2008-01-01

    Zircon the main mineral of zirconium is a silicate mineral product (ZrSiO 4 ) obtained from beach sand deposits, along with other minerals such as kyanite, ilmenite, and rutile. All zircons contain some radioactive impurities due to the presence of uranium, thorium and their respective decay products in the crystalline structure of zircon, as well as potassium-40. Uranium and thorium substitute Zr 4+ in the mineral through an internal process called isomorphous replacement of zirconium. For this study, samples were collected both from a mineral sand processing plant located in the coastal region of Northeastern brazil and from the beach sands used in the process. The aim of this study was to assess the 238 U, 232 Th and 40 K contents in the beach sands and in the mineral products extracted from the sands in that facility, with special emphasis on zircon. Measurements were performed through gamma spectrometry, by using a high-purity germanium detector (HPGe) coupled to a multichannel analyzer. Activity concentration for 238 U and 232 Th in zircon sands ranged from 5462±143 to 19286±46 Bq kg -1 and from 1016±7 to 7162±38 Bq kg -1 , respectively. For 40 K, on the other hand, activity concentration values ranged from 81±14 to 681±26 Bq Kg -1 . The results of the measurements carried out for raw sand samples showed activity concentrations between 2.7±0.6 and 7.9±0.9 Bq kg -1 and 6.5±0.4 and 9.4±0.6 Bq kg -1 for 238 U and 23T h respectively, and from 48.8±3.1 to 76.1±2.4 Bq kg -1 for 40 K. Activity concentrations of 238 U and 232 Th in kyanite, ilmenite and rutile samples were also determined. (author)

  20. Chemical characteristics of zircon from A-type granites and comparison to zircon of S-type granites

    Czech Academy of Sciences Publication Activity Database

    Breiter, Karel; Lamarão, C. N.; Krás Borges, R. M.; Dall'Agnol, R.

    1192/195, April (2014), s. 208-225 ISSN 0024-4937 Institutional support: RVO:67985831 Keywords : zircon * A-type granites * S-type granites * Wiborg batholith * Brazil * Krušné hory/Erzgebirge Subject RIV: DD - Geochemistry Impact factor: 4.482, year: 2014

  1. Characterization of inclusions in terrestrial impact formed zircon: Constraining the formation conditions of Hadean zircon from Jack Hills, Western Australia

    Science.gov (United States)

    Faltys, J. P.; Wielicki, M. M.; Sizemore, T. M.

    2017-12-01

    Due to the discovery and subsequent geochemical analysis of Hadean terrestrial material (e.g. detrital zircon from Jack Hills, Western Australia), a dramatic paradigm shift has occurred in the hypothesized near surface conditions of the first 500 million years of Earth's evolution. From a hellish setting riddled with impactors and not fit for life to a much milder environment that may have been uniquely suitable for the origin of life. Geochemical analyses of these ancient materials have been used to suggest the presence of water at or near the surface as well as the existence of continental crust during the Hadean, both of which have been suggested as necessary for the origin of life. However, the intensity of extraterrestrial bombardment during the Hadean and the effects of such events on the origin of life remains poorly understood. Clearly, as evidenced by Phanerozoic impact events, extraterrestrial impactors have the potential to dramatically effect the environment, particularly the biosphere. Early Earth likely experienced multiple large impact events, as evidenced by the lunar record, however whether those impacts were sufficient to frustrate the origin of life remains an open question. Although multiple lines of evidence, including the inclusion population, suggest the formation of Hadean zircon from Jack Hills as crystallizing in an under-thrust environment from S-type magmas, a recent study has suggested their formation in an impact melt environment analogous to a portion of the Sudbury Igneous Complex at the Sudbury impact structure. To determine between these two formation scenarios we have under-taken an inclusion study of terrestrial impact formed zircon from four of the largest terrestrial impact structures (Sudbury, Canada; Manicouagan, Canada; Vredefort, South Africa; Morokweng, South Africa), to compare to the vast inclusion dataset that exists for Jack Hills zircon. Preliminary data suggests a different inclusion population, from Hadean zircon

  2. Multi-dimensional microanalysis of masklessly implanted atoms using focused heavy ion beam

    International Nuclear Information System (INIS)

    Mokuno, Yoshiaki; Iiorino, Yuji; Chayahara, Akiyoshi; Kiuchi, Masato; Fujii, Kanenaga; Satou, Mamoru

    1992-01-01

    Multi-dimensional structure fabricated by maskless MeV gold implantation in silicon wafer was analyzed by 3 MeV carbon ion microprobe using a microbeam line developed at GIRIO. The minimum line width of the implanted region was estimated to be about 5 μm. The advantages of heavy ions for microanalysis were demonstrated. (author)

  3. Defect imaging and channeling studies using channeling scanning transmission ion microscopy

    NARCIS (Netherlands)

    King, PJC; Breese, MBH; Smulders, PJM; Wilshaw, PR; Grime, GW

    The technique of channeling scanning transmission ion microscopy (CSTIM) can be used to produce images of individual crystal defects (such as dislocations and stacking faults) using the scanned, focused ion beam from a nuclear microprobe. As well as offering a new method for studies of crystal

  4. Nuclear microprobe local characterization of YBaCuO superconductors

    Science.gov (United States)

    Berger, P.; Berthier, B.; Revel, G.; Trocellier, P.

    1995-09-01

    Stoichiometric local characterizations of YBaCuO oxides have been performed using a 1.4 MeV deuteron microbeam. A beam with a size of 10 × 15 μm 2 allows the observation of variations of x = 0.2 in sintered YBa 2Cu 3O 7-x. Local variations of oxygen stoichiometry in a melt-textured sample, correlated with the microstructure, have been observed. In spite of the degradation of the sample under the beam, oxygen measurements seem to remain significant for doses above 10 18 ions/cm 2.

  5. A novel technique for producing antibody-coated microprobes using a thiol-terminal silane and a heterobifunctional crosslinker.

    Science.gov (United States)

    Routh, V H; Helke, C J

    1997-02-01

    Antibody-coated microprobes are used to measure neuropeptide release in the central nervous system. Although they are not quantitative, they provide the most precise spatial resolution of the location of in vivo release of any currently available method. Previous methods of coating antibody microprobes are difficult and time-consuming. Moreover, using these methods we were unable to produce evenly coated antibody microprobes. This paper describes a novel method for the production of antibody microprobes using thiol-terminal silanes and the heterobifunctional crosslinker, 4-(4-N-maleimidophenyl)butyric acid hydrazide HCl 1/2 dioxane (MPBH). Following silation, glass micropipettes are incubated with antibody to substance P (SP) that has been conjugated to MPBH. This method results in a dense, even coating of antibody without decreasing the biological activity of the antibody. Additionally, this method takes considerably less time than previously described methods without sacrificing the use of antibody microprobes as micropipettes. The sensitivity of the microprobes for SP is in the picomolar range, and there is a linear correlation between the log of SP concentration (M) and B/B0 (r2 = 0.98). The microprobes are stable for up to 3 weeks when stored in 0.1 M sodium phosphate buffer with 50 mM NaCl (pH 7.4) at 5 degrees C. Finally, insertion into the exposed spinal cord of an anesthetized rat for 15 min produces no damage to the antibody coating.

  6. The composition of zircon in Variscan granites from Northern Portugal

    Directory of Open Access Journals (Sweden)

    Martins, H. C.B.

    2014-12-01

    Full Text Available A group of slightly peraluminous Variscan plutons in Northern Portugal were selected from the study of zircon composition. The selected plutons are: the Vila Pouca de Aguiar and the Lavadores-Madalena plutons with I-type affinities and the Vieira do Minho pluton, an l-S transitional type. Zircon occurs as euhedral to subhedral crystals and exhibit finely concentric oscillatory magmatic zoning mainly related to variations of Hf, Y, U and Th concentrations. Most zircon crystals show the dominant “xenotime” substitution. The zircon crystals have Zr/Hf ratio in the range of 21 to 52, with no significant differences between the different granites. These values are in the same range of other peraluminous granites and are in accordance with a crustal signature of zircon. Moreover, the range of Zr/Hf values in zircon crystals overlaps with that of crustal sources and consequently to the potential protoliths proposed in the genesis of the Vieira do Minho and the Vila Pouca de Aguiar plutons, namely meta-igneous crustal sources at different levels. Although zircon from the Lavadores-Madalena pluton has a compositional range similar to the other plutons, an origin by hibridisation has been proposed. However, similar zircon chemistry between this pluton and Vila Pouca de Aguiar and Vieira do Minho plutons could also suggest a similar crustal source.Se han seleccionado tres plutones graniticos variscos en el norte de Portugal para el estudio de la composición del circón. Los plutones son: Vila Pouca de Aguiar y Lavadores-Madalena con afinidad de tipo-I y el plutón de Vieira do Minho de tipo transicional I-S. Los circones se presentan en cristales euhédricos a subhédricos y tienen zonados magmáticos, concéntricos oscilatorios finos ligados principalmente a variaciones de las concentraciones del Hf, Y, U y Th. La mayoría de los cristales de circón muestran la sustitución dominante “xenotima”. Los zircones tienen relaciones Zr/Hf que var

  7. Investigation of the additive induced doping effects in gelcast soft lead zirconate titanate ceramics

    International Nuclear Information System (INIS)

    Guo Dong; Cai Kai; Li Longtu; Gui Zhilun

    2009-01-01

    Due to the high sensitivity of the electrical properties of electronic ceramics to various factors, knowledge about the possible influence of the processing procedure on their electrical performance is critical for applying a new technique to the fabrication of the materials. In this study, various electrical parameters, complex impedance spectra, ferroelectric hysteresis loops, and microstructures of soft lead zirconate titanate (PZT) ceramics formed by the gelcasting technique from suspensions with various dispersants were investigated in comparison with those of the conventional dry pressed ones. We found that the sodium ion, which is the main cation in many commercial surfactants, exhibited obvious hard doping effects; thus causing deteriorated performance of the gelcast PZT ceramics. While a certain impurity ion introduced by a dispersant was also found to induce soft doping characteristics and improve the electrical performance of the materials. The results suggest that the doping effects of the metal ions or impurities introduced by the dispersants, or other additives, should be generally considered for applying a wet processing technique to forming multicomponent electronic ceramics.

  8. Characterisation of corrosion processes of using electron micro-probe, scanning probe microscopy and synchrotron-generated x-ray fluorescence imaging

    International Nuclear Information System (INIS)

    Neufeld, A.K.; Cole, I.S.; Furman, S.A.; Isaacs, H.S.

    2002-01-01

    Full text: With recent advances in computerized technology, the study of chemical reactions can now be visualized as they occur in real time and has resulted in analytical techniques with orders of magnitude greater sensitivity and resolution. This ability offers the corrosion scientist a unique opportunity to study the processes relevant to degradation science which could only be theoretically considered. Neufeld el al (1,2) have attempted to explain in great detail the mechanism of corrosion initiation of zinc by using X-ray micro-probe, Scanning Kelvin probe, and more recently by using synchrotron-generated X-rays and X-ray fluorescence imaging. New results are presented from the synchrotron studies where the transport of ions in-situ has been investigated. The synthesis of information from the techniques will also be discussed in its relevance to atmospheric corrosion processes. Copyright (2002) Australian Society for Electron Microscopy Inc

  9. Zircon and baddeleyite from the economic ultramafic-mafic Noril'sk-1 intrusion (Russia): Hf-isotope constraints on source composition

    Science.gov (United States)

    Malitch, K. N.; Belousova, E. A.; Badanina, I. Yu.; Griffin, W. L.

    2012-04-01

    of the Noril'sk-1 intrusion, which served as the favorable factor for accumulation of ores of unique scales and concentrations, To test this hypothesis, in situ Hf-isotope data were collected on the dated spots within single zircon grains. The analysis used a New Wave LUV213 laser-ablation microprobe attached to a Nu plasma MC-ICP-MS at GEMOC (Griffin et al. 2002). Hf-isotope results grouped on the basis of lithology show notable differences. Zircons from the unmineralized 'layered rock sequence' (e.g., olivine-free gabbro, olivine-bearing gabbro and olivine gabbro) are characterized by the most 'radiogenic' initial 176Hf/177Hf and some of ɛHf values close to those of the Depleted Mantle. Irrespective of zircon population most radiogenic Hf-isotope compositions are typical for olivine-free gabbro (mean ɛHf 7.3 ± 1.1 for sample N1-4), olivine-bearing gabbro (9.2 ± 3.8, sample N1-5) and olivine gabbro (8.3 ± 2.0, sample N1-6). In contrast, zircons from the leucogabbro that encloses the low-sulphide horizon (N1-3), and plagiowehrlite (N1-7) and taxitic-textured rocks (N1-8 and N1-9) with disseminated sulphide ores have less radiogenic Hf-isotope values (e.g., mean ɛHf6.2 ± 1.4, 5.9 ± 2.3, 6.4 ± 1.2 and 4.9±1.4, respectively). The least radiogenic values (ɛHffrom -2.9 to +2.3, mean ɛHf = 0.1 ± 1.9) are recorded in gabbro-diorite from the upper part of intrusion. The baddeleyite from olivine-free gabbro has the narrowest range of ɛHf values (e.g. 6.8-8.4), with a mean of ɛHfof 7.6 ± 0.8, closely matching that of zircon (mean ɛHf= 7.3 ± 1.1). Zircons from the leucogabbro that hosts the low-sulphide horizon (N1-3), and ultramafic and taxitic-textured lithologies with disseminated sulphide ores (N1-7, N1-8 and N1-9) have less radiogenic ɛHf values than those in barren lithologies. The Hf-isotope data for zircons from ore-bearing rocks thus suggest that the Noril'sk magmas represent mixing between a juvenile source equivalent to the Depleted Mantle and a

  10. Elemental distribution and sample integrity comparison of freeze-dried and frozen-hydrated biological tissue samples with nuclear microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Vavpetič, P., E-mail: primoz.vavpetic@ijs.si [Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Vogel-Mikuš, K. [Biotechnical Faculty, Department of Biology, University of Ljubljana, Jamnikarjeva 101, SI-1000 Ljubljana (Slovenia); Jeromel, L. [Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Ogrinc Potočnik, N. [Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); FOM-Institute AMOLF, Science Park 104, 1098 XG Amsterdam (Netherlands); Pongrac, P. [Biotechnical Faculty, Department of Biology, University of Ljubljana, Jamnikarjeva 101, SI-1000 Ljubljana (Slovenia); Department of Plant Physiology, University of Bayreuth, Universitätstr. 30, 95447 Bayreuth (Germany); Drobne, D.; Pipan Tkalec, Ž.; Novak, S.; Kos, M.; Koren, Š.; Regvar, M. [Biotechnical Faculty, Department of Biology, University of Ljubljana, Jamnikarjeva 101, SI-1000 Ljubljana (Slovenia); Pelicon, P. [Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia)

    2015-04-01

    The analysis of biological samples in frozen-hydrated state with micro-PIXE technique at Jožef Stefan Institute (JSI) nuclear microprobe has matured to a point that enables us to measure and examine frozen tissue samples routinely as a standard research method. Cryotome-cut slice of frozen-hydrated biological sample is mounted between two thin foils and positioned on the sample holder. The temperature of the cold stage in the measuring chamber is kept below 130 K throughout the insertion of the samples and the proton beam exposure. Matrix composition of frozen-hydrated tissue is consisted mostly of ice. Sample deterioration during proton beam exposure is monitored during the experiment, as both Elastic Backscattering Spectrometry (EBS) and Scanning Transmission Ion Microscopy (STIM) in on–off axis geometry are recorded together with the events in two PIXE detectors and backscattered ions from the chopper in a single list-mode file. The aim of this experiment was to determine differences and similarities between two kinds of biological sample preparation techniques for micro-PIXE analysis, namely freeze-drying and frozen-hydrated sample preparation in order to evaluate the improvements in the elemental localisation of the latter technique if any. In the presented work, a standard micro-PIXE configuration for tissue mapping at JSI was used with five detection systems operating in parallel, with proton beam cross section of 1.0 × 1.0 μm{sup 2} and a beam current of 100 pA. The comparison of the resulting elemental distributions measured at the biological tissue prepared in the frozen-hydrated and in the freeze-dried state revealed differences in elemental distribution of particular elements at the cellular level due to the morphology alteration in particular tissue compartments induced either by water removal in the lyophilisation process or by unsatisfactory preparation of samples for cutting and mounting during the shock-freezing phase of sample preparation.

  11. Differential lead retention in zircons: implications for nuclear waste containment.

    Science.gov (United States)

    Gentry, R V; Sworski, T J; McKown, H S; Smith, D H; Eby, R E; Christie, W H

    1982-04-16

    An innovative ultrasensitive technique was used for lead isotopic analysis of individual zircons extracted from granite core samples at depths of 960, 2170, 2900, 3930, and 4310 meters. The results show that lead, a relatively mobile element compared to the nuclear waste-related actinides uranium and thorium, has been highly retained at elevated temperatures (105 degrees to 313 degrees C) under conditions relevant to the burial of synthetic rock waste containers in deep granite holes.

  12. Studies on upgrading quality of zircon concentrate by flotation method

    International Nuclear Information System (INIS)

    Nguyen Duy Phap; Nguyen Duc Hung; Nguyen Duc Thai and others

    2004-01-01

    Results of this study show that it is possible to apply flotation to upgrading quality of zircon concentrate based on a simple technological flow-sheet and simple flotation agents. It is possible to use flotation equipment of Mexanov. Product criteria include ZrO 2 >64%; TiO 2 2 O 3 <0.1%. Flotation agents are simple, little noxious and easy for preparation. (PQM)

  13. Preparation of high quality zirconium oxychloride from zircon of Vietnam

    International Nuclear Information System (INIS)

    Ngo Van Tuyen; Vu Thanh Quang; Trinh Giang Huong; Vuong Huu Anh

    2007-01-01

    This paper introduces a sodium hydroxide decomposition method for zirconium oxychloride production from zircon sand of Vietnam such as Ha Tinh, Hue, Binh Thuan seaside. Techniques for separation of impurities in ZOC final product such as SiO 2 , Fe 2 O 3 , TiO 2 , rare earths, uranium, and thorium have also been introduced. Content of uranium and thorium in the final product of ZOC is less than 1 ppm. (author)

  14. Theoretical modeling of infrared spectra of twinned lead zirconate

    Czech Academy of Sciences Publication Activity Database

    Dočekalová, Zuzana; Pasciak, Marek; Hlinka, Jiří

    2017-01-01

    Roč. 90, č. 1 (2017), s. 17-23 ISSN 0141-1594 R&D Projects: GA ČR GA15-04121S Institutional support: RVO:68378271 Keywords : domains * IR spectroscopy * dielectric permittivity * lead zirconate * shell model * Born effective charge Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 1.060, year: 2016

  15. Feasibility of infrared analysis of iron in zircon

    International Nuclear Information System (INIS)

    Heard, I. Jr.

    1980-05-01

    A feasibility study has concluded that quantitative infrared analysis can be employed to determine the concentration of iron in zircon. The spectral transmission curves have shown that the iron absorption band is located at 1.15 microns. These curves also revealed a second absorption band at 1.49 microns. The source of this second peak is not known; but it exhibits some features which suggest its dependance on natural α-recoil damage. 23 references, 14 figures, 2 tables

  16. False colour backscatter electron images and their application during electron microprobe analysis of ores and host rocks

    International Nuclear Information System (INIS)

    Cousens, D.R.; French, D.H.; Ramsden, A.R.

    1989-01-01

    The limited contrast range of conventional black and white imaging does not enable full use to be made of the dynamic range of the video signal obtained from a scanning electron microscope or microprobe. The use of false colour substantially increases the information that can be derived from such images enabling relationships to be displayed that cannot be observed in black and white. This capability is now used extensively in combination with quantitative electron microprobe analysis as a research tool for ore characterization and host rocks studies related to minerals exploration in the CSIRO Div.sion of Exploration Geoscience. Thus the CAMEBAX scanning electron microprobe has been modified to allow digital images acquisition and software (IMAGE) developed which allows false colour backscatter electron (BSE) images to be obtained during the course of routine electron microprobe analysis. 1 fig

  17. Combining Raman Microprobe and XPS to Study High Temperature Oxidation of Metals

    International Nuclear Information System (INIS)

    Windisch, Charles F.; Henager, Charles H.; Engelhard, Mark H.; Bennett, Wendy D.

    2011-01-01

    Raman microprobe spectroscopy was applied in studies of high-temperature air oxidation of a ferritic alloy (HT-9) in the absence and presence of zirconia coatings with the objective of evaluating the technique as a way to quickly screen candidate cladding materials and actinide-based mixed oxide fuel mixtures for advanced nuclear reactors. When oxidation was relatively uniform, Raman spectra collected using microscope optics with low spatial resolution were found to be similar to those collected with conventional Raman spectroscopy. These spectra could be used to identify major oxide corrosion products and follow changes in the composition of the oxides due to heating. However, when the oxidation films were comprised of multiple layers of varying composition, or with layers containing metallic phases, techniques with higher depth resolution and sensitivity to zero-valence metals were necessary. The requirements were met by combining Raman microprobe using different optical configurations and x-ray photoelectron spectroscopy.

  18. Perfect zircon for rock dating no fairy tale

    International Nuclear Information System (INIS)

    Anon

    2000-01-01

    The scheme used to date rocks is based on the radioactive decay of uranium. Minute traces of uranium locked inside the zircon crystals have been decaying over aeons, producing lead. Scientists know that the decay occurs at a fixed rate and how quickly it happens. By measuring the relative amounts of uranium and lead encased in the crystals, scientists can determine how old the rock is. But sometimes lead is lost from zircon crystals via processes such as weathering (if the rocks were exposed on the surface) or deformation and metamorphism (if the rocks had crystallised deep in the earth and been subjected to high temperatures and pressure). Hence the special nature of the Temora rocks- a 417 million years old zirconium-containing rock which have been partially exposed in recent times in a remote paddock in NSW, Australia. SHRIMP dating was used for initial tests on the Temora rocks. Then, in December last year, the sample was sent to the world-recognised authority, Canada's Royal Ontario Museum, for independent analysis and dating via chemical decomposition. The museum confirmed the near perfect quality of the zircon and its age

  19. Zircon Supported Copper Catalysts for the Steam Reforming of Methanol

    Science.gov (United States)

    Widiastri, M.; Fendy, Marsih, I. N.

    2008-03-01

    Steam reforming of methanol (SRM) is known as one of the most favorable catalytic processes for producing hydrogen. Current research on zirconia, ZrO2 supported copper catalyst revealed that CuO/ZrO2 as an active catalyst for the SRM. Zircon, ZrSiO4 is available from the by-product of tin mining. In the work presented here, the catalytic properties of CuO/ZrSiO4 with various copper oxide compositions ranging from 2.70% (catalyst I), 4.12% (catalyst II), and 7.12%-mass (catalyst III), synthesized by an incipient wetness impregnation technique, were investigated to methanol conversion, selectivity towards CO formation, and effect of ZnO addition (7.83%CuO/8.01%ZnO/ZrSiO4 = catalyst V). The catalytic activity was obtained using a fixed bed reactor and the zircon supported catalyst activity was compared to those of CuO/ZnO/Al2O3 catalyst (catalyst IV) and commercial Kujang LTSC catalyst. An X-ray powder diffraction (XRD) analysis was done to identify the abundant phases of the catalysts. The catalysts topography and particle diameter were measured with scanning electron microscopy (SEM) and composition of the catalysts was measured by SEM-EDX, scanning electron microscope-energy dispersive using X-ray analysis. The results of this research provide information on the possibility of using zircon (ZrSiO4) as solid support for SRM catalysts.

  20. Extrapolation of zircon fission-track annealing models

    International Nuclear Information System (INIS)

    Palissari, R.; Guedes, S.; Curvo, E.A.C.; Moreira, P.A.F.P.; Tello, C.A.; Hadler, J.C.

    2013-01-01

    One of the purposes of this study is to give further constraints on the temperature range of the zircon partial annealing zone over a geological time scale using data from borehole zircon samples, which have experienced stable temperatures for ∼1 Ma. In this way, the extrapolation problem is explicitly addressed by fitting the zircon annealing models with geological timescale data. Several empirical model formulations have been proposed to perform these calibrations and have been compared in this work. The basic form proposed for annealing models is the Arrhenius-type model. There are other annealing models, that are based on the same general formulation. These empirical model equations have been preferred due to the great number of phenomena from track formation to chemical etching that are not well understood. However, there are two other models, which try to establish a direct correlation between their parameters and the related phenomena. To compare the response of the different annealing models, thermal indexes, such as closure temperature, total annealing temperature and the partial annealing zone, have been calculated and compared with field evidence. After comparing the different models, it was concluded that the fanning curvilinear models yield the best agreement between predicted index temperatures and field evidence. - Highlights: ► Geological data were used along with lab data for improving model extrapolation. ► Index temperatures were simulated for testing model extrapolation. ► Curvilinear Arrhenius models produced better geological temperature predictions

  1. Point defects in crystalline zircon (zirconium silicate), ZrSiO4: electron paramagnetic resonance studies

    Science.gov (United States)

    Tennant, W. C.; Claridge, R. F. C.; Walsby, C. J.; Lees, N. S.

    This article outlines the present state of knowledge of paramagnetic defects in crystalline zircon as obtained mainly, but not exclusively, from electron paramagnetic resonance (EPR) studies in crystalline zircon (zirconium silicate, ZrSiO4). The emphasis is on single-crystal studies where, in principle, unambiguous analysis is possible. Firstly, the crystallography of zircon is presented. Secondly, the relationships between available crystal-site symmetries and the symmetries of observed paramagnetic species in zircon, and how these observations lead to unambiguous assignments of point-group symmetries for particular paramagnetic species are detailed. Next, spin-Hamiltonian (SH) analysis is discussed with emphasis on the symmetry relationships that necessarily exist amongst the Laue classes of the crystal sites in zircon, the paramagnetic species occupying those sites and the SH itself. The final sections of the article then survey the results of EPR studies on zircon over the period 1960-2002.

  2. Lateral diffusion study of the Pt-Al system using the NAC nuclear microprobe.

    Science.gov (United States)

    de Waal, H.; Pretorius, R.

    1999-10-01

    In this study a nuclear microprobe (NMP) was used to analyse phase formation during reaction in Pt-Al lateral diffusion couples. Phase identification was done by Rutherford backscattering spectroscopy. These results were compared with phase formation during conventional thin film Pt-Al interactions. The co-existence of multiple phases in lateral diffusion couples is discussed with reference to the effective heat of formation (EHF) model.

  3. Lateral diffusion study of the Pt-Al system using the NAC nuclear microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Waal, H. de E-mail: dewalla@nac.ac.za; Pretorius, R

    1999-09-02

    In this study a nuclear microprobe (NMP) was used to analyse phase formation during reaction in Pt-Al lateral diffusion couples. Phase identification was done by Rutherford backscattering spectroscopy. These results were compared with phase formation during conventional thin film Pt-Al interactions. The co-existence of multiple phases in lateral diffusion couples is discussed with reference to the effective heat of formation (EHF) model.

  4. Total quantitative recording of elemental maps and spectra with a scanning microprobe

    International Nuclear Information System (INIS)

    Legge, G.J.F.; Hammond, I.

    1979-01-01

    A system of data recording and analysis has been developed by means of which simultaneously all data from a scanning instrument such as a microprobe can be quantitatively recorded and permanently stored, including spectral outputs from several detectors. Only one scanning operation is required on the specimen. Analysis is then performed on the stored data, which contain quantitative information on distributions of all elements and spectra of all regions

  5. Application of the microprobe dredging operation in the treatment of the meibomian gland dysfunction(MGD

    Directory of Open Access Journals (Sweden)

    Qing-Qiang Wang

    2014-07-01

    Full Text Available AIM: To evaluate the function of the microprobe dredging technology in the treatment of meibomian gland dysfunction(MGDand to provide fast, efficient, economical and practical method of treatment for meibomian gland dysfunction(MGD. METHODS:The 100μm diameter stainless steel wire was made as the microprobe with the total length of 3cm, which the needle was about 5mm and hand shank was about 2.5cm. Selected 140 cases with dry eyes of meibomian gland dysfunction(MGD, patients were divided into two groups and made them have comparability. Observation group(n=70used microprobe to dredge meibomian gland pipe accompanied with drugs, hot compress and meibomian gland massage treatment. The control group(n=70was given conventional drugs, hot compress and meibomian massage treatment. To compare the tear break-up time(BUT, efficient rate and the cure rate of the two groups after treatment of 1d, 1wk, 2wk, 1 mo, 2mo and 3mo.RESULTS: BUT were significantly prolonged in observation group and control group after treatment, and the observation group improved more obviously; the efficient rate and cure rate of the observation group were significantly higher than that of the control group after 1d, 1wk, 2wk, 1mo, 2mo and 3mo treatment. CONCLUSION:Using microprobe to unclog the meibomian gland tube can provide the fast and efficient, economical and practical treatment for meibomian gland dysfunction(MGD, which can be promoted in the clinical practice.

  6. Distribution of copper and other elements in ryegrass roots, determined with a scanning proton microprobe

    International Nuclear Information System (INIS)

    Mazzolini, A.P.; Legge, G.J.F.

    1982-01-01

    A scanning proton microprobe has been used to determine the distribution of Cu and other elements in Wimmera ryegrass roots grown in solution cultures. Cu was found to be localized on or near the surface of the roots in randomly distributed discrete zones. The distribution of Cu was partially correlated with those of Fe, P and Ca and possibly indicates some form of association; co-precipitation in a precipitate of ferric phosphate or hydroxy-oxide is favoured

  7. The study of voids in the AuAl thin-film system using the nuclear microprobe

    Science.gov (United States)

    de Waal, H. S.; Pretorius, R.; Prozesky, V. M.; Churms, C. L.

    1997-07-01

    A Nuclear Microprobe (NMP) was used to study void formation in thin film gold-aluminium systems. Microprobe Rutherford Backscattering Spectrometry (μRBS) was utilised to effectively obtain a three-dimensional picture of the void structure on the scale of a few nanometers in the depth dimension and a few microns in the in-plane dimension. This study illustrates the usefulness of the NMP in the study of materials and specifically thin-film structures.

  8. Trace elemental analysis of bituminous coals using the Heidelberg proton microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Chen, J R; Kneis, H; Martin, B; Nobiling, R; Traxel, K [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany, F.R.); Heidelberg Univ. (Germany, F.R.). Physikalisches Inst.); Chao, E C.T.; Minkin, J A [Geological Survey, Reston, VA (USA)

    1981-03-01

    Trace elements in coal can occur as components of either the organic constituents (macerals) or the inorganic constituents (minerals). Studies of the concentrations and distribution of the trace elements are vital to understanding the geochemical milieu in which the coal was formed and in evaluating the attempts to recover rare but technologically valuable metals. In addition, information on the trace element concentrations is important in predicting the environmental impact of burning particular coals, as many countries move toward greater utilization of coal reserves for energy production. Traditionally, the optical and the electron microscopes and more recently the electron microprobe have been used in studying the components of coal. The proton-induced X-ray emission (PIXE) microprobe offers a new complementary approach with an order of magnitude or more better minimum detection limit. We present the first measurements with a PIXE microprobe of the trace element concentrations of bituminous coal samples. Elemental analyses of the coal macerals-vitrinite, exinite, and inertinite - are discussed for three coal samples from the Eastern U.S.A., three samples from the Western U.S.A., and one sample from the Peoples Republic of China.

  9. The Mars Microprobe Mission: Advanced Micro-Avionics for Exploration Surface

    Science.gov (United States)

    Blue, Randel

    2000-01-01

    The Mars Microprobe Mission is the second spacecraft developed as part of the New Millennium Program deep space missions. The objective of the Microprobe Project is to demonstrate the applicability of key technologies for future planetary missions by developing two probes for deployment on Mars. The probes are designed with a single stage entry, descent, and landing system and impact the Martian surface at speeds of approximately 200 meters per second. The microprobes are composed of two main sections, a forebody section that penetrates to a depth below the Martian surface of 0.5 to 2 meters, and an aftbody section that remains on the surface. Each probe system consists of a number of advanced technology components developed specifically for this mission. These include a non-erosive aeroshell for entry into. the atmosphere, a set of low temperature batteries to supply probe power, an advanced microcontroller to execute the mission sequence, collect the science data, and react to possible system fault conditions, a telecommunications subsystem implemented on a set of custom integrated circuits, and instruments designed to provide science measurements from above and below the Martian surface. All of the electronic components have been designed and fabricated to withstand the severe impact shock environment and to operate correctly at predicted temperatures below -100 C.

  10. Quantitative elemental imaging of octopus stylets using PIXE and the nuclear microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Doubleday, Zoe [Marine Research Laboratories, Tasmanian Aquaculture and Fisheries Institute, University of Tasmania, Private Bag 49, Tasmania 7001 (Australia)], E-mail: zoeanned@utas.edu.au; Belton, David [CSIRO Exploration and Mining, University of Melbourne (School of Physics), Melbourne 3010 (Australia); Pecl, Gretta; Semmens, Jayson [Marine Research Laboratories, Tasmanian Aquaculture and Fisheries Institute, University of Tasmania, Private Bag 49, Tasmania 7001 (Australia)

    2008-01-15

    By utilising targeted microprobe technology, the analysis of elements incorporated within the hard bio-mineralised structures of marine organisms has provided unique insights into the population biology of many species. As hard structures grow, elements from surrounding waters are incorporated effectively providing a natural 'tag' that is often unique to the animal's particular location or habitat. The spatial distribution of elements within octopus stylets was investigated, using the nuclear microprobe, to assess their potential for determining dispersal and population structure in octopus populations. Proton Induced X-ray Emission (PIXE) was conducted using the Dynamic Analysis method and GeoPIXE software package, which produced high resolution, quantitative elemental maps of whole stylet cross-sections. Ten elements were detected within the stylets which were heterogeneously distributed throughout the microstructure. Although Ca decreased towards the section edge, this trend was consistent between individuals and remained homogeneous in the inner region of the stylet, and thus appears a suitable internal standard for future microprobe analyses. Additional analyses used to investigate the general composition of the stylet structure suggested that they are amorphous and largely organic, however, there was some evidence of phosphatic mineralisation. In conclusion, this study indicates that stylets are suitable for targeted elemental analysis, although this is currently limited to the inner hatch region of the microstructure.

  11. Quantitative elemental imaging of octopus stylets using PIXE and the nuclear microprobe

    International Nuclear Information System (INIS)

    Doubleday, Zoe; Belton, David; Pecl, Gretta; Semmens, Jayson

    2008-01-01

    By utilising targeted microprobe technology, the analysis of elements incorporated within the hard bio-mineralised structures of marine organisms has provided unique insights into the population biology of many species. As hard structures grow, elements from surrounding waters are incorporated effectively providing a natural 'tag' that is often unique to the animal's particular location or habitat. The spatial distribution of elements within octopus stylets was investigated, using the nuclear microprobe, to assess their potential for determining dispersal and population structure in octopus populations. Proton Induced X-ray Emission (PIXE) was conducted using the Dynamic Analysis method and GeoPIXE software package, which produced high resolution, quantitative elemental maps of whole stylet cross-sections. Ten elements were detected within the stylets which were heterogeneously distributed throughout the microstructure. Although Ca decreased towards the section edge, this trend was consistent between individuals and remained homogeneous in the inner region of the stylet, and thus appears a suitable internal standard for future microprobe analyses. Additional analyses used to investigate the general composition of the stylet structure suggested that they are amorphous and largely organic, however, there was some evidence of phosphatic mineralisation. In conclusion, this study indicates that stylets are suitable for targeted elemental analysis, although this is currently limited to the inner hatch region of the microstructure

  12. The significance of zircon characteristic and its uranium concentration in evaluation of uranium metallogenetic prospect

    International Nuclear Information System (INIS)

    Li Yaosong; Zhu Jiechen; Xia Yuliang

    1992-02-01

    Zircon characteristic and its relation to uranium metallogenetic process have been studied on the basis of physics properties and chemical compositions. It is indicated that the colour of zircon crystal is related to uranium concentration; on the basis of method of zircon population type of Pupin J.P., the sectional plan of zircon population type has been designed, from which result that zircon population type of uranium-producing rock body is distributed mainly in second section, secondly in fourth section; U in zircon presents synchronous increase trend with Th, Hf and Ta; the uranium concentration in zircon from uranium-producing geologic body increases obviously and its rate of increase is more than that of the uranium concentration in rock; the period, in which uranium concentration in zircon is increased, is often related to better uranium-producing condition in that period of this area. 1785 data of the average uranium concentration in zircon have been counted and clear regularity has been obtained, namely the average uranium concentrations in zircon in rich uranium-producing area, rock, geologic body and metallogenetic zone are all higher than that in poor or no uranium-producing area, rock, geologic body and metallogenetic zone. This shows that the average uranium concentration in zircon within the region in fact reflects the primary uranium-bearing background in region and restricts directly follow-up possibility of uranium mineralization. On the basis of this, the uranium source conditions of known uranium metallogenetic zones and prospective provinces have been discussed, and the average uranium concentrations in zircon from magmatic rocks for 81 districts have been contrasted and graded, and some districts in which exploration will be worth doing further are put forward

  13. Quantification of the distribution of hydrogen by nuclear microprobe at the Laboratory Pierre Sue in the width of zirconium alloy fuel clad of PWR reactors; Quantification de la repartition de l'hydrogene a la microsonde nucleaire du Laboratoire Pierre Sue dans l'epaisseur de tubes de gainage du combustible des REP en alliage de zirconium

    Energy Technology Data Exchange (ETDEWEB)

    Raepsaet, C. [CEA Saclay, Dept. de Recherche sur l' Etat Condense, les Atomes et les Molecules (DSM/DRECAM/LPS-CNRS) UMR9956, 91 - Gif sur Yvette (France); Bossis, Ph. [CEA Saclay, Dept. des Materiaux pour le Nucleaire (DEN/DANS/DMN/SEMULM2E), 91 - Gif-sur-Yvette (France); Hamon, D.; Bechade, J.L.; Brachet, J.C. [CEA Saclay, Dept. des Materiaux pour le Nucleaire (DEN/DANS/DMN/SRMALA2M), 91 - Gif-sur-Yvette (France)

    2007-07-01

    Among the analysis techniques by ions beams, the micro ERDA (Elastic Detection Analysis) is an interesting technique which allows the quantitative distribution of the hydrogen in materials. In particular, this analysis has been used for hydride zirconium alloys, with the nuclear microprobe of the Laboratory Pierre Sue. This probe allows the characterization of radioactive materials. The technique principles are recalled and then two examples are provided to illustrate the fuel clad behavior in PWR reactors. (A.L.B.)

  14. Morphology versus U-Pb systematics in zircon: A high-resolution isotopic study of a zircon population from a Variscan dike in the Central Alps

    International Nuclear Information System (INIS)

    Bossart, P.J.; Meier, M.; Oberli, F.; Steiger, R.H.

    1986-01-01

    U/Pb isotopic measurements on individual zircon crystals combined with morphological analyses permit the identification of three distinct components within the zircon population of the Saedelhorn diorite, a Variscan dike from the western Gotthard (Central Alps, Switzerland): (i) 94% of the grains in the zircon population are elongate crystals with pronounced skeletal morphology indicative of rapid growth from a supercooled melt. (ii) 5% of the population consist of turbid, mostly subhedral zircons frequently showing D-type morphology and elevated uranium contents compared to the skeletal variety. Single-crystal and multi-grain U-Pb isotopic data of group (i) and (ii) zircons define an intrusion age of 293 + 5/ -4 m.y. for the dike. (iii) Rare, transparent zircon crystals (< 1% of the zircons population) yield apparent U-Pb ages in the range of 370-490 m.y. and display morphological and isotopic characteristics closely resembling those of a Caledonian orthogneiss intruded by the dike. This implies presence of assimilated wall-rock components in the macroscopically homogeneous dike sample. (orig./WB)

  15. Mechanisms of strain accommodation in plastically-deformed zircon under simple shear deformation conditions during amphibolite-facies metamorphism

    Science.gov (United States)

    Kovaleva, Elizaveta; Klötzli, Urs; Wheeler, John; Habler, Gerlinde

    2018-02-01

    This study documents the strain accommodation mechanisms in zircon under amphibolite-facies metamorphic conditions in simple shear. Microstructural data from undeformed, fractured and crystal-plastically deformed zircon crystals are described in the context of the host shear zone, and evaluated in the light of zircon elastic anisotropy. Our work challenges the existing model of zircon evolution and shows previously undescribed rheological characteristics for this important accessory mineral. Crystal-plastically deformed zircon grains have axis oriented parallel to the foliation plane, with the majority of deformed grains having axis parallel to the lineation. Zircon accommodates strain by a network of stepped low-angle boundaries, formed by switching between tilt dislocations with the slip systems {010} and {110} and rotation axis [001], twist dislocations with the rotation axis [001], and tilt dislocations with the slip system {001} and rotation axis [010]. The slip system {110} is newly described for zircon. Most misorientation axes in plastically-deformed zircon grains are parallel to the XY plane of the sample and have [001] crystallographic direction. Such behaviour of strained zircon lattice is caused by elastic anisotropy that has a direct geometric control on the rheology, deformation mechanisms and dominant slip systems in zircon. Young's modulus and P wave velocity have highest values parallel to zircon [001] axis, indicating that zircon is elastically strong along this direction. Poisson ratio and Shear modulus demonstrate that zircon is also most resistant to shearing along [001]. Thus, [001] axis is the most common rotation axis in zircon. The described zircon behaviour is important to take into account during structural and geochronological investigations of (poly)metamorphic terrains. Geometry of dislocations in zircon may help reconstructing the geometry of the host shear zone(s), large-scale stresses in the crust, and, possibly, the timing of

  16. The bio-PIXE setup on the Debrecen scanning proton microprobe

    International Nuclear Information System (INIS)

    Kertesz, Zs.; Szikszai, Z.; Uzonyi, I.; Simon, A.; Kiss, A.Z.

    2004-01-01

    Complete text of publication follows. Besides the ongoing applications in archeometry, geology, material science and atmospheric aerosol study, in recent years the IBA Group in Debrecen has joined several biological and biomedical research projects. Such studies require the knowledge of accurate quantitative elemental concentrations and distributions in organic, inhomogeneous thin samples on a microscopic scale. In most cases, to carry out quantitative investigations on biomedical samples down to the cell level, the combination of proton induced X-ray emission (PIXE), Rutherford backscattering (RBS) spectrometry and scanning transmission ion microscopy (STIM) analytical methods are used simultaneously. STIM provides information on the density and structure of the sample, PIXE measures the concentration of the inorganic major and trace elements, and finally RBS serves to characterize the organic matrix, to determine the beam dose, and sometimes the sample thickness. The drawback of this combined method is that to evaluate the RBS data the hydrogen to carbon ratio in the sample must be known. The setup developed at the Debrecen microprobe facility [1] is based on the combined application of on-axis STIM and simultaneous PIXE-PIXE analytical techniques. In the PIXE-PIXE method the sample matrix is determined directly by measuring X-rays from all elements in the sample including the light elements such as carbon and oxygen, using two Si(Li) X-ray detectors. In this arrangement an ultra thin windowed Si(Li) X-ray detector serves to characterize the matrix by measuring low energy X-ray lines (0.2-9 keV) while a large area Be-windowed detector is used to detect the medium and high energy X-ray lines (>4 keV). In this way elements with atomic number higher than 5 can be detected simultaneously, reducing both radiation damage of the sample and measurement time. In addition, the knowledge of the hydrogen content of the sample is not needed, since it influences the

  17. What can zircon ages from the Jack Hills detrital zircon suite really tell us about Hadean geodynamics?

    Science.gov (United States)

    Whitehouse, Martin; Nemchin, Alexander

    2015-04-01

    As the only direct sample of the Hadean Earth, detrital zircon grains from the Jack Hills, Western Australia, have been the subject of intense investigation over the almost three decades since their discovery. A wide variety of geochemical and isotopic analyses of these grains, as well as their mineral inclusions, have been used variously to support two fundamentally different models for Hadean geodynamics: (i) Some form of (not necessarily modern-style) plate recycling generating felsic (continental-type?) crust at the boundaries [1, 2], or conversely (ii) the persistence of a long-lived, stagnant basaltic lid within which magmatism occurred as a result of internal temperature perturbations and/or impacts [3, 4], a model also generally consistent with a wide range of observations from post-Hadean geochemical reservoirs. Despite the considerable time and resources expended, the majority of these studies uncritically accept the individual U-Pb zircon ages, even though their veracity is key to many of the interpretations [5, 6]. We report here the results of an in-depth evaluation of all published (and new) U-Pb ages from the Jack Hills zircon suite in order to define age populations that can be used with a high degree of confidence in geodynamic interpretations. A notable problem in the interpretation of U-Pb data from ancient zircon grains (including those as young as the Neoarchean) is that disturbance of the systematics even several 100 Ma after crystallization causes data to spread along the concordia curve without becoming discernably discordant within the relatively large error bounds associated with U/Pb ages from in situ dating methods (e.g. SIMS). While 207Pb/206Pb ages are typically more precise, individually they provide no means to detect Pb-loss-induced younging. However, if two or preferably more analyses have been made in the same zircon growth zone, a reasonable evaluation of the possibility of Pb-loss can be made. In the available Jack Hills zircon

  18. Empirical constraints on the effects of radiation damage on helium diffusion in zircon

    Science.gov (United States)

    Anderson, Alyssa J.; Hodges, Kip V.; van Soest, Matthijs C.

    2017-12-01

    In this study, we empirically evaluate the impact of radiation damage on zircon (U-Th)/He closure temperatures for a suite of zircon crystals from the slowly cooled McClure Mountain syenite of south-central Colorado, USA. We present new zircon, titanite, and apatite conventional (U-Th)/He dates, zircon laser ablation (U-Th)/He and U-Pb dates, and zircon Raman spectra for crystals from the syenite. Titanite and apatite (U-Th)/He dates range from 447 to 523 Ma and 88.0 to 138.9 Ma, respectively, and display no clear correlation between (U-Th)/He date and effective uranium concentration. Conventional zircon (U-Th)/He dates range from 230.3 to 474 Ma, while laser ablation zircon (U-Th)/He dates show even greater dispersion, ranging from 5.31 to 520 Ma. Dates from both zircon (U-Th)/He datasets decrease with increasing alpha dose, indicating that most of the dispersion can be attributed to radiation damage. Alpha dose values for the dated zircon crystals range from effectively zero to 2.15 × 1019 α /g, spanning the complete damage spectrum. We use an independently constrained thermal model to empirically assign a closure temperature to each dated zircon grain. If we assume that this thermal model is robust, the zircon radiation damage accumulation and annealing model of Guenthner et al. (2013) does not accurately predict closure temperatures for many of the analyzed zircon crystals. Raman maps of the zircons dated by laser ablation document complex radiation damage zoning, sometimes revealing crystalline zones in grains with alpha dose values suggestive of amorphous material. Such zoning likely resulted in heterogeneous intra-crystalline helium diffusion and may help explain some of the discrepancies between our empirical findings and the Guenthner et al. (2013) model predictions. Because U-Th zoning is a common feature in zircon, radiation damage zoning is likely to be a concern for most ancient, slowly cooled zircon (U-Th)/He datasets. Whenever possible, multiple

  19. Use of X-ray microprobe to diagnose bone tissue demineralization after caffeine administration Use of X-ray microprobe to diagnose bone tissue demineralization after caffeine administration

    Directory of Open Access Journals (Sweden)

    Marek Tomaszewski

    2012-10-01

    Full Text Available Caffeine is a methylxanthine which permeates the placenta. In studies on animals, it has been
    shown to produce teratogenic and embryotoxic effects in large doses. The objective of this study was to
    assess the influence of caffeine on the development of bone tissue, with particular reference to elemental
    bone composition using an X-ray microprobe. The research was conducted on rats. The fertilized females
    were randomly divided into an experimental and a control group. The experimental group was
    given caffeine orally in 30 mg/day doses from the 8th to the 21st day of pregnancy, while the control group
    was given water. The fetuses were used to assess the growth and mineralization of the skeleton. On the
    basis of double dyeing, a qualitative analysis of the bone morphology and mineralization was conducted.
    For calcium and potassium analysis, an X-ray microprobe was used. In 67 fetuses from the experimental
    group, changes in skeleton staining with the alcian-alizarin method were noticed. The frequency of the
    development of variants in the experimental group was statistically higher. In the experimental group,
    a significant decrease in the calcium level, as well as an increase in the potassium level, was observed.
    The X-ray microprobe’s undoubted advantage is that is offers a quick qualitative and quantitative analysis
    of the elemental composition of the examined samples. Employing this new technique may furnish us
    with new capabilities when investigating the essence of the pathology process.Caffeine is a methylxanthine which permeates the placenta. In studies on animals, it has been
    shown to produce teratogenic and embryotoxic effects in large doses. The objective of this study was to
    assess the influence of caffeine on the development of bone tissue, with particular reference to elemental
    bone composition using an X-ray microprobe. The research was conducted on

  20. Positron annihilation lifetime study of radiation-damaged natural zircons

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, J. [Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, The Australian National University, Canberra (Australia); Gaugliardo, P. [Centre for Antimatter-Matter Studies, School of Physics, University of Western Australia (Australia); Farnan, I.; Zhang, M. [Department of Earth Sciences, University of Cambridge (United Kingdom); Vance, E.R.; Davis, J.; Karatchevtseva, I.; Knott, R.B. [Australian Nuclear Science and Technology Organisation (Australia); Mudie, S. [The Australian Synchrotron, Victoria (Australia); Buckman, S.J. [Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, The Australian National University, Canberra (Australia); Institute for Mathematical Sciences, University of Malaya, Kuala Lumpur (Malaysia); Sullivan, J.P., E-mail: james.sullivan@anu.edu.au [Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, The Australian National University, Canberra (Australia)

    2016-04-01

    Zircons are a well-known candidate waste form for actinides and their radiation damage behaviour has been widely studied by a range of techniques. In this study, well-characterised natural single crystal zircons have been studied using Positron Annihilation Lifetime Spectroscopy (PALS). In some, but not all, of the crystals that had incurred at least half of the alpha-event damage of ∼10{sup 19} α/g required to render them structurally amorphous, PALS spectra displayed long lifetimes corresponding to voids of ∼0.5 nm in diameter. The long lifetimes corresponded to expectations from published Small-Angle X-ray Scattering data on similar samples. However, the non-observation by PALS of such voids in some of the heavily damaged samples may reflect large size variations among the voids such that no singular size can be distinguished or. Characterisation of a range of samples was also performed using scanning electron microscopy, optical absorption spectroscopy, Raman scattering and X-ray scattering/diffraction, with the degree of alpha damage being inferred mainly from the Raman technique and X-ray diffraction. The observed void diameters and intensities of the long lifetime components were changed somewhat by annealing at 700 °C; annealing at 1200 °C removed the voids entirely. The voids themselves may derive from He gas bubbles or voids created by the inclusion of small quantities of organic and hydrous matter, notwithstanding the observation that no voidage was evidenced by PALS in two samples containing hydrous and organic matter. - Highlights: • Study of a range of naturally occurring zircons damaged by alpha radiation. • Characterised using a range of techniques, including PALS spectroscopy. • Effects on hydrous material appear important, rather than direct radiation damage. • Annealing is shown to remove the observed voids.

  1. Trace element analysis in geochemistry using a nuclear microprobe. Ionoluminescence and particle induced X-ray emission

    International Nuclear Information System (INIS)

    Homman, P.

    1994-01-01

    In PIXE analysis of geological specimens based on X-ray detection with Si(Li) detectors, effects of detector tailing, pulse pileup, and gamma-ray production are pronounced. In this work the tailing effect has been addressed through characterization of the response function of a Si(Li) detector using an absorber technique. The pileup interval, in the pulse forming electronics of a PIXE detection system, has been improved to 100 ns X-ray energies above 8 keV by means of pulse shape analysis. Pulses due to tailing effects were also isolated but no major improvement was obtained. A means of reducing the increased background in the PIXE spectrum due to Compton scattering of high energetic gamma-rays in the Si(Li) crystal has been investigated by installation of an anti-Compton shield consisting of an organic scintillator mounted inside the detector cryostat and read out by a photomultiplier. Ionoluminescence, a new analytical technique for the nuclear microprobe, has shown to be a technique that can be employed as a fast diagnostic tool in imaging applications. The technique is based on analysis of the light that often can be observed when an ion beam impinges on a geological specimen. This light, luminescence, can often be associated with impurities in the crystal lattice or other structural defects. It can therefore be employed for revealing some chemical information about the specimens in contradiction to PIXE which is rather insensitive to chemical variations. The potential of the method is demonstrated and discussed both as an imaging tool and for spectroscopic studies. 19 refs, 10 figs

  2. Teaching material for radiation education using zircon sand

    International Nuclear Information System (INIS)

    Kamata, Masahiro; Okamoto, Miho

    2005-01-01

    In this paper, we introduced safe and inexpensive student experiment using zircon and containing a uranium series, as well as a similar experiment using several chemicals and foods containing potasium 40. In practice, our experiments were confirmed to be available in classes of Chemistry and/or Earth Science. It should be noted here that they are also expected to be useful in many places other than senior high school because they do not need any dangerous chemicals or special techniques, and can make younger students more interested in radioactivity in their environment. (J.P.N.)

  3. Microstructural and analytical analysis of plasma dissociated zircon

    International Nuclear Information System (INIS)

    Minnaar, E G; Neethling, J H; Lee, M E; Snyders, E

    2012-01-01

    The investigation of the microstructure and distribution of impurities was carried out on plasma dissociated zircon (PDZ). The morphology of the PDZ and crystalline nature of the zirconia was determined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) while energy dispersive X-ray spectrometry (EDS) provided compositional information. The SEM and TEM results indicate that the morphology and crystalline nature of the zirconia varies as a result of the existence of a thermal gradient. The EDS results show that the majority of the impurities segregates to the silica phase of the PDZ.

  4. Study of the pelletizing process zirconium oxide and zircon sand

    International Nuclear Information System (INIS)

    Seo, E.S.M.; Paschoal, J.O.A.; Acevedo, M.T.P.

    1990-12-01

    The study of the process to obtain zirconium tetrachloride under development at IPEN, can be divide into two steps: pelletizing and chlorination. Pelletizing is an important step in the overall process as it facilitates greater contact between the particles and permits the production of pellets with dimensional uniformity and mechanical strength. In this paper, the results of the study of pelletizing zirconium oxide and zircon sand are presented. The influence of some variables related to the process and the equipment on the physical characteristics of the pellets are discussed. (author)

  5. Microwave-assisted hydrothermal synthesis of lead zirconate fine powders

    Directory of Open Access Journals (Sweden)

    Apinpus Rujiwatra

    2011-01-01

    Full Text Available A rapid synthesis of lead zirconate fine powders by microwave-assisted hydrothermal technique is reported. The influences of type of lead precursor, concentration of potassium hydroxide mineraliser, applied microwave power and irradiation time are described. The synthesised powders were characterised by powder X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopic microanalysis and light scattering technique. The merits of the microwave application in reducing reaction time and improving particle mono-dispersion and size uniformity as well as the drawbacks, viz. low purity of the desired phase and increasing demand of mineraliser, are discussed in relation to conventional heating method.

  6. Dielectric behaviors of lead zirconate titanate ceramics with coplanar electrodes

    International Nuclear Information System (INIS)

    Wang, Y.; Cheng, Y.L.; Zhang, Y.W.; Chan, H.L.W.; Choy, C.L.

    2003-01-01

    This paper reports on the dielectric behaviors of lead zirconate titanate (PZT) capacitors with coplanar electrodes. Usually a ferroelectric device has a metal-ferroelectric-metal configuration (parallel plate capacitor); when both the electrodes are on one side of a ceramic to form a coplanar capacitor, different dielectric behaviors will be anticipated because of the change in the distribution of the test field inside the dielectrics. This paper describes how the capacitance and dielectric loss of PZT-based coplanar capacitors change with electrode distance, area and test frequency

  7. Phase quantification of mullite-zirconia and zircon commercial powders using PAC and XRD techniques

    Energy Technology Data Exchange (ETDEWEB)

    Rendtorff, Nicolas M.; Conconi, Maria S.; Aglietti, Esteban F. [Centro de Tecnologia de Recursos Minerales y Ceramica (CETMIC: CONICET-CIC) (Argentina); Chain, Cecilia Y.; Pasquevich, Alberto F. [Universidad Nacional de La Plata, Departamento de Fisica, IFLP, Facultad de Ciencias Exactas (Argentina); Rivas, Patricia C. [CONICET (Argentina); Martinez, Jorge A., E-mail: toto@fisica.unlp.edu.ar; Caracoche, Maria C. [Universidad Nacional de La Plata, Departamento de Fisica, IFLP, Facultad de Ciencias Exactas (Argentina)

    2010-06-15

    The short range technique of the Perturbed Angular Correlation (PAC) and x-ray diffraction (Rietveld) methods have been employed to determine the phase content in commercial mullite-zirconia and zircon raw materials that are ordinarily used to produce ceramic materials. The PAC technique, which probes zirconium-containing compounds at nanoscopic level, showed that zircon contains crystalline ZrSiO{sub 4} and an important amount of a structurally distorted zircon, which is also observed accompanying monoclinic zirconia in mullite-zirconia. This particular zircon phase was not detected by the long range x-ray diffraction-Rietveld technique. After an annealing treatment, important changes in crystalline contents of the powders allow confirming, by the x-ray diffraction-Rietveld method, the preexistence of this particular zircon phase. This fact must be taken into account when preparing multicomposites based on the present raw materials.

  8. Application of tomographic techniques to two-dimensional surface analysis using the Harwell nuclear microprobe

    International Nuclear Information System (INIS)

    Huddleston, J.; Hutchinson, I.G.; Pierce, T.B.

    1983-01-01

    Nuclear methods of surface analysis are discussed briefly, and the circumstances are described in which a two-dimensional analysis of the sample surface is desirable to enable the surface composition to be mapped accurately. Tomographic techniques of data manipulation are outlined. Data acquisition in the present case is performed by moving the sample in a defined sequence of positions, at each of which analytical data are gathered by the proton microprobe. The method and equipment are outlined. Data processing leading to the reconstruction of the image is summarised. (U.K.)

  9. A new Krakow scanning nuclear microprobe performance tests and early application experienc

    CERN Document Server

    Lebed, S; Polak, W; Potempa, A W; Stachura, Z; Paszkowski, M

    2001-01-01

    A new scanning nuclear microprobe (MP) with a short-length probe forming system was designed,installed and tested at the 3MV Van de Graaff accelerator in Krakow.The MP resolution of 3.3 mu m was reached for 2.4 MeV proton beam in the high-current mode (>= 100pA).The MP facility provides a local,non-destructive,quantitative elemental microanalysis using a Proton Induced X-ray Emission (PIXE) technique.As example of possible application an analysis of a geological sample containing monazite crystals investigated by PIXE method is presented.

  10. Characterisation of candidate reference materials by PIXE analysis and nuclear microprobe PIXE imaging

    International Nuclear Information System (INIS)

    Jaksic, M.; Pastuovic, Z.; Bogdanovic, I.; Tadic, T.

    2002-01-01

    In order to test whether some candidate reference materials show homogeneity that can satisfy quality control of the PIXE technique, six bottles of each of the two Candidate RM's - Lichen (IAEA 338) and Algae (IAEA 413) were tested. Four different tests were performed. First, two pellets from each bottle were prepared and analysed using broad beam (φ = 5 mm) PIXE. Second and third was analysis of homogeneity using scanning focussed beam at the nuclear microprobe. Scans of 50x50 μm 2 and 240x260 μm 2 were performed. Finally, individual grains with composition differing from the rest of the sample, were analysed using PIXE and RBS. (author)

  11. CMB v. 1.1 Data Acquisition and Evaluation System of the Cracow Nuclear Microprobe

    International Nuclear Information System (INIS)

    Lekki, J.; Hajduk, R.; Potempa, A.; Pieprzyca, T.; Stachura, Z.; Zieblinski, M.; Styczen, J.; Lebed, S.

    2000-11-01

    An overview of the Cracow nuclear microprobe together with its data acquisition and control system is presented. Magnetic deflection was applied for beam scanning, while detector signals acquisition is performed by the NIM/CAMAC modules under supervision of a Windows operating system running on a PC equipped with the GPIB controller card. Total spectra from every detector are accessible on-line during the measurement, while full information about detected energy and beam position is stored to a disk file in the list mode to allow off-line data analysis. System hardware and software setups together with software operations and data formats used for information storing are described. (author)

  12. X-ray microprobe measurements of the chemical compositions of ALH84001 carbonate globules

    International Nuclear Information System (INIS)

    Flynn, G.J.; Sutton, S.R.; Keller, L.P.

    2004-01-01

    We measured minor element contents of carbonate from ALH84001 and report trends in tbe Ca, V, Mn and Sr in carbonate and the associated magnetite bands. McKay et al. suggested that carbonate globules in the ALH84001 meteorite from Mars contained evidence consistent with the development of bacterial life early in the history of Mars. This result provoked an extensive study of the ALH84001 meteorite. More recently Thomas-Keprta et al. have published a study showing that the magnetite associated with carbonate rims are of the size and shape produced by terrestrial bacteria. This paper has revived interest in ALH84001. The typical ALH84001 carbonate globule consists of four regions: a core of Fe-rich carbonate, a thin magnetite-rich band, a rim of Mn-rich carbonate, and another thin magnetite-rich band. Trace element analysis of each of these phases may allow us to address several important questions about these carbonates: (1) The origin of the magnetite-rich bands in the ALH84001 carbonate globules. If the magnetites are derived from the underlying carbonate through thermal decomposition (as proposed by Golden et al.), then we expect to see 'inherited' trace elements in these magnetite bands. (2) The origin of the rim carbonate, by determining whether the carbonate in the core has the same trace elements as the rim carbonates. (3) The age of the rim carbonate. Borg et al. dated the formation of the rim carbonate using the Rb/Sr chronometer. Borg et al. performed their measurements on an aliquot of what they called a high-Rb, low-Sr carbonate separate from the rim. We previously measured the trace element contents of chips from core and rim carbonates from an ALH84001 carbonate globule using an X-Ray Microprobe on Beamline X26A at the National Synchrotron Light Source. These measurements showed the rim carbonate had a very low Rb content, with Sr>>Rb, inconsistent with the ∼5 ppm Rb reported by Borg et al. in the sample they dated by the Rb/Sr chronometer. The large

  13. Individual precipitates in Al alloys probed by the Bonn positron microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Balarisi, Osman; Eich, Patrick; Haaks, Matz; Klobes, Benedikt; Korff, Bjoern; Maier, Karl; Sottong, Reinhard [Helmholtz-Institut fuer Strahlen- und Kernphysik, Nussallee 14-16, 53115 Bonn (Germany); Huehne, Sven-Martin; Mader, Werner [Institut fuer Anorganische Chemie, Roemerstrasse 164, 53117 Bonn (Germany); Staab, Torsten [Fraunhofer ISC, Neunerplatz 2, 97082 Wuerzburg (Germany)

    2010-07-01

    Positron annihilation spectroscopy (PAS) is a unique tool for the characterization of open-volume defects such as vacancies. Therefore, age hardenable Al alloys, whose decomposition is mainly driven by the vacancy mechanism of diffusion, are often characterized by PAS techniques. Nevertheless, probing the defect state of individual precipitates grown in Al alloys requires a focused positron beam and has not been carried out up to now. In this respect we present the first investigations of the defect state of individual precipitates utilizing the Bonn Positron Microprobe (BPM). Furthermore, the analysis of the experimental data has to be facilitated by theoretical calculations of the observables of positron annihilation spectroscopy.

  14. $ANBA; a rapid, combined data acquisition and correction program for the SEMQ electron microprobe

    Science.gov (United States)

    McGee, James J.

    1983-01-01

    $ANBA is a program developed for rapid data acquisition and correction on an automated SEMQ electron microprobe. The program provides increased analytical speed and reduced disk read/write operations compared with the manufacturer's software, resulting in a doubling of analytical throughput. In addition, the program provides enhanced analytical features such as averaging, rapid and compact data storage, and on-line plotting. The program is described with design philosophy, flow charts, variable names, a complete program listing, and system requirements. A complete operating example and notes to assist in running the program are included.

  15. Applications of petrography and electron microprobe analysis to the study of Indian stone sculpture

    International Nuclear Information System (INIS)

    Newman, R.

    1992-01-01

    Examples of research on ancient Indian stone artefacts utilizing petrographic examination coupled with qualitative and quantitative electron beam microprobe analysis of specific minerals are described. Types of artefacts discussed include Gandharan schist sculptures, Pala dynasty phyllite and schist objects from eastern India. Hoysala sculptures from Karnataka state (southern India), and sandstone objects from northern India. In spite of the rich history of stone sculpture in the Indian subcontinent, characterization studies to date have been limited in scope, typically involving unprovenanced artefacts. The examples described point to areas in which more extensive research could produce useful information for the provenancing of artefacts. (author)

  16. Microprobe analysis of PuO2--UO2 nuclear fuel

    International Nuclear Information System (INIS)

    Clark, W.I.; Rasmussen, D.E.; Carlson, R.L.; Highley, D.M.

    1977-01-01

    For the preirradiation characterization of FFTF UO 2 --PuO 2 fuel, a program was developed to determine the preirradiation porosity, grain structure, and microcomposition of the fuel. Two computer programs, MITRAN and MERIT, were developed to evaluate the homogeneity of the fuel. These programs use elemental composition data generated by the electron microprobe. MITRAN determines information on the size and frequency of individual regions, whereas MERIT provides an index of the thermal performance of the fuel and calculated statistical data for comparison to other fuel batches

  17. Effect of magnetic quadrupole lens alignment on a nuclear microprobe resolution

    International Nuclear Information System (INIS)

    Kolinko, S.V.; Ponomarev, A.G.

    2016-01-01

    The paper reports the research trends in developing probe-forming systems with high demagnification and analysis factors that limit a nuclear microprobe resolution. Parasitic aberrations caused by tilts and offsets of magnetic quadrupoles are studied in terms of their effect on probe parameters on a target. The most common arrangements of probe-forming systems such as a triplet and “Russian quadruplet” with separated geometry are considered. The accuracy prerequisites for the positioning of the quadrupoles are defined, and practical guidelines for alignment of probe-forming systems with high demagnification factors are suggested.

  18. Dating Metasomatism: Monazite and Zircon Growth during Amphibolite Facies Albitization

    Directory of Open Access Journals (Sweden)

    Cailey B. Condit

    2018-04-01

    Full Text Available We present coupled textural observations and trace element and geochronological data from metasomatic monazite and zircon, to constrain the timing of high-grade Na-metasomatism (albitization of an Archean orthogneiss in southwest Montana, USA. Field, mineral textures, and geochemical evidence indicate albitization occurred as a rind along the margin of a ~3.2 Ga granodioritic orthogneiss (Pl + Hbl + Kfs + Qz + Bt + Zrn exposed in the Northern Madison range. The metasomatic product is a weakly deformed albitite (Ab + Bt + OAm + Zrn + Mnz + Ap + Rt. Orthoamphibole and biotite grew synkinematically with the regional foliation fabric, which developed during metamorphism that locally peaked at upper amphibolite-facies during the 1800–1710 Ma Big Sky orogeny. Metasomatism resulted in an increase in Na, a decrease in Ca, K, Ba, Fe, and Sr, a complete transformation of plagioclase and K-feldspar into albite, and loss of quartz. In situ geochronology on zoned monazite and zircon indicate growth by dissolution–precipitation in both phases at ~1750–1735 Ma. Trace element geochemistry of rim domains in these phases are best explained by dissolution–reprecipitation in equilibrium with Na-rich fluid. Together, these data temporally and mechanistically link metasomatism with high-grade tectonism and prograde metamorphism during the Big Sky orogeny.

  19. Air abrasion experiments in U-Pb dating of zircon

    Science.gov (United States)

    Goldich, S.S.; Fischer, L.B.

    1986-01-01

    Air abrasion of zircon grains can remove metamict material that has lost radiogenic Pb and zircon overgrowths that were added during younger events and thereby improve the precision of the age measurements and permit closer estimates of the original age. Age discordance that resulted from a single disturbance of the U-Pb isotopic decay systems, as had been demonstrated by T.E. Krogh, can be considerably reduced, and, under favorable conditions, the ages brought into concordancy. Two or more events complicate the U-Pb systematics, but a series of abrasion experiments can be helpful in deciphering the geologic history and in arriving at a useful interpretation of the probable times of origin and disturbances. In east-central Minnesota, U.S.A., Penokean tonalite gneiss is dated at 1869 ?? 5 Ma, and sheared granite gneiss is shown to have been a high-level granite intrusion at 1982 ?? 5 Ma in the McGrath Gneiss precursor. Tonalite gneiss and a mafic granodiorite in the Rainy Lake area, Ontario, Canada, are dated at 2736 ?? 16 and 2682 ?? 4 Ma, respectively. The tonalitic phase of the Morton Gneiss, southwestern Minnesota, is dated at 3662 ?? 42 Ma. ?? 1986.

  20. Synthesis, Characterization and Thermal Diffusivity of Holmium and Praseodymium Zirconates

    Directory of Open Access Journals (Sweden)

    Stopyra M.

    2016-06-01

    Full Text Available A2B2O7 oxides with pyrochlore or defected fluorite structure are among the most promising candidates for insulation layer material in thermal barrier coatings. The present paper presents the procedure of synthesis of holmium zirconate Ho2Zr2O7 and praseodymium zirconate Pr2Zr2O7 via Polymerized-Complex Method (PCM. Thermal analysis of precursor revealed that after calcination at relatively low temperature (700°C fine-crystalline, single-phase material is obtained. Thermal diffusivity was measured in temperature range 25-200°C, Ho2Zr2O7 exhibits lower thermal diffusivity than Pr2Zr2O7. Additionally, PrHoZr2O7 was synthesized. The powder in as-calcined condition is single-phase, but during the sintering decomposition of solid solution took place and Ho-rich phase precipitated. This material exhibited the best insulating properties among the tested ones.

  1. Zircons reveal magma fluxes in the Earth's crust.

    Science.gov (United States)

    Caricchi, Luca; Simpson, Guy; Schaltegger, Urs

    2014-07-24

    Magma fluxes regulate the planetary thermal budget, the growth of continents and the frequency and magnitude of volcanic eruptions, and play a part in the genesis and size of magmatic ore deposits. However, because a large fraction of the magma produced on the Earth does not erupt at the surface, determinations of magma fluxes are rare and this compromises our ability to establish a link between global heat transfer and large-scale geological processes. Here we show that age distributions of zircons, a mineral often present in crustal magmatic rocks, in combination with thermal modelling, provide an accurate means of retrieving magma fluxes. The characteristics of zircon age populations vary significantly and systematically as a function of the flux and total volume of magma accumulated in the Earth's crust. Our approach produces results that are consistent with independent determinations of magma fluxes and volumes of magmatic systems. Analysis of existing age population data sets using our method suggests that porphyry-type deposits, plutons and large eruptions each require magma input over different timescales at different characteristic average fluxes. We anticipate that more extensive and complete magma flux data sets will serve to clarify the control that the global heat flux exerts on the frequency of geological events such as volcanic eruptions, and to determine the main factors controlling the distribution of resources on our planet.

  2. Phase transformations in lead zirconate-titanate doped with lanthanum

    Energy Technology Data Exchange (ETDEWEB)

    Ishchuk, V M; Morozov, E M

    1979-07-01

    Presented are the results of studies on the character of phase transitions of the lead-lanthanum zirconate-titanate (LLZT) system. The replacement of lead by lanthanum leads to the expansion of the region of antisegnetoelectric (ASE) states of solid solutions of lead zirconate-titanate (LZT) in the direction of PbTiO/sub 3/ concentration growth. An intermediate region is revealed between segnetoelectric (SE) and ASE states, material properties in which depend on their prehistory: annealed samples are in the ASE state, whereas the application of electric field exceeding some critical value induces the SE state. A family of phase diagrams obtained at consequent replacement of lead by lanthanum permits to identify phase states in any series of LLZT with a constant ratio of Zr:Ti, in the x/65/35 series in particular. Thermally depolarized state of materials of this series at x<6.5 is shown to be antisegnetoelectric at all the temperatures below the Curie point Tsub(c), and heating causes phase transition of ASE..-->..PE (paraelectric state) at Tsub(c). Polarized samples being heated, a successiveness of phase transitions of SE..-->..ASE takes place at T/sub 0/, and that of ASE reversible PE at Tsub(C) (Tsub(0)..ASE phase transition in the LZT system.

  3. Synthesis and characterization of some inorganic ion exchange materials and its application in the treatment of hazardous waste

    International Nuclear Information System (INIS)

    El-Deeb, A.B.I.M.

    2008-01-01

    inorganic ion exchange materials play an important role in the last decays in the fields of industry, medicine, agriculture and nuclear technology due to their stabilities towards thermal and radiation and their resistance to chemical attack. the most important property of inorganic ion exchangers enabling their use in the various chemical separation is the selectivity. the selectivity behaviour of synthetic inorganic ion exchanges are still far from being clearly understood. this work had been done in an attempt to synthesize of inorganic ion exchangers such as zircon-titanate and doping alkali metals with zircon-titanate to produce a new developed ion exchanger with properties allow to used in the treatment of hazardous wastes. this work is concerned with the preparation of zircon-titanate and the doping of some alkali metals (K,Na,Li and Cs)with zircon-titanate. characterization of the synthesized ion exchangers using x-ray diffraction, x-ray fluorescence, infrared spectroscopy, surface area and thermal analysis were conducted. equilibrium measurements and effect of batch factor, ph of the medium on percent uptake were determined. capacity measurements and sorption isotherm studies were also investigated on zircon-titanate and its dopant products.

  4. PROTON MICROPROBE ANALYSIS OF TRACE-ELEMENT VARIATIONS IN VITRINITES IN THE SAME AND DIFFERENT COAL BEDS.

    Science.gov (United States)

    Minkin, J.A.; Chao, E.C.T.; Blank, Herma; Dulong, F.T.

    1987-01-01

    The PIXE (proton-induced X-ray emission) microprobe can be used for nondestructive, in-situ analyses of areas as small as those analyzed by the electron microprobe, and has a sensitivity of detection as much as two orders of magnitude better than the electron microprobe. Preliminary studies demonstrated that PIXE provides a capability for quantitative determination of elemental concentrations in individual coal maceral grains with a detection limit of 1-10 ppm for most elements analyzed. Encouraged by the earlier results, we carried out the analyses reported below to examine trace element variations laterally (over a km range) as well as vertically (cm to m) in the I and J coal beds in the Upper Cretaceous Ferron Sandstone Member of the Mancos Shale in central Utah, and to compare the data with the data from two samples of eastern coals of Pennsylvanian age.

  5. A hard X-ray scanning microprobe for fluorescence imaging and microdiffraction at the Advanced Photon Source

    International Nuclear Information System (INIS)

    Cai, L.; Lai, B.; Yun, W.; Ilinski, P.; Legnini, D.; Maser, J.; Rodrigues, W.

    1999-01-01

    A hard x-ray scanning microprobe based on zone plate optics and undulator radiation, in the energy region from 6 to 20 keV, has reached a focal spot size (FWHM) of 0.15 microm (v) x 0.6 microm (h), and a photon flux of 4 x 10 9 photons/sec/0.01%BW. Using a slit 44 meters upstream to create a virtual source, a circular beam spot of 0.15 microm in diameter can be obtained with a photon flux of one order of magnitude less. During fluorescence mapping of trace elements in a single human ovarian cell, the microprobe exhibited an imaging sensitivity for Pt (L a line) of 80 attograms/microm 2 for a count rate of 10 counts per second. The x-ray microprobe has been used to map crystallographic strain and multiquantum well thickness in micro-optoelectronic devices produced with the selective area growth technique

  6. In situ titanium dioxide nanoparticles quantitative microscopy in cells and in C. elegans using nuclear microprobe analysis

    Energy Technology Data Exchange (ETDEWEB)

    Le Trequesser, Quentin [Université de Bordeaux, CENBG, Chemin du solarium, 33175 Gradignan (France); CNRS, UMR 5797, CENBG, Chemin du solarium, 33175 Gradignan (France); CNRS, Université de Bordeaux, ICMCB, 87 avenue du Dr. A. Schweitzer, Pessac F-33608 (France); Saez, Gladys; Devès, Guillaume; Michelet, Claire; Barberet, Philippe [Université de Bordeaux, CENBG, Chemin du solarium, 33175 Gradignan (France); CNRS, UMR 5797, CENBG, Chemin du solarium, 33175 Gradignan (France); Delville, Marie-Hélène [CNRS, Université de Bordeaux, ICMCB, 87 avenue du Dr. A. Schweitzer, Pessac F-33608 (France); Seznec, Hervé, E-mail: herve.seznec@cenbg.in2p3.fr [Université de Bordeaux, CENBG, Chemin du solarium, 33175 Gradignan (France); CNRS, UMR 5797, CENBG, Chemin du solarium, 33175 Gradignan (France)

    2014-12-15

    Detecting and tracking nanomaterials in biological systems is challenging and essential to understand the possible interactions with the living. In this context, in situ analyses were conducted on human skin cells and a multicellular organism (Caenorhabditiselegans) exposed to titanium dioxide nanoparticles (TiO{sub 2} NPs) using nuclear microprobe. Coupled to conventional methods, nuclear microprobe was found to be suitable for accurate description of chemical structure of biological systems and also for detection of native TiO{sub 2} NPs. The method presented herein opens the field to NPs exposure effects analyses and more generally to toxicological analyses assisted by nuclear microprobe. This method will show applications in key research areas where in situ imaging of chemical elements is essential.

  7. Investigating the Early Carbon Cycle Using Carbonaceous Inclusions and Dissolved Carbon in Detrital Zircon

    Science.gov (United States)

    Bell, E. A.; Boehnke, P.; Harrison, M.; Mao, W. L.

    2015-12-01

    Because the terrestrial rock record extends only to ~4 Ga and older materials thus far identified are limited to detrital zircons, information about volatile abundances and cycles on early Earth is limited. Carbon, for instance, plays an important role not only in the modern biosphere but also in deep recycling of materials between the crust and mantle. We are investigating the record of carbon abundance and origin in Hadean zircons from Jack Hills (W. Australia) using two main approaches. First, carbon may partition into the zircon structure at trace levels during crystallization from a magma, and better understanding of this partitioning behavior will allow for zircon's use as a monitor of magmatic carbon contents. We have measured carbon abundances in zircon from a variety of igneous rocks (gabbro; I-, A-, and S-type granitoids) via SIMS and found that although abundances are typically low (average raw 12C/30Si ~ 1x10-6), S-type granite zircons can reach a factor of 1000 over this background. Around 10% of Hadean zircons investigated show similar enrichments, consistent with other evidence for the derivation of many Jack Hills zircons from S-type granitoids and with the establishment of modern-level carbon abundances in the crust by ca. 4.2 Ga. Diamond and graphite inclusions reported in the Jack Hills zircons by previous studies proved to be contamination by polishing debris, leaving the true abundance of these materials in the population uncertain. On a second front, we have identified and investigated primary carbonaceous inclusions in these zircons. From a population of over 10,000 Jack Hills zircons, we identified one concordant 4.10±0.01 Ga zircon that contains primary graphite inclusions (so interpreted due to their enclosure in a crack-free zircon host as shown by transmission X-ray microscopy and their crystal habit). Their δ13CPDB of -24±5‰ is consistent with a biogenic origin and, in the absence of a likely inorganic mechanism to produce such a

  8. Fast probing of glucose and fructose in plant tissues via plasmonic affinity sandwich assay with molecularly-imprinted extraction microprobes.

    Science.gov (United States)

    Muhammad, Pir; Liu, Jia; Xing, Rongrong; Wen, Yanrong; Wang, Yijia; Liu, Zhen

    2017-12-01

    Determination of specific target compounds in agriculture food and natural plant products is essential for many purposes; however, it is often challenging due to the complexity of the sample matrices. Herein we present a new approach called plasmonic affinity sandwich assay for the facile and rapid probing of glucose and fructose in plant tissues. The approach mainly relies on molecularly imprinted plasmonic extraction microprobes, which were prepared on gold-coated acupuncture needles via boronate affinity controllable oriented surface imprinting with the target monosaccharide as the template molecules. An extraction microprobe was inserted into plant tissues under investigation, which allowed for the specific extraction of glucose or fructose from the tissues. The glucose or fructose molecules extracted on the microprobe were labeled with boronic acid-functionalized Raman-active silver nanoparticles, and thus affinity sandwich complexes were formed on the microprobes. After excess Raman nanotags were washed away, the microprobe was subjected to Raman detection. Upon being irradiated with a laser beam, surface plasmon on the gold-coated microprobes was generated, which further produced plasmon-enhanced Raman scattering of the silver-based nanotags and thereby provided sensitive detection. Apple fruits, which contain abundant glucose and fructose, were used as a model of plant tissues. The approach exhibited high specificity, good sensitivity (limit of detection, 1 μg mL -1 ), and fast speed (the whole procedure required only 20 min). The spatial distribution profiles of glucose and fructose within an apple were investigated by the developed approach. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. X-ray microprobe characterization of materials: the case for undulators on advanced storage rings

    International Nuclear Information System (INIS)

    Sparks, C.J. Jr.

    1984-01-01

    The unique properties of X rays offer many advantages over electrons and other charged particles for the microcharacterization of materials. X rays are more efficient in exciting characteristic X-ray fluorescence and produce higher fluorescent signals to backgrounds than obtained with electrons. Detectable limits for X rays are a few parts per billion and are 10 -3 to 10 -5 less than for electrons. Energy deposition in the sample by X rays is 10 -3 to 10 -4 less than for electrons for the same detectable concentration. High-brightness storage rings, especially in the 6 GeV class with undulators, will be approximately 10 3 brighter in the X-ray energy range from 5 keV to 35 keV than existing storage rings and provide for X-ray microprobes that are as bright as the most advanced electron probes. Such X-ray microprobes will produce unprecedented low levels of detection in diffraction, EXAFS, Auger, and photoelectron spectroscopies for both chemical characterization and elemental identification. These major improvements in microcharacterization capabilities will have wide-ranging ramifications not only in materials science but also in physics, chemistry, geochemistry, biology, and medicine

  10. Data smoothing techniques applied to proton microprobe scans of teleost hard parts

    International Nuclear Information System (INIS)

    West, I.F.; Gauldie, R.W.; Coote, G.E.

    1992-01-01

    We use a proton microprobe to examine the distribution of elements in otoliths and scales of teleost (bony) fish. The elements of principal interest are calcium and strontium in otoliths and calcium and fluorine in scales. Changes in the distribution of these elements across hard structures may allow inferences about the life histories of fish. Otoliths and scales of interest are up to a centimeter in linear dimension and to reveal the structures of interest up to 200 sampling points are required in each dimension. The time needed to accumulate high X-ray counts at each sampling point can be large, particularly for strontium. To reduce microprobe usage we use data smoothing techniques to reveal changing patterns with modest X-ray count accumulations at individual data points. In this paper we review performance for revealing pattern at modest levels of X-ray count accumulations of a selection of digital filters (moving average smoothers), running median filters, robust locally weighted regression filters and adaptive spline filters. (author)

  11. Nuclear microprobe studies of elemental distribution in the seagrass Thalassodendron ciliatum

    Energy Technology Data Exchange (ETDEWEB)

    Barnabas, A.D. E-mail: alban@pixie.udw.ac.za; Przybylowicz, W.J.; Mesjasz-Przybylowicz, J.; Pineda, C.A

    1999-09-02

    Elemental levels and distributions in various organs (leaves, upright stems, rhizomes and roots) of the seagrass Thalassodendron ciliatum were determined using the NAC nuclear microprobe. Elemental distributions were obtained using the true elemental imaging system Dynamic Analysis (DA). Cl was the most abundant element present in the organs, occurring in all tissues, but present in relatively low concentrations in epidermal cells of leaves and roots. Na, K, S and Mg were also abundant and occurred in all organ tissues. Ca concentration was highest in the leaves, especially in the epidermis. Low concentrations of P were found and its tissue distribution was limited. Although Fe, Cu, Zn, Mn, Br, Ti and Si were present in relatively small amounts, enrichment of the epidermis with Fe, Ti and Si in all organs, was observed. Fe concentration was the highest in rhizomes while Si concentration was highest in upright stems. The significance of these elemental distribution patterns and the value of the nuclear microprobe in elemental analysis of seagrasses are discussed.

  12. Color electron microprobe cathodoluminescence of Bishunpur meteorite compared with the traditional optical microscopy method

    Directory of Open Access Journals (Sweden)

    Amanda Araujo Tosi

    Full Text Available Abstract Cathodoluminescence (CL imaging is an outstanding method for sub classification of Unequilibrated Ordinary Chondrites (UOC - petrological type 3. CL can be obtained by several electron beam apparatuses. The traditional method uses an electron gun coupled to an optical microscope (OM. Although many scanning electron microscopes (SEM and electron microprobes (EPMA have been equipped with a cathodoluminescence, this technique was not fully explored. Images obtained by the two methods differ due to a different kind of signal acquisition. While in the CL-OM optical photography true colors are obtained, in the CL-EPMA the results are grayscale monochromatic electronic signals. L-RGB filters were used in the CL-EPMA analysis in order to obtain color data. The aim of this work is to compare cathodoluminescence data obtained from both techniques, optical microscope and electron microprobe, on the Bishunpur meteorite classified as LL 3.1 chondrite. The present study allows concluding that 20 KeV and 7 nA is the best analytical condition at EPMA in order to test the equivalence between CL-EPMA and CL-OM colour results. Moreover, the color index revealed to be a method for aiding the study of the thermal metamorphism, but it is not definitive for the meteorite classification.

  13. An extended magnetic quadrupole lens for a high-resolution nuclear microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Breese, M.B.H. E-mail: m.breese@surrey.ac.uk; Grime, G.W.; Linford, W.; Harold, M

    1999-09-02

    This paper describes the design requirements and initial performance of a new style of magnetic quadrupole lens for use in a high-resolution nuclear microprobe, which is presently being constructed in Oxford. Such a microprobe necessitates the use of a small image distance from the exit face of the final quadrupole lens to the image plane in order to produce a large demagnification. This means that the final lens should be as close to the sample chamber as possible. However, with conventional magnetic quadrupoles the current-carrying coils protrude by a typical distance of 10-20 mm beyond the pole face, thereby significantly limiting the minimum image distance. The approach taken here is to recess the coils into the body of the lens, so that they are almost flush with the pole pieces and lens yoke, enabling an image distance of 55 mm. Three-dimensional magnetic field calculations within this lens structure predict that the field in the extended pole piece 'nose' region is only slightly less than that in the main lens body. Experimental field profiles, measured using a Hall probe, are used to confirm these calculations.

  14. An extended magnetic quadrupole lens for a high-resolution nuclear microprobe

    International Nuclear Information System (INIS)

    Breese, M.B.H.; Grime, G.W.; Linford, W.; Harold, M.

    1999-01-01

    This paper describes the design requirements and initial performance of a new style of magnetic quadrupole lens for use in a high-resolution nuclear microprobe, which is presently being constructed in Oxford. Such a microprobe necessitates the use of a small image distance from the exit face of the final quadrupole lens to the image plane in order to produce a large demagnification. This means that the final lens should be as close to the sample chamber as possible. However, with conventional magnetic quadrupoles the current-carrying coils protrude by a typical distance of 10-20 mm beyond the pole face, thereby significantly limiting the minimum image distance. The approach taken here is to recess the coils into the body of the lens, so that they are almost flush with the pole pieces and lens yoke, enabling an image distance of 55 mm. Three-dimensional magnetic field calculations within this lens structure predict that the field in the extended pole piece 'nose' region is only slightly less than that in the main lens body. Experimental field profiles, measured using a Hall probe, are used to confirm these calculations

  15. Development of a scanning proton microprobe - computer-control, elemental mapping and applications

    International Nuclear Information System (INIS)

    Loevestam, Goeran.

    1989-08-01

    A scanning proton microprobe set-up has been developed at the Pelletron accelerator in Lund. A magnetic beam scanning system and a computer-control system for beam scanning and data aquisition is described. The computer system consists of a VMEbus front-end computer and a μVax-II host-computer, interfaced by means of a high-speed data link. The VMEbus computer controls data acquisition, beam charge monitoring and beam scanning while the more sophisticated work of elemental mapping and spectrum evaluations is left to the μVax-II. The calibration of the set-up is described as well as several applications. Elemental micro patterns in tree rings and bark has been investigated by means of elemental mapping and quantitative analysis. Large variations of elemental concentrations have been found for several elements within a single tree ring. An external beam set-up has been developed in addition to the proton microprobe set-up. The external beam has been used for the analysis of antique papyrus documents. Using a scanning sample procedure and particle induced X-ray emission (PIXE) analysis, damaged and missing characters of the text could be made visible by means of multivariate statistical data evaluation and elemental mapping. Also aspects of elemental mapping by means of scanning μPIXE analysis are discussed. Spectrum background, target thickness variations and pile-up are shown to influence the structure of elemental maps considerably. In addition, a semi-quantification procedure has been developed. (author)

  16. Study of the toughening mechanisms in bone and biomimetic hydroxyapatite materials using Raman microprobe spectroscopy.

    Science.gov (United States)

    Pezzotti, Giuseppe; Sakakura, Seiji

    2003-05-01

    A Raman microprobe spectroscopy characterization of microscopic fracture mechanisms is presented for a natural hydroxyapatite material (cortical bovine femur) and two synthetic hydroxyapatite-based materials with biomimetic structures-a hydroxyapatite skeleton interpenetrated with a metallic (silver) or a polymeric (nylon-6) phase. In both the natural and synthetic materials, a conspicuous amount of toughening arose from a microscopic crack-bridging mechanism operated by elasto-plastic stretching of unbroken second-phase ligaments along the crack wake. This mechanism led to a rising R-curve behavior. An additional micromechanism, responsible for stress relaxation at the crack tip, was recognized in the natural bone material and was partly mimicked in the hydroxyapatite/silver composite. This crack-tip mechanism conspicuously enhanced the cortical bone material resistance to fracture initiation. A piezo-spectroscopic technique, based on a microprobe measurement of 980 cm(-1) Raman line of hydroxyapatite, enabled us to quantitatively assess in situ the microscopic stress fields developed during fracture both at the crack tip and along the crack wake. Using the Raman piezo-spectroscopy technique, toughening mechanisms were assessed quantitatively and rationally related to the macroscopic fracture characteristics of hydroxyapatite-based materials. Copyright 2003 Wiley Periodicals, Inc.

  17. Compaction of polydimethylsiloxane due to nitrogen ion irradiation and its application for creating microlens arrays

    Czech Academy of Sciences Publication Activity Database

    Nagy, G. U. L.; Lavrentiev, Vasyl; Banyasz, I.; Szilasi, S. Z.; Havránek, Vladimír; Voseček, Václav; Huszank, R.; Rajta, I.

    2017-01-01

    Roč. 636, AUG (2017), s. 634-638 ISSN 0040-6090 R&D Projects: GA MŠk LM2015056 Institutional support: RVO:61389005 Keywords : ion microbeam * microprobe * polydimethylsioloxane * microlens Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders OBOR OECD: Nuclear physics Impact factor: 1.879, year: 2016

  18. Suppression of X-radiation from 2 MeV ion electrostatic accelerator

    International Nuclear Information System (INIS)

    Ignat'ev, I.G.; Miroshnichenko, V.I.; Sirenko, A.M.; Storizhko, V.E.

    2008-01-01

    The paper presents results concerning studies of X-radiation from 2 MeV ion electrostatic accelerator 'Sokol' used for nuclear microprobe analysis. The radiation protection system of the accelerator was developed and tested. Tests of the system of the accelerator show that it reduces doses rate by two orders of magnitude

  19. Reply to Comment on "Zircon U-Th-Pb dating using LA-ICP-MS: Simultaneous U-Pb and U-Th dating on the 0.1 Ma Toya Tephra, Japan"

    Science.gov (United States)

    Ito, Hisatoshi

    2015-04-01

    Guillong et al. (2015) mentioned that corrections for abundance sensitivity for 232Th and molecular zirconium sesquioxide ions (Zr2O3+) are critical for reliable determination of 230Th abundances in zircon for LA-ICP-MS analyses. There is no denying that more rigorous treatments are necessary to obtain more reliable ages than those in Ito (2014). However, as shown in Fig. 2 in Guillong et al. (2015), the uncorrected (230Th)/(238U) for reference zircons except for Mud Tank are only 5-20% higher than unity. Since U abundance of Toya Tephra zircons that have U-Pb ages Ito (2014) obtained U-Th ages of the Toya Tephra by comparison with Fish Canyon Tuff (FCT) data. Because both the FCT and the Toya Tephra have similar trends of overestimation of 230Th, the effect of overestimation of 230Th to cause overestimation of U-Th age should be cancelled out or negligible. Therefore the pivotal conclusion in Ito (2014) that simultaneous U-Pb and U-Th dating using LA-ICP-MS is possible and useful for Quaternary zircons holds true.

  20. Response of zircon to melting and metamorphism in deep arc crust, Fiordland (New Zealand): implications for zircon inheritance in cordilleran granites

    Science.gov (United States)

    Bhattacharya, Shrema; Kemp, A. I. S.; Collins, W. J.

    2018-04-01

    The Cretaceous Mount Daniel Complex (MDC) in northern Fiordland, New Zealand was emplaced as a 50 m-thick dyke and sheet complex into an active shear zone at the base of a Cordilleran magmatic arc. It was emplaced below the 20-25 km-thick, 125.3 ± 1.3 Ma old Western Fiordland Orthogneiss (WFO) and is characterized by metre-scale sheets of sodic, low and high Sr/Y diorites and granites. 119.3 ± 1.2 Ma old, pre-MDC lattice dykes and 117.4 ± 3.1 Ma late-MDC lattice dykes constrain the age of the MDC itself. Most dykes were isoclinally folded as they intruded, but crystallised within this deep-crustal, magma-transfer zone as the terrain cooled and was buried from 25 to 50 km (9-14 kbar), based on published P-T estimated from the surrounding country rocks. Zircon grains formed under these magmatic/granulite facies metamorphic conditions were initially characterized by conservatively assigning zircons with oscillatory zoning as igneous and featureless rims as metamorphic, representing 54% of the analysed grains. Further petrological assignment involved additional parameters such as age, morphology, Th/U ratios, REE patterns and Ti-in-zircon temperature estimates. Using this integrative approach, assignment of analysed grains to metamorphic or igneous groupings improved to 98%. A striking feature of the MDC is that only 2% of all igneous zircon grains reflect emplacement, so that the zircon cargo was almost entirely inherited, even in dioritic magmas. Metamorphic zircons of MDC show a cooler temperature range of 740-640 °C, reflects the moderate ambient temperature of the lower crust during MDC emplacement. The MDC also provides a cautionary tale: in the absence of robust field and microstructural relations, the igneous-zoned zircon population at 122.1 ± 1.3 Ma, derived mostly from inherited zircons of the WFO, would be meaningless in terms of actual magmatic emplacement age of MDC, where the latter is further obscured by younger (ca. 114 Ma) metamorphic overgrowths

  1. Lithium in Jack Hills zircons: Evidence for extensive weathering of Earth's earliest crust

    Science.gov (United States)

    Ushikubo, Takayuki; Kita, Noriko T.; Cavosie, Aaron J.; Wilde, Simon A.; Rudnick, Roberta L.; Valley, John W.

    2008-08-01

    In situ Li analyses of 4348 to 3362 Ma detrital zircons from the Jack Hills, Western Australia by SIMS reveal that the Li abundances (typically 10 to 60 ppm) are commonly over 10,000 times higher than in zircons crystallized from mantle-derived magmas and in mantle-derived zircon megacrysts (typically Jack Hills zircons also have fractionated lithium isotope ratios ( δ7Li = - 19 to + 13‰) about five times more variable than those recorded in primitive ocean floor basalts (2 to 8‰), but similar to continental crust and its weathering products. Values of δ7Li below - 10‰ are found in zircons that formed as early as 4300 Ma. The high Li compositions indicate that primitive magmas were not the source of Jack Hills zircons and the fractionated values of δ7Li suggest that highly weathered regolith was sampled by these early Archean magmas. These new Li data provide evidence that the parent magmas of ancient zircons from Jack Hills incorporated materials from the surface of the Earth that interacted at low temperature with liquid water. These data support the hypothesis that continental-type crust and oceans existed by 4300 Ma, within 250 million years of the formation of Earth and the low values of δ7Li suggest that weathering was extensive in the early Archean.

  2. Inorganic ion exchangers. Application to liquid effluent processing

    International Nuclear Information System (INIS)

    Dozol, M.

    1983-10-01

    Main inorganic ion exchangers used for radioactive liquid effluents presented in this report are: synthetic and natural zeolites, in titanium oxides, titanates, niobates, tantalates, zirconates, some insoluble salts of zirconium, molybdenum and tin, heteropolyacids and polyantimonic acid. Properties of these ion exchangers are described: structure, adsoption, radiation effects and thermal stability, application to waste processing, radioactive waste storage uranium and cesium 137 recovery are evoked [fr

  3. Automated electron microprobe identification of minerals in stream sediments for the national uranium resources evaluation program

    International Nuclear Information System (INIS)

    Mosley, W.C. Jr.

    1979-01-01

    Over 500 stream sediment particles have been analyzed. About 96% have been identified as distinct minerals. Most of the others appeared to be mixtures. Only zinc-bearing gahnite had to be analyzed further for positive identification. Monazite and zircon were the only minerals with concentrations of uranium significantly above the detection limit. The Frantz Isodynamic Magnetic Separator isolated the monazite into the 1.0 fraction. Monazite particles in anomalous sediments contained up to 3.7 wt % uranium. This uranium concentration is unusually high for monazite, which normally has about 0.5 wt % uranium, and may be the cause of the anomaly

  4. Strontium zirconate as silicon and aluminum scavenger in yttria stabilized zirconia

    DEFF Research Database (Denmark)

    Andersen, Thomas; Hansen, Karin Vels; Chorkendorff, Ib

    2011-01-01

    Here we report on strontium zirconate as a getter for silicon dioxide and aluminum oxide in yttria stabilized zirconia (YSZ) single crystals for cleaning purposes. YSZ single crystals were covered with strontium zirconate powder and heat treated at 1450°C in water vapor. After treatment the YSZ...... by transmission electron microscopy (TEM) the interface region between bump and YSZ single crystal bulk was examined. EDS showed a homogeneous distribution of silicon and aluminum through the cross section of a bump. The results suggest strontium zirconate as a good getter for silicon and aluminum from bulk...

  5. Determination of Uranium, Thorium and Radium 226 in Zircon containig sands by alpha spectrometry

    International Nuclear Information System (INIS)

    Spezzano, P.

    1985-01-01

    The industrial utilization of Zircon sands for the production of refractories presents radiological problems owing to the risk of inhalation of Uranium, Thorium and their decay products, present in high concentrations in such materials. A method of analysis was realized for the determination of Uranium, Thorium and Radium-226 in Zircon sands, including the total dissolution of the sample, radiochemical separation and final measurement by alpha spectrometry with surface barrier detector. The concentrations of the main alpha-emitting radionuclides presents in two samples of Zircon sands have been determined and the possibility of disequilibrium along the decay series has been pointed out

  6. Improvement of conditions for ceramics sintering on the base of lead zirconate-titanate

    International Nuclear Information System (INIS)

    Glinchuk, M.D.; Kim, P.V.; Bykov, I.P.; Lyashchenko, A.B.

    1989-01-01

    Lead zirconate-titanate powders of different graininess are studied for their phase composition. The finest grains of the powder consist of lead zirconate-titanate with the rhombohedral structure. Grains of 3-5 μm size are a mixture of lead zirconate-titanate and lead titanate, the latter exceeding 50% (by weight) causes the effect of anomalous expansion in the process of sintering. Control of the technological parameters of the synthesis permits producing powder with favourable correlation of the above phases and grain sizes. Sintering of such a powder induces no effect of the anomalous expansion with an increased density of the product attained

  7. Emerging technologies for processing and utilization of zircon

    International Nuclear Information System (INIS)

    Rao, S.M.; Balkishan, B.

    2013-01-01

    Zirconium occupies a prominent place in today's industry due to diverse applications of its chemical compounds. About 95% of zirconium is consumed in the form of zircon, zirconia and zirconium chemicals. The balance 5% of zirconium is consumed as the metal and its alloys. Because of its attractive nuclear properties zirconium alloys with very low hafnium content are used in the nuclear industry. Bio-compatibility, corrosion resistance and mechanical strength of zirconium alloys make them suitable for the manufacture of human organs and medicinal and pharmaceutical equipment. Other commercial areas of application of zirconium compounds include foundry, refractory, abrasives, opacifiers, oxygen sensors, catalysis, advanced ceramics, gems, paint dryers, pigments etc. The talk outlines the technologies involved in the production of nuclear grade zirconium alloys, manufacture of zirconium metal powder, gem grade zirconia and zirconium compounds like oxy-chloride, basic sulphate and basic carbonate etc. (author)

  8. Ferroelastic domain switching fatigue in lead zirconate titanate ceramics

    International Nuclear Information System (INIS)

    Pojprapai, Soodkhet; Jones, Jacob L.; Studer, Andrew J.; Russell, Jennifer; Valanoor, Nagarajan; Hoffman, Mark

    2008-01-01

    The influence of the frequency and amplitude of cyclic mechanical loading on soft, tetragonal lead zirconate titanate (PZT) ceramics was investigated via neutron diffraction. Intensity change in the {2 0 0} reflections provided quantitative measurements of domain switching behavior, domain texture and the strain resulting from domain switching. The results are explained using a viscoelasticity model. It was found that the magnitude of applied stress affects the level of strain accumulated, while its frequency affects the time taken for the strain to reach saturation. Furthermore, markedly different behaviors are exhibited by poled and unpoled samples. For samples loaded under identical conditions, the frequency effect is more pronounced in unpoled samples and the accumulated ferroelastic strain is greater in poled samples

  9. Ferroelectric devices using lead zirconate titanate (PZT) nanoparticles.

    Science.gov (United States)

    Paik, Young Hun; Kojori, Hossein Shokri; Kim, Sung Jin

    2016-02-19

    We successfully demonstrate the synthesis of lead zirconate titanate nanoparticles (PZT NPs) and a ferroelectric device using the synthesized PZT NPs. The crystalline structure and the size of the nanocrystals are studied using x-ray diffraction and transmission electron microscopy, respectively. We observe PZT NPs and this result matches dynamic light scattering measurements. A solution-based low-temperature process is used to fabricate PZT NP-based devices on an indium tin oxide substrate. The fabricated ferroelectric devices are characterized using various optical and electrical measurements and we verify ferroelectric properties including ferroelectric hysteresis and the ferroelectric photovoltaic effect. Our approach enables low-temperature solution-based processes that could be used for various applications. To the best of our knowledge, this low-temperature solution processed ferroelectric device using PZT NPs is the first successful demonstration of its kind.

  10. New phase transitions in lead zirconate-titanate

    International Nuclear Information System (INIS)

    Ishchuk, V.M.; Morozov, E.M.; Klimov, V.V.

    1977-01-01

    Processes of disordering are considered in the paraelectric phase of lead zirconate-titanate. Te investigations were carried out on poly- and single-crystal specimens of the composition PbZrsub(1-x)Tisub(x)O 3 (0< x(<=)0.5). The results are presented of measurements of the temperature dependence of the dielectric constant and the dependence of the polarization on the temperature and the electric field. Anomaly is observed of the investigated characteristics above the Curie point due to a first-type phase transition. The results are interpreted within the framework of the model proposed by Coms, Lambert, and Guiniot, according to which this transition is due to the disordering of chains of unit cells existing above the Curie point

  11. Preparation of lead titanate zirconate from metal citrates

    International Nuclear Information System (INIS)

    Bastos, C.M.R.

    1994-01-01

    Lead titanate zirconate (PZT) preparation from its metal constituent citrates have been investigated. Metal citrates were obtained by forced precipitation using a dehydration alcohol mixture. Salt solutions of lead nitrate and octahydrated zirconyl chloride, and titanium tetrachloride were treated separately with citric acid and ammonium hydroxide. Zirconium, titanium and lead oxides resulted from thermal decomposition of corresponding citrates at 500 0 C, 450 0 C and 250 0 C, respectively. Lead titanate (PT) and lead zirconate (P Z) were obtained by calcining at 450 0 C and 500 0 C, respectively, after adequate heating of citrates mechanically mixed in ethyl ether. PZT samples were obtained with different starting stoichiometry. Rhombohedral PZT-1 53/47 sample was prepared from co precipitating zirconyl ammonium and ammonium lead citrates in presence of ethanolic titanium oxide dispersion, and calcinating at 800 0 C. Rhombohedral PZT-q 52/48 sample was obtained from heating at 500 0 C for 2 hours a mixture of metal citrates coprecipitated by dehydration mixture of acetone-ethanol-formic acid (2:1:0,06). Tetragonal PZT-m stoichiometry 53/47 sample were obtained by calcining at after 600 0 C for 2 hours after heating a mechanically mixed metal citrates. PT phase arose at 400 0 C. PZT-m powders obtained in a range of 400 0 C-800 0 C were isostatically pressed, and sintered at 1100 0 C and 1200 0 C in saturated Pb O atmosphere. Rhombohedral sintered PZT was obtained with 7,78 g.cm -3 at 1200 0 C. (author). 123 refs, 53 figs, 32 tabs

  12. New capabilities of the Zagreb ion microbeam system

    International Nuclear Information System (INIS)

    Jaksic, M.; Bogdanovic Radovic, I.; Bogovac, M.; Desnica, V.; Fazinic, S.; Karlusic, M.; Medunic, Z.; Muto, H.; Pastuovic, Z.; Siketic, Z.; Skukan, N.; Tadic, T.

    2007-01-01

    The installation of a new 1.0 MV Tandetron accelerator and a recent upgrade of the 6.0 MV Tandem Van de Graaff accelerator increased the application possibilities of the Zagreb ion microbeam system. Several ion sources enable now the selection of a wide variety of ions. Most of them can be focused by the existing microprobe system. Sample positioning tools and new scanner control options are implemented in the new generation of SPECTOR data acquisition system. Details of the upgrades are presented

  13. Microprobe analyses of uranium and thorium in uraninite from the Witwatersrand, South Africa, and Blind River, Ontario, Canada

    International Nuclear Information System (INIS)

    Grandstaff, D.E.

    1981-01-01

    Microprobe analyses of uranium and thorium in uraninite grains from the Witwatersrand, South Africa, and Blind River, Ontario, reveal that although individual grains are fairly homogeneous, the assemblage of grains is quite heterogeneous. This heterogeneity appears to favor genetic concepts advocating a detrital, placer origin for the uraninite

  14. Highly focused ion beams in integrated circuit testing

    International Nuclear Information System (INIS)

    Horn, K.M.; Dodd, P.E.; Doyle, B.L.

    1996-01-01

    The nuclear microprobe has proven to be a useful tool in radiation testing of integrated circuits. This paper reviews single event upset (SEU) and ion beam induced charge collection (IBICC) imaging techniques, with special attention to damage-dependent effects. Comparisons of IBICC measurements with three-dimensional charge transport simulations of charge collection are then presented for isolated p-channel field effect transistors under conducting and non-conducting bias conditions

  15. Microprobe monazite constraints for and early (ca. 790 Ma) Braziliano orogeny: The Embu Terrane, southeastern Brazil

    International Nuclear Information System (INIS)

    Vlach, Silvio R.F

    2001-01-01

    The evolution of the Mantiqueira Orogenetic System, Southeastern Brazil, comprises discrete episodes of tectonic collage and docking of remnants of Rodinia break-up in the borders of the Sao Francisco Craton. This system is related to the closure of the Adamastor ocean and assemblage of the western Gondwana super-continent during Neoproterozoic times (ca. 610-530 Ma, Brito Neves et al., 1999; Campos Neto, 2000). This report presents monazite microprobe dating results for metassediments from the Embu Complex, an important lithological unit from the Ribeira Belt, currently included in the Juiz de Fora terrane, a unit added to the Sao Francisco Craton at ca. 600-580 Ma. (Campos Neto, 2000). The age results unravel a main metamorphic episode and related orogeny at ca. 790 Ma and bring new insights concerning the agglutination of Gondwana in this region during the Neoproterozoic (au)

  16. The non-destructive analysis of fluid inclusions in minerals using the proton microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, C.G.; Van Achterbergy, E. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), North Ryde, NSW (Australia). Div. of Exploration Geoscience; Heinrich, C.A. [ETH Zentrum, Zurich, (Switzerland). Department Erdwissenschaften; Mernagh, T.P. [Max-Planck-Institut fuer Chemie (Otto-Hahn-Institut), Mainz (Germany); Zaw, K. [Tasmania Univ., Sandy Bay, TAS (Australia)

    1996-12-31

    The study of ore forming fluids trapped as fluid inclusions in minerals is the key to understanding fluid flow paths at the time of ore formation and to predicting the location of ore bodies within large-scale magmatic hydrothermal systems. The large penetration depths and the predictable nature of MeV proton trajectories and X-ray absorption enables reliable modelling of PIXE yields and the development of standardless quantitative analytical methods. This permits quantitative microanalysis of minerals at ppm levels, and more recently has enabled the development of methods for quantitative trace-element imaging and the quantitative, non-destructive analysis of individual fluid inclusions. This paper reports on recent developments in Proton Microprobe techniques with special emphasis on ore systems and fluid inclusion analysis. 6 refs., 2 figs.

  17. Trace element partitioning between aqueous fluids and silicate melts measured with a proton microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Adam, J.; Green, T.H. [Macquarie Univ., North Ryde, NSW (Australia). School of Earth Sciences; Sie, S.H. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), North Ryde, NSW (Australia). Div. of Exploration Geoscience

    1996-12-31

    A series of experiments were performed to examine the capacity of H{sub 2}O-fluids to concentrate and transport incompatible elements through peridotitic mantle and metamorphosed (eclogitic) ocean crust. Two naturally occurring rock compositions, trondhjemitic and basanitic, were used in experiments. The proton microprobe was used to determine the trace element concentrations in the solutes from H{sub 2}O-fluids equilibrated at 900-1100 degree C, 2.0 GPa with water saturated melts of trondhjemitic and basanitic compositions. Partitioning data for H{sub 2}O-fluids and silicate melts show that H{sub 2}O-fluids equilibrated with mantle peridotites will not be strongly enriched in trace elements relative to their wallrocks, and thus they melts do not strongly concentrate alkaline earths Th and U, relative to high-field strength elements. 3 refs., 1 tab., 2 figs.

  18. The non-destructive analysis of fluid inclusions in minerals using the proton microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, C G; Van Achterbergy, E [Commonwealth Scientific and Industrial Research Organisation (CSIRO), North Ryde, NSW (Australia). Div. of Exploration Geoscience; Heinrich, C A [ETH Zentrum, Zurich, (Switzerland). Department Erdwissenschaften; Mernagh, T P [Max-Planck-Institut fuer Chemie (Otto-Hahn-Institut), Mainz (Germany); Zaw, K [Tasmania Univ., Sandy Bay, TAS (Australia)

    1997-12-31

    The study of ore forming fluids trapped as fluid inclusions in minerals is the key to understanding fluid flow paths at the time of ore formation and to predicting the location of ore bodies within large-scale magmatic hydrothermal systems. The large penetration depths and the predictable nature of MeV proton trajectories and X-ray absorption enables reliable modelling of PIXE yields and the development of standardless quantitative analytical methods. This permits quantitative microanalysis of minerals at ppm levels, and more recently has enabled the development of methods for quantitative trace-element imaging and the quantitative, non-destructive analysis of individual fluid inclusions. This paper reports on recent developments in Proton Microprobe techniques with special emphasis on ore systems and fluid inclusion analysis. 6 refs., 2 figs.

  19. Elemental analysis of single phytoplankton cells using the Lund nuclear microprobe

    International Nuclear Information System (INIS)

    Pallon, Jan; Elfman, Mikael; Kristiansson, Per; Malmqvist, Klas; Graneli, Edna; Sellborn, Anders; Karlsson, Chatarina

    1999-01-01

    The occurrence of annual marine phytoplankton blooms is becoming a global problem. In Europe, the NUTOX project supported by the EC investigates if unbalanced nutrient compositions in the water promote the dominance of harmful phytoplankton species. One of the tasks is the determination of the elemental composition of single phytoplankton cells. This is carried out using the Lund Nuclear Microprobe with a special focus on C, N, P and K. The overall aim is to understand the mechanism leading to toxin production, model it and eventually propose a counteracting method. The preparative method, used to isolate single living cells while reducing their salt environment, is an important part of the analytical procedure. A comparison of light element detection using backscattering from protons and nuclear reaction analysis using deuterons is made

  20. Electron microprobe investigations of ore minerals of the Altenberg tin deposit (Erzgebirge, GDR). 3

    International Nuclear Information System (INIS)

    Foerster, H.J.; Hunger, H.J.; Grimm, L.

    1987-01-01

    Members of the scheelite-powellite solid solution series filling thin fractures or mantling wolframite were found in association with fluorite within a small polymineralic quartz vein traversing a topaz-protolithionite-quartz greisen. The composition of the mixed-crystal series determined by means of an automated ARL SEMQ energy-dispersive electron microprobe is characterized by a great variability and heterogeneity which has not previously been reported from any specimen nor from this special mode of occurrence yet. With an amount of powellite component between 3.2 and 58 mole percent, the molybdoscheelites from Altenberg show the today known extent of complete miscibility in the natural scheelite-powellite series. Final remarks deal with the possibilities of using the mineral series, together with some other tungsten minerals, as an indicator of the physicochemical conditions of ore formation. (author)

  1. Elemental characterization of individual glia and glioma cells in the nuclear microprobe

    International Nuclear Information System (INIS)

    Lindh, U.

    1982-01-01

    To investigate whether variations in levels of microelements are reflected at the cellular level, a study of cultured cells was undertaken. For elemental characterization were chosen human glia and glioma cell lines. The cells were freeze-dried and about 1000 cells of each line were analyzed in the nuclear microprobe with a probe diameter of 10 μm. Scanning of the specimens under the beam made possible heat reduction and the X-ray spectrum induced was continuously recorded and subsequently processed in the computer. Elemental maps of the cells were then generated and the information from each member of the cell populations could be considered as well as the population statistics. Mass determination was accomplished by means of the bremsstrahlung continuum intensity. The main feature resulting from the characterization was that the glioma cells in average held appreciably higher contents of copper and zinc than did the glia cells. (orig.)

  2. A new method for true quantitative elemental imaging using PIXE and the proton microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, C G [Commonwealth Scientific and Industrial Research Organisation (CSIRO), North Ryde, NSW (Australia). Div. of Exploration Geoscience; Jamieson, D N [Melbourne Univ., Parkville, VIC (Australia). School of Physics; Churms, C L; Pilcher, J V [National Accelerator Centre, Faure (South Africa)

    1994-12-31

    Traditional methods for X-ray imaging using PIXE and the Proton Microprobe have used a simple gate set on an X-ray peak in a spectrum from a Si(Li) detector to provide an image of the distribution of an element. This method can produce artefacts in images, due to overlapping X-ray lines from interfering elements, charge collection tails on peaks, background variation, Si escape peaks and pileup, all of which can render images misleading or qualitative at best. To address this problem, a matrix transform method has been developed at the CSIRO which not only eliminates most artefacts, but can be implemented on-line. The method has been applied to study trace gold distribution in a complex gold bearing ore from Fiji , and more recently has been installed for direct on-line elemental imaging at the NAC in South Africa. 4 refs., 2 figs.

  3. Laser ablation microprobe inductively coupled plasma mass spectrometry study on diffusion of uranium into cement materials

    International Nuclear Information System (INIS)

    Sugiyama, D.; Chida, T.; Cowper, M.

    2008-01-01

    The diffusion of uranium (U(VI)) in solid cement monoliths of ordinary portland cement (OPC) and low-heat portland cement containing 30 wt.% fly ash (FAC) was measured by an in-diffusion technique. Detailed sharp depth profiles of uranium in the solid cement matrices were successively and quantitatively measured using laser ablation microprobe inductively coupled plasma mass spectrometry (LAMP-ICP-MS), and the apparent (D a ) and effective (D e ) diffusion coefficient of uranium in cement matrix were calculated as: D a =∝ 4 x 10 -16 m 2 s -1 and D e =∝ 3 x 10 -11 m 2 s -1 for OPC, and D a =∝ 2 x 10 -17 m 2 s -1 and D e =∝ 6 x 10 -13 m 2 s -1 for FAC. (orig.)

  4. Progress of the new CSIRO-GEMOC nuclear microprobe: first results, performance and recent applications

    International Nuclear Information System (INIS)

    Ryan, C.G.; Cripps, G.; Sie, S.H.; Suter, G.F.; Jamieson, D.N.; Griffin, W.L.; Commonwealth Scientific and Industrial Research Organisation

    1999-01-01

    The new CSIRO-GEMOC Nuclear Microprobe (NMP) features a number of technical advances for high resolution, high sensitivity microanalysis. It was designed at the CSIRO and developed as collaboration between the CSlRO, the GEMOC key-centre at Macquarie University and the MARC group of the University of Melbourne. For imaging applications, it also features a software system using a powerful algorithm called Dynamic Analysis, developed at the CSIRO for unmixing elemental signatures in proton induced X-ray emission (PIXE) data, to provide a tool for rapid quantitative imaging of trace and major element spatial distribution in minerals. This paper reports on the performance of the NMP and examples of its application over the past 6 months since completion

  5. A new method for true quantitative elemental imaging using PIXE and the proton microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, C.G. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), North Ryde, NSW (Australia). Div. of Exploration Geoscience; Jamieson, D.N. [Melbourne Univ., Parkville, VIC (Australia). School of Physics; Churms, C.L.; Pilcher, J.V. [National Accelerator Centre, Faure (South Africa)

    1993-12-31

    Traditional methods for X-ray imaging using PIXE and the Proton Microprobe have used a simple gate set on an X-ray peak in a spectrum from a Si(Li) detector to provide an image of the distribution of an element. This method can produce artefacts in images, due to overlapping X-ray lines from interfering elements, charge collection tails on peaks, background variation, Si escape peaks and pileup, all of which can render images misleading or qualitative at best. To address this problem, a matrix transform method has been developed at the CSIRO which not only eliminates most artefacts, but can be implemented on-line. The method has been applied to study trace gold distribution in a complex gold bearing ore from Fiji , and more recently has been installed for direct on-line elemental imaging at the NAC in South Africa. 4 refs., 2 figs.

  6. Experimental investigations into sample preparation of Alzheimer tissue specimens for nuclear microprobe analysis

    Energy Technology Data Exchange (ETDEWEB)

    Pinheiro, T [CEC-JRC, Central Bureau for Nuclear Measurements, Geel (Belgium); Tapper, U A.S. [Dept. of Nuclear Physics, Lund Inst. of Science and Tech. (Sweden); Sturesson, K; Brun, A [Div. of Neuropathology, Dept. of Pathology, Lund University Hospital (Sweden)

    1991-03-01

    Nuclear microprobe analysis was applied to the study of elemental distribution in brains sections of patients with a diagnosis of Alzheimer's disease. Stained and nonstained cryosections were studied. The work carried out shows that serious elemental losses follow the sample staining procedure. Major losses occurred in a simple rinse of the tissue section, probably reducing most of the in-vivo gradients, which show that generally very little information can be gained from stained sections. However, in many cases stained sections are compulsory because of the requirement to recognize the area which is to be studied. All the elemental maps obtained for the neurofibrillary deposits indicate a localized concentration for Si and probably also Al, associated with the senile plaque core. Neither of these elements were found in the staining solutions used. The validity of the results is discussed as well as the possible link of Al and/or Si in the development of Alzheimer's desease. (orig.).

  7. Microprobe and SEM Analysis of a Meteorite from the Campo del Cielo Fall

    International Nuclear Information System (INIS)

    Cabanillas, E. D.; Palacios, T. A.

    2003-01-01

    Full Text: Meteorites are unique pieces in nature having not only the enigmatic connotations of the unknown but also are the easier obtained samples of the exterior universe. Furthermore they are the unique alloys that suffered modifications done during enormous periods of time in space and in land The Campo del Cielo fall, occurred more than 5000 years ago, gave hundredths of pieces some of them well studied. We have studied one of the minor pieces from the fall and with microprobe and scanning electronic microscopy analysis we determined the composition of Schreibersite and Rhabdite phosphides of iron and nickel. This study was performed to establish relationships between the duration of alloys and the design of disposal of high level and long lived radioactive waste

  8. Physical aspects of quantitative particles analysis by X-ray fluorescence and electron microprobe techniques

    International Nuclear Information System (INIS)

    Markowicz, A.

    1986-01-01

    The aim of this work is to present both physical fundamentals and recent advances in quantitative particles analysis by X-ray fluorescence (XRF) and electron microprobe (EPXMA) techniques. A method of correction for the particle-size effect in XRF analysis is described and theoretically evaluated. New atomic number- and absorption correction procedures in EPXMA of individual particles are proposed. The applicability of these two correction methods is evaluated for a wide range of elemental composition, X-ray energy and sample thickness. Also, a theoretical model for composition and thickness dependence of Bremsstrahlung background generated in multielement bulk specimens as well as thin films and particles are presented and experimantally evaluated. Finally, the limitations and further possible improvements in quantitative particles analysis by XFR and EPXMA are discussed. 109 refs. (author)

  9. Trace element partitioning between aqueous fluids and silicate melts measured with a proton microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Adam, J; Green, T H [Macquarie Univ., North Ryde, NSW (Australia). School of Earth Sciences; Sie, S H [Commonwealth Scientific and Industrial Research Organisation (CSIRO), North Ryde, NSW (Australia). Div. of Exploration Geoscience

    1997-12-31

    A series of experiments were performed to examine the capacity of H{sub 2}O-fluids to concentrate and transport incompatible elements through peridotitic mantle and metamorphosed (eclogitic) ocean crust. Two naturally occurring rock compositions, trondhjemitic and basanitic, were used in experiments. The proton microprobe was used to determine the trace element concentrations in the solutes from H{sub 2}O-fluids equilibrated at 900-1100 degree C, 2.0 GPa with water saturated melts of trondhjemitic and basanitic compositions. Partitioning data for H{sub 2}O-fluids and silicate melts show that H{sub 2}O-fluids equilibrated with mantle peridotites will not be strongly enriched in trace elements relative to their wallrocks, and thus they melts do not strongly concentrate alkaline earths Th and U, relative to high-field strength elements. 3 refs., 1 tab., 2 figs.

  10. Hg diffusion in books of XVIII and XIX centuries by synchrotron microprobe

    International Nuclear Information System (INIS)

    Pessanha, S.; Carvalho, M.L.; Manso, M.; Guilherme, A.; Marques, A.F.; Perez, C.A.

    2009-01-01

    The pigment vermilion (HgS) was used to color the fore edge, tail and head of books. Dissemination and quantification of Hg present in the ink used to color books from XVIII and XIX centuries are reported. Mercury is a very toxic element for the human body, therefore it is extremely important to know whether Hg tends to disseminate throughout the paper or stays confined to the borders of the books with less danger for readers. Synchrotron X-ray microprobe was used to evaluate Hg dissemination from the border to the centre of the paper sheet. The diffusion pattern of Hg was compared with the results obtained by a portable X-ray fluorescence spectrometer and mean quantitative calculations were obtained by a stationary X-ray fluorescence system with triaxial geometry. The results showed high concentrations of Hg in the external regions, but no diffusion was observed for the inner parts of the paper.

  11. Trace element composition and distribution in micron area of dinosaur eggshell fossils determined by proton microprobe

    International Nuclear Information System (INIS)

    Chen Youhong; Zhu Jieqing; Wang Xiaohong; Wang Yimin

    1997-01-01

    The scanning proton microprobe and micro-PIXE quantitative analysis technique have been used to determine composition and distribution of the trace elements in micron areas of dinosaur eggshell fossils from the stratum of Upper Cretaceous system at Nanxiong Basin in Guangdong Province, China. The study shows that the trace elements mainly include Ti, V, Cr, Mn, Co, Ni, Cu, Zn, As, Rb, Sr, Y, Zr, Sb, Ba and Pb in the micron area, but they present different distributions. While the element Sr is mainly enriched in the near surface layer, others mainly reside in the near inner layer. A preliminary discussion on the reason of the dinosaur extinction is given based on the above study

  12. Trace element composition and distribution in micron area of dinosaur eggshell fossils determined by proton microprobe

    International Nuclear Information System (INIS)

    Chen Youhong; Zhu Jieqing; Wang Xiaohong; Wang Yimin

    1997-01-01

    The scanning proton microprobe and micro-PIXE quantitative analysis technique have been used to determine composition and distribution of the trace elements in micron areas of dinosaur eggshell fossils from the stratum of Upper Cretaceous system at Nanxiong Basin in Guangdong Province, China. The study shows that the trace elements mainly include Ti, V, Cr, Mn, Co, Ni, Cu, Zn, As, Rb, Sr, Y, Zr, Sb, Ba and Pb in the micron area, but they present different distributions. While the elements Sr is mainly enriched in the near surface layer, others mainly reside in the near inner layer. A preliminary discussion on the reason of the dinosaur extinction is given based on the above study

  13. Study of ancient Islamic gilded pieces combining PIXE-RBS on external microprobe with sem images

    International Nuclear Information System (INIS)

    Ynsa, M.D.; Gutierrez, P.C.; Enguita, O.; Chamon, J.; Pardo, A.I.; Arroyo, M.; Barrio, J.; Gomez-Morilla, I.; Ferretti, M.; Climent-Font, A.

    2008-01-01

    Numerous metallic objects with very aesthetic and technological qualities have been recovered by archaeological excavations. Adequate processes of restoration and conservation treatments require the accurate determination of the elemental composition and distribution within the objects, as well as the identification of the nature and distribution of the corrosion products. Ideally the identification method should cause no alteration in the sample. In this work, different archaeological pieces with a gilded look have been characterized using simultaneously PIXE and RBS at the CMAM external microprobe in order to study the gilding metalworking done in the Iberian Peninsula during the Middle Ages. The gold layer thickness and its elemental concentrations of Ag, Au and Hg were determined by both techniques and compared with the scanning electron microscopy images obtained for some fragments of pieces. (orig.)

  14. Microprobe study of fission product behavior in high-burnup HTR fuels

    International Nuclear Information System (INIS)

    Kleykamp, H.

    Electron microprobe analysis of irradiated coated particles with high burnup (greater than 50 percent fima) gives detailed information on the chemical state and the transport behavior of the fission products in UO 2 and UC 2 kernels and in the coatings. In oxide fuel kernels, metallic inclusions and ceramic precipitations are observed. The solubility behavior of the fission products in the fuel matrix has been investigated. Fission product inclusions could not be detected in carbide fuel kernels; post irradiation annealed UC 2 kernels, however, give information on the element combinations of some fission product phases. Corresponding to the chemical state in the kernel, Cs, Sr, Ba, Pd, Te and the rare earths are released easily and diffuse through the entire pyrocarbon coating. These fission products can be retained by a silicon carbide layer. The initial stage of a corrosive attack of the SiC coating by the fission products is evidenced

  15. Measurements of impurity migration in graphite at high temperatures using a proton microprobe

    International Nuclear Information System (INIS)

    Shroy, R.E.; Soo, P.; Sastre, C.A.; Schweiter, D.G.; Kraner, H.W.; Jones, K.W.

    1978-01-01

    The migration of fission products and other impurities through the graphite core of a High Temperature Gas Cooled Reactor is of prime importance in studies of reactor safety. Work in this area is being carried out in which graphite specimens are heated to temperatures up to 3800 0 C to induce migration of trace elements whose local concentrations are then measured with a proton microprobe. This instrument is a powerful device for such work because of its ability to determine concentrations at a part per million (ppm) level in a circular area as small as 10 μm while operating in an air environment. Studies show that Si, Ca, Cl, and Fe impurities in graphite migrate from hotter to cooler regions. Also Si, S, Cl, Ca, Fe, Mn, and Cr are observed to escape from the graphite and be deposited on cooler surfaces

  16. Present status of research and development on X-ray microprobe

    International Nuclear Information System (INIS)

    Koike, Masaki; Suzuki, I.H.

    1991-01-01

    X-ray beam micro-analysis has advanced rapidly in these years in conjunction with the development of powerful X-ray sources. Among a variety of methods being attempted, the method using a collimated narrow beam has been important because of high brightness, and of usability in both regions of soft and hard X-rays. In the soft X-ray region, the focused beam is formed by a fresnel zone plate or a Schwaltzschild mirror assembly, and can be used for scanning transmission microscope or scanning photoelectron microscope. In the hard X-ray region, the beam is formed by grazing incidence mirrors, and can be used for X-ray fluorescence micro-analysis for obtaining elemental mapping. In this report, the recent progress on the soft X-ray scanning microscopy and the X-ray microprobe has been surveyed, together with the improvement on the related optical elements. (author) 84 refs

  17. Current—voltage characteristics of lead zirconate titanate/nickel bilayered hollow cylindrical magnetoelectric composites

    International Nuclear Information System (INIS)

    De-An, Pan; Shen-Gen, Zhang; Jian-Jun, Tian; Li-Jie, Qiao; Jun-Sai, Sun; Volinsky, Alex A.

    2010-01-01

    Current–voltage measurements obtained from lead zirconate titanate/nickel bilayered hollow cylindrical magnetoelectric composite showed that a sinusoidal current applied to the copper coil wrapped around the hollow cylinder circumference induces voltage across the lead zirconate titanate layer thickness. The current–voltage coefficient and the maximum induced voltage in lead zirconate titanate at 1 kHz and resonance (60.1 kHz) frequencies increased linearly with the number of the coil turns and the applied current. The resonance frequency corresponds to the electromechanical resonance frequency. The current–voltage coefficient can be significantly improved by optimizing the magnetoelectric structure geometry and/or increasing the number of coil turns. Hollow cylindrical lead zirconate titanate/nickel structures can be potentially used as current sensors. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  18. High-temperature mechanical properties of a uniaxially reinforced zircon-silicon carbide composite

    International Nuclear Information System (INIS)

    Singh, R.N.

    1990-01-01

    This paper reports that mechanical properties of a monolithic zircon ceramic and zircon-matrix composites uniaxially reinforced with either uncoated or BN-coated silicon carbide monofilaments were measured in flexure between 25 degrees and 1477 degrees C. Monolithic zircon ceramics were weak and exhibited a brittle failure up to abut 1300 degrees C. An increasing amount of the plastic deformation was observed before failure above about 1300 degrees C. In contrast, composites reinforced with either uncoated or BN-coated Sic filaments were stronger and tougher than the monolithic zircon at all test temperatures between 25 degrees and 1477 degrees. The ultimate strength and work-of-fracture of composite samples decreased with increasing temperature. A transgranular matrix fracture was shown by the monolithic and composite samples tested up to about 1200 degrees C, whereas an increasing amount of the intergranular matrix fracture was displayed above 1200 degrees C

  19. Real-Time Salmonella Detection Using Lead Zirconate Titanate-Titanium Microcantilevers

    National Research Council Canada - National Science Library

    McGovern, John-Paul; Shih, Wan Y; Shih, Wei-Heng; Sergi, Mauro; Chaiken, Irwin

    2005-01-01

    .... We have developed and investigated the use of a lead zirconate titanate - titanium (PZT-Ti) microcantilever for in situ detection of the common food- and water-born pathogen, Salmonella typhimurium...

  20. Fabrication of wear-resistant silicon microprobe tips for high-speed surface roughness scanning devices

    Science.gov (United States)

    Wasisto, Hutomo Suryo; Yu, Feng; Doering, Lutz; Völlmeke, Stefan; Brand, Uwe; Bakin, Andrey; Waag, Andreas; Peiner, Erwin

    2015-05-01

    Silicon microprobe tips are fabricated and integrated with piezoresistive cantilever sensors for high-speed surface roughness scanning systems. The fabrication steps of the high-aspect-ratio silicon microprobe tips were started with photolithography and wet etching of potassium hydroxide (KOH) resulting in crystal-dependent micropyramids. Subsequently, thin conformal wear-resistant layer coating of aluminum oxide (Al2O3) was demonstrated on the backside of the piezoresistive cantilever free end using atomic layer deposition (ALD) method in a binary reaction sequence with a low thermal process and precursors of trimethyl aluminum and water. The deposited Al2O3 layer had a thickness of 14 nm. The captured atomic force microscopy (AFM) image exhibits a root mean square deviation of 0.65 nm confirming the deposited Al2O3 surface quality. Furthermore, vacuum-evaporated 30-nm/200-nm-thick Au/Cr layers were patterned by lift-off and served as an etch mask for Al2O3 wet etching and in ICP cryogenic dry etching. By using SF6/O2 plasma during inductively coupled plasma (ICP) cryogenic dry etching, micropillar tips were obtained. From the preliminary friction and wear data, the developed silicon cantilever sensor has been successfully used in 100 fast measurements of 5- mm-long standard artifact surface with a speed of 15 mm/s and forces of 60-100 μN. Moreover, the results yielded by the fabricated silicon cantilever sensor are in very good agreement with those of calibrated profilometer. These tactile sensors are targeted for use in high-aspect-ratio microform metrology.

  1. The mutual diffusion coefficient for (meth)acrylate monomers as determined with a nuclear microprobe

    International Nuclear Information System (INIS)

    Leewis, Christian M.; Mutsaers, Peter H.A.; Jong, Arthur M. de; Ijzendoorn, Leo J. van; Voigt, Martien J.A. de; Ren, Min Q.; Watt, Frank; Broer, Dirk J.

    2004-01-01

    The value of the mutual diffusion coefficient D V of two acrylic monomers is determined with nuclear microprobe measurements on a set of polymer films. These films have been prepared by allowing the monomers to diffuse into each other for a certain time and subsequently applying fast ultraviolet photo-polymerization, which freezes the concentration profile. The monomer diffusion profiles are studied with a scanning 2.1 MeV proton microprobe. Each monomer contains a marker element, e.g., Cl and Si, which are easily detected with proton induced x-ray emission. From the diffusion profiles, it is possible to determine the mutual diffusion coefficient. The mutual diffusion coefficient is dependent of concentration, which is concluded from the asymmetry in the Cl- and Si-profiles. A linear dependence of the mutual diffusion coefficient on the composition is used as a first order approximation. The best fits are obtained for a value of b=(0.38±0.15), which is the ratio of the diffusion coefficient of 1,3-bis(3-methacryloxypropyl)-1, 1,3,3-tetramethyldisiloxane in pure 2-chloroethyl acrylate and the diffusion coefficient of 2-chloroethyl acrylate in pure 1,3-bis(3-methacryloxypropyl)-1,1,3,3-tetramethyldisiloxane. Under the assumption of a linear dependence of the mutual diffusion coefficient D V on monomer composition, it follows that D V =(2.9±0.6)·10 -10 m 2 /s at a 1:1 monomer ratio. With Flory-Huggins expressions for the monomer chemical potentials, one can derive approximate values for the individual monomer diffusion coefficients

  2. Fabrication of an 8:1 ellipsoidal mirror for a synchrotron x-ray microprobe

    International Nuclear Information System (INIS)

    Jones, K.W.; Takacs, P.Z.; Hastings, J.B.; Casstevens, J.M.; Pionke, C.D.

    1987-01-01

    The fabrication of an 8:1 demagnifying ellipsoidal mirror to be used for an x-ray microprobe at the National Synchrotron Light Source X-26 beam port is described. The design aim was to produce a mirror that could be used over the photon energy range from about 3 to 17 keV. The 300-mm long mirror was required to operate at a grazing angle of 5 mr. The semimajor axis was 4500 mm and the semiminor axis 14.142 mm. Surface roughness of 1 nm or less and slope errors of 1 arc second parallel to the long axis and 200 arc seconds parallel to the short direction were specified. Production of the first electroless nickel-coated aluminum mirror using a diamond-turning technique has been completed. The mirror meets the 1 arc sec surface figure specification except for areas near the ends of the mirror. The reasons for these deviations arise from subtle details of the diamond-turning process which have not been fully incorporated in to the computer program that controls the diamond-turning machines. Further work in computer correction of repeatable errors of the diamond-turning machine can eliminate the waviness at the ends of the mirror. The diamond-turned mirror surface was not fully polished under this effort and therefore does not meet the roughness specification; however, surface smoothness of a fully polished cylindrical mirror manufactured using the same techniques does not meet the specification. It can be concluded that it is now technically feasible to meet the required specifications for the mirror and that the x-ray microprobe based on its use can be achieved

  3. Ancient xenocrystic zircon in young volcanic rocks of the southern Lesser Antilles island arc

    Science.gov (United States)

    Rojas-Agramonte, Yamirka; Williams, Ian S.; Arculus, Richard; Kröner, Alfred; García-Casco, Antonio; Lázaro, Concepción; Buhre, Stephan; Wong, Jean; Geng, Helen; Echeverría, Carlos Morales; Jeffries, Teresa; Xie, Hangqian; Mertz-Kraus, Regina

    2017-10-01

    The Lesser Antilles arc is one of the best global examples in which to examine the effects of the involvement of subducted sediment and crustal assimilation in the generation of arc crust. Most of the zircon recovered in our study of igneous and volcaniclastic rocks from Grenada and Carriacou (part of the Grenadines chain) is younger than 2 Ma. Within some late Paleogene to Neogene ( 34-0.2 Ma) lavas and volcaniclastic sediments however, there are Paleozoic to Paleoarchean ( 250-3469 Ma) xenocrysts, and Late Jurassic to Precambrian zircon ( 158-2667 Ma) are found in beach and river sands. The trace element characteristics of zircon clearly differentiate between different types of magmas generated in the southern Lesser Antilles through time. The zircon population from the younger arc (Miocene, 22-19 Ma, to Present) has minor negative Eu anomalies, well-defined positive Ce anomalies, and a marked enrichment in heavy rare earth elements (HREE), consistent with crystallization from very oxidized magmas in which Eu2 + was in low abundance. In contrast, zircon from the older arc (Eocene to mid-Oligocene, 30-28 Ma) has two different REE patterns: 1) slight enrichment in the light (L)REE, small to absent Ce anomalies, and negative Eu anomalies and 2) enriched High (H)REE, positive Ce anomalies and negative Eu anomalies (a similar pattern is observed in the xenocrystic zircon population). The combination of positive Ce and negative Eu anomalies in the zircon population of the older arc indicates crystallization from magmas that were variably, but considerably less oxidized than those of the younger arc. All the igneous zircon has positive εHf(t), reflecting derivation from a predominantly juvenile mantle source. However, the εHf(t) values vary significantly within samples, reflecting considerable Hf isotopic heterogeneity in the source. The presence of xenocrystic zircon in the southern Lesser Antilles is evidence for the assimilation of intra-arc crustal sediments and

  4. Provenance of zircon of the lowermost sedimentary cover, Estonia, East-European Craton

    Directory of Open Access Journals (Sweden)

    Konsa, M.

    1999-12-01

    Full Text Available Bulk and accessory mineral composition of fresh and weathered crystalline rocks, and sedimentary deposits overlying the crystalline-sedimentary unconformity have been examined in core samples from 28 drill holes in Estonia. Before the Late Vendian to Early Cambrian regional subsidence and sedimentation, the region represented a flat plateau within the Svecofennian Domain. Palaeo-and Mesoproterozoic crystalline rocks, regardless their different initial mineral composition, subcrop under the Upper Vendian/Lower Cambrian sedimentary cover as usually intensely weathered rocks (saprolites composed of residual quartz, altered micas and prevailing clay minerals mainly of the kaolinite group. Thus, the bulk mineral composition of any basement crystalline rocks imparts no specific inherited rock-forming minerals into the covering sedimentary rocks. From the variety of accessory and opaque minerals of crystalline rocks, only zircon populations survived in saprolites. Crystalline rocks of different origin yield different zircons. Relationships between the zircon typology of the basement rocks having specific areas of distribution and the sedimentary rocks immediately overlying those crystalline rocks were the main subject of this study. The result is that siliciclastic sedimentary rocks covering weathered crystalline rocks only in places inherited zircons with typological features characteristic of specific basement areas. In northeastern Estonia, local lenses of the Oru Member (the earliest Upper Vendian sedimentary rocks in Estonia resembling the debris of weathered crystalline rocks yield accessory zircon which in a 1-2 m thick layer above the basement surface is similar to the zircons of the underlying weathering mantle of certain crystalline rocks. In the next unit, the Moldova Member, up to 43 m above the basement surface, a mixture of zircons resembling those of various local basement rocks has been found. Further upwards, in the Vendian and Lower

  5. Do Hf isotopes in magmatic zircons represent those of their host rocks?

    Science.gov (United States)

    Wang, Di; Wang, Xiao-Lei; Cai, Yue; Goldstein, Steven L.; Yang, Tao

    2018-04-01

    Lu-Hf isotopic system in zircon is a powerful and widely used geochemical tracer in studying petrogenesis of magmatic rocks and crustal evolution, assuming that zircon Hf isotopes can represent initial Hf isotopes of their parental whole rock. However, this assumption may not always be valid. Disequilibrium partial melting of continental crust would preferentially melt out non-zircon minerals with high time-integrated Lu/Hf ratios and generate partial melts with Hf isotope compositions that are more radiogenic than those of its magma source. Dissolution experiments (with hotplate, bomb and sintering procedures) of zircon-bearing samples demonstrate this disequilibrium effect where partial dissolution yielded variable and more radiogenic Hf isotope compositions than fully dissolved samples. A case study from the Neoproterozoic Jiuling batholith in southern China shows that about half of the investigated samples show decoupled Hf isotopes between zircons and the bulk rocks. This decoupling could reflect complex and prolonged magmatic processes, such as crustal assimilation, magma mixing, and disequilibrium melting, which are consistent with the wide temperature spectrum from ∼630 °C to ∼900 °C by Ti-in-zircon thermometer. We suggest that magmatic zircons may only record the Hf isotopic composition of their surrounding melt during crystallization and it is uncertain whether their Hf isotopic compositions can represent the primary Hf isotopic compositions of the bulk magmas. In this regard, using zircon Hf isotopic compositions to trace crustal evolution may be biased since most of these could be originally from disequilibrium partial melts.

  6. Zircon ages in granulite facies rocks: decoupling from geochemistry above 850 °C?

    Science.gov (United States)

    Kunz, Barbara E.; Regis, Daniele; Engi, Martin

    2018-03-01

    Granulite facies rocks frequently show a large spread in their zircon ages, the interpretation of which raises questions: Has the isotopic system been disturbed? By what process(es) and conditions did the alteration occur? Can the dates be regarded as real ages, reflecting several growth episodes? Furthermore, under some circumstances of (ultra-)high-temperature metamorphism, decoupling of zircon U-Pb dates from their trace element geochemistry has been reported. Understanding these processes is crucial to help interpret such dates in the context of the P-T history. Our study presents evidence for decoupling in zircon from the highest grade metapelites (> 850 °C) taken along a continuous high-temperature metamorphic field gradient in the Ivrea Zone (NW Italy). These rocks represent a well-characterised segment of Permian lower continental crust with a protracted high-temperature history. Cathodoluminescence images reveal that zircons in the mid-amphibolite facies preserve mainly detrital cores with narrow overgrowths. In the upper amphibolite and granulite facies, preserved detrital cores decrease and metamorphic zircon increases in quantity. Across all samples we document a sequence of four rim generations based on textures. U-Pb dates, Th/U ratios and Ti-in-zircon concentrations show an essentially continuous evolution with increasing metamorphic grade, except in the samples from the granulite facies, which display significant scatter in age and chemistry. We associate the observed decoupling of zircon systematics in high-grade non-metamict zircon with disturbance processes related to differences in behaviour of non-formula elements (i.e. Pb, Th, U, Ti) at high-temperature conditions, notably differences in compatibility within the crystal structure.

  7. Lithofacies control in detrital zircon provenance studies: Insights from the Cretaceous Methow basin, southern Canadian Cordillera

    Science.gov (United States)

    DeGraaff-Surpless, K.; Mahoney, J.B.; Wooden, J.L.; McWilliams, M.O.

    2003-01-01

    High-frequency sampling for detrital zircon analysis can provide a detailed record of fine-scale basin evolution by revealing the temporal and spatial variability of detrital zircon ages within clastic sedimentary successions. This investigation employed detailed sampling of two sedimentary successions in the Methow/Methow-Tyaughton basin of the southern Canadian Cordillera to characterize the heterogeneity of detrital zircon signatures within single lithofacies and assess the applicability of detrital zircon analysis in distinguishing fine-scale provenance changes not apparent in lithologic analysis of the strata. The Methow/Methow-Tyaughton basin contains two distinct stratigraphic sequences of middle Albian to Santonian clastic sedimentary rocks: submarine-fan deposits of the Harts Pass Formation/Jackass Mountain Group and fluvial deposits of the Winthrop Formation. Although both stratigraphic sequences displayed consistent ranges in detrital zircon ages on a broad scale, detailed sampling within each succession revealed heterogeneity in the detrital zircon age distributions that was systematic and predictable in the turbidite succession but unpredictable in the fluvial succession. These results suggest that a high-density sampling approach permits interpretation of finescale changes within a lithologically uniform turbiditic sedimentary succession, but heterogeneity within fluvial systems may be too large and unpredictable to permit accurate fine-scale characterization of the evolution of source regions. The robust composite detrital zircon age signature developed for these two successions permits comparison of the Methow/Methow-Tyaughton basin age signature with known plutonic source-rock ages from major plutonic belts throughout the Cretaceous North American margin. The Methow/Methow-Tyaughton basin detrital zircon age signature matches best with source regions in the southern Canadian Cordillera, requiring that the basin developed in close proximity to the

  8. U-Pb ages in meta-rhyolite zircon from Arai Group and associated granites

    International Nuclear Information System (INIS)

    Pimentel, M.M.; Fuck, R.A.

    1991-01-01

    Geochronology results by V-Pb method in zircon of granite rocks from staniferous province of Goias and rhyolite Arai groups are revealed. Two distinct episode of acid magmatism in Paleo-and Meso proterozoic are presented. V-Pb data in zircon from Sucuri and Soledade granites of the province from Parana River with ages of higher intercepted are also defined. This ages are consider mistakes, similar the V-Pb age of a rhyolite from Arai group. (author)

  9. Ion beams: from plasma physics to applications in analysis and irradiation fields

    International Nuclear Information System (INIS)

    Khodja, Hicham

    2012-01-01

    In this HDR (Accreditation to supervise research) report, the author proposes an overview of his research activities. A first part comments a research which aimed at determining the distribution of ion populations in an electron cyclotron resonance (ECR) plasma. Then, after a brief recall of the principles and techniques of analysis based on ion beams, he presents some characteristics of the CEA/Saclay nuclear microprobe. He reports various works related to material science and to biology, and discusses the associated perspectives [fr

  10. Detrital zircon ages in Buller and Takaka terranes, New Zealand : constraints on early Zealandia history

    International Nuclear Information System (INIS)

    Adams, C.J.; Mortimer, N.; Campbell, H.J.; Griffin, W.L.

    2015-01-01

    Detrital zircon ages are presented for 34 early Palaeozoic sandstones from Buller and Takaka terranes, New Zealand, and formerly adjacent parts of Australia-Antarctica. The Buller-Takaka datasets always have two major groups: Ordovician-late Neoproterozoic, 444-700 Ma (but mainly 540-700 Ma), termed 'Gondwana Assembly' (GA), and early Neoproterozoic-Mesoproterozoic, 700-1600 Ma (but mainly 900-1200 Ma), termed 'Rodinia Assembly' (RA). In both terranes, significant age components within these groups are strikingly similar and also have RA/GA ratios, 0.6-1.8. The Cambrian volcanic arc of the Takaka Terrane has contributed little to the zircon patterns. Proportions of Late Cambrian-Early Ordovician zircons, characteristic of granitoid sources in the Ross-Delamerian Orogen are low. The zircons are predominantly reworked with contemporary zircons only evident in a few Buller datasets. The zircon patterns suggest that two major sources (late Mesoproterozoic and late Neoproterozoic), enduring over 120 Ma, were widely distributed and it is postulated they form Precambrian basement beneath southern Zealandia. (author).

  11. On the connection of the ESR characteristics of zircons with the degree of their defectiveness

    International Nuclear Information System (INIS)

    Matyash, I.V.; Brik, A.E.; Derski, L.S.; Larikov, A.L.; Ponomarenko, A.N.

    1989-01-01

    The dynamic characteristics of the electron-hole centres (EHC) in zircons with various degree of defectiveness have been studied. Crystalline and amorphous regions are typical of different sets of EHC, having essentially different relaxation characteristics. Lack of cross-relaxation between these centres shows that they are localized in different parts of the crystal. The influence of autoirradiation and of corresponding defectiveness of the matrix upon the intensity of the EHC signals (V i ) has been studied. In the specimens of high crystallinity V i increases as the content of radioactive elements and defectiveness increases. In the essentially metamict specimens the situation reverses. Interpretation of this effect is given considering the dose dependence of the ESR signals and the ratio of the crystal and metamict volumes in the studied object. The transformations of the EHC set is traced along the amorphization of the zircon matrix due to the autoirradiation. ESR signals corresponding to different phases in zircon have been recorded. The correlation of the zircon grain size and the static magnetic susceptibility with V i have been studied. In the specimens of high crystallinity such correlation is absent and in metamict specimens the intensities V i decrease as the grain sizes decrease. The interpretation of this fact is proposed. It has been shown that the ESR studies reflect the processes of income and migration of the impurity elements in zircons and the ways of the zircon crystal matrix decay in a geological time scale. The factors controlling such a decay have been found. (author)

  12. Structural analysis of radiation damage in zircon and thorite: An X-ray absorption spectroscopic study

    International Nuclear Information System (INIS)

    Farges, F.; Calas, G.

    1991-01-01

    Metamictization effects have been investigated in zircon, thorite, uranothorite, and thorogummite using X-ray absorption spectroscopy at Zr-K, Th-L III edges. Extended X-ray absorption fine structure (EXAFS) spectra of metamict samples are characterized by a major contribution due to the O nearest neighbors with some contributions from next-nearest neighbors (Si and Zr in zircon, Si in thorite). In zircon, Zr-O distances decrease by ∼0.1 angstrom while the coordination number of Zr decreases from 8 to 7. In contrast, the eightfold coordination of Th in crystalline thorite is preserved in metamict thorite, Si second neighbors around Zr or Th are generally observed in metamict samples with distances close to those measured in crystalline phases. No other contribution to EXAFS is observed in thorite, but Zr-Zr distances are observed in zircon. They decrease by ca. 0.3 Angstrom as a function of zircon metamictization. Metamictization processes are characterized by a loss of medium range order. There is no evidence for decomposition into crystalline oxides. The structural interpretation of EXAFS data must take into account the creation of O vacancies arising from a displacement or tilting of the SiO 4 tetrahedra during metamictization of zircon-like structures. If the cation can take a lower coordination number (as in the case of Zr), a coordination change allows the local structure to be partly maintained during metamictization. If not, as for Th, the local structure is rapidly destroyed

  13. The first discovery of Hadean zircon in garnet granulites from the Sutam River (Aldan Shield)

    Science.gov (United States)

    Glukhovskii, M. Z.; Kuz'min, M. I.; Bayanova, T. B.; Lyalina, L. M.; Makrygina, V. A.; Shcherbakova, T. F.

    2017-09-01

    For the first time in Russia, a Hadean zircon grain with an age of 3.94 Ga (ID-TIMS) has been discovered in high-aluminous garnet granulites of the Aldan Shield among the U-Pb zircons with an age from 1.92 Ga. In this connection, the problems of its parental source, the petrogenesis of granulites that captured this zircon, and the mechanism of occurrence of these deep rocks in the upper horizons of the crust have been solved. The comparison of the geochemistry of garnet granulites and the middle crust has shown that the granulites are enriched in the entire range of rare-earth elements (except for the Eu minimum), as well as in Al2O3, U, and Th and are depleted in the most mobile elements (Na, Ca, Sr). In the upper part of the allitic weathering zone of the middle crust, which formed under conditions of arid climate, this zircon grain was originated from the weathered granites from the middle crust. In the latter case, they were empleced discretely in the upper granite-gneiss crust under high pressure conditions (the rutile age is 1.83-1.82 Ga). The zircon with an age of 3.94 Ga is comparable to the Hadean zircons from orthogneisses of the Acasta region (Canadian Shield, 4.03-3.94 Ga).

  14. Zircon evidence for incorporation of terrigenous sediments into the magma source of continental basalts.

    Science.gov (United States)

    Xu, Zheng; Zheng, Yong-Fei; Zhao, Zi-Fu

    2018-01-09

    Crustal components may be incorporated into continental basalts by either shallow contamination or deep mixing. While the former proceeds at crustal depths with common preservation of refractory minerals, the latter occurs at mantle depths with rare survival of relict minerals. Discrimination between the two mechanisms has great bearing to subcontinental mantle geochemistry. Here we report the occurrence of relict zircons in Cenozoic continental basalts from eastern China. A combined study of zircon U-Pb ages and geochemistry indicates that detrital zircons were carried by terrigenous sediments into a subcontinental subduction zone, where the zircon were transferred by fluids into the magma sources of continental basalts. The basalts were sampled from three petrotectonic units with distinct differences in their magmatic and metamorphic ages, making the crustal contamination discernible. The terrigenous sediments were carried by the subducting oceanic crust into the asthenospheric mantle, producing both soluble and insoluble materials at the slab-mantle interface. These materials were served as metasomatic agents to react with the overlying mantle wedge peridotite, generating a kind of ultramafic metasomatites that contain the relict zircons. Therefore, the occurrence of relict zircons in continental basalts indicates that this refractory mineral can survive extreme temperature-pressure conditions in the asthenospheric mantle.

  15. Electrical conductivity of zirconia and yttrium-doped zirconia from Indonesian local zircon as prospective material for fuel cells

    International Nuclear Information System (INIS)

    Apriany, Karima; Permadani, Ita; Rahmawati, Fitria; Syarif, Dani G.; Soepriyanto, Syoni

    2016-01-01

    In this research, zirconium dioxide, ZrO 2 , was synthesized from high-grade zircon sand that was founded from Bangka Island, Sumatra, Indonesia. The zircon sand is a side product of Tin mining plant industry. The synthesis was conducted by caustic fusion method with considering definite stoichiometric mole at every reaction step. Yttrium has been doped into the prepared zirconia by solid state reaction. The prepared materials were then being analyzed by X-ray diffraction equipped with Le Bail refinement to study its crystal structure and cell parameters. Electrical conductivity was studied through impedance measurement at a frequency range of 20 Hz- 5 MHz. Morphological analysis was conducted through Scanning Electron Microscopy (SEM) equipped with Energy Dispersive X-ray (EDX) for elemental analysis. The results show that the prepared yttrium stabilized zirconia, YSZ, was crystallized in the cubic structure with a space group of P42/NMC. The sintered zirconia and yttrium stabilized zirconia at 8 mol% of yttrium ions (8YSZ) show dense surface morphology with a grain size less than 10 pm. Elemental analysis on the sintered zirconia and 8YSZ show that sintering at 1500°C could eliminate the impurities, and the purity became 81.30%. Impedance analysis shows that ZrO 2 provide grain and grain boundary conductivity meanwhile 8YSZ only provide grain mechanism. The yttrium doping enhanced the conductivity up to 1.5 orders. The ionic conductivity of the prepared 8YSZ is categorized as a good material with conductivity reach 7.01 x10 -3 at 700 °C. The ionic conductivities are still lower than commercial 8YSZ at various temperature. It indicates that purity of raw material might significantly contribute to the electrical conductivity. (paper)

  16. Detrital zircon study along the Tsangpo River, SE Tibet

    Science.gov (United States)

    Liang, Y.; Chung, S.; Liu, D.; O'Reilly, S. Y.; Chu, M.; Ji, J.; Song, B.; Pearson, N. J.

    2004-12-01

    The interactions among tectonic uplift, river erosion and alluvial deposition are fundamental processes that shape the landscape of the Himalayan-Tibetan orogen since its creation from early Cenozoic time. To better understand these processes around the eastern Himalayan Syntaxis, we conducted a study by systematic sampling riverbank sediments along the Tsangpo River, SE Tibet. Detrital zircons separated from the sediments were subjected to U-Pb dating by the SHRIMP II at the Beijing SHRIMP Center and then in-situ measurements of Hf isotope ratios using LA-MC-ICPMS at GEMOC. These results, together with U-Pb ages and Hf isotope data that we recently obtained for the Transhimalayan plutonic and surrounding basement rocks, allow a more quantitative examination of the provenance or protosource areas for the river sediments. Consequently, the percentage inputs from these source areas can be estimated. Our study indicates that, before the Tsangpo River flows into the Namche Barwa Syntaxis of the eastern Himalayas where the River forms a 180° Big Bend gorge and crosscuts the Himalayan sequences, the Gangdese batholith that crops out just north of the River appear to be an overwhelming source accounting for ˜50 % of the bank sediments. The Tethyan Himalayan sequences south of the River are the second important source, with an input of ˜25 %. The proportion of sediment supply changes after the River enters the Big Bend gorge and turns to south: ˜25 % of detrital zircons are derived from the Greater Himalayas so that the input from the Tethyan Himalayas decreases (< 10 %) despite those from the Gangdese batholith remains high ( ˜40 %). Comparing with the sediment budget of the Brahmaputra River in the downstream based on literature Sr, Nd and Os isotope information, which suggests dominant ( ˜90-60 %) but subordinate ( ˜10-40 %) contributions by the (Greater and Lesser) Himalayan and Tibetan (including Tethyan Himalayan) rocks, respectively, the change is interpreted

  17. Paleozoic and Paleoproterozoic Zircon in Igneous Xenoliths Assimilated at Redoubt Volcano, Alaska

    Science.gov (United States)

    Bacon, C. R.; Vazquez, J. A.; Wooden, J. L.

    2010-12-01

    Historically active Redoubt Volcano is a basalt-to-dacite cone constructed upon the Jurassic-early Tertiary Alaska-Aleutian Range batholith. New SHRIMP-RG U-Pb age and trace-element concentration results for zircons from gabbroic xenoliths and crystal-rich andesitic mush from a late Pleistocene pyroclastic deposit indicate that ~310 Ma and ~1865 Ma igneous rocks underlie Redoubt at depth. Two gabbros have sharply terminated prismatic zircons that yield ages of ~310 Ma. Zircons from a crystal mush sample are overwhelmingly ~1865 Ma and appear rounded due to incomplete dissolution. Binary plots of element concentrations or ratios show clustering of data for ~310-Ma grains and markedly coherent trends for ~1865-Ma grains; e.g., ~310-Ma grains have higher Eu/Eu* than most of the ~1865-Ma grains, the majority of which form a narrow band of decreasing Eu/Eu* with increasing Hf content which suggests that ~1865-Ma zircons come from igneous source rocks. It is very unlikely that detrital zircons from a metasedimentary rock would have this level of homogeneity in age and composition. One gabbro contains abundant ~1865 Ma igneous zircons, ~300-310 Ma fluid-precipitated zircons characterized by very low U and Th concentrations and Th/U ratios, and uncommon ~100 Ma zircons. We propose that (1) ~310 Ma gabbro xenoliths from Redoubt Volcano belong to the same family of plutons dated by Aleinikoff et al. (USGS Circular 1016, 1988) and Gardner et al. (Geology, 1988) located ≥500 km to the northeast in basement rocks of the Wrangellia and Alexander terranes and (2) ~1865 Ma zircons are inherited from igneous rock, potentially from a continental fragment that possibly correlates with the Fort Simpson terrane or Great Bear magmatic zone of the Wopmay Orogen of northwestern Laurentia. Possibly, elements of these Paleoproterozoic terranes intersected the Paleozoic North American continental margin where they may have formed a component of the basement to the Wrangellia

  18. Molten salt synthesis of lead lanthanum zirconate titanate ceramic powders

    International Nuclear Information System (INIS)

    Cai Zongying; Xing Xianran; Li Lu; Xu Yeming

    2008-01-01

    Lead lanthanum zirconate titanate (Pb 0.95 La 0.03 )(Zr 0.52 Ti 0.48 )O 3 (PLZT) was synthesized by one step molten salt method with the starting materials of PbC 2 O 4 , La 2 O 3 , ZrO(NO 3 ) 2 .2H 2 O and TiO 2 in the NaCl-KCl eutectic mixtures in the temperature range of 700-1000 deg. C. The single phase of (Pb 0.95 La 0.03 )(Zr 0.52 Ti 0.48 )O 3 powders was prepared at a temperature as low as 850 deg. C for 5 h. The effects of process parameters, such as soaking temperature and time, salt species, and the amount of flux with respect to the starting materials were investigated. The growth process of the PLZT particles in the molten salt undergoes a transition from a diffusion controlled mechanism to an interfacial reaction controlled mechanism at 900 deg. C

  19. Formation of zirconium nitride via mechanochemical decomposition of zircon

    International Nuclear Information System (INIS)

    Puclin, T.; Kaczmarek, W.A.

    1996-01-01

    In this paper we report some results of the mechanochemical reduction of zircon, and for the first time subsequent reaction with nitrogen to form zirconium nitride (ZrN). This process can be described by the equation: 3ZrSiO 4 + 8Al + 1.5N 2 = 4Al 2 O 3 + 3ZrN + 3Si. Milling was carried out in three steps: 1) low speed grinding of Al+ZrSiO 4 in vacuum, 2) high speed milling to effect the reduction, and 3) continued milling after the addition of nitrogen. Powders produced were examined by X-ray diffraction. The first step showed no reaction occurred during low speed grinding. The second step proved to be a slow reaction without the 'ignition' often seen in other mechanochemical reduction works. The final step was also gradual, and did not always go to full nitridation over the duration of the experiment, giving a product of composition ZrN 0.6 to ZrN l.0 . This is quite acceptable as transition metal nitrides are often non-stoichiometric. These results show that the formation of a useful hard material such as ZrN can be formed from a raw mineral by two stage mechanochemical processing. Further investigations are currently being undertaken to eliminate Fe contamination and produce pure ceramic oxide-nitride composites

  20. New Insights on the Recrystallization and New Growth of Extensively Radiation-damaged Zircon

    Science.gov (United States)

    Hanchar, J. M.; Schmitz, M. D.; Wirth, R.

    2012-12-01

    Approximately 10 grams of cm-sized nearly metamict zircon crystals from the Saranac Prospect in the Bancroft District of Ontario were combined by breaking into small pieces and then ground under ethanol to a fine powder with an agate mortar and pestle in order to make enough homogeneously mixed material for multiple powder X-Ray and diffraction scans, high-resolution transmission electron microscopy (HR-TEM) measurements, and chemical abrasion isotope dilution thermal ionization mass spectrometry (CA-TIMS). While these large zircon crystals ground to a powder have a larger surface area and not in the same physical state (i.e., brown and metamict) as what is typically analyzed in single zircon CA-ID-TIMS U-Pb analysis (clear euhedral grains), the physical and chemical changes that occur during the heat treatment used in CA-TIMS are thought to be similar processes. Aliquots of the ground zircon powder were annealed in situ using a Pt furnace in a powder diffractometer during which time simultaneous powder diffraction patterns were acquired starting at 25°C, at elevated temperature (from 500°C to 1400°C) at selected time intervals, and then again at 25°C. The powder X-ray diffraction results indicate that below ~900°C the recrystallization of the zircon powder commences but is incomplete, even after 36 hours, with diffuse low intensity diffraction peaks. At 1150°C the zircon powder shows significant recrystallization. At 1150°C, the recrystallization is essentially complete in less than one hour. Before heating the zircon powder samples consisted of clear, transparent to brown, translucent, complexly zoned fragments. After heating at 900°C the zircon powder retained a smaller percentage of clear or brown complexly zoned fragments, while the majority of material had transformed to oscillatory or irregularly zoned, dominantly white opaque microcrystalline fragments. The clear fragments were hypothesized to be preexisting original crystalline zircon, the brown

  1. Separation of zircon from the beach sand deposit of Srikurmam area, Srikakulam district, Andhra Pradesh - a case study

    International Nuclear Information System (INIS)

    Rao, G.V.S.U.; Sharma, A.K.; Seshadrinath, S.T.; Fahmi, Sohail; William Prasad, Ch.; Nagabhushanam, B.

    2011-01-01

    Beach sand placer deposits occur along the eastern and western coasts of India, which contain heavy minerals, such as ilmenite, rutile, garnet, monazite, zircon and sillimanite. Among these, zircon is used in zircaloys (nuclear industry), ceramics, refractories, abrasives, etc. Separation and chemical characterization of pure zircon is a prelude for understanding the different elements and impurities present and its industrial application. In recent times, several methods are developed for beneficiation and separation of individual heavy minerals from beach sands. In this paper, separation of zircon from beach sand of Srikurmam area, Andhra Pradesh was taken up as a case study. The process flow sheet adopted for separation and isolation of pure zircon from beach sand sample consists of desliming of beach sand, wet tabling of sand fraction, removal of magnetite by low intensity magnetic separation from table concentrate, perm roll magnetic separation and induced roll magnetic separation of table concentrate. The concentrates were further subjected to iso-dynamic magnetic separator after observing impurity present in the sample under binocular stereomicroscope. In the present process, about 95% pure zircon was obtained. Further concentration of zircon was carried out under the binocular stereomicroscope by hand picking of impurity to obtain 99.5% pure zircon concentrate. The pure zircon concentrate was analyzed for major, minor and trace elements by chemical method for characterization of zircon and cross validation of physical processes through which the zircon concentrate was obtained. Chemical analysis of the pure zircon concentrate indicated 63.15 to 64.79% ZrO 2 and 32.2 to 32.8% SiO 2 . These values are nearer to that of pure zircon, which stoichiometrically contains 67.2% ZrO 2 and 32.8 % SiO 2 with little iron. In the present study, ZrO 2 +HfO 2 content varies from 65.27 to 66.17% and hafnium from 1.25 to 1.46% HfO 2 in the zircon concentrate. The variation

  2. Composition of zircons from the Cornubian Batholith of SW England and comparison with zircons from other European Variscan rare-metal granites

    Czech Academy of Sciences Publication Activity Database

    Breiter, Karel; Müller, A.; Shail, R.; Simons, B.

    2016-01-01

    Roč. 80, č. 7 (2016), s. 1-17 ISSN 0026-461X R&D Projects: GA ČR GA14-13600S Institutional support: RVO:67985831 Keywords : zircon * chemical composition * Cornwall * rare-metal granite Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.285, year: 2016

  3. Detrital zircon geochronology and provenance of the Chubut Group in the northeast of Patagonia, Argentina

    Science.gov (United States)

    Navarro, Edgardo L.; Astini, Ricardo A.; Belousova, Elena; Guler, M. Verónica; Gehrels, George

    2015-11-01

    The Chubut Group constitutes the most widespread sedimentary unit in NE Patagonia, characterized by variable-energy fluvial deposits. U-Pb analysis of detrital zircons from two sections of the Chubut Group constraint the age of the oldest sedimentary rocks in the northeast of the Somuncurá - Cañadón Asfalto Basin. In the Cañadón Williams area, at San Jorge section, 20 km NW of Telsen locality, dating of 56 detrital zircons from a medium to coarse sandstone indicated a maximum depositional age of 109 ± 1 Ma (n = 4). These sandstones were interpreted to represent shallow channels, associated with a lacustrine system. In the Telsen locality, a laser ablation analysis of 115 detrital zircons from a medium to coarse-grained sandstone, from fluvial channel facies, yielded a maximum depositional age of ca. 106 ± 1 Ma (n = 8). Both ages are consistent with volcanic events of the Barremian to Albian age in the central Patagonian Andes Region. Cathodoluminescence images of zircons from the San Jorge sample suggest an igneous origin, which is further supported by Th/U values above 0.5 in most of the grains. The distribution of the statistical modes of the main age populations of detrital zircons for the two samples [182, 185 and 189 Ma for Telsen sample (T2S) and 181 ± 1 Ma for San Jorge sample (SJS)] matches the age of the volcanic Marifil Formation. The rocks of the Marifil Formation of these ages are exposed NE to SE of the study area. The abundance of zircons of similar Jurassic ages (n = 52 for SJS and n = 105 for T2S) and the external morphology of the zircons in the sample SJS, implies a close proximity of the source area. Suggestion that the Marifil Formation was the main provenance source is also supported by northeast-southeasterly paleocurrents measured at the San Jorge and Telsen sections.

  4. Do Zircon age Spectra Record Magmatic Cyclicity at Soufrière (Saint Lucia, Lesser Antilles)?

    Science.gov (United States)

    Schmitt, A. K.; Stockli, D. F.; Lindsay, J. M.

    2007-12-01

    The Soufrière Volcanic Center (Saint Lucia, Lesser Antilles) is a long-lived arc-volcanic system that evolved over the past 5 - 6 Ma. Its most recent volcanic activity between 20 and 40 ka was concentrated within the prominent Qualibou topographic depression and produced two voluminous pyroclastic deposits: Choiseul and the overlying Belfond. In addition, several dacitic lava domes exist within the Qualibou depression. Because evidence of earlier volcanic activity in long-lived magma systems is frequently obliterated by subsequent eruptive or volcano-tectonic events, high spatial resolution U-Th dating of zircon combined with (U-Th)/He dating is a powerful tool to identify magma crystallization episodes at depth and to link these to the eruptive record. U-Th model ages and disequilibrium corrected U-Pb ages for 56 individual zircons from Soufrière lavas (Morne Bonin, Belfond, Terre Blanche) and pumice (Choiseul, Belfond) were determined by secondary ionization mass spectrometry. The majority of results is on unpolished zircons where analysis pits integrate over the outermost ~10 μm of individual grains with a lateral spatial resolution of ~40 μm. Selected grains were subsequently analyzed by (U-Th)/He methods. Belfond and Terre Blanche (U-Th)/He zircon ages (~20 ka) agree with previous 14C charcoal ages, whereas Morne Bonin ages are much older (~250 ka). Overall, the U-Th zircon crystallization age spectrum reveals a remarkable range between ~20 and ~600 ka and displays multiple peaks, among which the most prominent are tentatively identified at ~40 ka, ~80 ka, ~130 ka, ~200 ka and ~500 ka. The distribution of rim ages indicates that most zircons lack overgrowth dating from just prior to the eruption, but the youngest ages for each sample overlap with the eruption ages. Soufrière zircons thus reveal magma intrusion, cooling, and crystallization cycles within the underlying plutonic system for which the volcanic stratigraphic record is sketchy.

  5. Numerical studies of triplet and Russian quadruplet quadrupole lens systems with the given spot size on the target, for use in a microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Brazhnik, V A; Lebed, S A; Ponomarev, A G; Storizhko, V E [Ukrainian Academy of Sciences, Sumy (Ukraine). Applied Physics Institute; Dymnikov, A D [University of St Petersburg, Stary (Russian Federation). Institute of Computational Mathematics and Control Processes; Jamieson, D N; Legge, S A [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1994-12-31

    In a nuclear microprobe the focusing system is an essential component which determines the beam spot size, i.e. the microprobe resolution. A small beam cross section at the target is the most important of the many conflicting requirements imposed on the beam The second most important factor is the current of the beam which at the given brightness is proportional to the phase volume (or emittance) of the beam. Existing microprobes frequently use a triplet or a Russian quadruplet as the focusing systems. This paper describes the numerical studies of some optimal quadrupole lens systems consisting of three or four lenses suitable for use in a nuclear microprobe taking into account geometrical aberrations of third order. The maximum emittance of changed particle beams for these systems has been found. It is shown how the maximum emittance depends on the spot size. 2 refs., 2 figs.

  6. Numerical studies of triplet and Russian quadruplet quadrupole lens systems with the given spot size on the target, for use in a microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Brazhnik, V.A.; Lebed, S.A.; Ponomarev, A.G.; Storizhko, V.E. [Ukrainian Academy of Sciences, Sumy (Ukraine). Applied Physics Institute; Dymnikov, A.D. [University of St Petersburg, Stary (Russian Federation). Institute of Computational Mathematics and Control Processes; Jamieson, D.N.; Legge, S.A. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1993-12-31

    In a nuclear microprobe the focusing system is an essential component which determines the beam spot size, i.e. the microprobe resolution. A small beam cross section at the target is the most important of the many conflicting requirements imposed on the beam The second most important factor is the current of the beam which at the given brightness is proportional to the phase volume (or emittance) of the beam. Existing microprobes frequently use a triplet or a Russian quadruplet as the focusing systems. This paper describes the numerical studies of some optimal quadrupole lens systems consisting of three or four lenses suitable for use in a nuclear microprobe taking into account geometrical aberrations of third order. The maximum emittance of changed particle beams for these systems has been found. It is shown how the maximum emittance depends on the spot size. 2 refs., 2 figs.

  7. Numerical studies of triplet and Russian quadruplet quadrupole lens systems with the given spot size on the target, for use in a microprobe

    International Nuclear Information System (INIS)

    Brazhnik, V.A.; Lebed, S.A.; Ponomarev, A.G.; Storizhko, V.E.; Dymnikov, A.D.; Jamieson, D.N.; Legge, S.A.

    1993-01-01

    In a nuclear microprobe the focusing system is an essential component which determines the beam spot size, i.e. the microprobe resolution. A small beam cross section at the target is the most important of the many conflicting requirements imposed on the beam The second most important factor is the current of the beam which at the given brightness is proportional to the phase volume (or emittance) of the beam. Existing microprobes frequently use a triplet or a Russian quadruplet as the focusing systems. This paper describes the numerical studies of some optimal quadrupole lens systems consisting of three or four lenses suitable for use in a nuclear microprobe taking into account geometrical aberrations of third order. The maximum emittance of changed particle beams for these systems has been found. It is shown how the maximum emittance depends on the spot size. 2 refs., 2 figs

  8. Finding the "true" age: ways to read high-precision U-Pb zircon dates

    Science.gov (United States)

    Schaltegger, U.; Schoene, B.; Ovtcharova, M.; Sell, B. K.; Broderick, C. A.; Wotzlaw, J.

    2011-12-01

    Refined U-Pb dating techniques, applying an empirical chemical abrasion treatment prior to analysis [1], and using a precisely calibrated double isotope Pb, U EARTHTIME tracer solution, have led to an unprecedented two problems: (A) Post-crystallization Pb loss from decay damaged areas is considered to be mitigated by applying chemical abrasion techniques. The success of such treatment can, however, not be assumed a priori. The following examples demonstrate that youngest zircons are not biased by lead loss but represent close-to-youngest zircon growth: (i) coincidence of youngest zircon dates with co-magmatic titanite in tonalite; (ii) coincidence with statistically equivalent clusters of 206Pb/238U dates from zircon in residual melts of cogenetic mafic magmas; (iii) youngest zircons in ash beds of sedimentary sequences do not violate the stratigraphic superposition, whereas conventional statistical interpretation (mean or median values) does; (iv) results of published inter-laboratory cross-calibration tests using chemical abrasion on natural zircon crystals of the same sample arrive at the same 206Pb/238U result within case of single, significantly younger dates (>3 sigma), and are common in many pre-Triassic and hydrothermally altered rocks. (B) Pre-eruptive/pre-intrusive growth is found to be the main reason for scattered zircon ages in igneous rocks. Zircons crystallizing from the final magma batch are called autocrystic [3]. Autocrystic growth will happen in a moving or stagnant magma shortly before or after the rheological lockup by the crystals. Last crystallizing zircons in the interstitial melt may therefore postdate emplacement of the magma. The range of 206Pb/238U ages may yield a time frame for the cooling of a given magma batch, which could be added to quantitative thermal models of magma emplacement and cooling. Hf isotopes and trace elements of the dated zircon are used to trace the nature of the dated grains [4], specifically for identification of

  9. Late magmatic stage of the zoned Caleu pluton (Central Chile): insights from zircon crystallization conditions

    Science.gov (United States)

    Molina, P. G.; Parada, M.; Gutierrez, F. J.; Chang-Qiang, M.; Jianwei, L.; Yuanyuan, L.

    2012-12-01

    The Caleu pluton consists of three N-S elongated lithological zones: Gabbro-Diorite Zone (GDZ), Tonalite Zone (TZ) and Granodiorite Zone (GZ); western, middle and eastern portions of the pluton, respectively. The zones are thought to be previously differentiated in a common, isotopically depleted (Sr-Nd), subjacent magma reservoir at a 4 kbar equivalent depth. The emplacement should have occurred at the climax of the Cretaceous rifting. We present preliminary results of U238/Pb206 zircon geochronology; zircon saturation, Tsat(Zrn), and crystallization temperatures (Ti-in-Zrn); as well as relative oxidation states at time of crystallization, based on: (i) the sluggish REE and HFSE subsolidus diffusivities in zircon; (ii) the behavior of Ti4+↔Si4+ and Ce4+↔Zr4+ isovalent replacement, in addition to a constrained TiO2 activity in almost all typical crustal rocks; and (iii) relative oxidation states at time of crystallization, respectively. The latter are obtained by interpolation of the partition coefficients of trivalent (REE) and tetravalent (HFSE) curves in Onuma diagrams for each zircon, and then estimating relative Ce(IV)/Ce(III) ratios. Results obtained from 4 samples (a total of 77 zircon grains) collected from the three mentioned lithological zones indicate U/Pb ages of approximately 99.5 ±1.5 Ma, 96.8 ±0.6 Ma, and 94.4 +2.2 -0.8 Ma; and Ti-in Zrn ranges of ca. 720-870°C, ca. 680-820°C and ca. 750-840°C, for the GDZ, TZ and GZ samples, respectively. On the other hand Tsat(Zrn) of ca. 750-780°C in the TZ, and ca. 830-890°C in the GZ, were obtained. As expected saturation temperatures are similar or higher than Ti-in-Zrn obtained in zircon grains of TZ and GZ, respectively. Cathodoluminiscence images in zircon suggest a magmatic origin, due to absence of complex zoning patterns and fairly well conserved morphologies. Exceptionally the GDZ sample zircons show evidence of inheritance, indicating a xenocrystic and/or antecrystic origin. A relative Ce

  10. Ion Microprobe Measurements of Comet Dust and Implications for Models of Oxygen Isotope Heterogeneity in the Solar System

    Science.gov (United States)

    Snead, C. J.; McKeegan, K. D.; Keller, L. P.; Messenger, S.

    2017-01-01

    The oxygen isotopic compositions of anhydrous minerals in carbonaceous chondrites reflect mixing between a O-16-rich and O-17, O18-rich reservoir. The UV photodissociation of CO (i.e. selfshielding) has been proposed as a mass-independent mechanism for producing these isotopically distinct reservoirs. Self-shielding models predict the composition for the CO gas reservoir to be O-16-rich, and that the accreting primordial dust was in isotopic equilibrium with the gaseous reservoir [1, 2]. Self-shielding also predicts that cometary water, presumed to represent the O-17, O-18-rich reservoir, should be enriched in O-17 and O-18, with compositions of 200 -1000per mille, and that the interaction with this O-17, O-18-rich H2O reservoir altered the compositions of the primordial dust toward planetary values. The bulk composition of the solar nebula, which may be an approximation to the 16O-rich gaseous reservoir, has been constrained by the Genesis results [3]. However, material representing the O-17, O-18-rich end-member is rare [4], and dust representing the original accreting primordial dust has been challenging to conclusively identify in current collections. Anhydrous dust from comets, which accreted in the distal cold regions of the nebula at temperatures below approximately 30K, may provide the best opportunity to measure the oxygen isotope composition of primordial dust. Chondritic porous interplanetary dust particles (CP-IDPs) have been suggested as having cometary origins [5]; however, until direct comparisons with dust from a known comet parent body were made, link between CP-IDPs and comets remained circumstantial. Oxygen isotope analyses of particles from comet 81P/Wild 2 collected by NASA's Stardust mission have revealed surprising similarities to minerals in carbonaceous chondrites which have been interpreted as evidence for large scale radial migration of dust components from the inner solar nebula to the accretion regions of Jupiter- family comets [6]. These studies have been largely focused on the coarse-grained terminal particles extracted from aerogel collectors; hypervelocity capture into aerogel resulted in fine-grained material that was melted and intimately mixed with the SiO2 capture medium. Hypervelocity impacts into Al foils surrounding the aerogel tiles produced impact craters that captured material from the impactor without significant oxygen contamination, allowing for analysis of both the coarse and fine-grained components of the Wild 2 dust. To date, no particles with definitive hydrated mineralogy have been observed in Stardust samples, though this may be a result of alteration due to hypervelocity capture. High-carbon hydrated CS-IDPs have been suggested as resulting from the aqueous alteration of CP-IDPs [7], and may retain evidence for interaction with O-17, O-18-enriched "cometary" water predicted by CO self-shielding. Here we present results of oxygen isotope measurements of twelve Stardust foil craters and four C-rich hydrated IDPs [8, 9], and discuss implications for models of oxygen isotope heterogeneity in the early solar system.

  11. Rapid rock analysis and microprobe scanning of dermatological material using proton-induced x-ray and γ-ray emission

    International Nuclear Information System (INIS)

    Carlsson, L.E.

    1983-01-01

    The dissertation report comprises 6 articles that have or will appear in open literature. The use of PIXE and PIGE analysis techniques on geological materials, and also on drill cores, is discussed. The accuracy of the methods have been tested on standards. The effect of sample thickness has been studied. A proton microprobe has been compared with an electron microprobe on human skin sections. Both probes give highly reproducible results, but a small systematic deviation between the probes is found. (author)

  12. A short and long range study of mullite-zirconia-zircon composites

    Energy Technology Data Exchange (ETDEWEB)

    Rendtorff, Nicolas M.; Conconi, Maria S.; Aglietti, Esteban F. [Centro de Tecnologia de Recursos Minerales y Ceramica (CETMIC: CONICET-CIC) (Argentina); Chain, Cecilia Y.; Pasquevich, Alberto F. [Universidad Nacional de La Plata, Departamento de Fisica, IFLP, Facultad de Ciencias Exactas (Argentina); Rivas, Patricia C. [CONICET (Argentina); Martinez, Jorge A., E-mail: toto@fisica.unlp.edu.ar; Caracoche, Maria C. [Universidad Nacional de La Plata, Departamento de Fisica, IFLP, Facultad de Ciencias Exactas (Argentina)

    2010-06-15

    In the field of refractory materials, ceramics containing mullite-zirconia are the basis of those most used in the industry of glass and steel. It is known that the addition of zircon improves the behavior of the refractory used in service. Knowing that some mullite-zirconia composites properties as fracture strength and the elastic modulus E are associated with the material microstructure integrity, the eventual thermal decomposition of zircon into zirconia and silica could seriously alter the material elastic properties. In this paper the phase content of a series of mullite-zirconia-zircon (3Al{sub 2}O{sub 3}.2SiO{sub 2}-ZrO{sub 2}-ZrSiO{sub 4}) composites is determined at atomic level via perturbed angular correlations (PAC) and compared with that derived from the long range X-ray diffraction technique. PAC results on the as-prepared materials indicate that all nominal zircon is present and that it involves two types of nanoconfigurations, one of them describing aperiodic regions. The thermomechanical properties already reported for these materials could be related to the crystalline to aperiodic zircon concentrations ratio they exhibit.

  13. Evaluation of the odd-even effect in limits of detection for electron microprobe analysis of natural minerals

    Energy Technology Data Exchange (ETDEWEB)

    Verma, Surendra P., E-mail: spv@cie.unam.mx [Departamento de Sistemas Energeticos, Centro de Investigacion en Energia, Universidad Nacional Autonoma de Mexico, Priv. Xochicalco s/no., Col Centro, A.P. 34, Temixco, Mor. 62580 (Mexico); Pandarinath, Kailasa [Departamento de Sistemas Energeticos, Centro de Investigacion en Energia, Universidad Nacional Autonoma de Mexico, Priv. Xochicalco s/no., Col Centro, A.P. 34, Temixco, Mor. 62580 (Mexico); Velasco-Tapia, Fernando [Facultad de Ciencias de la Tierra, Universidad Autonoma de Nuevo Leon, Carretera Linares-Cerro Prieto km. 8, Linares, N.L. 67700 (Mexico); Rodriguez-Rios, Rodolfo [Facultad de Ingenieria e Instituto de Geologia, Universidad Autonoma de San Luis Potosi, Av. Dr. Manuel Nava No. 8, Zona Universitaria, San Luis Potosi, S.L.P. 78240 (Mexico)

    2009-04-13

    Limit of detection (LOD), being a fundamental quality parameter for analytical techniques, has been recently investigated and a systematic behavior has been observed for most odd-even element pairs for many techniques. However, to the best of our knowledge very few LOD data are available in published literature for electron microprobe analysis; these consist of three papers, two being on rare-earth elements and the third covering a large number of elements of atomic number between 21 and 92. These data confirm the systematic behavior of LODs for many odd-even pairs. To initiate to full this gap, we determined LODs for several major rock-forming chemical elements from Na to Fe with atomic numbers between 11 and 26, during the microprobe analysis of common minerals (olivine, plagioclase, pyroxene, amphibole, quartz, and opaques) in volcanic rocks. The odd-even effect of nuclear stability seems to be present in LOD data for most odd-even pairs investigated. Nevertheless, the experimental strategy concerning the reference materials, calibration procedure, and blank measurements, should be substantially modified to better evaluate the systematic behavior of LOD values in microprobe analysis.

  14. Evaluation of the odd-even effect in limits of detection for electron microprobe analysis of natural minerals

    International Nuclear Information System (INIS)

    Verma, Surendra P.; Pandarinath, Kailasa; Velasco-Tapia, Fernando; Rodriguez-Rios, Rodolfo

    2009-01-01

    Limit of detection (LOD), being a fundamental quality parameter for analytical techniques, has been recently investigated and a systematic behavior has been observed for most odd-even element pairs for many techniques. However, to the best of our knowledge very few LOD data are available in published literature for electron microprobe analysis; these consist of three papers, two being on rare-earth elements and the third covering a large number of elements of atomic number between 21 and 92. These data confirm the systematic behavior of LODs for many odd-even pairs. To initiate to full this gap, we determined LODs for several major rock-forming chemical elements from Na to Fe with atomic numbers between 11 and 26, during the microprobe analysis of common minerals (olivine, plagioclase, pyroxene, amphibole, quartz, and opaques) in volcanic rocks. The odd-even effect of nuclear stability seems to be present in LOD data for most odd-even pairs investigated. Nevertheless, the experimental strategy concerning the reference materials, calibration procedure, and blank measurements, should be substantially modified to better evaluate the systematic behavior of LOD values in microprobe analysis.

  15. Nuclear microprobe analysis of serpentine from the mid-Atlantic ridge

    International Nuclear Information System (INIS)

    Orberger, Beate; Metrich, Nicole; Mosbah, Michelle; Mevel, Catherine; Fouquet, Yves

    1999-01-01

    At mid-ocean ridges, ultramafic rocks are serpentinized by interaction with seawater-derived fluids. Elements, dissolved in large quantities in seawater, e.g., Na, K, Cl, Br, Ca and Sr, can be, in small amounts, incorporated as traces into the crystal structure of the various serpentine minerals (Mg 3 Si 2 O 5 (OH) 4 ). These trace elements can be used to track the composition of the reacting fluids and to constrain physico-chemical conditions. This paper represents the first application of particle-induced X- and γ-ray emission (PIXE/PIGE) analysis to serpentine using the nuclear microprobe at the Laboratoire Pierre Suee (CEA-CNRS). Three types of serpentine, belonging to two different serpentinization generations, have been analysed in samples collected from the Mid-Atlantic Ridge (14 deg. 45'N/45 deg. W) that exposes serpentinized peridotites on which the Logachev black smoker is placed. The trace elements Cl, F, S, Cu, Zn, Ca, K, Ni, Cr and Mn were detected from several tens to several thousands of ppm. Bromine, As and Sr are close to the detection limit of about 5 ppm. The trace element concentrations and interelement relationships in serpentines vary (a) with the serpentine type and (b) with the geographic location to the black smoker. Chlorine and in part S originated from seawater, whereas Cu, Zn, Ca, K, Ni, Cr and Fe and the major amount of S were mobilized from the unaltered host rock and partitioned between the serpentine and the aqueous solution

  16. The use of field indentation microprobe in measuring mechanical properties of welds

    International Nuclear Information System (INIS)

    Haggag, F.M.; Wong, H.; Alexander, D.J.; Nanstad, R.K.

    1989-01-01

    A field indentation microprobe (FIM) was conceived for evaluating the structural integrity of metallic components (including base metal, welds, and heat-affected zones) in situ in a nondestructive manner. The FIM consists of an automated ball indentation (ABI) unit for determining the mechanical properties (yield strength, flow properties, estimates of fracture toughness, etc.) and a nondestructive evaluation (NDE) unit (consisting of ultrasonic transducers and a video camera) for determining the physical properties such as crack size, material pileup around indentation, and residual stress presence and orientation. The laboratory version used in this work performs only ABI testing. ABI tests were performed on stainless steel base metal (type 316L), heat-affected zone, and welds (type 308). Excellent agreement was obtained between yield strength and flow properties (true-stress/true-plastic-strain curve) measured by the ABI tests and those from uniaxial tensile tests conducted on 308 stainless steel welds, thermally aged at 343/degree/C for different times, and on the base material. 4 refs., 17 figs

  17. Raman and luminescence spectroscopy of zirconium oxide with the use of the MOLE microprobe

    International Nuclear Information System (INIS)

    Doyle, T.E.; Alvarez, J.L.

    1984-01-01

    Raman and luminescence spectroscopy with the use of the MOLE microprobe has been used to characterize ZrO 2 originating from oxidized fuel-rod cladding in nuclear accidents. Micro-Raman analysis of samples from Three Mile Island Unit 2 and the Power Burst Facility identified tetragonal and cubic ZrO 2 . The tetragonal and cubic phases are high-temperature polymorphs of ZrO 2 and provide information about temperatures and hydrogen formation in the TMI-2 core. The data suggest that the tetragonal ZrO 2 in TMI-2 samples was stabilized by a crystallite size effect, whereas cubic ZrO 2 in PBF debris samples was stabilized by impurities. Luminescence was used to differentiate yttria-stabilized ZrO 2 ceramics and oxidized fuel-rod cladding in PBF debris samples. The ZrO 2 ceramics produced strong, sharp luminescence peaks which indicated the presence of titanium and yttria in the ZrO 2 . Oxidized fuel-rod cladding displayed no luminescence

  18. Treatment of dentin with stannous fluoride - SEM and electron microprobe study

    International Nuclear Information System (INIS)

    Ellingsen, J.E.; Roella, G.

    1987-01-01

    The effect of SnF 2 -treatment of dentin surfaces was investigated by means of scanning electron microscopy (SEM) and electron microprobe analysis. Human dentin was treated with aqueous SnF 2 solutions of concentrations varying from 1 to 10%. The treatment periods lasted for 1, 5, 10 or 60 min. Both tin and fluoride were identified on the surfaces. The concentration varied depending on the extensiveness of the treatment. Immersion in 1 M KOH for 15 h removed both tin and fluoride from the surfaces. This reaction was not observed after immersion in H 2 O for the same time period. Examination of the SnF 2 -treated dentin surfaces showed a dense layer of globular particles and in addition some larger particles. The dentinal tubules were totally covered even after the treatment with the lowest concentration of SnF 2 . Deposition of tin- and fluoride-containing globules on dentin surfaces may be of clinical interest. This layer may have importance both for the caries resistance of dentin and for hypersensitivity reactions. (author)

  19. Performance of a high-resolution x-ray microprobe at the Advanced Photon Source

    International Nuclear Information System (INIS)

    Cai, Z.; Lai, B.; Yun, W.; McNulty, I.; Khounsary, A.; Maser, J.; Ilinski, P.; Legnini, D.; Trakhtenberg, E.; Xu, S.; Tieman, B.; Wiemerslage, G.; Gluskin, E.

    1999-01-01

    The authors have developed a x-ray microprobe in the energy region from 6 to 20 keV using undulator radiation and zone-plate optics for microfocusing-based techniques and applications at a beamline at the Advanced Photon Source (APS). The performance of the beamline was shown to meet the design objectives, including preservation of the source brilliance and coherence, selectable transverse coherence length and energy bandwidth, high angular stability, and harmonic suppression of the beam. These objectives were achieved by careful thermal management and use of a novel mirror and crystal monochromator cooling geometry. All beamline optical components are water cooled, and the x-ray beam in the experiment station is stable in beam intensity, energy, and position over many days with no active feedback. Using a double-crystal Si(111) monochromator, they have obtained a focal spot size (FWHM) of 0.15 (micro)m (v) x 1.0 (micro)m (h), and a photon flux of 4 x 10 9 photons/sec at the focal spot, and thus a photon flux density gain of 15,000. A circular beam spot of 0.15 (micro)m in diameter can be achieved by reducing the horizontal source size using a white beam slit located 43.5 meters upstream of the zone plate, with an order of magnitude less flux in the focal spot

  20. Nuclear microprobe studies of elemental distributions in dormant seeds of Burkea africana

    Science.gov (United States)

    Witkowski, E. T. F.; Weiersbye-Witkowski, I. M.; Przybyłowicz, W. J.; Mesjasz-Przybyłowicz, J.

    1997-07-01

    Seed nutrient stores are vital post-germination for the establishment of seedlings in harsh and unpredictable environments. Plants of nutrient-poor environments allocate a substantial proportion of total acquired nutrients to reproduction (i.e. seeds). We propose that differential allocation of mineral resources to specific seed tissues is an indication of a species germination and establishment strategy. Burkea africana Hook is a leguminous tree typical of broad-leaved nutrient-poor savannas in southern Africa. Elemental distributions in dormant B. africana seed structures were obtained using the true elemental imaging system (Dynamic Analysis) of the NAC Van de Graaff nuclear microprobe. Raster scans of 3.0 MeV protons were complemented by simultaneous BS and PIXE point analyses. Mineral nutrient concentrations varied greatly between seed tissues. Elevated levels of metals known to play an important role as plant enzyme co-factors were found in the seed lens and embryonic axis. Distributions of most of these metals (Ca, Mn, Fe and Zn, but not K or Cu) were positively correlated with embryonic P distribution, and probably represent phytin deposits. The distribution of metals within seed structures is 'patchy' due to their complexation with P as electron-dense globoid phytin crystals, which constrains the interpretation of PIXE point analyses.