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SIMS: Secondary Ion Mass Spectrometry
Published in Terrance E. Conners, Sujit Banerjee, Surface Analysis of Paper, 2020
Lisa D. Detter-Hoskin, Kenneth L. Busch
If secondary ions are to be sputtered from insulating surfaces, a residual charge can accumulate on the surface that prevents further ion sputtering. Charge compensation is accomplished by using a low energy electron (< 10 eV) flood gun placed near the surface. An essentially neutral surface is maintained through a balance of the arrival of positive ions, the creation and capture of low energy electrons, and the departure from the surface of sputtered ions and electrons. The ion extraction optics of a SIMS instrument vary with the intended use and resolution required. Quadrupole-based SIMS instruments provide low resolution mass spectra, and can achieve moderate spatial resolution. Sector-based instruments can provide higher resolution mass spectral data, and dynamic emittance matching is used in a sophisticated ion optical system to maintain congruous transmission of ions into the mass analyzer from a small surface area. In an ion microscope, secondary ions from a relatively large irradiated surface area pass through the instrument optics in such a way that the image of the surface is preserved. An ion microprobe uses a scanning approach in which the position of the primary ion beam on the surface is rastered, and the ions that pass through the extraction optics to the detection system at any specified time are referenced to the surface position of the rastered beam.
Characterization of Individual Environmental Particles by Beam Techniques
Published in Jacques Buffle, Herman P. van Leeuwen, Environmental Particles, 2019
C. Xhoffer, L. Wouters, P. Artaxo, A. Van Put, R. Van Grieken
SIMS offers special capabilities for particle analysis. Heterogeneities in the composition in single particles are frequently observed from site to site. The distribution of constituents with depth in a particle is another microstructural feature of interest. SIMS is capable of obtaining signals from a depth of about 1 to 2 nm and this information originates from the surface of the sample. SIMS can also be used as a microanalysis technique with a minimum sampling volume of 0.01 jxm.3 The capabilities of SIMS for detection of all elements, compound detection, isotope ratio measurements, depth profiling, and ion imaging of specific constituents are described25 with special reference to particle studies. Depth profiling can be successfully applied to individual particles; however, irregular topography of particles can degrade the depth resolution. Ion specific images of elemental or molecular constituents can be obtained in the ion microscope or ion microprobe.26 The limiting lateral resolution is about 0.5 μm for the ion microscope and about 1 μm for the scanning ion microprobe.
Late Paleoproterozoic deposition and Mesoproterozoic metamorphism of detrital material in the southernmost Baltic Sea region (Gdańsk IG1 borehole): monazite versus zircon and chemical versus isotopic age record
Published in GFF, 2023
Dominik Gurba, Anna Grabarczyk-Gurba, Ewa Krzemińska
For monazite analyses, fourteen grains of high clarity were mounted with monazite standard WB.T.329 from the Thompson Mine, Manitoba (1766 Ma; Williams et al. 1996; Williams 2001). The backscattered electron (BSE) imaging for monazite was prepared on the Hitachi SU3500 SEM. The primary beam current was reduced to 1 nA to prevent the ion counter from the damaging ThO+ signal. Energy filtering, employed to minimize multi-element isobaric interference on 204Pb+ and Zr2O+ species, was replaced with 140Ce31P16O2. Isotopic ratios were measured using the SHRIMP IIe/MC ion microprobe without applying any correction for hydride interferences or isotopic mass fractionation. The reference Thompson Mine monazite crystals were analyzed once in every three sample spots.
Solstad, a Co-Se-bearing copper ore in the Västervik quartzites, Sweden
Published in GFF, 2022
Kjell Billström, Johan Söderhielm, Curt Broman, Krister Sundblad
The rationale behind the U-Pb zircon work was to clarify the nature of the protolith of the quartz-rich host rock. However, the effects of hydrothermal alteration impose problems to find an ideal sample and, in this situation, a typical mineralized specimen (dump sample D, Table 1) was selected. About 0.5 kg of this sample was crushed and processed with heavy liquids and magnetic techniques resulting in a high yield of zircons of which grains selected for isotopic analysis were hand-picked. The U-Pb in situ isotope work was carried out by secondary ion mass spectrometry (SIMS) using an ion microprobe (NORDSIM facility) at the Department of Geological Sciences at NRM, Stockholm. Zircons were mounted in epoxy resin and coated with gold. Cracks and inclusions of other minerals were avoided during analysis. The SIMS analyses, utilizing 35–40 µm spot sizes, followed well-established routines described in Whitehouse et al. (1999) and Whitehouse & Kamber (2005). Basically, negative ions were analysed on a Cameca 1270 using an oxygen flow to increase the yield. Tabulated errors on ratios and ages are 1σ and include propagated errors on the standard (Geostandards 91500; 1065 Ma, Wiedebeck et al. 1995) analyses.
The Mesozoic terrane boundary beneath the Taupo Volcanic Zone, New Zealand, and potential controls on geothermal system characteristics
Published in New Zealand Journal of Geology and Geophysics, 2021
Sarah D. Milicich, Nick Mortimer, Pilar Villamor, Colin J. N. Wilson, Isabelle Chambefort, Matt W. Sagar, Trevor R. Ireland
Age determinations on zircons from samples PK8, BR47, NM6, RK23 and TH17 were made using Secondary Ion Mass Spectrometry (SIMS) techniques on the Sensitive High-Resolution Ion Microprobe-Reverse Geometry (SHRIMP-RG) instrument at the Research School of Earth Sciences, Australian National University (ANU) using the R33 age standard (Black et al. 2004). The techniques used were those described in Wilson et al. (2010). Age determinations on zircons from sample RQ1 were made using laser ablation inductively coupled plasma mass spectrometry (LA–ICPMS) at the Otago Community Trust Centre for Trace Element Analysis, University of Otago with TEMORA 2 (Black et al. 2004) as the age standard. Instrumental operating conditions and data reduction methods are identical to those described in Sagar et al. (2019). For all analyses, the presence of common Pb was monitored by comparing the counts on 204Pb to background levels, and ages corrected to the isochron using the measured 207Pb/206Pb ratios and the Stacey and Kramers (1975) Pb-isotope terrestrial evolution model. Probability density function-histogram plots were generated with Isoplot (Ludwig 2009).