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Secondary Ion Mass Spectrometry (SIMS) Laboratory – Ion Microprobe

The isotopic chemistry laboratory is hosted in the the Pavia headquarter of IGG.

The Laboratory

Secondary Ion Mass Spectrometry (SIMS) is used to determine the chemical and isotopic composition of solid samples. All minor and trace elements (typically in the ppm-ppb range) between hydrogen and uranium can be analyzed, from the first atomic layers to depths of tens of microns, over areas ranging from a few μm to tens of μm, with a material consumption in the ng range.

Local microanalysis is made possible by using a column of high-energy primary ions (Ar+, O-, O2+, Cs+) (in the range of 5–17.5 kV) and three electrostatic lenses. This system can vary the probe diameter from 200 μm, while maintaining a high current density.

The bombardment of the surface causes the sputtering process, i.e. the emission of particles from the sample, in the form of atoms, molecules, monoatomic ions, ion clusters, etc. SIMS analysis is based on the small fraction of monoatomic secondary ions, positive or negative.

Secondary ions are filtered for energy and mass by a double-focusing mass spectrometer. With the energy filtering technique, ions emitted within a wide range of kinetic energies are selected in the medium-high energy component, thus excluding interfering complex molecular ions, which are more abundant in the low-energy region.

A unique feature of SIMS compared to other spectrometric techniques is the ability to produce ion images, using secondary ions coming from the bombardment zone.

Instruments

The instrumentation present in the laboratory consists of a Cameca IMS 4f ion microprobe (no.116), acquired in 1986 by the 05-CNR Committee as part of the National Strategic Project: Ion microprobe for advanced research in the Earth Sciences sector.

Microsonda ionica Cameca IMS 4f (no.116)
Detail of the Cameca IMS 4f ion microprobe. The sources of the primary ions Cs+, O2+, O-, and some pumps of the vacuum system are visible.
Detail of the two primary ion sources: for Cs+, in front, and the duoplasmatron (for O2+, O-), on the right
Laminar flow table for sample handling
Type of samples that can be analyzed with the Cameca IMS 4f ion microprobe: thin rock sections, crystals embedded in epoxy resin, crystals embedded in tubes with epoxy resin and inserted in a metal mount with multiple holes

The samples are polished, ultrasonically cleaned, and then coated with gold (Au) or platinum (Pt) to make the surface conductive. Note the sample holder supplied with the Cameca IMS 4f ion microprobe, and a metal cylinder to hold the preparation inside. The permitted dimensions are 2.54 cm Ø.

A high-magnification sample observation system, consisting of an optical microscope (reflected and transmitted light), connected to a camera and monitor, which allows the sample surface to be visualized and instantaneously micrographs of the areas of interest at various magnifications. Optical micrographic (and SEM) documentation is essential for SIMS investigations.
A sputter coater used in the SIMS laboratory to depose a conductive film onto the sample by sputtering prior to SIMS analysis. The materials used are Au or Pt.
Detail of the Cameca IMS 4f ion microprobe: control panel of the vacuum system (pumps, high vacuum gauges, ..) on the right, and selection and control panels of the analytical conditions for the primary and secondary ion columns, on the left and in the center
Ion optics system (Cameca IMS 4f ion microprobe)

Electrostatic lenses extract and transport secondary ions from the sample, while maintaining their spatial relationship. The mass spectrometer (electrostatic sector + magnetic prism) allows focusing in the radial and axial planes, and in energy.
The ion image, resolved in mass, is magnified and transformed into an equivalent electronic image, visible on a fluorescent screen. Ion currents are measured on a Faraday cup or electron multiplier.

Staff and Contacts

The laboratory staff is composed of:

  • Dr. Alberto Zanetti (CNR Researcher – Laboratory Manager)
  • Marco Palenzona (CNR Technician – Instrument Maintenance)
  • Roberto Gastoni (CNR Technician – Sample Preparation)

Contacts:

Phones

  • Dr. Alberto Zanetti: +39 0382 985867
  • Marco Palenzona: +39 0382 985798
  • Roberto Gastoni: +39 0382 985906

email:

  • alberto.zanetti@igg.cnr.it
  • marco.palenzona@igg.cnr.it
  • roberto.gastoni@igg.cnr.it

Methods and Applications

Since the birth of the ion microprobe laboratory in Pavia, the development of SIMS procedures has been aimed at the quantitative analysis of elements, some of which, such as H, cannot be analyzed in situ with conventional spectrometric techniques.

The analytical techniques currently in use are based on energy filtering and the use of reference samples (standards) to calibrate ionic signals and convert them into elemental concentrations. Quantification involves both the use of peak stripping procedures (developed at the SIMS laboratory in Pavia) to remove residual interferences (rare earth oxides and other sample constituents) from the mass spectrum of secondary ions, and the use of mathematical corrections on ionic products, in the investigation of:

  • Trace and minor elements (Rare Earths, K, Na, Sc, Ti, V, Cr, Sr, Zr, Y, Ba, Cs, Nb, Rb, Hf, U, Th), light (Li, Be, B) and volatile (H, F and Cl) in silicate minerals, melt inclusions in minerals, natural and artificial glasses
  • Rare earths and other trace elements in apatites
  • H, B, F, Cl in experimental charges
  • Li in phosphates-Li

The SIMS laboratory in Pavia is currently the only one in Italy operating in the field of Earth Sciences.

Temperature dependence of the Li/(Li+Na) ratios for phosphates synthesized in the LiNa2MnxFe3-x2+ Fe3+(PO4)4 system (x = 1.054, 1.502, 1.745), obtained using the SIMS technique for Li measurement, with the development of the Na geothermometer in triphylite. Circles = alluaudites, triangles = triphylite, squares = X-phase, crosses = marićite (Hatert et al., 2011)
SEM-BSE image of phlogopite VUT191_11 (Mt. Vulture, Southern Italy) after removal of the Pt coating used for ion probe analysis. SIMS craters are indicated by arrows. The contrast due to chemical inhomogeneity is clearly visible (Scordari et al., 2010). This investigation is part of the study of the crystal chemistry of volcanic micas and benefited from in-situ SIMS measurement of Li and volatiles (H, F) on single crystals.
Micrograph of crystallographically oriented, prismatic pyroxene needles in garnets. Studying samples of orogenic peridotites from Otrøy (western Norway), it was found that the decompression microstructures present in the garnet originated at a depth ≥ 350 km, much greater than the thickness of the oldest continents (~ 200 km) and close to the Mantle Transition Zone (Spengler et al., 2006). Note the small size of the cpx, whose SIMS analysis was at the limit of instrumental capabilities, both in terms of spatial resolution (a few µm) and compositional resolution (<<1 µg/g Rare Earths).
Micrograph of volcanic dust analyzed with the Pavia ion microprobe as part of the RESET (Response of Humans to Abrupt Environmental Transitions) Consortium (http://c14.arch.ox.ac.uk/reset/embed.php?File=index.html). On the volcanic dust, embedded in epoxy resin and polished, the areas selected for ion bombardment are indicated by arrows. The SIMS technique proved to be the only one capable of quantitatively analyzing trace elements (ppm-sub ppm) on small micro-areas, at the limits of the capabilities of the CNR equipment.
Reflected-light optical micrographs of opx in BM90-6 (Balmuccia, Western Alps, Italy), showing SIMS spots and corresponding Cl contents (ppm). Orthopyroxene reacted in the presence of a metasomatic agent with Cl incorporation that appears to follow a diffusive law. Cl enrichment is highest along the crystal edge—with contents up to 108 ppm Cl—and indicates that the metasomatic agent diffused along the grain boundaries, represented by white spots in the micrograph (Ottolini & Le Fevre, 2008).

Scientific Projects and Interests

  • Development of analytical methodologies for the measurement of:
    • Trace constituents in volcanic ash (RESET Consortium)
    • H, F and C in porous minerals (Prin 2008 call, “Compositional and structural characteristics of minerals of applicative interest: sodalites and cuspids from Somma-Vesuvius”).
  • Optimization of SIMS procedures for the analysis of:
    • Li, Be, B and volatiles in the study of the crystal chemistry of micas,
    • Rare earths in decompression structures in orogenic peridotite samples (Western Norway).
  • Development of SIMS methods for the measurement of Li and Be in phosphates-Be-Li and phosphates-Be.
  • Analytical collaboration with:
    • 2013 PNRA Call for Proposals “Stability of Hydrated Phases in the Lithospheric Mantle of Large Continental Rift Systems: A Petrological-Experimental Approach to Nodules and Basic Lavas from Northern Victoria Land”
    • Prin Call (2014-2016, prot. 20125JKANY) “Birth of an ocean in the Red Sea: High-resolution geodynamics, geochemistry and plate kinematics”

Main scientific interests include:

  • Study of SIMS matrix effects for light and volatile elements in phosphates
  • Development of quantitative procedures for volatiles (H, C, F, Cl) in apatites
  • Improving the precision and accuracy in the analysis of trace constituents (sub ppm wt) in minerals and glasses, having dimensions ≤10 µm
  • Quantitative analysis of H in silicates with very low H2O content and investigation of H in nominally anhydrous minerals
SIMS analyses in subcontinental spinel peridotites (Outer Ligurids) have confirmed the existence of Ti and Zr depletions in clinopyroxenes, but have highlighted, for the first time, concomitant enrichments in coexisting orthopyroxenes. Therefore, Ti and Zr in cpx cannot be used as exclusive factors to infer the existence of mantle sectors depleted in high-field elements ( Rampane et al. , 1991) .Rampone et al., 1991)

Cryptotephra TP 9.70 from the terrestrial site of Tenaghi Philippon (NE Greece) was identified and geochemically characterized for the first time by SIMS analysis. It showed a compositional range consistent with that of Y-3 tephra (indicated on the map by M25/4-12), compatible with a source in the Campi Flegrei (CF). This correlation extends the dispersion of Y-3 tephra eastwards, more than 800 km from the CF, and implies that the area affected by volcanic dust deposition is greater than 550,000 km2 (Albert et al., 2015)

irst direct evidence of nitrogen (14N+in mica (tobelite) samples obtained with the Pavia ion microprobe with a mass resolving power of 1250 (M/ΔM). We can see the resolved peaks (from left to right): 28Si2+, 14N+ . 12CH2+ (Ottolini et al., 2014). The results of this study underline the capabilities of the SIMS technique in the in situ analysis of N and indicate the possibility of developing reference materials (standards) for the quantitative SIMS analysis of nitrogen in ammonium micas.

Publications

  • Rampone E., Bottazzi P., Ottolini L.: Complementary Ti and Zr anomalies in orthopyroxene and clinopyroxene from mantle peridotites, Nature, 354, (1991), 518-520.
  • Ottolini L., Bottazzi P., Vannucci R.: Quantification of Lithium, Beryllium and Boron in Silicates by Secondary Ion Mass Spectrometry Using Conventional Energy Filtering, Anal. Chem., 65, (1993), 1960-1968.
  • Ottolini L., Bottazzi P., Zanetti A., Vannucci R.: Determination of Hydrogen in Silicates by Secondary Ion Mass Spectrometry, The Analyst, 120, (1995), 1309-1313.
  • Schiano P., Clocchiatti R., Ottolini L., Busa’ T.: Transition of Mount Etna lavas from a mantle-plume to an island-arc magmatic source, Nature, 412, (2001), 900-904.
  • Bonatti E., Ligi M., Brunelli D., Cipriani A., Fabretti P., Ferrante V., Gasperini L., Ottolini L.: Mantle thermal pulses below the Mid-Atlantic Ridge and temporal variations in the formation of oceanic lithosphere, Nature, 423, (2003), 29 May Issue, 499-505.
  • Ottolini L., Le Fevre B., Vannucci R.: Direct assessment of mantle boron and lithium contents and distribution by SIMS analyses of peridotite minerals, Earth Planet. Sci. Lett., 228, (2004), 19-36.
  • Schiano P., Clocchiatti R., Ottolini L., Sbrana A.: The relationship between potassic, calc-alkaline and Na-alkaline magmatism in South Italy volcanoes: A melt inclusion approach, Earth Planet. Sci. Lett., 220, (2004), 121-137.
  • Scambelluri M., Müntener O., Ottolini L., Pettke T.T., Vannucci R.: The fate of B, Cl and Li in the subducted oceanic mantle and in the antigorite breakdown fluids, Earth Planet. Sci. Lett., 222, (2004), 217-234.
  • Ligi M., Bonatti E., Cipriani A., Ottolini L.: Water-rich basalts at mid-ocean-ridge cold spots, Nature, 434, (2005), 3 March Issue, 66-69.
  • Spengler D., Van Roermund H.L.M., Drury M.R, Ottolini L., Mason P.R.D., Davies G.R.: Deep origin and hot melting of an Archaean orogenic peridotite massif in Norway. Nature, 440, (2006), 913-917.
  • Ottolini L. P., Le Févre B.: SIMS analysis of chlorine in metasomatised upper-mantle rocks, Microchim. Acta, 161, (2008), 329-336.
  • Pappalardo L., Ottolini L., Mastrolorenzo G.: The Campanian Ignimbrite (southern Italy) geochemical zoning: insight on the generation of a super-eruption from catastrophic differentiation and fast withdrawal, Contrib. Mineral. Petrol., 156, (2008), 1-26.
  • Ottolini L., Laporte D., Raffone N., Devidal J.-L., Le Fèvre B.: New experimental determination of Li and B partition coefficients during upper mantle partial melting, Contrib. Mineral. Petrol., 157, (2009), 313-325.
  • Scordari F., Dyar M.D., Schingaro E., Lacalamita M., Ottolini L.: XRD, micro-XANES, EMPA, and SIMS investigation on phlogopite single crystals from Mt. Vulture (Italy), Amer. Mineral., 95, (2010), 1657-1670.
  • Trua T., Clocchiatti R., Schiano P., Ottolini L., Marani M.: The heterogeneous nature of the Southern Tyrrhenian mantle: Evidence from olivine-hosted melt inclusions from back-arc magmas of the Marsili seamount, Lithos, 118, (2010) 1-16.
  • Hatert F., Ottolini L., Schmid-Beurmann P.: Experimental investigation of the alluaudite + triphylite assemblage, and development of the Na-in-triphylite geothermometer: applications to natural pegmatite phosphates, Contrib. Mineral. Petrol., 161, (2011), 531-546.
  • Ottolini L., Schingaro E., Scordari F.: Contribution of Secondary Ion Mass Spectrometry (SIMS) to the Study of Crystal Chemistry of mica minerals, Mass Spectrometry Handbook, Chapter 43/Ceramics, (2012), 1017-1059, Ed. Mike S. Lee, JOHN WILEY & SONS, INC., PUBLICATION.
  • Ottolini L.P., Scordari F., Mesto E.: A new application of SIMS to the analysis of nitrogen in mica minerals: tobelite, IOP Conference Series: Materials Science and Engineering Vol. 55, conference 1, (2014), EMAS 2013 Workshop: 13th European Workshop on Modern Developments and Applications in Microbeam Analysis, 012014 doi:10.1088/1757-899X/55/1/012014.
  • Albert P.G., Hardiman M., Keller J., Tomlinson E. L., Smith V.C., Bourne A.J., Wulf S., Zanchetta G., Sulpizio R., Müller U.C., Pross J., Ottolini L., Matthews I.P., Blockley S.P.E., Menzies M.A.: Revisiting the Y-3 tephrostratigraphic marker: a new diagnostic glass geochemistry, age estimate, and details on its climatostratigraphical Context, Quaternary Science Reviews, 118, (2015) 105-121.
  • Barton R.N.E., Lane C.S., Albert P.G., White D., Collcutt S.N., Bouzouggar A., Ditchfield P., Farr L., Oh A., Ottolini L., Smith V.C., Van Peer P., Kindermann K.: The role of cryptotephra in refining the chronology of Late Pleistocene human evolution and cultural change in North Africa, Quaternary Science Reviews, 118, (2015) 151-169.