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Mass spectrometry

Once meteorite samples are processed through the Isotope Cosmochemistry and Geochronology Laboratory, we analyze their isotopic composition using our multicollector mass spectrometers, Marge and Marie.

Marge Marie 2020Marge (named in honor of trailblazing astrophysicist Margaret Burbidge, first author of the famed B2FH paper on the synthesis of elements in stars):

  • Thermo Neptune Plus high resolution multicollector ICP-MS.
  • Axial secondary electron multiplier (SEM) and RPQ.
  • Configured for U-Pb isotopic analysis.
  • Equipped with deflection module, 3 off-axis ion counters (MIC channeltrons; 1x SEM, 2x CDD), and additional Faraday collector.

Marie (named for two-time Nobel Laureate Marie Curie):

  • Thermo Neptune high resolution multicollector ICP-MS.
  • Axial SEM with RPQ energy filter.
  • Configured for low-level Pb isotope analysis.
  • Equipped with 3 off-axis MIC channeltrons and 9 Faraday collectors.

How it works

Our mass spectrometers:

  1. Ionize the sample by stripping off electrons and directing the ions, using electrostatic lenses in a high vacuum, to an electromagnet (or other type of mass analyzer).

  2. Separate the ions by atomic weight.

  3. Direct ions to one or a series of detectors.

  4. Feed the resulting signals into a computer that calculates isotope ratios and analytical uncertainties.

Soumya Ray on NeptuneSample solution introduction is facilitated by specialized systems, including the ESI Apex Ω, ESI Apex with optional Spiro desolvation module, Aridus II, or conventional glass spray chamber, and ESI SC-2 DX autosamplers are employed for automated analyses.
 

Our mass spectrometry facility has the ability to analyze both sample solutions and solid samples, the latter by way of a Photo Machines 193 nm laser ablation system.