Thermal Ionization Mass Spectrometry (TIMS) is used to measure isotopic compositions for the elements Mg, Ca, Cr, Sr, Nd, Pb, Hf, and others. These measurements are traditionally used to conduct geological or protoplanetary studies in one of two ways: to determine geological ages of formation of a wide variety of materials, and to identify subtle geochemical "fingerprints" that reveal interaction among different reservoirs for the terrestrial planets and early formed nebular materials. A recent novel development is the detailed study of isotopic fractionation of middle mass elements (e.g., Mg and Ca), which have the potential to reveal distinct physiochemical formation mechanisms for planetary and early solar system materials.
A generation of measurements of planetary materials were made utilizing Thermo-Finnigan MAT 261 and 262 solid source mass spectrometers. Each was equipped with multi-collectors and capable of high precision Sr (±15 parts per million in the ratio with 100 ng total Sr) and Nd (±10 ppm in the ratio with 100 ng total Nd). These units have since been retired from ARES and are no longer in use.
Our newest TIMS is the Thermo-Finnigan Triton TI that has eight movable Faraday bucket collectors. It is designed for a wide mass range, t is particularly useful for non-traditional middle mass isotope work. Its capability for very high-precision isotopic measurements will enhance our search for the nucleosynthetic components of our solar system and the evolution of our protoplanetary disk, Lunar and Martian chronology, and magmatic processes of differentiated asteroids and terrestrial planets.
We are in the process of modernizing our cleanroom facilities, part of which is devoted to a clean chemistry laboratory for low-blank separation of elements of interest for isotopic studies. The main part of the clean laboratory is designed to provide a general level class 10,000 air, with specified class 1,000 to class 100 work areas. Controlled clean mineral separation and rock preparation laboratories are used for preparing meteorite and planetary samples.
Support facilities used in sample preparation include a Frantz isodynamic magnetic separator, exhaust fume hood for heavy liquids separation, a low-flow particle hood and binocular microscope for mineral picking, and a microMill drilling system designed for precise low-volume in situ sampling. All instruments are dedicated for the processing of meteorite and lunar samples.