Thermal Ionization Mass Spectrometers (TIMS)

The DCIG Mass Spectrometry Laboratory currently houses three solid source mass spectrometers, a filament degassing apparatus, DOS-and Windows-based microcomputers, and two laminar flow benches for sample loading. The mass spectrometers have dedicated positive and negative ion collimators.

Our thermal mass spectrometers are a Sector 54-IT (bought in 1992) with 8 Faraday collectors and a 20-sample turret, a GV Instruments IsoProbe T system (bought in 2007) with 9 Faraday collector, 4 channeltrons and a new-generation ISOTOPX Phoenix system with 8 Faraday collectors and a rear-end SEM counting device. With the axial Faraday cup moved out of place, small ion beams may be measured using a Daly knob-photomultiplier tandem.

The instruments are routinely used for Sm-Nd, Rb-Sr, and U-Th-Pb isotope analyses, and lately the analytical schemes for non-traditional stable isotopes (Cr and Ce) have been implemented. In negative polarity, high abundance Os samples have commonly been analyzed using multiple faraday cups. The two newer instruments also have an electron multiplier which can be used to measure small negative ion beams.

Left: GV Instruments IsoProbe T system. Right: ISOTOPX Phoenix system. Photos: Kent Pørksen