TIMS (Thermal Ionisation Mass Spectrometry)
Definition
An instrument that ionises a sample deposited on a metal filament and measures ion beam intensities with Faraday collectors. The gold standard for high-precision radiogenic isotope ratios such as Rb-Sr and U-Pb.
- Ionisation method
- Sample on a heated metal filament
- Detector
- Faraday collectors measuring ion beam intensity
- Best for
- High-precision radiogenic isotope ratios
- Example systems
- Rb-Sr and U-Pb isotope ratios
Common questions
Why is TIMS still the reference method despite newer techniques like MC-ICP-MS?+
TIMS produces very stable, low-background ion beams from a solid sample loaded on a filament, giving it exceptional precision for certain isotope systems that remains a benchmark against which faster plasma-source methods are validated.
What does TIMS contribute to a forensic provenance case?+
Radiogenic isotope ratios from TIMS can be matched against geological reference databases to narrow down the geographic region a mineral, metal or other inorganic material originated from, supporting questions of source and trafficking route.
Related terms
- Delta Notation (δ)
- A notation expressing the isotope ratio of a sample relative to an international standard in parts per thousand (per mil, ‰). Positive...
- Epsilon Notation (ε)
- Similar to delta but expressed in parts per ten thousand, used for radiogenic systems where variation is very small. Epsilon Nd and...
- MC-ICP-MS (Multi-Collector Inductively Coupled Plasma Mass Spectrometry)
- An instrument that ionises a liquid or laser-ablated sample in an argon plasma at about 8,000 K and simultaneously collects multiple ion...
- Radiogenic Isotope
- An isotope produced by radioactive decay of a parent nuclide over geological time. Its abundance in a rock or mineral increases predictably...
- Stable Isotope
- An isotope that does not undergo radioactive decay. Ratios of stable isotopes change only through physical or biological fractionation, such as evaporation...