Randall R. Parrish, Randall R. Parrish, Stephen R. Noble; Zircon U-Th-Pb Geochronology by Isotope Dilution — Thermal Ionization Mass Spectrometry (ID-TIMS). Reviews in Mineralogy and Geochemistry ; 53 (1): 183–213. doi: https://doi.org/10.2113/0530183
ID-TIMS is the acronym for Isotope Dilution Thermal Ionization Mass Spectrometry. This refers to the addition of an isotope tracer to a dissolved sample to make a homogeneous isotopic mixture, and the measurement of isotopic composition of the mixture using a thermal ionization mass spectrometer. The method is one of the most accurate and precise methods of isotopic techniques because it is relatively insensitive to chemical yields or mass spectrometric sensitivity. It is a method very widely applied both in earth and many other areas of science involving the measurement of element or isotope concentrations and isotopic ratios.