Thermal Ionisation Mass Spectrometry

Thermal ionisation, also known as surface ionisation, was one of the first ionisation techniques developed for mass spectrometry, having been invented as early as 1918. The ionization process, described by the empirically derived “fractionation laws”, is widely understood. Isotope ratio measurements can be achieved with high precision and accuracy. Due to this, thermal ionisation has paved the way for great scientific achievements including: the discovery of new isotopes, the determination of radioactive half-lives and atomic weights of the elements, the accurate determination of the age of the earth and investigations on human society in the past such as mobility and trade. TIMS is still regarded as ‘golden standard’ in isotope ratio measurements. Thus the method is a reference technique that remains at the forefront of isotopic analysis particularly in the fields of metrology. A concise overview is given here of the technical background of thermal ionisation as well as the numerous applications of this technique in earth sciences, industry, metrology, and nuclear forensics.