09402 IUPAC Gold Book - g index 10.1351/goldbook.09402 09402 current 1 Power for the ratio of mass intensities in two mass spectra measured for two different primary ion conditions, used to generate the G-SIMS spectrum. The different primary ion conditions can be two, well-separated, energies for the same primary ion or two different primary ions, usually at the same beam energy. A value of 13 has been found to be effective for the g index in generating G-SIMS spectra and a continuous variation between 0 and 40 for analysis. G-SIMS https://goldbook.iupac.org//terms/view/09186 primary ion https://goldbook.iupac.org//terms/view/09414 PAC, 2020, 92, 1781. 'Glossary of methods and terms used in surface chemical analysis (IUPAC Recommendations 2020)' on page 1839 (https://doi.org/10.1515/pac-2019-0404) https://goldbook.iupac.org/terms/view/09402/html https://goldbook.iupac.org/terms/view/09402/json https://goldbook.iupac.org/terms/view/09402/plain Citation: 'g index' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.09402 The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) for individual terms. If you are interested in licensing the Gold Book for commercial use, please contact the IUPAC Executive Director at executivedirector@iupac.org . The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using. 2026-08-04T18:08:16+00:00