https://doi.org/10.1351/goldbook.09419
In dynamic secondary-ion mass spectrometry, coefficient for an element by which the measured intensity for an isotope of that element, divided by the measured intensity for a matrix ion, is multiplied to yield the atomic concentration of that isotope of the element present in the sample.
Note: Matrix terms are strong, and the matrix, bombarding species, incident-ion energy, and angle of incidence, as well as the spectrometer operating conditions, all affect relative elemental sensitivity factors significantly.