BS ISO 20411:2018

Surface chemical analysis. Secondary ion mass spectrometry. Correction method for saturated intensity in single ion counting dynamic secondary ion mass spectrometry. | Status: Current, Project Underway

1 Scope This document specifies a method for determining the maximum count rate for an acceptable limit of divergence from linearity of the intensity scale in pulse counting magnetic sector-type secondary ion mass spectrometers or quadrupole secondary ion mass spectrometers. It uses a test based on depth profile analysis of two isotopes in a reference material which has a gradual concentration change between low and high concentration regimes. It also includes a correction method for saturated intensity caused by the dead time of the detector. The correction can increase the intensity range for 95 % linearity so that a higher maximum count rate can be employed for those spectrometers for which the relevant correction equations have been shown to be valid. This document does not apply to time of flight mass spectrometers. This document is only applicable to elements with minor isotopes. It is not applicable if the element is monoisotopic or contains isotopes with equal abundances.