ISO/TC 201/SC 6/WG 4 - Organic and Nano SIMS

This document specifies a method for determining the maximum count rate for an acceptable limit of divergence from linearity of the intensity scale in single ion counting time-of-flight (TOF) secondary ion mass spectrometers using a test based on isotopic ratios in spectra from poly(tetrafluoroethylene) (PTFE). It also includes a method to correct for intensity nonlinearity arising from intensity lost from a microchannel plate (MCP) or scintillator and photomultiplier followed by a time-to-digital converter (TDC) detection system caused by secondary ions arriving during its dead-time. The correction can increase the intensity range for 95 % linearity by a factor of up to more than 50 so that a higher maximum count rate can be employed for those spectrometers for which the relevant correction formulae have been shown to be valid.

This document specifies a method for measuring and reporting argon cluster sputtering yield volumes of a specific organic material. The method requires one or more test samples of the specified material as a thin, uniform film of known thickness between 50 and 1 000 nanometres on a flat substrate which has a different chemical composition to the specified material. This document is applicable to test samples in which the specified material layer has homogeneous composition in depth and is not applicable if the depth distribution of compounds in the specified material is inhomogeneous. This document is applicable to instruments in which the sputtering ion beam irradiates the sample using a raster to ensure a constant ion dose over the analysis area.

This document specifies a method to optimize the mass calibration accuracy in time-of-flight secondary ion mass spectrometry (SIMS) instruments used for general analytical purposes. It is only applicable to time-of-flight instruments but is not restricted to any particular instrument design. Guidance is provided for some of the instrumental parameters that can be optimized using this procedure and the types of generic peaks suitable to calibrate the mass scale for optimum mass accuracy.

ISO 17862:2014 specifies a method for determining the maximum count rate for an acceptable limit of divergence from linearity of the intensity scale in single ion counting time-of-flight (TOF) secondary ion mass spectrometers using a test based on isotopic ratios in spectra from poly(tetrafluoroethylene) (PTFE). It also includes a method to correct for intensity nonlinearity arising from intensity lost from a microchannel plate (MCP) or scintillator and photomultiplier followed by a time-to-digital converter (TDC) detection system caused by secondary ions arriving during its dead-time. The correction can increase the intensity range for 95 % linearity by a factor of up to more than 50 so that a higher maximum count rate can be employed for those spectrometers for which the relevant correction formulae have been shown to be valid. ISO 17862:2014 can also be used to confirm the validity of instruments in which the dead-time correction is already made but in which further increases can or cannot be possible.