New method for the calibration of three-dimensional atom-probe mass spectra

A new method for the calibration of three-dimensional atom-probe (3DAP) microscopy mass spectra has been developed. This method is based on a linear regression procedure that takes full advantage of the large number of data points collected during a typical 3DAP analysis. The data analysis procedures involved in the method are direct, relying only on simple scripting routines written in a spreadsheet program. When performed properly, the calibration ensures that all of the peaks in a mass spectrum lie at their expected positions, making subsequent peak identification and mass window determination procedures relatively unambiguous. One of the distinct advantages of the method is that mass windows determined for one 3DAP spectrum can be applied directly to subsequent spectra from similar specimens, avoiding the need to re-examine the individual peaks in each spectrum. The example of the calibration of a tungsten 3DAP mass spectrum is presented. With minor modifications, the method can be applied to the calibration of spectra from other techniques that utilize time-of-flight mass spectrometry.