Processing APT Spectral Backgrounds for Improved Quantification.

Area of Science:

• Materials Science
• Analytical Chemistry
• Physics

Background:

• Atom Probe Tomography (APT) generates mass spectra with inherent background noise.
• Accurate background estimation is crucial for reliable quantification and analysis of low-concentration species.

Purpose of the Study:

• To develop a general method for estimating background noise in APT mass spectra.
• To enhance background correction and improve quantification accuracy in APT data.
• To enable more robust analysis of low ionic count species.

Main Methods:

• A mathematically general method is proposed to estimate background noise based on Poisson noise characteristics.
• The method utilizes z-coordinate and mass-to-charge-state data, with optional inclusion of acquisition voltage.
• It can be applied retrospectively to existing APT datasets.

Main Results:

• The method accurately estimates background noise in real experimental APT data.
• Improved estimation of background variance leads to more robust quantification.
• Demonstrated suppression of false positives in peak detection and accurate quantification of low-concentration elements (e.g., 121-Sb in Si).

Conclusions:

• The developed method provides a significant improvement for background correction and quantification in APT.
• It is broadly applicable to all APT data acquisition modes and enhances the analysis of trace elements.
• This technique offers a more reliable approach for identifying and quantifying low ionic count species in complex materials.