Beam sampling: taking samples at the micro-scale.

Area of Science:

• Analytical Chemistry
• Materials Science
• Metrology

Background:

• In situ beam measurements inherently involve sampling.
• Measurement uncertainty must account for sampling processes.
• Analyte heterogeneity is a primary source of sampling uncertainty.

Purpose of the Study:

• To highlight the necessity of including sampling uncertainty in beam measurements.
• To emphasize the importance of reliable uncertainty estimates for fitness-for-purpose.
• To demonstrate the broad applicability of this approach across different scales and techniques.

Main Methods:

• Implicit sampling in beam-based analysis.
• Quantification of uncertainty stemming from analyte heterogeneity.
• Application to various analytical techniques.

Main Results:

• Sampling uncertainty often dominates beam measurement uncertainty.
• Reliable uncertainty estimation enables rigorous interpretation.
• The approach is scalable from millimeter (pXRF) to micron (SIMS) scales.

Conclusions:

• Accounting for sampling uncertainty is essential for accurate in situ beam measurements.
• Fitness-for-purpose assessment relies on robust uncertainty quantification.
• This framework supports the reliable analytical assessment of materials across diverse scales.