ISO 14594:2024

Overview

ISO 14594:2024 - Microbeam analysis: Electron probe microanalysis (EPMA) provides standardized guidelines for selecting and determining experimental parameters when performing wavelength dispersive X‑ray spectroscopy (WDS/WDX) on well‑polished specimens with normal beam incidence. This third edition (revising ISO 14594:2014) defines procedures and measurement practices to ensure reliable, reproducible EPMA results and is explicitly not applicable to energy dispersive X‑ray spectroscopy (EDS/EDX).

Key topics and technical requirements

• Experimental scope: Parameters covering the electron probe, wavelength spectrometers, and specimen preparation and geometry.
• Electron probe parameters:
  • Accelerating voltage (typical range 2–30 keV) and its influence on sensitivity and analysis volume.
  • Probe current: measurement, calibration, stability and correction (scaling peak/background intensities when current varies).
  • Probe diameter and magnification calibration for scanning modes.
• Wavelength spectrometer parameters:
  • Take‑off angle, wavelength resolution (FWHM), detector and pulse‑height analyser considerations.
  • Peak location, background definition and subtraction methods.
• Specimen‑related parameters:
  • Analysis area, analysis depth, analysis volume (definitions based on a defined fraction of emitted X‑rays, e.g., 95%).
  • Surface roughness, stage positioning, and X‑ray line choice.
• Measurement procedures:
  • Methods for determining probe current and diameter, dead time correction, wavelength resolution of detected peaks, and background subtraction.
  • Informative annexes include estimation methods for analysis area/depth and Monte Carlo simulation for analysis volume.
• Quality and reporting:
  • Test report content and links to laboratory competence standards (e.g., ISO/IEC 17025:2017).

Applications and users

ISO 14594:2024 is intended for laboratories and professionals performing quantitative and qualitative EPMA with WDS, including:

• Materials science and metallurgy labs for phase and composition analysis.
• Geoscience and mineralogy researchers mapping elemental distributions.
• Semiconductor and thin‑film analysis where high spectral resolution is required.
• Failure analysis, corrosion studies, and quality control in manufacturing.
• Calibration and testing laboratories seeking reproducible measurement protocols and traceable reporting.

Related standards

• ISO/IEC 17025:2017 - General requirements for the competence of testing and calibration laboratories (normative reference).
• ISO 23833 (terminology and related microbeam analysis definitions referenced in ISO 14594).

ISO 14594:2024 is essential for EPMA practitioners who require clear, standardized guidance on setting experimental parameters for wavelength dispersive spectroscopy (WDS/WDX) to improve measurement accuracy, reproducibility, and reporting.