Simulating electron-excited energy dispersive X-ray spectra with the NIST DTSA-II open-source software platform

Area of Science:

• Materials Science
• Analytical Chemistry
• Physics

Background:

• Electron-excited X-ray microanalysis is crucial for elemental composition determination.
• Energy Dispersive Spectrometry (EDS) is a common technique, but accurate spectral simulation is challenging.
• NIST DTSA-II provides a comprehensive platform for EDS analysis.

Purpose of the Study:

• To evaluate the accuracy of NIST DTSA-II's EDS spectral simulations.
• To assess the software's utility in developing analytical strategies for microanalysis.

Main Methods:

• Utilized Monte Carlo electron trajectory simulation for X-ray generation and transport.
• Included physical processes: characteristic and continuum X-ray generation, self-absorption, EDS window absorption, and energy-to-charge conversion.
• Simulated spectra on an absolute basis using electron dose and spectrometer parameters.

Main Results:

• Simulated K-shell and L-shell characteristic X-ray peaks (1-11 keV) showed good agreement (± 25%) with measured spectra.
• M-shell intensity predictions exceeded measured values by 1.4-2.2 (1-3 keV).
• X-ray continuum (bremsstrahlung) intensity agreed within ± 10% (1-10 keV) for elements B to Bi.

Conclusions:

• NIST DTSA-II offers reliable spectral simulations for K and L shells and continuum radiation.
• The software is a valuable tool for optimizing EDS analytical strategies and assessing trace element detection.
• Further refinement may be needed for accurate M-shell intensity predictions.