X-Ray Spectroscopy in a charged-particle microscope

A charged particle microscope comprising:

• a source, for producing a beam of charged particles, and directing the beam of charged particles onto said specimen;
• a detector for detecting X-ray radiation emanating from the specimen in response to said irradiation, and, in response, to produce a spectrum comprising X-ray characteristic peaks on a Bremsstrahlung background;
• a controller for controlling at least some operational aspects of the microscope, said controller configured to:
• use an elemental decomposition algorithm to analyze the characteristic peaks in said spectrum;
• determine based on the characteristic peaks in said spectrum, a reference group of major chemical elements contributing to the spectrum;
• calculate an average atomic number for said reference group;
• generate, with a predictive model, a calculated Bremsstrahlung profile for the reference group;
• fit said calculated Bremsstrahlung profile to the Bremsstrahlung background in said spectrum and
• attribute a discrepancy between the Bremsstrahlung profile and the Bremsstrahlung background to a residual element absent from, or incorrectly quantified in, said reference group.

A method comprising:

• acquiring an x-ray spectrum of a sample, the spectrum at least including characteristic peaks of a reference group of elements forming the sample and a Bremsstrahlung background;
• based on the x-ray spectrum, determining an average atomic number of the reference group of elements;
• based on the average atomic number, determining a Bremsstrahlung profile for the reference group of elements;
• comparing the Bremsstrahlung profile to the Bremsstrahlung background to determine a difference;
• and
• based on the difference, determine whether a residual element is absent from or incorrectly quantified in the reference group of elements.