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Glossary terms about X-rays

X-rays

X-rays are electromagnetic radiation with wavelengths in the range 0.01 to 10 nm.

▼2 more terms contain X-rays

X-rays

X-rays are electromagnetic radiation with wavelengths in the range 0.01 to 10 nm.

Bremsstrahlung X-rays

Braking radiation. X-rays produced by slowing down of the primary-beam electrons by the electric field around atomic nuclei in the sample.

Characteristic X-rays

X-rays with discrete energies reflecting the electronic configuration of the parent atom, produced after ionization of an inner electron shell and subsequent relaxation of the excited atom.

22 pages mention X-rays

Accuracy, Precision and Detection Limits

It depends on the number of x-rays in the spectrum and the statistics related to that number. 

Additional material

 

Auger animation

 

Background information - What is energy dispersive X-ray spectroscopy?

Two types of x-rays result from these interactions: Bremsstrahlung x-rays, which means ‘braking radiation’ and are also referred to as Continuum or background x-rays, and Characteristic x-rays. 

Bremsstrahlung animation

 

Bremsstrahlung X-ray generation

Two types of x-rays are produced by interaction of the electron beam with the sample in both the SEM and TEM: Bremsstrahlung (which means ‘braking radiation’) and Characteristic x-rays. 

Characteristic X-ray generation

 

Characteristic X-rays

Characteristic x-rays are produced by electron transitions between the electron shells. 

EDS spectral artifacts

Several artifacts can be produced in ED X-ray spectra because of the way the x-rays are detected and processed. 

EDS spectral resolution

Characteristic x-rays have discrete energies but in the process of detecting and measuring them the discrete lines spread into Gaussian peaks. 

Generation of X-rays in the Electron Microscope

In the SEM, secondary electrons are produced from the surface of the sample or topmost part of the interaction volume; backscattered electrons come from the top half of the interaction volume; and x-rays are generated within the whole of the interaction volume. 

Introduction

The input beam may comprise light (including laser beams), x-rays and other electro-magnetic waves, electrons, protons or ions. 

K-lines animation

 

KL-lines animation

 

L-lines animation

 

M-lines animation

 

Qualitative EDS X-ray microanalysis using SEM and TEM

If this is the case in the SEM, the higher energy X-ray lines may not be efficiently generated and low-energy x-rays will have to be used for element identification, e. 

Quantitative EDS X-ray microanalysis using SEM

The spectra are processed to remove Bremsstrahlung x-rays and spectral artifacts, and then the Characteristic x-rays are compared with data measured from standard reference materials. 

The photoelectric effect

 

X-ray detection by EDS

The most commonly used system in both SEMs and TEMs for detecting the x-rays that are generated and emitted from the sample is the energy dispersive X-ray spectrometer (EDS, EDX or XEDS). 

X-ray intensity

Factors related to the sample, the system used to generate the x-rays and the detector used to measure the X-ray spectrum can all influence the height of the X-ray peaks. 

X-Ray mapping

The raw data for the image is a matrix of integers corresponding to the number of x-rays counted at each point and these are mapped to a single-band image with 0-255 levels.