X-Rays and Their Characteristic Lines in the Spectrum
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X-rays are a type of electromagnetic radiation with very short wavelengths and high frequencies.
How is X-ray radiation generated?
In principle, there are two ways in which X-rays can be generated:
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Option #1: X-rays are generated through the acceleration (or deceleration) of electric charges. According to electrodynamics, accelerated electric charges produce electromagnetic radiation. The wavelength of the generated electromagnetic radiation depends on the strength of the acceleration. Bremsstrahlung are fast electrons which collide with an anode, producing X-rays due to their acceleration.
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Option #2: X-rays are generated using energy levels within an atom. Characteristic Radiation is X-ray radiation that occurs when electrons transition from higher energy levels to the lowest energy levels. In this process, X-rays are emitted that are dependent on the atomic species (hence, "characteristic").
An electron moves to a lower energy state and emits electromagnetic radiation.
Characteristic lines (K-alpha, K-beta) in the X-ray spectrum
The intensity \(I\) of the light (or count rate of the photons) is plotted as a function of the wavelength \(\lambda\). \( K_{\alpha} \) and \( K_{\beta} \) are two characteristic spectral lines that occur during the emission of X-rays. The main difference between these two lines lies in their energy and frequency.
\( K_{\alpha} \)-line has a higher energy and frequency than the \( K_{\beta} \)-line. K-alpha is created when an electron falls from the K-shell of the atom onto a hole in the L-shell, while the K-beta line is created by the transition of an electron from the K-shell to a hole in the M-shell.
The differences in the energy levels and electron transitions lead to different frequencies and energy emissions, which makes it possible to specifically identify and distinguish them. In X-ray spectroscopy, these characteristic lines are used to identify the atom or molecule that has emitted the X-rays.