Kalpha

Kalpha, often written as Kα, refers to a family of characteristic X-ray emission lines produced when an electron transitions to the K shell (n = 1) of an atom from a higher shell. The Kα family primarily comprises two closely spaced lines, Kα1 and Kα2, which arise from transitions from the L3 and L2 subshells to the K shell, respectively, due to fine structure in the L shell.

Production of Kα radiation occurs when a vacancy is created in the K shell, typically by ionizing radiation, high-energy electrons, or particle impact. As electrons from higher shells fill the vacancy, the energy released is emitted as a photon with an energy specific to the element and the transition. The Kα photon energy equals the difference between the binding energies of the two shells involved.

The energy of Kα photons is characteristic of the element and increases with atomic number. Consequently, Kα lines provide elemental fingerprints and are widely used for qualitative and quantitative analysis. In practice, Kα radiation is observed in X-ray fluorescence (XRF), electron probe microanalysis (EPMA), and related spectroscopic techniques, where the line positions and intensities help identify and quantify elements in a sample. The Kα lines are related to other transitions such as Kβ (to the K shell from the M shell) and are analyzed within the broader framework of X-ray spectroscopy and Moseley’s law, which links line energies to atomic number.