https://doi.org/10.1351/goldbook.09374
Particle energy after an elastic collision divided by the energy before the collision, in the laboratory frame of reference.
Note: The symbol \(K\) is often used for the kinematic factor and might have a subscript added in ion-scattering spectrometry or Rutherford backscattering spectrometry measurements, denoting the target atom as either, say, \(K_{\ce{Si}}\) or \(K_{28}\). The subscript for atomic mass is preferred, since the isotope is correctly identified.