Internal Ionization of an Atom due to β-Decay of Tritium
The problem of internal ionization in beta decay of tritium due to the Coulomb interaction of a beta electron and a bound electron is discussed. The total probability of the process is calculated. The one-electron probability distributions of the momentum and kinetic energy are constructed. In all calculations, the identity of electrons is taken into account. The modification of the beta spectrum due to internal ionization is of interest for the KATRIN experiment, designed to measure the mass of an electron antineutrino. The high luminosity of the source also makes it possible to search for keV-scale sterile neutrinos in the middle part of the beta spectrum, where the internal ionization effect is significant.