On the emission of the fast $\delta-$electrons during nuclear   $\beta^{-}$-decay in few-electron atoms
  We discuss a possibility to observe fast secondary electrons ($\delta-$electrons) during nuclear $\beta^{-}$-decay in few-electron atoms and ions. Formulas for the corresponding probabilities and explicit expression for the energy spectrum of $\delta-$electrons are derived in the closed analytical forms. 
Alexei M. Frolov
nucl-th physics.atom-ph