Related Processes

Abstract

Cross sections for nuclear reactions leading to a change in mass and/or identity of the projectile are much smaller than for atomic processes except for relativistic heavy ions with more than several hundred MeV/u, at which energies they may become comparable. This is illustrated in Fig. 11.1 where the nuclear reaction probability is calculated for different ions in carbon, aluminum and lead. The total nuclear-reaction cross section applied in this calculation consists of a pure nuclear part calculated according to Shen & al. (1989) and a component due to electromagnetic dissociation (Bertulani and Baur, 1988), which contributes mainly for large \(Z_1\) and/or \(Z_2\). The comparison demonstrates that for lighter projectiles and lighter stopping media the losses due to nuclear reactions are severe. This is the reason why light materials like beryllium are preferred as production targets in high-energy fragmentation reactions. Conversely, for electromagnetic dissociation of relativistic projectiles, lead targets are used successfully in studies and applications of exotic nuclei (Geissel, 1997). ...