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 stop** 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). ...