Proton-induced reactions

Proton-induced reactions can be measured in an in-beam experiment or with the activation approach. In an in-beam experiment in standard kinematics, the probe is irradiated with a proton beam provided by an accelerator and the number of reactions is determined generally by the detection of the ejectiles of the reaction (e.g., the emitted photons in a (p,γ) reaction). For the activation approach, the number of the unstable reaction products is determined after the irradiation in a background-reduced setup. This is usually realised by γ or x-ray spectroscopy. In more complicated cases, alternative methods like, e.g., accelerator mass spectrometry are used.

If proton-induced reactions on unstable isotopes are to be investigated inverse kinematics can be used, i.e., the roles of probe and projectile are exchanged. The proton probe can be realized as a gas target or as solid state target with a chemical compound. While the first case is based on a technically complicated system, the second case requires additional measurements to subtract the contributions of the other elements in the compound. If the unstable isotopes are kept in a storage ring the reaction products can be separated by their different tracks in the ring. Another approach is to measure not only in inverse kinematics but in addition also the time-reversed reaction (inverse reaction). Here, the role of incoming and outgoing channel are exchanged which sometimes yields in an easier experiment.


FRANZ at Uni Frankfurt
Notre Dame