Topic: How to determine astrophysically relevant energies

Frequently it is important to know at which energies a change in a cross section or S-factor actually leads to a change in the resulting astrophysical reaction rate. Usually it is only a narrow energy range which is important but it depends on the temperature.

Approximation formulas for charged and neutral projectiles are given in textbooks but those are insufficient for the application to intermediate and heavy targets.

A large scale study of the proper energy windows has been published in Physical Review C 81, 045807 (2010), including an extended table with the actual energy windows. It was found that the relevant energy range can be shifted by several MeV (or sometimes tens of MeV) with respect to the energies obtained from the standard approximations. Although the results were obtained with cross sections averaged over many resonances, the derived energy windows are also applicable to resonant reactions, where they show the energy range of relevant resonances (although the individual contribution of resonances, i.e., how much each resonances contributes within the window, cannot be estimated).

It is recommended that the energy windows are taken from this table instead of using the standard approximation.

(see also this topic)