Nuclear Reactions & Astrophysics

A nuclear reaction is a rather general term to describe the most fundamental phenomenon that Nuclear Physics deals with. The baby steps of Nuclear Science were completed on investigations of nuclear reactions with alpha particles emitted from radiation sources, such the Ra-226 alpha source Rutherford used to discover the atomic nucleus.

Nuclear Reactions are the most essential tools to probe nuclear matter and obtain critical information on new phenomena. The structure of isotopes is investigated via reactions that force the nuclei to shake and reveal their essence. There are several types of reactions and most of them deal with transmutation of nuclei, where the strong and weak nuclear forces are rulers of the phenomena. However, electromagnetic interactions between beams and targets are also considered nuclear reactions; a very common example is Coulomb excitation, commonly used to study the electromagnetice properties of nuclei.

With the advent of radioactive beams, scientists use reactions between exotic species to investigate the extremes of the nuclear chart. In that direction, nuclear astrophysics is a subject that has been boosted significantly in recent years. Exotic probes and unstable systems can be now used to explore phenomena that drive the production of nuclear fuel in distant stars and trace down the birth, life and death of cosmic objects. Universal matter is created and transmutes via certain paths of interconnected nuclear reactions that may take millions of years to complete. Since this information is very hard to reproduce at the lab, it is desirable to measure the probability of a nuclear reaction in a large network by means of individual cross section measurements.

Moreover, nuclear reactions are in the core of the nuclear analytical techniques with a great number of applications to several scientific fields, such as geochemistry, nanoscience, biology etc. Techniques such as Rutherford BackScattering (RBS) or Nuclear Reaction Analysis (NRA) have become common tools to obtain the thickness, stoichiometry, density and several other properties of samples. Applications are virtually endless.

The NuSTRAP has several joint activities in experiments with nuclear reactions, focused on three main directions: a) investigate the dynamics of nuclear reactions via spin polarization measurements b) understand the role of exotic species in the star formation and c) use nuclear reactions to study the role of natural elements in the geochemical and environmental cycle.