Use of internal targets for investigations of accelerated-particle beams in atomic physics

The methods of experiments in atomic physics with linear and cyclic accelerators and in external particle beams with the use of various internal targets (corpuscular, photon, and in the form of spatially localized electromagnetic fields) are reviewed. The features of forming secondary particles coming from the beam and measurements of cross sections for elementary processes are described. Examples of generating various charge and quantum states of beam particles and investigations using them based on targets of a different kind separated or superimposed on the path length are given. It is shown that the atomic processes proceeding in this case can be controlled by applying appropriate electric, magnetic, and electromagnetic fields in the interaction region.