A method and apparatus for conducting ion to charged species reactions, more particularly reactions wherein the charged species is an electron, such as ECD. The apparatus comprises first and second pathways which are orthogonal to one another. The first pathway through which ions are introduced comprises multiple multipoles with a gap situated there between. The second pathway introduces the charged species through the gap orthogonally to the first pathway. In this way, a cross-type reaction device allows ion-charged species interactions to occur.