Gradient-field electron guides for conversion electron studies

This article describes the general concept of the gradient field solenoid lens. Its properties concerning focusing/defocusing and non-dispersivity are underlined. Such a lens can be coupled with other more classical lenses and is well adapted to the measurement of conversion electron transitions, for radioactive decay or in-beam studies. The product of its energy range × luminosity can be very large. Various configurations are discussed and a specific construction is described.