Generation of beams of charged particles with transverse energy

The paper describes the operation and construction of an electron gun designed to form beams with variable transverse energy and a variable spread of magnetic moments. Transverse energy is acquired by the electrons as the beam passes through a weakly non-adiabatic magnetic step, and in an adiabatic motion through a growing magnetic field. The small spread of magnetic moments of the beam electrons is achieved by fulfilling the so-called focusing conditions which ensure that the spread of moments resulting from different initial radii of the particles is compensated by their initial radial velocities.