#electron_beam__beam__ray  a group of nearly parallel lines of electromagnetic radiation
  supertype:  electromagnetic_radiation__electromagneticradiation__electromagnetic_wave__electromagneticwave__nonparticulate_radiation  radiation consisting of waves of energy associated with electric and magnetic fields resulting from the acceleration of an electric charge
  subtype:  cathode_ray__cathoderay  a beam of electrons emitted by the cathode of an electrical discharge tube
  subtype:  particle_beam  a collimated flow of particles (atoms or electrons or molecules)
     subtype:  ion_beam__ionbeam__inoic_beam__inoicbeam  a beam of ions moving in the same direction at the same speed

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