FIELD: acceleration equipment, development of betatrons with extracted electron beam for radiation therapy. SUBSTANCE: method includes expansion of orbit of accelerated electrons, scattering of accelerated electrons over metal foil mounted in disengagement orbit where radial focusing forces of controlling field are equal to zero. In this case scattering is conducted within controlled solid angle by selection of thickness and material of scattering foil mounted perpendicular to axis of beam. Its azimuthal position relative to extraction window of acceleration chamber is chosen depending on obtainment of maximum efficiency of extraction of accelerated electrons. EFFECT: formation of electron fields of large linear dimensions in vertical and horizontal planes. 9 dwg
