Electromagnet for a betatron

The betatron electromagnet comprising a multicolumn reverse magnetic circuit is described. In its centre poles realized in a form of a central cylindrical core with ridges, magnetization coil enbracing the poles and the output coil located on the poles surface. With the aim of increasing the output efficiency of accelerated electrons the pole ridges are realized in such a manner that one of their lateral sides is radius directed and the other - tangentdirected to the cirde of the central core. Such betatron electromagnet fabrication permits firstly to increase the output efficiency of the accelerated electrons approximately up to 80% and, in the second, place to decrease the magnetic field energy required for electrons out put out side the accelerator