Focusing electromagnet device in particle accelerator

In a focusing electromagnet device disposed in a particle accelerator, large-scaled power sources had to be provided individually for controlling the intensity of magnetic fields, and electric currents had to be controlled individually and being related to with each other. Then, a pair of electromagnetic main bodies for focusing in a horizontal direction and a vertical direction are arranged in the direction of an orbit of charged particles. An identical current is supplied to each of the electromagnet main bodies from a common power source. Transfer mechanisms are disposed for transferring the respective electromagnet main bodies individually along with the orbit direction. The intensity of the magnetic fields is controlled by controlling the current supplied from the common power source to the pair of electromagnet main bodies, and each of the electromagnet main bodies is transferred forward and backward in the orbit direction by the transfer mechanism, to control the position. The intensity of the magnetic fields can be controlled more easily and more accurately compared with a conventional case. In addition, since a large-scaled power source can be reduced to one half, it is advantageous in view of installation cost and space saving. (N.H.)