Fast electromagnet device

A fast electromagnet device which receives a high voltage pulse from a pulse power supply through a transmission line and excites an electromagnet at high speed, so as to bend a charged particle beam, said fast electromagnet device comprising:

• an electromagnet which is formed with a space penetrating in a traveling direction of the charged particle beam, and instantaneously generates a magnetic field in the space with the high voltage pulse applied, so as to bend the particle beam passing through the space, said electromagnet being equivalent to a circuit element of a lumped constant circuit;
• and
• an auxiliary circuit which constitutes a matching circuit in combination with said electromagnet, so that an input impedance of the matching circuit and a characteristic impedance of the transmission line connected to an input terminal of the matching circuit are matched,
• wherein the matching circuit includes a bridged-T four-terminal circuit connected to the transmission line, a bridge of said bridged-T four-terminal circuit being a coil which constitutes said electromagnet.