CYCLOTRON AND QUENCH BACK METHOD OF SUPERCONDUCTING COIL

PROBLEM TO BE SOLVED: To provide a cyclotron capable of realizing highly reliable quench back and a quench back method of a superconducting coil.SOLUTION: A cyclotron 1 is provided with superconducting coils 2,3 arranged inside a vacuum chamber 4 and a refrigerator 7 which cools down the superconducting coils 2,3, and also provided with a control section 11 which detects quench of the superconducting coils 2,3, and controls supply of quenching gas for quenching the superconducting coils 2,3, and a gas flow passage 13 for sending the quenching gas to the vicinity of the superconducting coils 2,3. In the case where the control section 11 detects the quench of one superconducting coil and does not detect the quench of the other superconducting coil out of the superconducting coils 2,3, the control section quenches the other superconducting coil by supplying the quenching gas to the vicinity of the other superconducting coil through the gas flow passage 13 to raise the temperature of the coil.