| 摘要 |
PURPOSE:To suppress eddy current down to a small level at a fully fast speed by increasing the excitation current of a magnet in compliance with a specific function form and decreasing the excitation current just by a specified value in compliance with the similar fucntion form when a time constant or the time that is close to the constant elapses. CONSTITUTION:Suppose that the time constant is T, the time is t, and T is set to half to one tenth of T in a circuit 7 where eddy current flows, being generated for the purpose of varying the strength of a magnetic field in response to the ion with the different mass number in relation to a magnet 6 that generates the magnetic field which varies the motion of a charged particle such as an ion depending upon the mass number, the excitation current of the magnet 6 is increased in compliance with the function form of (1-e-t/T). In addition, when the time constant T or the time hat is close to it elapses, the excitation current is decreased depending upon the fucntion form of k(1-e-t/T) where k is a constant. For example, a magnet drive circuit 5 is driven by outputting a current waveform control signal B to a constant current circuit 4 from a current waveform control circuit 1 provided with a time constant circuit 1f and the like with the same time constant as the time constant T of the eddy current circuit 7. |
