Beam-extraction method using a fast Q-magnet assisted by RF-knockout and the beam characteristics

A slow beam extraction from a synchrotron ring has been proposed, based on controlling a quadrupole field with a fast response (FQ), assisted by a transverse RF-field (RF-knockout). This method can extract prescribed particles at required timings quickly and precisely, because it is controlled with only the fast Q-field. A proof-of-principle experiment has been already carried out at the HIMAC synchrotron successfully. In the following experiment with a Q-magnet coil current of a chopping wave with a constant peak value, it has been shown that the coil current level at beam extraction was almost constant using RF-knockout with colored noise signal. (author)