Beam extraction of the PoP FFAG with a massless septum

We propose a new extraction scheme with a massless septum magnet in FFAG accelerator, with which the DC beam can be extracted. The system consists of a combination of massless and ordinary septa without kickers. After passing through the massless septum, the beam tail is stretched by the field gradient of the massless septum magnet, and that can be extracted with an ordinary septum. From the result of the tracking simulation, the principle of the extraction scheme is verified. The result of the performance test of the massless septum indicates that the magnet works well as designed, and this scheme is feasible.