Resonant Extraction at the Zero Gradient Synchrotron (ZGS)

A resonant extraction scheme utilizing the ¿r = 1 integral resonance has been successfully used at the ZGS. The system consists of a full sextupole magnet used to drive the unstable protons radially inward toward a 1.5-mm septum magnet located three octants (¿ 0.3 betatron wavelengths) downstream. The thin septum magnet jumps the protons radially inward across the thick septum of the regular extraction magnet two octants further downstream. This magnet drives the beam outward into the extraction chain one octant later. Due to the scalloping of ZGS orbits at high energy, it is not necessary to plunge any of these magnets.