New Injection Scheme at the ZGS
A new scheme of injection into the Zero Gradient Synchrotron (ZGS) from the 50 MeV linac was implemented, and we have obtained a factor of two in the accelerated beam intensity. The new scheme consists of lowering the B during the early acceleration period in order to enlarge the RF bucket area and injection period, tuning the debuncher to achiieve the minimum instantaneous energy spread of ±100 keV, and ramping the debuncher phase so that the instantaneous momentum of the injected beam during the injection period follows the rise of the ring magnetic field strength. By doing so, the betatron amplitude is set close to minimum, and the total energy spread accumulated during the injection period due to the energy ramp by the debuncher phase ramp would fit the RF acceptance. This method has been used for all three operating modes of the ZGS (unpolarized proton, polarized proton, and H- injection).