Control of the Beam Spill at the PPA

The PPA machine operates on a 20 cycle per second machine rate and is not flat topped. Due to these two factors spill lengths in the region of 5 - 10 milliseconds are not only "long" but contain up to 10% energy modulations. Conversely "short" spills are those occuring in less than a few hundred microseconds. Another unusual feature of the PPA machine is the one to two nanosecond rf bunch width at spill time. This feature was inherent with the first spill techniques and has proven invaluable to experimenters doing time of flight measurements in neutral secondary beams and separating K\´s from ¿\´s.