Micro & mini-bunching of the slow external beam at the AGS

The AGS's prime function when RHIC comes on line will be as a heavy ion injector, free time will exist for unique operation that can be tailored and dedicated to users. Many of the next generation of experiments require RF time structure in the spill as it is extracted to time events or assure no background during decay times. Two methods have been developed to meet these needs. Micro-bunching where the beam is forced between empty buckets producing bursts at arbitrary integer harmonics of rotation period, and mini-bunching where the beam is kept bunched to provide high extinction between bursts. With an RF dipole the period may be increased to three times the rotation period of the beam. Further modelling and test results with beam will be presented. At high beam currents above transition, tight clusters of beam form causing severe random spike structure in the spill. Forcing the beam between empty buckets before extraction breaks up these clusters with minimal modulation of the spill at the RF frequency. Results of spill structure and loss reduction will be given.