Barrier bucket experiment for accumulating de-bunched beam in the GAS

摘要

The AGS accumulates four batches of two bunches from the 1.5GeV Booster at 7.5Hz. At an intensity of 6 x 10(sup 13) protons per AGS cycle, slow beam loss during the 400ms accumulation time is important. The experiment demonstrated the principle of accumulating beam and storing it in an essentially debunched state by using barrier cavities. When the beam is de-bunched the peak-to-average current ratio drops by an order of magnitude. By using two barriers with time varying relative phase, any number of injections is possible, limited only by the momentum acceptance of the ring. In a test with beam, six injections of one bunch yielded 3 x 10(sup 13) protons in the AGS. The benefits of reduced space charge tune shift from lower peak current suggest that barrier cavities may be a path to higher AGS intensities.