An isochronous lattice for PEP

It is demonstrated that an isochronous lattice design is compatible with the Positron Electron Project (PEP) given a minimum of hardware modifications. The configuration is based on a succession of supercells (3 FODO cells each) with regions of negative dispersion and betatron phase advance between pairs of compensating sextupoles fixed at (2n+1) pi . The configuration requires no magnet relocations or quadrupole polarity reversals and does not exceed power load ratings for a 9-GeV beam. The theoretical bunch length is about 3.5 mm at 9 GeV (V/sub RF/= 15 MV), but smaller values could in principle be reached by correcting the longitudinal chromaticity with additional sextupole families.<
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