Swamp plots for dynamic aperture studies of PEP-II lattices

Abstract

With a newly developed algorithm using resonance ba sis Lie generators and their evaluation with action-angle Poisson bracket maps (nPB tracking) we have been able Lo perform fasl tracking for dynamic aperture studies of PEP-II lattices as well as incorporate lattice n on linearities in beam-beam studies [l]. We have been able to better un derstand the relationship between dynamic apertures and the tune shift and resonance coefficients in the generators of the one-turn rr»aps [2]. To obtain swamp plots (dynamic aperture vs. working point) of the PEP-II lattices, we firsL compute a one-turn resonance basis map for a nominal working point and then perform nPB tracking by switch ing the working point while holding fixed all other terms in the map. Results have been spot-checked by comparing with element-by-element tracking.

Lattice design for the High Energy Ring of the SLAC B-Factory (PEP-II)

“…The synchro-betatron sidebands of the half-integer resonance 2vz -nv, are troublesome due to the imperfect correction of the high order chromaticity. Nevertheless, the performance in those regions equals that of the interleaved scheme and vastly outperforms it elsewhere in the tune diagram [5].…”

Analytic nonlinear methods for beam optics

“…In this way the behavior of our lattices could be studied in the entire tune plane, rather than just one point. [13] …”