Abstracts Brochure - CERN

THPLS087
THPLS088
THPLS089
THPLS090
29-Jun-06 16:00 - 18:00 THPLS — Poster Session
A Control Theory for Dynamic Aperture
The dynamic aperture problem dates back
J. Bengtsson (BNL)
to the design of the first synchrotrons. Over
time, both analytical and numerical methods
have been pursued. In the former case mainly by applying techniques developed for celestial mechanics to rather
simplified equations of motion. Over the last decade, analysis of the Poincare map has become the method of choice.
In particular, application of symplectic integrators, truncated power series algebra, and Lie series techniques has
led to a complete set of tools for self-consistent numerical simulations and analytic treatment of realistic models.
Nevertheless, a control theory for the general nonlinear case remains elusive. We summarize how to apply this
framework to the design of modern synchrotron light sources. Moreover, we also outline how a control theory can be
formulated based on the Lie generators for the nonlinear terms.
Optimizing the Dynamic Aperture for Triple Bend Achromatic Lattices
The Triple Bend Achromatic (TBA) lattice has
S.L. Kramer, J. Bengtsson (BNL)
the potential for lower natural emittance per
period than the Double Bend Achromatic
(DBA) lattice for high brightness light sources. However, the DBA has been chosen for 3rd generation light sources
more often due to the higher number of undulator straight section available for a comparable emittance. The TBA has
considerable flexibility in linear optics tuning while maintaining this emittance advantage. We have used the tune
and chromaticity flexibility of a TBA lattice to minimize the lowest order nonlinearities using a high order achromatic
tune condition, while maintaining a constant emittance. This frees the geometric sextupoles to counter the higher
order nonlinearities. This procedure is being used to improve the nonlinear dynamics of the TBA as a proposed lattice
for the NSLS-II facility. The flexibility of the TBA lattice will also provide for future upgrade capabilities of the beam
parameters.
Comparison of Double Bend and Triple Bend Achromatic Lattice Structures for NSLS-II
The Double Bend Achromatic (DBA) and the
S.L. Kramer (BNL)
Triple Bend Achromatic (TBA) lattice have
been studied rather extensively for use for
the NSLS-II storage ring. The well known advantage of the TBA compared to the DBA is that the emittance per period
has the potential to be considerably lower. However, the DBA has been chosen more often due to the greater number
of ID straight sections for the users for a desired emittance. We present a comparison of these lattice structures based
on the optimization of the non-linear driving terms from the chromatic sextupole and the ease of compensation of
these terms using the higher order achromatic cancellation.
Consideration of the Double Bend Achromatic Lattice for NSLS-II
We present the results of a study of the Dou-
S. Krinsky, J. Bengtsson, S.L. Kramer (BNL)
ble Bend Achromatic (DBA) lattice as a possible
choice for the NSLS-II storage ring. The
DBA possesses a large number of straight sections with easily tunable beta functions which can be used for insertion
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