| DATE: |
2007-12-12 13:30 - 15:30 |
| PLACE: |
Meeting room at KEKB control building |
| TITLE: |
Optics measurement, modeling, and correction with MIA --- The PEP-II experience |
| SPEAKER: |
Yan Yiton (SLAC) |
| LANGUAGE: |
English |
| ABSTRACT: |
With a model-independent analysis (MIA) for precision linear orbit measurement and providing almost unlimited Green's functions, we have
been able to obtain accurate lattice models, called virtual machines that match the PEP-II Low-Energy Ring (LER) or High-Energy Ring (HER) in optics. Once a virtual machine is obtained, we may try to find and adjust one or two magnets with noticeable differences from expectation. However, a more common practice is to search for an easily-approachable better-optics model by pre-selecting and fitting a group of normal and skew quadrupoles and/or orbit correctors (for sextupole bumps). The corresponding magnet changes are then dialed into the real accelerator. These procedures have been successfully
applied to PEP-II LER and HER for beta beat fixing, coupling and dispersion
correction, large working tune jump, IP optics optimization, and have helped
PEP-II overcome milestones in luminosity enhancement.
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