The Joint Accelerator Conferences Website (JACoW) is an international collaboration that publishes the proceedings of accelerator conferences held around the world.
TY - CONF AU - Li, Y. AU - Cheng, W.X. AU - Rainer, R.S. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Bayesian Approach for Linear Optics Correction J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - With a Bayesian approach, the linear optics correction algorithm for storage rings is revisited. In modern ring-based accelerators, optics corrections are determined from repetitive measurements which help identify systematic and random quadrupole errors in presence of various measurement noises. This process is a multivariate nonlinear regression problem driven by either a completed lattice model or a Jacobian matrix. Starting from the Bayes’ theorem, ’likelihood functions’ and ’prior probability’ distributions are extracted from a complete linear optics model. Under some assumptions, the least square algorithm and then the Jacobian matrix approach can be re-derived. The coherence of the correction algorithm is ensured through specifying a self-consistent regularization coefficient to prevent overfitting. Optimal weights for different correction objectives are obtained based on their measurement noise level. A new technique has been developed to resolve degenerated quadrupole errors when observed at a few select BPMs. A necessary condition of being distinguishable is that their optics response vectors seen at these specific BPMs should be near-orthogonal. PB - JACoW Publishing CP - Geneva, Switzerland SP - 390 EP - 392 KW - quadrupole KW - optics KW - lattice KW - GUI KW - distributed DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-MOPGW114 UR - http://jacow.org/ipac2019/papers/mopgw114.pdf ER -