Department of Microbiology

University of Florida, Gainesville, Florida, USA

Application of Adaptive Simulated Annealing to Optimization of Gradient Coils with Concentric Return Paths.

Marian Buszko , Daniel C. Wang, Marek F. Kempka, E. Szczesniak, and E. Raymond Andrew

Simulated annealing is a well-known and widely used method of finding the global minimum of a function. For the purpose of optimization of transverse magnetic-field gradient coils, one of the most powerful algorithms presently available - Adaptive Simulated Annealing (ASA) - has been adapted and used. The most prominent feature of this program is periodical reannealing of parameter temperatures.

Gradient coils with concentric return paths present an interesting and elegant alternative to classical transverse "Golay" coils that are currently in widespread use. A family of coils with 8-16 building blocks carrying equal current has been optimized; the function being minimized included terms involving gradient linearity and efficiency. The software has also been adapted to more complex design where the radii of return paths were optimized. The results show that the ASA code is capable of performing numerical optimization of the coils. The ASA-optimized coils appear to provide larger volume of linear gradient than the coils previously described. They are likely to be applied in modern imaging and spectroscopic applications.

For discussion and/or more details, please contact marian@micro.ifas.ufl.edu)