STUDIES ON THE PERFORMANCE OF CIRCULAR AND ELLIPTIC Z-GRADIENT COILS USING A SIMULATED ANNEALING ALGORITHM

Elliptical z-gradient coils with different ellipticities are optimized using a simulated annealing algorithm, This study demonstrates that w hen the coil ellipticity was changed from 1.0 to 1.67, the gradient st rength was increased by 21% and the coil inductance was reduced by abo ut 34%. At the same time, the gradient inhomogeneity was increased by a factor between 15 to 47%. In these examples we also observed that wh en the coil ellipticity was increased from 1.0 to 1.11, the gradient i nhomogeneity was reduced by a factor between 16 to 19%. This study pro vides a quantitative assessment of the advantages and disadvantages in coil performance obtained by using elliptical z-gradient coils, (C) 1 997 Elsevier Science Inc.