Shielding Requirements for a Complete 3rd Order Shim Set for a 31cm Bore 9.4T System

¹Physics and Astronomy, University of Western Ontario, London , Ontario, Canada; ²Physics and Astronomy, University of Western Ontario, London, Ontario, Canada

Our goal is to develop and optimize high-strength, dynamic shim systems. It is clear that dynamic shim systems will need to be actively shielded. We investigate the performance of shielded shim coils as a function of shim order in a complete 3rd order shim set. The efficiency of unshielded shims is better than that of shielded shim, as expected. However, the difference decreases considerably with increasing shim order. This suggests that there is more freedom with higher order shields than lower orders.