Faraday shields within a solenoidal coil to reduce sample heating: Numerical comparison of designs and experimental verification

Author(s):
Park, B.; Neuberger, T.; Webb, A.G.; Bigler, D.C.; Collins, C.M.
Published
2010
Publication type
Article / Letter to editor

Abstract

A comparison of methods to decrease RF power dissipation and related heating in conductive samples using passive conductors surrounding a sample in a solenoid coil is presented. Full-Maxwell finite difference time domain numerical calculations were performed to evaluate the effect of the passive conductors by calculating conservative and rnagnetically-induced electric field and magnetic field distributions. To validate the simulation method, experimental measurements of temperature increase were conducted using a solenoidal coil (diameter 3 mm), a saline sample (10 mM NaCl) and passive copper shielding wires (50 mu m diameter). The temperature increase was 58% lower with the copper wires present for several different input powers to the coil. This was in good agreement with simulation for the same geometry, which indicated 57% lower power dissipated in the sample with conductors present. Simulations indicate that some designs should be capable of reducing temperature increase by more than 85%. (C) 2009 Elsevier Inc. All rights reserved.

Solenoidal coil Shield SAR Sample heating solid-state nmr biological samples resonator probes fields
Date issued
2010-01-31
Language
English
Is part of
Journal of Magnetic Resonance (2010), Vol. 202, no. 1, p. 72-77
hdl
1887/110327