Fig. 3.

SNR as a function of main magnetic field strength, at different distances from the center of the spherical sample. Ultimate intrinsic SNR is compared to the SNR of finite arrays of loop coils, with 8 and 64 elements, uniformly distributed around the spherical object. The case in which only sample-derived noise contributions are considered is shown separately from the case in which both sample-derived and coil-derived noise contributions are considered. Adding coil-derived noise in the model reduces SNR, especially at high field. For each plot, data are normalized to the highest value.