Figure 7
Assessing the performance of dynamic nulling. (a) The time-series data from a series of 15 OPMs placed in an empty scanner-cast in an empty MSR with no dynamic nulling applied. Here and in (b), vertical dashed lines show the approximate times that a train arrived at either Russell Square or Holborn stations, thick lines indicate two trains arriving at approximately the same time. (b) Time-series data from the same OPMs with the dynamic nulling switched on. (c) The median power spectral density of the sensor outputs for the two cases across all sensors. (d) The shielding factor of the system.
