Figure 3:

Circuit schematic of the ²³Na transmit coil and ²³Na receive array with interface. (a) The ²³Na transmit solenoid. The interface of the ²³Na transmit solenoid has a similar setup as the one implemented for the ¹H transmit/receive solenoid. T/R switches were implemented in order to enable reception with the ²³Na solenoids to facilitate debugging; the array is used for signal reception during normal operation. The three loops of the ²³Na solenoid were connected in series. Series diodes D in two locations were used to detune the solenoids when receiving with the array. (b) ²³Na receive array. Cable traps tuned to the two frequencies of interest were implemented on the interface along with bazooka baluns on coaxial cables longer than a quarter-wavelength between the coil and the interface. Each ²³Na coil included three proton traps to suppress ¹H currents, an active detuning circuit and a fuse F. RFC: radiofrequency choke; RFS: radiofrequency short.