A solenoid-like coil producing transverse RF fields for MR imaging

A multi-purpose, rolled-up, double-helix resonator

Multilayer flexible substrates offer a means to combine high lateral precision and resolution with roll-up processes, allowing layer-based manufacturing to reach into the third dimension. Here we explore this combination to achieve an otherwise hard-to-manufacture resonator geometry: the double-helix. The use of commercial flexPCB technology enabled optimal winding connections and a versatile adjustment to various operation fields, sample volumes and resonance numbers. The sensitivity of the design is shown to greatly benefit from the fabrication method, though optimal electrical connections and several radially-wound windings, and was measured to outperform an equivalent solenoid despite the known geometrical disadvantage.

Double helix dipole design applied to magnetic resonance: a novel NMR coil

A new radio frequency coil design for NMR experiments is presented. The coil generates a magnetic field purely perpendicular to the longitudinal axis of the main magnet, and its sensitivity is higher than the traditional transversal resonators. This is achieved by adding the contribution of two tilted solenoid coils fed with opposite currents. The work presents the mathematical model for the new coil, numerical simulations performed to validate that model and a comparison with an equivalent saddle coil. The new design is tested experimentally in low- and high-field NMR experiments and compared with results obtained with equivalent saddle coils. The results lead to conclude that the new design provides better sensitivity than the transverse resonators commonly used in NMR.

Motional relativity and industrial NMR sensors

We explore the implications of motional relativity in NMR and show that sample translation can be used to acquire NMR signals without the need for pulsed RF excitation or pulsed magnetic field gradients. Novel single-shot, on-line NMR acquisition protocols for samples being conveyed at high speed are discussed and preliminary results using a low-cost, on-line prototype NMR sensor are presented.