Second order proton traps for multi-nuclear RF coils: Applied for 13C MRS in humans at 7T

The concept of second order proton traps (consisting of an inductor and two capacitors) in coils for non-proton NMR allows control over the resonance frequency, the blocking frequency and the trap mode frequency. Effective proton traps with relatively high LTr, and thus very effective blocking, can be constructed, which impose only small degradation of the non-1H coil sensitivity