Figure 8.
Two frequently used resonator designs for EPR spectrometer. a: Surface bridged, loop-gap resonator (LGR). The LGR resonator structure is housed inside a metallic tubular shield. Legends: i, active surface area for sample; ii, filed modulation coils; iii, resonator shield; iv, RF input connector; v, coupling adjustment ring. The connector for field modulation coil is not visible from this view. The resonant frequency of this unloaded LGR was 1.25 GHz. b: Volume reentrant resonator (RER). The RER houses a cylindrical cavity of 24 mm diameter and 22 mm of effective length. Legends: i, sample cavity opening; ii, modulation coils; iii, connector of modulation coils; iv, RF input connector; v, coupling adjustment knob. The resonant frequency of this unloaded RER was 1.27 GHz