A coherent nuclear quadrupole pulse and double resonance spectrometer

A coherent pulse and double resonance NQR spectrometer system, for investigations in the pure quadrupole regime, has been described. The pulsed NQR spectrometer is capable of operation typically over the range of 10-40 MHz and can be adapted with ease for spin echo investigations, relaxation time measurements and double resonance experiments such as spin echo double resonance (SEDOR) and double resonance in the rotating frame (DRRF). Besides the Hartmann and Hahn DRRF scheme, a DRRF scheme involving off-resonance irradiation of the abundant spins can also be implemented. To simplify construction, commercially available devices have been extensively incorporated into the spectrometer system. The general features of the spectrometer are presented and the performance is illustrated by a few typical signal recordings