Spin locking spin echo in nitrogen-14 quadrupolar spin-system with axially symmetric electric field gradient tensor

The behaviour of the nuclear quadrupole resonance (NQR) signals in hexamethylenetetramine (C6H12N4) has been studied using the modified spin-locking multi-pulse (SLMP) technique. As a result a train of spin-echo (SE) signals in `observation windowsʹ between RF pulses of a multi-pulse sequence has been detected. Spin-locking effect has also been observed in such spin-system. The dependence of the effective relaxation time T2e and the SE signal amplitude on parameters of SLMP sequences have also been investigated which resulted in revealing certain peculiarities in the behaviour of the signals obviously characteristic of a spin-system with axially symmetric electric field gradient tensor.