Abstract: An echo sequence with broad band excitation bandwidth and shortexcitation time is proposed for use in deuterium NMR system in powders, which consists of four 90°pulses and an additional single pulse with flip angle of about 45° It is shown by numerical calculations that the excitation bandwidth of the ECHO sequence is nearly twice as broad as that of the conventional quadrupole echo sequence. The superiority of the ECHO sequence over the conventional quadrupole echo sequence is confirmed experimentally by a ²D-PMMA powder sample.

Key words: ²D-NMR, Broadband excitation, Echo sequence