A transmit-receive section of a pulsed nuclear magnetic resonance spectrometer

A transmit-receive section used in a prototype of the human-body drug detector, which can be applied in pulsed nuclear magnetic and quadrupole resonance spectrometers for investigations of solid samples, is described. The working frequency of the section is 11.3 MHz, the sample volume is ∼140 cm3, and the maximal amplitude of the high-frequency pulse in the circuit is 2000 V. A section recovery time of ∼2 μs was obtained due to the use of simple active high- and low-level dampers and quickly recovered preamplifier.