Zakład Fizyki Wysokich Ciśnień - publikacje

Abstract: A new NMR probe is described for use at low frequencies with an active damping circuit, which uses a quarter wave network and diode expander to dampen the ringing of the probe after RF excitation. The damping does not operate during the reception of the nuclear signal and therefore there is no loss in sensitivity as would be the case for permanent damping. The high voltage portion of the ringdown is damped by means of a resistor. The probe is most efficient at low frequencies and a fivefold reduction in recovery time to 10 μs has been obtained at 7 MHz (Q = 58). At this low frequency, the signal/noise ratio has been increased by using a sample coil with two segments connected in parallel. The damper pulse generator is also described. © 1987.