Abstract: The present paper proposes a simple scheme, which involves synchronous gated circuit with the radio-frequency pulses, to construct probe that exhibits different Q values between the transmitting and receiving periods. This proposal results in a dramatic reduction of the recovery time of the probe without attenuating the S/N of ¹⁴N NQR spectra. The experimental result demonstrates that with suitably chosen R, the damping resistor, the "dead-time" of the spectrometer can be confined in 20μs by using the suggested probe circuit.

Key words: ¹⁴N NQR, Probe, Fast recovery