AUTOMATICALLY TUNED PROBE HEAD SYSTEM FOR PULSED NQR SPECTROSCOPY IN EXTREME THERMODYNAMIC CONDITIONS

A complete NQR probe-head system operating in the frequency ranges 0.5 -150 and-150-300 MHz is described. The head is particularly suited for NQR experiments carried out at a remote location, for example in a lo w-temperature cryostat or high-pressure chamber. Moreover, the head sy stem includes a microprocessor-controller for automated tuning of the probe to the operating frequency of the associated NQR spectrometer. T he controller can be easily interfaced to a PC via standard serial por t.