Abstract: An apparatus and a method for producing a multi-pulse sequence for irradiating a substance provided with quadrupole nuclei with either integer or half-integer spins to detect an NQR signal emitted therefrom. The apparatus has pulse sequence generating means adapted to produce a combination of two or more pulse sequences, arranged so that a definite regularity of the phase alteration of pulses in each of the pulse sequences occurs that is equivalent to a shift of spectral components of the pulse sequences in relation to each other. Furthermore, in at least one of the pulse sequences, there are not less than two phases alternating. A preparatory pulse may be included in one of the pulse sequences to reduce the effect of temperature, increase the intensity of the NQR signal and simultaneously eliminate intensity anomalies. Alternatively, the combination of pulse sequences may be different from a combination of PAPS and NPAPS, and none of the pulse sequences contain a preparatory pulse.

Abstract: An apparatus and method for producing a multi-pulse sequence for irradiating a substance provided with quadrupole nuclei with either integer or half-integer spins to detect an NQR signal emitted therefrom. The apparatus has pulse sequence generating means adapted to produce multi-pulse sequences with pulse intervals exceeding T2* and containing a preparatory pulse or group of pulses for creating echo signals between the pulses. The pulse sequence is organised so that the resulting signal contains a prevailing echo component produced by the preparatory pulse or group of pulses.

Abstract: A coil assembly (11) comprising two coil sections (13a and 13b). Each of the sections (13) consists of a combinat of a spiral coil (15) having a variable coil pitch arranged in a saddle shape configuration. The saddle shape has a central port (17) and a pair of outer coextending portions (19). The coil sections (13) are located opposite each other with the central p(17) of the respective sections disposed in parallel spaced apart relationship and the corresponding coextending portions (19) of respective sections disposed in coplanar alignment with each other so that the sections combine to circumscribe a scanned volume within which the target substance is to be disposed.

Abstract: An apparatus for exciting and detecting NQR in a substance containing quadrupole nuclei responsive to the NQR phenomenon. The apparatus includes a coil 15 for irradiating an item that may contain a substance with RF waves to excite NQR in quadrupole nuclei within the substance and for receiving an NQR signal emitted in response thereto. A transmitter unit 10 is provided for producing and transmitting an RF pulse to the probe to create said RF waves. A receiver unit 11 is provided to receive and treat a received signal from said probe for subsequent processing and detection of a said NQR signal therein. A sensing means is included in the apparatus for sensing an extraneous parameter that may influence the detection of the NQR signal from the item to be scanned.

Abstract: A probe (80) for irradiating a sample with RF energy during transmitting periods and detecting an NQR or NMR signal from a substance contained within the sample during receiving periods. The probe (80) comprises a variable impedance unit (20) for changing the Q-factor of the probe and a probe coil. The probe (80) is responsive to powerful RF pulses applied thereto to excite an RF magnetic field in the probe coil during the transmitting periods. The variable impedance unit (20) is controllable to provide a Q-factor for the probe (80) at: (i) an optimal level during a prescribed transmitting period of an RF pulse for irradiating the sample with said RF energy; (ii) a minimal level during a prescribed recovery period immediately following said transmitting period to rapidly dampen transient signals from the probe; and (iii) a maximal level during a prescribed receiving period for detecting an NQR or NMR signal from the target substance if present, immediately following the recovery period.