| 摘要 |
The invention relates to a detector and a method for detecting substances with explosive character and drugs, which is meant to check luggage and persons in check-points requiring an accurate control against terrorist actions and traffic of prohibited substances. According to the invention, the detector comprises a central unit (UC) connected to a storage, data processing and interface unit (USPI) provided with a console (IC) for the user and with a scanning head (CS1) for the foot level and a scanning head (CS2) for suspect objects in the ground or objects which cannot be moved, and which has a compact construction including the hardware modules and the software components needed for operation, it consisting of a radio processing system (SPR) which comprises a programmable radio-frequency signal generator (DDS) which transmits RF impulses to a power amplifier (AP) coupled with a gain control and reflected-signal level acquisition interface (IAP), a circuit (CA) consisting of a plane spiral coil (L) provided with a central ferrite core and two variable capacitors (CV1, CV2) actuated by two step-by-step-type electric motors (M1, M2) controlled by a module (MAA), by means of some control interfaces, known per se. As claimed by the invention, the method consists in measuring the environment temperature with a sensor, the digital conversion of the temperature value and the reading thereof within the program controlling the radio processing system (SPR), in computing the frequency (f) of the nuclear quadrupole resonance, the control of some radio-frequency impulses of a certain duration during which the signal frequency gradually grows in 10 steps within a preset interval about fand the substance identification by discriminating in real time the signal received with a set of four combined criteria applied to the spectral answer obtained by the fast Fourier transform method. |
