Polarization enhanced two-channel NQR/NMR detection of solid and liquid explosives using multi-pulse sequences

• Main Authors: JANKO, LUZNIK, LAHAJNAR, GOJMIR, DR, TRONTELJ, ZVONKO, DR, BLINC, ROBERT, DR, SELIGER, JANEZ, DR, TOMAZ, APIH
• Format: Patent
• Language: English; French; German
• Published: 23.07.2008
• Subjects: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; MEASURING; MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES; PHYSICS; TESTING

The objective of the present invention is the polarization enhanced two-channel NQR/NMR (PE NQR/NMR) detection of solid and liquid explosives by using the multi-pulse sequences. This is a two-channel technique of detection of solid and liquid explosives, based on the polarization enhanced nuclear quadrupole resonance (PE NQR) and proton nuclear magnetic resonance (NMR). The invention enables the detection of small amounts of solid and liquid explosives (about 100g) in burned mines or elsewhere, containing only a very small ammount of metal (arround 0.5 g in a triggering mechanism). The detection of solid and liquid explosives according to this invention is achieved by the use of a magnet for initial polarization of hydrogen nuclei in a non-zero magnetic field B 0 ‰ 0, followed by the application of a fast NMR radio-frequency (RF) Carr-Purcell pulse sequence in the NMR channel I to see whether the proton NMR spin-spin relaxation time T 2 is short (microseconds) or long (milliseconds), when in the latter case it is highly probable that one deals with a liquid explosive, and with a solid explosive in the former case. The liquid explosive is further characterized in the NMR channel I, and the solid explosive in the NQR channel II. In the final step of identification of a tested explosive, the data of both channels are compared - by making use of a suitable electronic software - te with those of a data bank of all known explosives.