Electricity: measuring and testing – Particle precession resonance – Using a nuclear resonance spectrometer system
Patent
1992-11-30
1994-11-15
Tokar, Michael J.
Electricity: measuring and testing
Particle precession resonance
Using a nuclear resonance spectrometer system
324300, G01R 3320
Patent
active
053651715
ABSTRACT:
Acoustic ringing and adverse effects from variations in the NQR detection of explosives and narcotics are minimized or eliminated. A specimen is irradiated with a modified steady state steady state free precession (SSFP) pulse sequence which combines a phase-alternated pulse sequence (PAPS) with a non-phase-alternated pulse sequence (NPAPS). The resulting signals from the PAPS and NPAS may then be coadded to cancel out the FID contributions to the signals. By canceling out the FID contributions to the signals, the effects of probe ringing and other extraneous responses, as well as the effect of temperature variation, are minimized or removed. The present method is especially effective in the detection of explosives and narcotics having .sup.14 N or .sup.35,37 Cl nuclei. A steady state free precession pulse which is especially useful with the method of the present invention is the strong off-resonance comb (SORC). In another embodiment of the invention, the effects of probe ringing can also be minimized or removed by repeating the detection procedure at a frequency which is sufficiently off-resonance so that only frequency independent effects, such as probe-ringing, can be observed.
REFERENCES:
patent: 4438400 (1984-03-01), Patt
patent: 4887034 (1989-12-01), Smith
patent: 5023551 (1991-06-01), Kleinberg et al.
patent: 5026942 (1991-06-01), Fellmann et al.
patent: 5159617 (1992-10-01), King et al.
patent: 5168224 (1992-12-01), Maruizumi et al.
patent: 5206592 (1993-04-01), Buess et al.
patent: 5233300 (1993-08-01), Buess et al.
Buess et al., Acoustic Ringing Effects in Pulsed Nuclear Magnetic Resonance robes, Rev. Sci. Instrum. 49(8), Aug. 1978, pp. 1151-1155.
Fukushima et al., "Spurious Ringing in Pulse NMR," Journ. of Magnetic Resonance, 33, 199-203 (1979).
Gerothanassis, "Method of Avoiding the Effects of Acoustic Ringing in Pulsed Fourier Transform Nuclear Magnetic Resonance Spectroscopy," Progress in NMR Spectroscopy, vol. 19, pp. 267-329, 1987.
Peterson et al., "N Nuclear Quadrupole Resonance and Relaxation Measurements of Sodium Nitrite," The Journ. of Chemical Physics, vol. 64, No. 2, 15 Jan 1976.
Karpowicz et al., "Librational Motion of Hexahydro-1,3,5-Trinitro-s-Triazine Based on the Temperature Dependence of the Nitrogen-14 Nuclear Quadrupole Resonance Spectra: The Relationship to Condensed-Phase Thermal Decomposition," J. Phys. Chem. 1983, 87, pp. 2109-2112.
Carr, "Steady-State Free Precession in Nuclear Magnetic Resonance," Physical Review, vol. 112, No. 5, 1958, pp. 1701.
Ernest et al., "Application of Fourier Transform Spectroscopy to Magnetic Resonance," The Review of Scientific Instruments, vol. 37, No. 1, 1966, pp. 93-102.
Hinshaw, "Image Formation by Nuclear Magnetic Resonance: The Sensitive-Point Method," J. of Applied Phys., vol. 47, No. 8, 1976, pp. 3709-3721.
Gyngell, "The Steady-State Signals in Short-Repetition-Time Sequences," J. of Magnetic Resonance 81, 474-483, 1989.
Buess Michael L.
Garroway Allen N.
Yesinowski James P.
Edelberg Barry A.
McDonnell Thomas E.
The United States of America as represented by the Secretary of
Tokar Michael J.
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