Research about   explosives detection using

                          NQR method



Resonance Techniques
Explosives Detection Using Magnetic and Nuclear


The detection of explosives at airports, land borders and seaports is an important area for preventing terrorism and organized crime. It forms one aspect of the general effort to prevent the transport of illicit materials, which includes also small arms, nuclear material and narcotics. A number of different methods of explosive detection have been developed in the past that can detect such material from a very small up to a very large quantity.  The nitro and nitrate component of some common explosives are the base of some detection methods, the nitrogen density of common materials and explosives are represented at next slides.
Many detection devices readily detect conventional explosives made of organic nitro and nitrate compounds, but fail to detect explosives made of inorganic nitrates or non-nitrogenous compounds.  In particular, many nitrogen-based detection devices fail to detect explosives such as ANFO (ammonium nitrate in fuel oil), and triacetone triperoxide (TATP). (Related characteristics of some plastic and liquids explosives are presented below in the description of the new threats). The original vapor-based explosives detector is, of course, the dog, which is very effective for some purposes, but which has some serious “canine factor” limitations.
Many different types of explosive exist and certain types may be more used by particular groups or at particular times, depending on availability, information etc. Currently, a particular danger is perceived from plastic and liquid explosives. The sources from which terrorists may acquire explosives are from the military, from industry and by making them themselves. Blocking terrorist acquisition of military and industrial explosives is dependent on the rigorous following of security procedures for storage, transport and use, including careful documentation. Technology, such as radio-frequency tracking devices, may also help. Prevention of illicit fabrication of explosives is currently a subject of significant attention. The main difficulties are that precursor materials are legitimately available and in widespread use, not only by industry but even as household chemicals, and recipes have been widely disseminated via the internet.
Nuclear quadrupole resonance

"NQR" redirects here. For the Tufts University tradition, see Naked Quad Run.

Nuclear quadrupole resonance spectroscopy or NQR is a chemical analysis technique related to nuclear magnetic resonance (NMR).

In NMR, nuclei with spin ≥ 1/2 have a magnetic dipole moment so that their energies are split by a magnetic field, allowing resonance absorption of energy related to the difference between the ground state energy and the excited state. In NQR, on the other hand, nuclei with spin ≥ 1 , such as 14N, 35Cl and 63Cu, also have an electric quadrupole moment so that their energies are split by an electric field gradient, created by the electronic bonds in the local environment.

Since unlike NMR, NQR is done in an environment without a static (or DC) magnetic field, it is sometimes called "zero field NMR". Many NQR transition frequencies depend strongly upon temperature.

Any nucleus with more than one unpaired nuclear particle (protons or neutrons) will have a charge distribution which results in an electric quadrupole moment. Allowed nuclear energy levels are shifted unequally due to the interaction of the nuclear charge with an electric field gradient supplied by the non-uniform distribution electron density (e.g. from bonding electrons) and/or surrounding ions.

The NQR effect results when transitions are induced between these nuclear levels by an externally applied radio frequency (RF) magnetic field. The technique is very sensitive to the nature and symmetry of the bonding around the nucleus. The energy level shifts are much larger than the chemical shifts measured in NMR. Due to symmetry, the shifts become averaged to zero in the liquid phase, so NQR spectra can only be measured for solids.

There are several research groups around the world currently working on ways to use NQR to detect explosives. Units designed to detect landmines and explosives concealed in luggage have been tested.
A detection system consists of a radio frequency (RF) power source, a coil to produce the magnetic excitation field and a detector circuit which monitors for a RF NQR response coming from the explosive component of the object.
Another practical use for NQR is measuring the water/gas/oil coming out of an oil well in realtime.
This particular technique allows local or remote monitoring of the extraction process, calculation of the well's remaining capacity and the water/detergents ratio the input pump must send to efficiently extract oil.  
The strong temperature dependence of NQR's frequency allows to make a precise temperature sensor with resolution 10-4 °C.
Appendix K: Nuclear quadrupole resonance, by Allen N. Garroway, Naval Research Laboratory. In Jacqueline MacDonald, J. R. Lockwood: Alternatives for Landmine Detection. Report MR-1608, Rand Corporation, 2003.
Leigh, James R. (1988). Temperature measurement & control. London: Peter Peregrinus Ltd.. p. 48. ISBN 0 86341 111 8.


see also :


1. "Nuclear Quadrupole Resonance", T.P. Das and E.L. Hahn, Chapter in Solid State

Physics, Suppl.l, Academic Press, New York, 1958.

2. Abragam, The Principles of Nuclear Magnetism, Clarendon Press, 1961

3. "Steady State Free Precession in Nuclear Magnetic Resonance," H.Y. Carr, Physical

Review, 112, 1693-1701, 1958.

4. "Nitrogen-14 NQR Study of Energetic Materials," R.A.Marino, R.F. Connors, and

L.Leonard (Block Engineering), Final Report to on U.S.Army Research Office

Contract DAAG29 79 C 0025, September 1982.

5. "Multiple Spin Echoes in Pure Quadrupole Resonance," R.A. Marino and S.M.

Klainer, Journal of Chemical Physics, 67,3388-3389, 1977.

6. "Explosives Detection by Pure 14N NQR", A.N. Garroway, J.B. Miller and M.L.

Buess, Proceedings of the 1st International Symposium on Explosive Detection

Technology, November 13-15,1991, Atlantic City, USA.

7. "Pulsed Spin Locking in Nuclear Quadrupole Resonance of 14N," D.Ya. Osokin,

Soviet Physics. JETP, 57(1), 69-71, 1983.

8. "Experimental Investigations of the Strong Off-Resonant Comb (SORC) Pulse

Sequence in 14N NQR," S.S.Kim, J.R.P.Jayakody, and R.A. Marino, Zeitshrift fur

Naturforschung, 47a, 415-420, 1992.

9. "Pulsed Fourier Transform NQR of 14N with a DC SQUID," M.D.Hurlimann,

C.H.Pennington, N.Q.Fan, J.Clarke, A.Pines, and E.L.Hahn, Physical Review Letters,

69, 684-687, 1992.

10. "SQUID Technology for Improved NMR/NQR Measurements Below 1MHz,"

Quantum Magnetics, Final Report on NSF Award 9160966, September 29, 1992.

11. "Librational Motion of Hexahydro-l,3,5-trinitro-s-triazine Based on the Temperature

Dependence of Nitrogen-14 Nuclear Quadrupole Resonance Spectra: The

Relationship to Condensed-Phase Thermal Decomposition," R.J. Karpowicz and

T.B.Brill, Journal of Physical Chemistry, 87, 2109-2112, 1983.

12. "Detection of Explosives by Nuclear Quadrupole Resonance (NQR)." A.N.

Garroway, J.B. Miller, J.P. Yesinowski, and M.L. Buess, Naval Research Laboratory,Final Report on Contract NEODTC N0464A92WR04515, FAA DTFA03-83-A-

00322, March 26 1993.

13. "Electronic Effects and Molecular Motion in ß-Octahydro-l,3,5,7-tetranitro-l,3,5,7- tetrazocine Based on 14N Nuclear Quadrupole Resonance Spectroscopy,"

A.G.Landers, T.B.Brill, and R.A. Marino, Journal of Physical Chemistry, 85, 2618- 2643, 1981.

14. "Nitrogen-14 Nuclear Quadrupole Resonance of Substituted Nitrobenzenes," S.N.Subbarao, E.G. Sauer, and P.J.Bray, Physics Letters, 42A, 461, 1973.

15. "Nitrogen-14 Nuclear Quadrupole Resonance Study of Substituted Nitrobenzenes,"S.N. Subbarao and P.J.Bray, Journal of Chemical Physics, 67(9), 3947-55, 1977.

16. "14N and 39K Nuclear Quadrupole Coupling in KN03," T.J. Barstow and S.N.

Stewart, Zeitschrift fur Naturforschung, 45a, 459-463, 1990.

17. "14N NQR Study of the Structural Phase Transitions in NH4NO3," J.Seliger, V.Zagar,

and RBlinc, Zeitschrift fur Physik B, Condensed Matter, 77, 439-443, 1989.

18. Private communication, R.A.Marino, Hunter College, CUNY, NY, September 1994.

19. "Nuclear Magnetic Resonance of 14N and 35C1 in Ammonium Perchlorate," T.J.

Barstow and S.N. Stewart, Journal of Physics: Condensed Matter, 1,4649-4657,


20. "Nitrogen-14 and Nitrogen-15 Wide-Line NMR Studies of Nitrocellulose," R.A.

Marino, Final Technical Report for Task 7-09, Department of Army, 30 October


21. "Detection of NQR in Explosives," V.S. Grechishkin, Russian Journal of Physics,

35(7), English Pages 637-640, 1992. Translation of Izvestiya Vysshikh Uchebnyykh

Zavedenii, Fizika, No.7, pp.62-65, July 1992.

22. Private Communication, T.J. Rayner, July 1994.

23. "Engineering Design Handbook: Explosives Series, Properties of Explosives of

Military Interest," U.S. Army Materiel Command, January 1971.


Other Relevant QR Papers Not Referenced

1. "Detection of Explosives and Narcotics by Low Power Large Sample Volume

Nuclear Quadrupole Resonance (NQR)", M.L. Buess, A.N. Garroway and J.B. Miller,

U.S. Patent 5206592..

2. "Detection of Explosives by Nuclear Quadrupole Resonance," M.L. Buess, J.B.

Miller, and A.N. Garroway, U.S. Patent 5233300.

3. "A Means for Removing Effects of Acoustic Ringing and Reducing the Temperature

Effects in the Detection of Explosives and Narcotics by Nuclear Quadrupole

Resonance," M.L. Buess, A.N. Garroway, and J.P. Yesinowski, Navy Case Number

74,325 (filed 30 Nov. 1992).

4. "Narcotics Detection using Nuclear Quadrupole Resonance," J. Shaw, Contraband

and Cargo Inspection Technology International Symposium, Washington D.C., 28-30

October 1992.

5. "A Search for NQR Signals in Heroin and Cocaine," R.A. Marino and J.R.P.

Jayakody, Final Technical Report on subcontract to Quantum Magnetics under US

Customs contract TC-91-031.

6. "NQR for Bomb Detection: Solution to the Plastics Problem ?" D. Noble, Analytical

Chemistry, 66 (5), 320A - 324A, March 1 1994.

7. "Explosives Detection by Nuclear Quadrupole Resonance (NQR)," A.N. Garroway,

M.L. Buess, J.P. Yesinowski, J.B.Miller, and R.A. Krauss, Report on results of

demonstration of prototype NQR explosives detector at FAA Technical Center in

May 1994..

8. "NQR Device for Detecting Plastic Explosives, Mines, and Drugs," V.S. Grechishkin,

Applied Physics, A55, 505-507, 1992.

9. "Short Range Remote NQR Measurments," T. Hirschfeld and S.M. Klainer, Journal

of Molecular Structure, 58, 63-77, 1980.

10. "A Pulsed NQR-FFT Spectrometer for Nitrogen-14," J.C.Harding, D.A.Wade, R.A.

Marino, E.G.Sauer, and S.M.Klainer, Journal of Magnetic Resonance, 36,21-33,


11. "New Methods of Nuclear Quadrupole Resonance," V.S. Grechishkin and N.Ja.

Sinjavsky, Zeitschrift fur Naturforschung, 45a, 559, 1990.