RDX Detection with THz Spectroscopy

  • Zoi-Heleni Michalopoulou
  • Suman Mukherjee
  • Yew Li Hor
  • Ke Su
  • Zhiwei Liu
  • Robert B. Barat
  • Dale E. Gary
  • John F. Federici


Spectroscopic analysis in the Terahertz frequency range, providing characteristic “signatures” for explosive and non-explosive materials, is proposed as an efficient and powerful tool for explosive identification. It is demonstrated that spectral responses of materials can be used as fingerprints that distinguish cyclotrimethylenetrinitramine (RDX) from other materials even with simple detectors and a limited number of available frequencies. Detection is performed using a modified least squares approach and multilayer perceptrons that operate on smoothed reflectance spectra. The performance of the detectors is evaluated through application to spectra of RDX and several common materials. A Receiver Operating Characteristic curve analysis demonstrates that our detectors exhibit the desirable properties of high probability of detection and low probability of false alarm.


THz spectroscopy Explosive detection Neural networks ROC curves 



The authors gratefully acknowledge the funding support by Rajen Patel and the U.S. Army - Picatinny Arsenal EWMTD through grants DAAE3003D1015-22 and DAAE3003D1015-33.


  1. 1.
    Choi, M.K., A. D. Bettermann, D. W. van der Wiede, Potential for detection of explosive and biological hazards with electronic terahertz systems. Phil. Trans. R. Soc. Lond. A, 2004. 362: p. 337–349.CrossRefGoogle Scholar
  2. 2.
    Bandyopadhyay, A., A. Sengupta, R.B. Barat, D.E. Gary, Z.-H. Michalopoulou, and J.F. Federici, Artificial neural network analysis in interferometric Terahertz imaging for detection of lethal agents. International Journal of Infrared and Millimeter Waves, 2006. 27(8): p. 1145–1158.CrossRefGoogle Scholar
  3. 3.
    Federici, J.F., B. Schulkin, F. Huang, D. Gary, R. Barat, F. Oliveira, D. Zimdars, THz imaging and sensing for security applications—Explosives, Weapons, and Drugs. Semicond. Sci. Technol., 2005. 20: p. S266–S280CrossRefGoogle Scholar
  4. 4.
    Huang, F., B. Schulkin, H. Altan, J. Federici, D. Gary, R. Barat, D. Zimdars, M. Chen, D. Tanner, Terahertz Study of 1,3,5-Trinitro-s-triazine (RDX) by Time Domain Spectroscopy and FTIR. Appl. Phys. Lett., 2004. 85: p. 5535–5537CrossRefGoogle Scholar
  5. 5.
    Federici, J.F., D. Gary, R. Barat, Z.-H. Michalopoulou, Detection of Explosives by Terahertz Imaging, in -Terrorism Detection Techniques of Explosives, J. Yinon, Editor. 2007, Elsevier.Google Scholar
  6. 6.
    Zorych, I., A. Sinyukov, Z.-H. Michalopoulou, R. Barat, D. Gary, J. F. Federici. Explosive identification with Terahertz spectroscopy: a model based approach. in SAFE 2007. 2007. Washington, D.C.Google Scholar
  7. 7.
    Kemp, M.C., P. F. Taday, B. E. Cole, J. A. Cluff, A. J. Fitzgerald, W. R. Tribe, Security applications of Terahertz technology, in Terahertz for Military and Security Applications, D.L.W. R. J. Hwu, Editor. 2003, SPIE. p. 44–52.Google Scholar
  8. 8.
    Liu, H.-B., Y. Chen , G.J. Bastiaans, X.-C. Zhang, Detection and identification of explosive RDX by THz diffuse reflection spectroscopy. Optics Express, 2006. 14(1): p. 415–423CrossRefGoogle Scholar
  9. 9.
    Zhong, H., A. Redo-Sanchez., X.-C. Zhang, Identification and classification of chemicals using terahertz reflective spectroscopic focal-plane imaging system. Optics Express, 2006. 14(20): p. 9130–9141.CrossRefGoogle Scholar
  10. 10.
    Wang, Y., Z. Zhao, Z. Chen, K. Kang, B. Feng, Y. Zhang, Terahertz absorbance spectrum fitting method for quantitative detection of concealed contraband. Journal of Applied Physics, 2007. 102(11): p. 1131081–1131086.Google Scholar
  11. 11.
    Lippmann, R.P., An introduction to computing with neural nets. IEEE ASSP, 1987: p. 4–22.Google Scholar
  12. 12.
    Zorych, I., Yew Li Hor, Alexander M. Sinyukov, Zoi-Heleni Michalopoulou, Robert B. Barat, Dale E. Gary, and John F. Federici A Statistical Approach to RDX Detection with THz Reflection Spectra, in CAMS Techical Report Series 2008–2009. 2008, New Jersey Institute of Technology.Google Scholar
  13. 13.
    Mittleman, D.M., Terahertz Imaging, in Sensing with Terahertz Radiation, D.M. Mittleman, Editor. 2003, Springer. p. 117–153.Google Scholar
  14. 14.
    Liu, Z., Ke Su, Dale E. Gary. John F. Federici, Robert B. Barat, Zoi-Heleni Michalopoulou, Video-rate terahertz interferometric and synthetic aperture imaging. Applied Optics, 2008: p. 3788–3795.Google Scholar
  15. 15.
    Hastie, T., R. Tibshirani, J. Friedman, The Elements of Statistical Learning. 2001: Springer.Google Scholar
  16. 16.
    Huang, Y.S., C. Y. Chen, A Method of Combining Multiple Experts for the Recognition of Unconstrained Handwritten Numerals. IEEE Transactions on Pattern Analysis and Machine Intelligence. 17: p. 90–94.Google Scholar

Copyright information

© Springer Science+Business Media, LLC 2010

Authors and Affiliations

  • Zoi-Heleni Michalopoulou
    • 1
  • Suman Mukherjee
    • 2
  • Yew Li Hor
    • 2
  • Ke Su
    • 2
  • Zhiwei Liu
    • 2
  • Robert B. Barat
    • 3
  • Dale E. Gary
    • 2
  • John F. Federici
    • 2
  1. 1.Department of Mathematical SciencesNew Jersey Institute of TechnologyNewarkUSA
  2. 2.Department of PhysicsNew Jersey Institute of TechnologyNewarkUSA
  3. 3.Otto York Department of Chemical EngineeringNew Jersey Institute of TechnologyNewarkUSA

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