Terahertz Detection of Substances for Security Related Purposes (original) (raw)

Terahertz detection of substances for security related purposes

Smart Structures, Devices, and Systems III, 2006

Terahertz (THz) radiation has many far reaching applications-of specific interest is that many non-metallic and non-polar substances are transparent in the THz frequency range. This provides many practical uses for security purposes, where it is possible to detect and determine various substances that may be hidden or undetectable via conventional methods such as X-rays. In addition to this property, terahertz radiation can either be used in reflection or transmission modes. This paper will look into the use of transmission techniques to detect various substances using a terahertz system. Common materials used in bags and suitcases such as nylon, polycarbonate (PC), and polyethylene (PE) are tested for transparency. These materials then sandwich various illicit substances, and are scanned by the terahertz system to obtain spectral data, simulating the probing of a suitcase. The sample materials are then subtracted from the obtained data, which is then compared with previously obtained data of known substances, and an examination of features in the sample is carried out to determine if a particular substance is present in the sample. Downloaded From: http://spiedigitallibrary.org/ on 10/16/2012 Terms of Use: http://spiedl.org/terms Proc. of SPIE Vol. 6414 64141U-2 Downloaded From: http://spiedigitallibrary.org/ on 10/16/2012 Terms of Use: http://spiedl.org/terms Proc. of SPIE Vol. 6414 64141U-5 Downloaded From: http://spiedigitallibrary.org/ on 10/16/2012 Terms of Use: http://spiedl.org/terms

Imagerie et spectroscopie Terahertz: applications aux problématiques de défense et de sécurité

2015

The aim of this work is to demonstrate the potential and capabilities of terahertz technology for parcels screening and inspection to detect threats such as weapons and explosives, without the need to open the parcel.In this study, we first present terahertz time-domain spectroscopy and spectral imaging for explosives detection. Two types of explosives as well as their binary mixture is analyzed. Due to the complexity of extracting information when facing such mixtures of samples, three chemometric tools are used: principal component analysis (PCA), partial least square analysis (PLS) and partial least squares-discriminant analysis (PLS-DA). The analyses are applied to terahertz spectral data and to spectral-images in order to: (i) describe a set of unknown data and identify similarities between samples by PCA; (ii) create a classification model and predict the belonging of unknown samples to each of the classes, by PLS-DA; (iii) create a model able to quantify and predict the explo...

Terahertz spectroscopy techniques for explosives detection

Analytical and Bioanalytical Chemistry, 2009

Spectroscopy in the terahertz frequency range has demonstrated unique identification of both pure and military-grade explosives. There is significant potential for wide applications of the technology for nondestructive and nonintrusive detection of explosives and related devices. Terahertz radiation can penetrate most dielectrics, such as clothing materials, plastics, and cardboard. This allows both screening of personnel and through-container screening. We review the capabilities of the technology to detect and identify explosives and highlight some of the critical works in this area.

Terahertz Detection of Halogen Additive-Containing Plastics

Optics and Photonics Journal, 2020

Terahertz (THz) waves are transparent with respect to non-polar substances, such as plastics. The refractive index at THz frequencies and the specific spectral features of plastic materials, such as polypropene (PP), polyethylene (PE), polyvinyl alcohol (PVC) and polyethylene terephthalate (PET) can be used to discriminate waste plastics into each material regardless of color. This is important since colored plastic cannot be identified by the present method of near-infrared (NIR) reflection spectroscopy due to absorption of NIR light by the coloring. In addition, the THz refractive index of acrylonitrile butadiene styrene (ABS) increases in proportion to the content of bromine (Br), which can be used to quantitatively evaluate the presence of halogen additives in waste plastic. We show that the non-contact THz identification of materials and additives in plastics can be an effective method for sorting plastic waste. Safe & efficient waste management is one of the most urgent social requirements for smart city innovation.

THz imaging and sensing for security applications---explosives, weapons and drugs

Semiconductor Science and Technology, 2005

Over the past 5 years, there has been a significant interest in employing terahertz (THz) technology, spectroscopy and imaging for security applications. There are three prime motivations for this interest: (a) THz radiation can detect concealed weapons since many non-metallic, non-polar materials are transparent to THz radiation; (b) target compounds such as explosives and illicit drugs have characteristic THz spectra that can be used to identify these compounds and (c) THz radiation poses no health risk for scanning of people. In this paper, stand-off interferometric imaging and sensing for the detection of explosives, weapons and drugs is emphasized. Future prospects of THz technology are discussed.

Comparison of terahertz technologies for detection and identification of explosives

Terahertz Physics, Devices, and Systems VIII: Advanced Applications in Industry and Defense, 2014

We present results on the comparison of different THz technologies for the detection and identification of a variety of explosives from our laboratory tests that were carried out in the framework of NATO SET-193 "THz technology for stand-off detection of explosives: from laboratory spectroscopy to detection in the field" under the same controlled conditions. Several laser-pumped pulsed broadband THz time-domain spectroscopy (TDS) systems as well as one electronic frequency-modulated continuous wave (FMCW) device recorded THz spectra in transmission and/or reflection.

Terahertz technology and its applications

Drug Invention Today, 2013

New advances in different technologies have made the previously unused terahertz frequency band accessible for imaging systems. The 'terahertz gap' has a frequency ranges from w0.3 THz to w10 THz in the electromagnetic spectrum which in between microwave and infrared. The terahertz radiations are invisible to naked eye & in comparison with Xray they are intrinsically safe, non-destructive and non-invasive. This is such a new field that researchers around the world race to build the first practical system. It resolves many of the questions left unanswered by complementary techniques, such as optical imaging, Raman and infrared. Terahertz spectroscopy has number of applications run from detecting defects in tablet coating, product inspection (industry), spectroscopy (chemistry, astronomy), material characterization (physics), weapons concealed under clothing (airports), detection of cancer and caries. In the pharmaceutical industries it enables nondestructive, internal, chemical analysis of tablets, capsules and other dosage forms. This paper tries therefore not only to provide a brief overview over the imaging technology, but also over the whole range of current systems and research in terahertz technology.

Segmentation of Concealed Objects Detected by Terahertz Imaging

2010

The detection of weapons concealed underneath a person’s clothing is an important obstacle to the improvement of the security of the general public as well as the safety of public assets like airports and buildings. Manual screening procedures for detecting concealed weapons such as handguns, knives, and explosives are common in controlled access settings like airports, entrances to sensitive buildings, and public events. It is desirable sometimes to be able to detect concealed weapons from a standoff distance, especially when it is impossible to arrange the flow of people through a controlled procedure. Terahertz radiation is emitted as part of the black body radiation from anything with temperatures greater than about 10 Kelvin.Terahertz waves maintain reasonable penetration depth in certain common materials, such as cloth, plastic, wood, sand and soil. Therefore, THz radiation can detect concealed weapons since many nonmetallic, non-polar materials are transparent to this type of...

Capability of Terahertz-Wave Instrumenta- tion for Non Destructive Testing of Liquids

2015

Abstract. Electromagnetic waves with frequencies between 0.3 and 10 terahertz (THz) ≡ 10 – 300 cm-1 ≡ 1 – 0.03 mm are described as THz radiation (t-ray’s). They are assigned in the electromagnetic spectrum between the microwave/millimeter and the far-infrared regions. The ability to penetrate packing materials, such as paper, cardboards, plastic, glass and clothing and its non ionizing character makes THz ra-diation very attractive for different imaging and spectroscopic applications. Espe-cially the security sector directed the attention to the new developments of the THz-technologies. Transmission and reflection properties of the solid explosives such as e.g. HMX and RDX were studied intensively to reveal characteristic “fingerprint” absorption spectra for further material identification during security checks. Re-cently, the visualization and verification of liquid explosives and flammable liquids became important. The literature reports only on few related THz spectroscopy ex-pe...