In order to enhance the supply chain security at airports, the German federal ministry of education and research has initiated the project ESECLOG (enhanced security in the air cargo chain) which has the goal to improve the threat detection accuracy using one-sided access methods. In this paper, we present a new X-ray backscatter technology for non-intrusive imaging of suspicious objects (mainly low-Z explosives) in luggage's and parcels with only a single-sided access. A key element in this technology is the X-ray backscatter camera embedded with a special twisted-slit collimator. The developed technology has efficiently resolved the problem related to the imaging of complex interior of the object by fixing source and object positions and changing only the scanning direction of the X-ray backscatter camera. Experiments were carried out on luggages and parcels packed with mock-up dangerous materials including liquid and solid explosive simulants. In addition, the quality of the X-ray backscatter image was enhanced by employing high-resolution digital detector arrays. Experimental results are discussed and the efficiency of the present technique to detect suspicious objects in luggages and parcels is demonstrated. At the end, important applications of the proposed backscatter imaging technology to the aviation security are presented.
In the context of the German aviation security research and development project SILUFRA (secure air freight transport chains), BAM has developed a high-resolution and high-energy X-ray imaging technology for the reliable detection of dangerous and illicit materials in densely packed air freight containers. In the developed technology, a novel combination of high-energy (2-7.5 MeV) X-ray betatron as the radiation source and a high-resolution digital detector array (DDA) for the X-ray imaging was utilized to improve the probability of detecting contraband and explosive materials by enhancing the spatial and contrast resolution in the digital X-ray image. In addition, flexible rotations of the high-energy X-ray source and the digital detector array can lead to clarify the suspicious region of interest (ROI) in air freight containers efficiently. Thus, reduces the false alarm rates and the need for expensive manual inspections of the whole container load. In order to evaluate the detection efficiency, we carried out the experimental investigations on a real air freight container loaded with typical cargo materials such as heavy automobile components and electronic products as well as mock-up dangerous and contraband materials. Furthermore, the material discrimination in the radiographic images was evaluated based on the dual high-energy X-ray imaging method. Finally, important applications of the proposed imaging technology to the air cargo security are discussed
The research and development (R&D) in the field of safety and security of sea-freight Containers has gained more importance after the U.S. house resolution 1 (H.R.1). According to this law, all the freight Containers which are transported from non-U.S. port of origin to U.S. ports should be inspected 100% against explosive and contraband materials using non-intrusive imaging equipment and radiation detectors. As the port of Hamburg and Bremerhaven are the leading Container ports in Europe, it is essential to develop reliable and high-resolution detection technologies for the non-destructive inspection of large sea-freight Containers.
For the radiographic investigation of large cargo Containers the energies of conventional Xray tubes are inadequately for certain layer thicknesses. In that case the high energy radiation sources like electron accelerators and gamma radiators (60CO) are adequate for the non invasive inspection of large Containers because of the high penetration through thick materials. Multiple imaging even enables to distinguish between different materials. The main challenging task in air and sea cargo Container inspection is to improve the detectability of contraband and dangerous materials which are hidden in the heterogeneously packed Containers by detailed analysis of cluttered radiographic images. So it is to be expected that objects of organic substances like certain explosives or their precursors are hard to identify behind thick walls of heavy metal objects such as engine-blocks with flat bottom holes. The primary aim here is to investigate the detectability of dangerous materials (typically of light elements) in cargo Containers using high energy X-ray digital radiography.
Reducing risks and confining them to an acceptable level can be regarded as an essential commitment of technical applications for safety purposes and the public security measures.
Rating the efficiency of such measures requires an assessment of the risk that is supposed to be reduced. However, approaching this subject means to face a plethora of existing literature and an ongoing discussion if and how this can be achieved. On one hand, it remains a rather uncertain estimate particularly if it comes to rare interrupting events. On the other hand, making a decision responsibly requires a certain rational base. Several approaches exist for assessing risks, from verbal to quantitative, depending on the individual case. The frequently quoted Delphi technique represents the verbal one, others such as the Bayesian statistics a quantitative one or the consequence/probability matrix in-between.
A problem remains with understanding probability. Even if an event is highly unlikely it may happen right now.
Safety and security both entail freedom from danger, i.e. unacceptable risk, whatever the cause might be. This
entails an understanding of the term 'risk' that is broadly used in areas such as economics, health, insurance etc.
According a rather popular definition used in the economical sciences for a long time (KNIGHT), risk has a lot
in common with uncertainty while the former is regarded quantifiable and the latter one is not. However, it has
to be taken into account that there are other understandings of 'uncertainty'. Particularly encountering rare
events never experienced before and recent contemporary definitions are weakening Knightfs differentiation.
This is reflected in some recent standard definitions. Attempts have been made to define a risk as common as
possible covering not only societal, ecological and financial areas but also natural and technical, ones. This is of
particular concern in non-destructive testing. This raises the question how far this can be achieved in a common
understanding, i.e. the discussion on this term seems not at all finished yet.
It is a common ambition to lower the risk by several actions including detection technologies. This entails that a
risk could be estimated somehow. The existence of numerous approaches indicates the complexity of this question.
The EFNDT (European Federation for Non-Destructive Testing) Working Group 5 took a commitment
also to tackle this central aspect of safety and security in its understanding as a bridging forum between these
two areas.
Die radiologische Untersuchung von Holz ist hinsichtlich der Durchführung
und Auswertung komplex. Im Gegensatz zu künstlich hergestellten Materialien zeichnet
sich Holz besonders durch seine Heterogenität und Individualität aus, kein Stück ist wie das
andere. Dies erschwert bei der radiologischen Inspektion die Fehlerdetektion, da diese teilweise
schwer von natürlichen Wachstumsmerkmalen zu unterscheiden sind. Insektenfraßgänge
und Hohlräume durch biologischen Abbau sind deutlich erkennbar, schwieriger
wird es bei feinen Rissen und Anzeichen für Fäulnis. Metallische Einbauten wie Nägel und
Bolzen sind natürlich gut zu erkennen, großflächigere Platten können jedoch den Einblick
in die benachbarten Gebiete versperren. Klebstoffschichten sind im Röntgenbild nur dann
sichtbar, wenn sie exakt parallel zum Strahlengang getroffen werden. Verschiedene
Strukturmerkmale treten also radiologisch recht unterschiedlich in Erscheinung, deshalb
liegt es nahe, zu deren Erkennung mehr als nur eine Durchstrahlungstechnologie
anzuwenden. Während bei immobilen Objekten, d.h. Bauwerken und Bäumen, mobile
Durchstrahlungstechniken mit Röntgen- oder Gammastrahlen (Se-75) in Frage kommen,
stehen im Labor auch (schnelle) Neutronen alternativ zur Verfügung. Die verschiedenen
Techniken, einschließlich der Tomographie mit Neutronen, werden an zwei größeren Prüfteilen
demonstriert, einer Brettschichtholzprobe und einem Knotenpunkt aus einer Holzbrücke
mit eingebauter Stahlplatte. Neutronen lassen Materialunterschiede differenzierter hervortreten
und durchdringen sperrige Metallteile besser, trotz verringerter Bildqualität. An
Verbesserungen wird derzeit gearbeitet.