Crime and Justice International Magazine - Sam Houston State University

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Feb 07th
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Home arrow Policing arrow Securing the Border: Cargo Security
Securing the Border: Cargo Security PDF Print E-mail
by Virginia T. Wilson   

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There has been a dramatic shift in the focus of smuggling across state and international borders over the past few years. Historically, the focus of smuggling has been on the drug trade and the use of “drug mules” to bring illegal drugs into the country; this focus has been replaced by the fear of human smuggling and weapons used in terrorist acts. An increase in attention has also been paid to those entering the country, due to illegal immigration concerns and potential terrorist admission.

Since 9/11, cargo security and screening measures have been a main focus of the national security industry, due in large part to the concern that the shipping industry can be targeted for large-scale attack and can be manipulated to ship harmful items for terrorist groups. Significant damage can occur if a cargo container filled with explosives or a dirty bomb is able to enter U.S. ports. Likewise, there is a significant threat that terrorist groups can take advantage of the shipping industry to ship weapons, including weapons of mass destruction.

It would be impossible to thoroughly examine the contents of each container entering the United States each day by physical and visual inspection, and in an effort to mitigate this threat, several technologies have been designed.

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With regard to security measures, the shipping industry, made up mostly of private industry, has historically been concerned with the balance between national security and efficiency. Before the implementation of technology-heavy solutions, containers had to be physically searched to ensure they did not contain dangerous materials. Instead of opening and physically searching the estimated 17 million containers that enter U.S. ports annually, technology such as radiation and atomic weight detectors allow crews to monitor container contents with both speed and accuracy.

The major complaint of cargo security has historically been both the inability to screen all cargos entering the ports and the lack of efficiency in screening measures. U.S. Customs and Border Protection (CBP), within the U.S. Department of Homeland Security (DHS), developed the Container Security Initiative (CSI) in January 2002. The three primary components of CSI are the identification of high-risk containers for additional screening measures, the prescreening and evaluation of containers before they enter U.S. ports (ideally at departure ports), and the use of technology in the screening of cargo and containers. Implementing new technological advances, the CSI has been able to meet the balance between efficiency and security in the 350 ports of entry around the country.

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One of the original technologies used in cargo screening is simple x-ray scans to determine the contents of containers. Similar to the medical community use of diagnostic x-rays to examine bone structure and large masses within humans, x-rays can look at the shape of objects inside containers. Even though the technology is slightly different between medical and commercial uses, both provide a fairly shallow image of secreted contents. In response to the ability to conceal dangerous matter from simple x-ray detection within larger, heavier objects (particularly when items are concealed within metal coating), several enhancements have been made to traditional x-ray capabilities.

New generation x-ray machines for cargo screening allows greater penetration compared to traditional models, which gives better scrutiny of objects that may be hidden deep within containers and within metal shelling. The traditional drawback of x-ray detection was its ability to only transmit two-dimensional images which posed difficulties for operators to effectively conduct a threat assessment of an object’s contents. A recent advancement in x-ray technology to overcome this weakness is the capability to view items both three dimensional and in color. In fact, this new technology even allows operators to manipulate an item’s three-dimensional image on the system’s computer screen to better detect prohibited or potentially threatening contents.

Radiation detection for cargo containers has become a hot topic in recent months, particularly with funding from the Department of Homeland Security to implement screening capabilities at both seaports and airports. Currently, officers rely on information-intelligence to determine the most at-risk containers to be screened; although this is not an ideal strategy, there are not enough screening detectors to scan all the containers that come through the ports. The Department anticipates that all containers (via sea and land) will be scanned by the end of 2008.

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Radiation detectors track ionizing radiation and can determine the radiation levels of items within concealed containers. Establishing radiation levels allows screeners to determine if a container’s contents pose a radiological threat, such as the secretion of plutonium or uranium which are used in weapons of mass destruction. Radiological weapons are considered the most serious terrorist threat against the U.S. by foreign enemies, and detection can help prevent the transport of such weapons into the country.

Both x-ray and radiation detectors emit low levels of radiation to screen containers. Even though these levels do not pose serious physical damage, such emissions can have negative consequences over long periods of time and on certain materials.

A more concise type of detector that does not emit radiation in the screening process is an atomic weight detector. These detection systems provide more specific screening measures than other systems and rely on molecular characteristics instead of traditional visual evaluations.

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One type of molecular approach is using naturally-existing muon interactions to determine the atomic weight of objects within containers. Muons are energetic particles that fall from the atmosphere uniform over the Earth’s surface (approximately 10,000 muons per square meter each minute). Although these particles are usually stopped only when they hit deep in the ground, they are subject to Multiple Cuolomb Scattering (MCS) as they pass through materials. As muons reflect off of materials, their trajectories are influenced by its nucleus and atomic characteristics. Simply put, these trajectories can be estimated for different types of molecular characteristics; items with high atomic charges (such as uranium and plutonium) have significantly different reactions than particles with low atomic charges (such as lead and aluminum).

Cargo screening measures differ in capability, technique, and cost. Some of the techniques rely on officer interpretation to determine if a container’s contents pose a threat, such as determining if an object in an x-ray image is a threat or just fits the parameters of a threatening object. Likewise, both x-ray imaging and radiation detection systems transmit low levels of radiation on objects to reflect back its image. This process can have negative effects both long term and on certain types of material. Atomic weight detectors resolve both these issues although the cost of implementation of these systems is quite high. Overall, the technology used in cargo screening is constantly improving and the needs of further screening capability will drive technological advances.

 
 
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