Detection technologies meet ever-changing threats

Many events over the last few years have served to concentrate minds. Defeating terrorism has been a necessity for decades - as has protecting soldiers in battle - with chemical or biological warfare the principal threat throughout the 20th century. Now the security focus has shifted. The globalisation of Western society is totally dependent on secure travel and the free flow of goods, safeguarded against terrorism and criminality. It is the general public that needs protection if traditional freedoms are to be preserved.

Just as the threat to the public has changed so the range of infrastructure targets has increased. Attacks and threats from chemical and biological agents are no longer confined to the battlefield. Public buildings that need protection: critical facilities (for instance, power stations, water supplies and postal sorting offices) and even private buildings (such as corporate headquarters or banks) have had to take steps to safeguard their assets.

The technology exists to offer a high level of protection but equipment suppliers have had to move fast to package that technology in a way that is practical and affordable. The industry has also changed and consolidated, with many small companies, each a specialist in its own field, coming together or being consumed by major corporations.

A new ‘detection’ sector has emerged which includesthe UK company Smiths Group. During the past three years Smiths has built on its existing military activities in chemical and biological agent detection by acquiring two major companies working in complementary areas: Barringer Instruments (trace detection of explosives) and Heimann Systems (x-ray).

The result is that Smiths Detection, as the new business is called, is in a position to offer the range of technologies and equipment necessary to meet the variety of threats. The company is also investing heavily in research and development that will provide the solutions required by current and future customers.

Facilities protection

One example of the complete security solution is Smiths Detection’s proposal to meet recent international requests for high-level security in a single package. The requirement was for a comprehensive system at the main entrance to monitor staff and visitors for a range of threats. The extent to which the system would be used may depend on the level of intelligence received - either specific information relating to the facility or general alerts that call for higher security levels.

The company’s answer has been to assemble a complete security suite in a container that can be conveyed by truck to the location and assembled outside the main entrance as a self-contained security checkpoint. Visitors will enter by one door and leave by another, with each person and his/her bags checked for weapons or illegal items (by x-ray and a metal detector arch), explosives (with the Sentinel portal and Sabre hand-held device) and the presence of any chemical agent with a product such as CAM.

In addition to these Smiths Detection products, the company can also add a biometric system for personnel identification, using the digital fingerprinting technique which Smiths Heimann Biometrics has installed on behalf of a number of law-enforcement units, including the systems supporting the UK National Automated Fingerprint Identification System.

Security for bulk goods delivered to the same buildings already comes in ready-made packages. Cargo screening is an area in which Smiths Heimann claims to be prominent, offering complete systems that range from small van-mounted x-ray units through to fixed location facilities for the inspection of fully loaded trucks and containers.

Inside facilities, protection against biological threats is also possible, especially in an area that has been seen to be vulnerable in recent years, the mail room. Biological agents such as anthrax and ricin have been sent to unsuspecting victims by post, leading to fatalities and expensive long-term closure of departments or complete buildings. Smiths Detection has taken identification technologies and applied them to such situations, providing results within 30 minutes, compared with the traditional practice of sending samples to the lab for analysis and report within 24-36 hours.

This year saw the launch of the world’s first mail-screening system that can simultaneously detect hazardous agents such as anthrax, ricin, tularaemia and bubonic plague. Called Mail Sentry, it can screen up to 2,000 pieces of flat mail per hour in a pressure-controlled environment and can also screen small packages.

Each of these technology solutions represent the most advanced approach to security screening available on an international scale. Some of them are examined in greater detail below.

Explosives trace detection

Many chemical substances, such as explosives, exude particles or vapours that are absorbed by or cling to the surfaces of materials and fibres with which they come into contact. Detection of these particles and vapours can therefore indicate the fact that the person is either carrying explosives or has come into contact with them.

The Canadian company Barringer Instruments, later acquired by Smiths Detection, pioneered trace particulate detection technology around 15 years ago by using ion mobility spectrometry (IMS) for the detection of explosives with low vapour pressure. IMS exploits the fact that the speed at which an ion drifts within an electromagnetic field is dependent on the ion’s mass and structure. When the particles are vapourised, positive and negative ions are formed. Explosive substances form negative ions and are drawn by an electric field at consistent speeds that allow recognition of the type of explosive within six to eight seconds.

IMS technology forms the basis of Smiths Detection’s trace detection products, each tailored to a particular requirement. The Ionscan 400B is a desktop machine about the size of a laser jet printer, which can detect more than 40 explosives. It has become the principal explosives detector selected by the US Transportation Security Administration to meet the need for improved security at over 400 airports. A smaller and even more versatile product is Sabre, a hand-held detector capable of both trace particle and vapour detection.

The Ionscan and Sabre are generally used to check baggage and small packages but equipment on a different scale is required to screen people. Additional technology to make that possible was acquired by Smiths Detection in the form of a licence from Sandia National Laboratories for a patented pre-concentrator which collects the trace particles for analysis. This led to Sentinel, one of the industry’s first high-reliability walk-through portals, which uses pulsed jets of air to dislodge particles from a person’s clothing, skin and hair in a process that takes around four seconds. That air is collected at a rate of about 20,000 litres a minute through vents at the base of the portal, and is pre-concentrated before presentation to the IMS detector.


For more than 100 years x-ray technology has been instrumental in exposing details hidden from the human eye. Radiation, detection and image-processing technologies instantly deliver superb images of scanned objects while maintaining the highest levels of operator safety. Since the early 1970s, Smiths Heimann has taken this technology into the security market, uniting the benefits of the scanning process with state-of-the-art image processing. Data gathered by ultra-sensitive semiconductor detectors is digitally stored, enabling detailed and high-contrast images to be shown on a colour monitor.

Numerous analysis functions help the operator to assess the scanned object. One of these is the HI-MAT feature which displays three groups of material (organic, inorganic, and metal according to its atomic number) in different colours. Another analysis function is HI-SPOT, which illuminates dark image areas by automatically detecting sections of high absorption. This section is analysed by a special enhancement filter software and is then locally illuminated without deteriorating the information from other image sections. HI-SPOT is a solution to finding weapons covered by steel. A popular feature in airports, to keep operators alert and improve their performance, is threat image projection (TIP). Complete x-ray images of fictional threat objects are automatically projected among the images of real baggage items without the operator being aware of the projection process.

Cargo inspection

Smiths Heimann developed its x-ray technologies to meet a new challenge, with the requirement to access a truck or a large container without entering it. Adoption of the technology helped to eliminate risks of freight damage or loss, risks which are associated with unnecessary and complicated manual inspection. A key feature has been the differentiation between organic and inorganic materials, allowing easier identification of suspicious objects. At the most powerful level, systems are available equipped with dual view (top and side x-rays) technology giving penetration up to 410mm of steel.

To complement the easy-to-assemble security container checkpoint at a facility described earlier, the likely solution is the SilhouetteScan Relocatable or Mobile unit for inspecting lighter container loads. The Relocatable system is designed for assembly and dismantling at short notice, allowing its rapid use at changing strategic focal points. It is a one-off investment that can be used in several locations. For short-term installations, the SilhouetteScan Mobile is a self-contained truck, an autonomous system that provides control wherever needed with an extremely short assembly time (it is operational in less than 30 minutes). The SilhouetteScan units can typically penetrate up to 160mm of steel and inspect up to 30 trucks per hour.

Bernhard Semling is director of product marketing/strategy and business development at Smiths Detection International

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