Case Stories

ITT Advanced Engineering & Sciences Leads in Development of Sensors for Chemical and Biological Defense Administration

In the crucial areas of biological, and chemical defense, ITT Advanced Engineering & Sciences (AES) is developing and building new technologies for sensing, monitoring, and mapping chemical and biological contamination.

Recent events make clear that an attack employing chemical and biological agents has moved from being a potential threat to a reality. The continuing danger of a chem/bio attack and the ability to detect these agents early is critical to the safety of U.S. military and civilian populations. The development and deployment of advanced sensor technology from AES to provide defense against a chem/bio attack is a key element in the U.S. defense strategy.

AES experience in chem/bio sensors stems from a legacy of arms control work performed for government agencies in verifying the chemical and biological weapons conventions. Through that work, AES scientists and engineers have supported R&D efforts for nuclear, biological, and chemical (NBC) sensor technology and have a long history in working on systems to detect chemical or biological agents in complex matrixes at very low concentrations.

Dr. Claudia Randolph, Manager of the Special Projects Department at AES, recalls that, "To support verification of the chemical and biological weapons conventions, we wrote programs, plans, and roadmaps for where we needed to go in chemical detection, research and development, and identified key technologies. Now, however, with the ability to actually produce these technologies, we have moved from being a research organization to actually building sensors for deployment on the battlefield and in civilian spaces."

Standoff Surface Detection

Chemical and biological detection systems are designed to protect personnel operating on the ground, at sea, or in the air. The goal of these detection systems is to provide the capability to detect, identify, locate, quantify, warn, and report chem/bio threats to give military forces enough of an early warning to avoid contamination.

One important technology for the protection of military and civilian assets is the ability to detect hazards on the ground or on any surface. There are many chemical agents of low volatility that remain in liquid form over a long period of time. An example of this would be VX, a powerful nerve agent.

Understandably, there is great concern about the ability to detect and map any contamination. Scott Higdon, Chief Scientist for the LIDAR and Laser Technology Section for AES notes that, "The only way to detect and measure any surface-deposited chemical contamination now is to go up and physically touch the agent and test it. The NBC reconnaissance vehicles used to perform this task use an extremely cumbersome and time-consuming process based on a mechanical sampling wheel system to test for chemical agents."

Because of tactical requirements to quickly detect and map out any contamination, especially where military forces in the field and on bases are concerned, the chemical defense community has a need for a system that can provide detection at a standoff distance.

To meet this requirement, AES has been working on the development of a technology known as Laser Interrogation of Surface Agents - LISA. The LISA system uses a laser sensor attached to a reconnaissance vehicle that looks for chemical agents on the ground or any surface. LISA uses a technique known a Raman Scattering (or Raman Effect), which is an optical property that can be exploited to identify known chemical agents. The LISA system has a 1.5-meter standoff range and will be able to provide detection on every single laser shot at 25 pulses per second. This will provide the soldiers manning the vehicle with the ability to perform on-the-move, real-time measurements of chemical agents on the ground. This will give detection teams the ability to create a map with chemical agent contours that build up as detection is taking place.

Randolph notes that, "For the chemical community, the number one priority has been the ability to be able to stand off at a distance and see what's out there."

Difficulty in Detection of Biological Agents

Standoff biological agent detection is several factors harder than chemical detection. It is difficult to discriminate and measure biological warfare agents from naturally occurring background materials. Real-time detection and measurement of biological agents in the environment is daunting because of the number of potential agents to be identified, the complex nature of the agents themselves, the countless number of similar microorganisms that are a constant presence in the environment, and the minute quantities of pathogen that can initiate infection. Potential biological agents can also disguise themselves in benign entities.

Overcoming these difficulties and providing sensors for timely and effective warning of biological warfare agents are issues that AES scientists and engineers are currently engaged in solving. Approaches for detecting biological agents differ somewhat from those technologies that are employed to detect chemical agents. While the molecules that comprise biological agents are extremely complex and large in comparison to chemical agents, they are only made up of a very limited number of unique building blocks. As Higdon explains, "In general, this makes it necessary to use a laser with very specific ultra-violet wavelengths to probe the biological agent in order to enhance its Raman signal."

Recent laboratory data indicates that the LISA technology can discriminate between chemical and biological materials and may have the ability to differentiate certain biological species. AES is beginning to explore this potential more deeply because of the critical need for a sensor that can detect biological agents on surfaces. Success in this area could lead to a revolutionary sensor that has the capability to detect both chemical and biological agents in a wide variety of situations and conditions. AES is also working on R&D efforts that employ differential scattering sensing technologies for detection and analysis of airborne biological agents.

Sensor Technologies Address Airborne Agents

AES is helping to develop a method of detecting and identifying airborne chemical agents from a distance for potential use on a joint services programs. The programs will use LIDAR (light detection and ranging) technology to analyze a vapor cloud. Higdon notes that, "We took a hard look at all of the technologies that perform standoff analysis of chemical agents in the air. It turns out that DIAL - Differential Absorption LIDAR - is the best technology for this particular application." DIAL employs at least two laser wavelengths for analysis. Measuring the difference in the way the wavelengths propagate through the atmosphere provides an analysis of the molecules in the vapor cloud.

The Future of Chem/Bio Sensors

In addition military missions, the application of new chem/bio sensor technologies to the area of "homeland defense" has gained new importance.

Randolph notes that the value AES brings to this technology sector is that, "In addition to knowing how to build the hardware, we are able to aggregate the signals coming out of the hardware so that people on the ground can make critical decisions."

As for the future of chem/bio sensor technology for the military and homeland defense, Randolph says that, "AES is looking at applying these emerging technologies to hand-held or backpack units where soldiers or emergency responders can quickly and efficiently go out and map an affected area."

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