Army scientists advance chemical detection techniques
June 11, 2013
- The Army is dedicated to the development of highly effective chemical detectors.
ABERDEEN PROVING GROUND, Md. (June 11, 2013) -- It's in the news on a regular basis. It's of increasing concern for the President of the United States. It's prompting U.S. forces to be more prepared. Chemical warfare is an increasingly real and dangerous threat to our nation, and the availability of accurate, quick detection is critical to the safety of the Warfighter and our nation.
The U.S. Army Research, Development and Engineering Command's chemical and biological center has the foremost Raman spectroscopy experts in the country dedicated to the development of highly effective chemical detectors.
At the Edgewood Chemical Biological Center's Laser Spectroscopy Branch, under the Research & Technology Directorate, the primary goal of the Branch is to conduct fundamental spectroscopic research as well as to test and evaluate systems that specialize in detection from proximal (sub 250 meters) to standoff (> 250 meters) distances.
This ability is vital to a soldiers' safety, as it can warn the soldier to don hazardous material clothing and protective equipment before being exposed to the chemical threat. It is essentially a capability to "detect to warn," as most of the chemical agents cannot be seen with the naked eye, especially from a distance.
The branch is made up of a diverse set of members, with backgrounds in spectroscopy, mechanical and electrical engineering, physics and chemistry. They leverage their individual strengths to excel in a variety of endeavors, with a specific focus on Raman spectroscopy.
Raman spectroscopy is a scattering-based phenomenon that utilizes a single laser source. The laser light interacts with the molecules shifting the wavelength based on the molecular structure of the molecules, which in turn generates a spectral signature.
Each signature of chemical or biological matter is unique, just like a fingerprint. These are then matched against the robust library of agents that the Army has built over the years for identification of the agent.
Over the years, members of the branch have worked on various projects from on the move chemical detectors to microscope systems that can non-invasively identify exogenous materials on fingerprints which can sequentially be attributed to the individual who deposited the original print.
The Army's work with detection systems has led to a number of cooperative research and development agreements with commercial customers. CRADAs are advantageous to both the Army and the commercial partner as it allows each to be on the ground floor of the research and development of a system.
One project that stemmed from a CRADA relationship is currently showing great potential; it has been moved into an extended user evaluation with Marine Forces Pacific Command for further assessment under the Rapid Area Sensitive-site Reconnaissance Advanced Technology Demonstration sponsored by the Defense Threat Reduction Agency.
"The company came to us with model number 002, at a very early stage of development," said Jason Guicheteau, Ph.D. "We saw the potential and, through several partnerships, the instrument grew to a more robust system. The company itself sought larger commercial partners and is looking to transition even further."
The Laser Spectroscopy Branch supported the science and technology side of the RASR ATD, while members of its sister organization in the Engineering Directorate, the Advanced Technology Demonstration Branch, served as the technical manager. They specifically coordinated early user assessments, ruggedization, the Dugway Proving Ground Integrated System Demonstration and the operation demonstration using marines and soldiers.
Through their work with spectroscopy, the Laser Spectroscopy Branch has also identified potential issues of transitioning smaller portable instruments into the field, including the issue of the angle of the detector and how that affects its ability to yield accurate results. For many techniques, Raman in particular, traditional systems are ideally operated in a perpendicular manner.
"As systems have gotten smaller it is harder to predict how the soldier will hold it in their hands, or how an unmanned vehicle will have it positioned on its arm in respect to the sample," Guicheteau said.
To address this issue, a joint effort was coordinated and sponsored by the Engineering Directorate, ATD Branch and DTRA for the Laser Spectroscopy Branch to develop a model to test the angle dependence of the Raman Return, or spectral signature. Their findings yielded that in most cases chemical identification is unaffected between 0 to 60 degrees to normal.
This advanced testing all stemmed from one piece of equipment evaluated under the branch, and demonstrates why this kind of partnership between ECBC, DTRA, Joint Program Managers and industry is important.
"Companies know that we will put their systems through the most rigorous testing and help them develop the most effective, accurate technologies. It is a great give and take between the Army and the company," Guicheteau said. "The company can ensure that they have a really good system before taking it to the next level to try to get it fielded. Most of the companies that come to us want detailed, constructive criticism and really want to improve their product. Plus, this shows that they are already partnering with the Army."
Surface Testing and Evaluation
One of the most important aspects to test is how the systems work on surfaces, as the type of surface can impact the actual detection capability. Recently the team has developed a methodology that can quantifiably deposit chemical materials on surfaces such as aluminum, plastics, cloth and wood, and test for a truly accurate detection capability.
"This hasn't really been done before. Previously, there was no way to accurately deposit materials on surfaces," Guicheteau said. "Now with our deposition method, systems can quantifiably and accurately be assessed at range. Once a detection limit baseline is established, modifications can then be made to a system in order to push the capability levels."
Through this new capability, Guicheteau is currently leading efforts to evaluate a Raman system capable of identifying energetic materials on a variety of surfaces from a distance up to 45 meters. The field test, done in conjunction with the Joint Improvised Explosive Device Defeat Organization, will be completed over a two-week period and is using over 150 samples prepared with this new methodology.
The purpose of detection is to be able to see where -- or if -- contamination exists, and if found, to evaluate what it is. Certain surfaces such as wood or asphalt will actually allow the chemical to seep in, or a chemical agent can interact with an existing chemical on the surface, causing a chemical reaction. An effective detector will be able to evaluate those or other concerns and effectively match the signature of the chemical.
"This is where the algorithm built into the system comes into play," said Guicheteau. "Most instruments we see all have the basic pieces -- laser, camera, detectors -- but it's the math behind their system that really sets them apart and can make or break a system."
Perhaps the most unique capability of the Laser Spectroscopy Branch is its Instrument Surety Assessment Suite, for which a team of ECBC scientists retrofitted an existing lab and added a three-sided chemical hood. ECBC's Mike Ellzy, Ph.D. and Darren Emge designed the lab, which allows for the testing of live agents from inside the hood and at standoff distances, with the ability to test multiple instruments at the same time.
Only ECBC personnel are allowed in the lab, but it boasts the unique capability of adjoining labs that can actually run the systems remotely, with communication devices that allow the scientists to talk freely with customers during testing.
"Our ISAS lab is a unique, one-of-a-kind facility," said Guicheteau. "It allows for us to significantly elevate our level of testing. It has been swamped with work from both national and international customers."
Future efforts in this field include partnering with companies to work on orthogonal technologies that can be put together and do much more than the current detector. As they exist now, there is no one technique that can do it all, so the ECBC team is looking to identify a way to put together various technologies to create one package that is much more effective. For example, there are existing technologies now that can locate the specific space that needs to be evaluated, and those that can assess that specific area for chemical agents.
"Right now, if someone tells us where to look, we can use Raman technology or various spectroscopic methods to detect what is there, but we can't tell you where to look," Guicheteau said. "We want to get to a point where we can scan a room with an instrument and say, 'look here and here,' and then use the adjoining detector to evaluate what is there."
These advances in technology will greatly enhance biological and chemical detection, and ECBC is at the forefront of such research. And with the versatility and ease of use of the ISAS lab, ECBC scientists look to evolve their capability to the next generation where they can evaluate biological and chemical agents in the same space.
"That would take our capability to the next level," Guicheteau explains. "There is a lot of excitement in this field right now and we're thrilled to be a part of it."
ECBC is part of the U.S. Army Research, Development and Engineering Command, which has the mission to develop technology and engineering solutions for America's Soldiers.
RDECOM is a major subordinate command of the U.S. Army Materiel Command. AMC is the Army's premier provider of materiel readiness -- technology, acquisition support, materiel development, logistics power projection, and sustainment -- to the total force, across the spectrum of joint military operations. If a Soldier shoots it, drives it, flies it, wears it, eats it or communicates with it, AMC provides it.