Scientists turn handheld JCAD into a dual-use chemical, explosives detector

By Edgewood Chemical Biological CenterNovember 24, 2014

Joint Chemical Agent Detector Chemical Explosive Detector
(Photo Credit: U.S. Army) VIEW ORIGINAL

ABERDEEN PROVING GROUND, Md. (Army News Service, Nov. 24, 2014) -- Scientists at the U.S. Army Edgewood Chemical Biological Center here, proved it is possible to teach an old dog new tricks by adding the ability to detect explosive materials to the Joint Chemical Agent Detector.

The original JCAD was developed and fielded to U.S. Forces nearly 25 years ago, to serve as a portable, automatic chemical warfare agent detector. Currently there are approximately 56,000 chemical warfare agent detecting JCADs in service within the Department of Defense.

Recent needs have required scientists to find ways to create a similar portable technology to detect explosive materials.

According to the Army, "Future Army forces require the capability to provide support to unified land operations by detecting, locating, identifying, diagnosing, rendering safe, exploiting, and disposing of all explosive ordnance, improvised explosive devices, improvised/homemade explosives, and weapons of mass destruction."

Funded through an Army Technology Objective, or ATO, program starting in 2010, under the requirement to assess which existing detectors could also detect explosives, ECBC's Point Detection Branch began to research different options.

Since so many JCADs are already in the hands of warfighters across all four services, the team explored the possibilities with that technology. ECBC Point Detection Branch handled the technical evaluation of the unit in collaboration with Smiths Detection, who is building the parts for the new capability.

"The JCAD is already fielded and in the hands of our warfighters, so that made it a good candidate to start with," said Gretchen Blethen of ECBC's Point Detection Branch.

While working to make the JCAD an explosives detector, the team had to overcome several challenges. On a programmatic level, the ATO requirement had restrictions against modifying the existing JCAD hardware. Also, the JCAD needed to maintain its original chemical warfare agent detector purpose.

Aside from the ATO requirements, making a chemical warfare agent detector into an explosives detector had some scientific challenges. The original JCAD is designed to detect vapors. However, explosive materials are usually low vapor pressure solids. ECBC scientists had to figure out how the JCAD could detect solid explosive materials, without changing the hardware or original intent of the detector. Given these parameters the scientists sought to determine how to modify this detector while essentially keeping it the same.

"Many of the emerging chemical threats and explosives share the challenge of presenting little to no detectable vapor for sampling. By conducting research into the detection of solid explosive residues, we have learned valuable lessons that are equally important for detecting nonvolatile solid and liquid chemical agent residues as well," said Dr. Augustus W. Fountain III, senior research scientist for chemistry.

The add-on pieces are a new JCAD Rain Cap with a Probe Swab and an inlet. Within the JCAD itself, scientists added two on-demand vapor generators: a calibrant and a dopant. The dopant changes the chemistry of the detector so that it can detect explosives easier.

To convert an ordinary JCAD into a JCAD Chemical Explosive Detector, or JCAD CED, the existing rain cap is replaced with one with a new inlet. Once in place, scientists wipe any surface using the probe swab, which then retracts back into inlet. With a simple button push, the probe swab tip with the explosives sample heats up to a certain temperature, vaporizing the explosive residue. These additional features allow an ordinary JCAD to now have the role of a portable, automated explosives detector.

"Within the Army, there is no other automatic, near real-time explosives detector at this time. There are many explosives detectors, but not ones that are dual-use and automatic," said Charles Harden, Ph.D., a Leidos contractor with ECBC's Point Detection Branch.

"The best part is that the technology is already out in the field, and warfighters have been trained on this equipment," Harden said. "All we're doing is introducing small add-ons that will have a big impact."

The swab allows users to pick up often-invisible residue from any surface and analyze it. The explosive residue can be transferred and easily detected using the instrument. The JCAD CED can already detect roughly a dozen compounds including TNT, RDX and EGN. Future efforts could increase the number of detectable compounds.

"There are several advantages with the improved JCAD CED system. First, its dual-functionality accurately detects vapors as well as explosive residue. Second, scientists successfully modified the system with easy-to-use add-ons, and the upgrade is cost effective and reduces the need for yearly maintenance," said Blethen.

Scientists plan to determine the amount of explosives that can be detected and develop a concept of operations. Other goals include developing a methodology for detecting homemade explosives, and reaching a technology readiness level 6. JCAD CED will be demonstrated in a fiscal year 2015 military utility assessment.

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