Hand-held scanner detects hazardous substances on site

04 Jun 2019

Sensor developed by CHEQUERS consortium detects explosive, toxic and other dangerous materials in real time, designed for emergency personnel.

Together with partners from research and industry, the Fraunhofer Institute for Applied Solid State Physics (IAF) has developed a hand-held scanner for the detection of hazardous substances, within the EU project CHEQUERS, which started in 2015.

The sensor detects explosive, toxic and other dangerous substances in real time and is designed to help emergency personnel in a variety of situations. The project consortium met at the end of April to report the successful completion of the project.

The reason for the four-year project is that portable, eye-safe scanners with the ability to identify numerous chemicals fast and remotely up to a distance of 1 m do not exist in a useful form, say the CHEQUERS members.

“Our hazardous substance scanner covers a large spectral range rapidly, provides precise results and can even be used by untrained personnel,” said explains Dr. Stefan Hugger, project manager and a scientist at IAF.

“This device is extremely useful at crime scenes, after terrorist attacks or after accidents in industrial plants in which chemicals spread in an uncontrolled way. Rescue forces can react immediately to a threat.”

The CHEQUERS consortium has developed a measuring device based on infrared backscattering spectroscopy. To achieve this, the team combined fast, widely tunable quantum cascade lasers with adjusted transmission and receiver optics, fast IR detectors and a fitting control and detection software.

CHEQUERS stands for Compact High Performance Laser Sensors. Since 2015, Fraunhofer IAF collaborated with the Fraunhofer Institutes IPMS and CAP, the Federal Criminal Police Office, as well as the companies Vigo Systems, M Squared Lasers and Modus Research & Innovation, in order to develop a hand-held scanner for hazardous substances. Project CHEQUERS was funded by the European Union within the program Horizon 2020.

Miniaturized quantum cascade laser

Hugger added, “Portable sensors for remote spectroscopic detections require especially compact and fast tunable laser sources. Such devices need to compensate the inevitable movements of the hand and still be able to detect a conclusive spectrum within a short amount of time.

“Together with Fraunhofer IPMS, we have developed a miniaturized quantum cascade laser with an external resonator that is able to scan the whole spectral range of the QC laser chip within a millisecond.”

The measuring principle is based on selective spectral lighting of the target in the wavelength range of 1000 – 1300 cm^-1. The chemical substance is identified based on the intensity of the backscattered light and the illumination wavelength. The spectral fingerprint is matched with the integrated database that contains a large amount of safety-relevant substances, and thus the substance can be identified.

The hand-held demonstrator has now passed a series of test measurements conducted by the Federal Criminal Police Office in cooperation with Fraunhofer IAF in early 2019.

“During the test measurements, the scanner for hazardous substances was able to detect many explosives and their precursor materials, and has thus proven that the technology works. The next step is to increase the robustness of the measuring system to make it ready for daily use.” said Hugger.