COVID-19: THz Technology
COVID-19: Passive THz Technology for Security Applications
December 2020: COVID-19 has revolutionized security practices along with other parts of everyday life: screening people via personal ‘patdowns' is no longer safe. ESA-developed passive terahertz technology – enabling the detection of items hidden under clothing from a distance – is helping to fill the gap. The US Customs and Border Protection agency is among the latest of more than 200 users of the technology, deploying it to secure the US border. 1) 2)
Those being screened do not have to walk into any special booth, but simply walk past the detector, without even noticing. They are not exposed to any radiation; instead the system relies on passively measuring terahertz radiation emitted by anything sufficiently warm, including the human body – a region of the electromagnetic spectrum first employed by satellites observing the Earth and deep space.
The technology has been commercialized by UK company ThruVision, with customers including airports around the world and the LA Metro as well as the US Customs and Border Protection agency, at selected southern border ports of entry.
"By detecting heat energy coming from a human body, we can easily spot detect any concealed items on a person that are blocking that energy," explains Colin Evans, CEO of Thruvision. "It's the functional equivalent of looking at someone with night vision goggles, except at a much lower frequency."
Figure 1: The US Customs and Border Protection agency is among the latest of more than 200 users of the passive terahertz imaging technology, co-patented by ESA and marketed by ThruVision, deploying it at selected southern border ports of entry (image credit: US Customs and Border Protection)
The global logistics and supply chain industry represents another focus of interest for passive terahertz screening. The massive distribution centers that serve the fast-growing e-commerce sector, staffed by thousands of employees, have proved attractive targets for theft by organized crime and individuals.
Traditionally such centers perform randomized employee patdowns using portable metal detectors, which are intrusive, unpopular and thanks to the COVID-19 pandemic, unsanitary. They are also ineffective, being unable to detect non-metallic objects.
Figure 2: Terahertz imaging to spot concealed items under clothes. The global logistics and supply chain industry represents a focus of interest for passive terahertz screening, co-patented by ESA and marketed by ThruVision. The massive distribution centers that serve the fast-growing e-commerce sector, staffed by thousands of employees, have proved attractive targets for theft by organized crime and individuals. Traditionally such centers perform randomized employee patdowns using portable metal detectors, which are intrusive, unpopular and thanks to the COVID-19 pandemic, unsanitary. They are also ineffective, being unable to detect non-metallic objects. Instead SONY Digital Audio Disc Corporation, the manufacturing logistics arm of SONY Corporation has begun using the passive terahertz system to routinely screen all its distribution centre workers. Operating from a distance of 3 m away, the technology can even detect very small metallic and non-metallic objects, such as CDs, cell phones or USB drives (image credit: ThruVision)
Instead SONY Digital Audio Disc Corporation, the manufacturing logistics arm of SONY Corporation has begun using the passive terahertz system to routinely screen all its distribution center workers. Operating from a distance of 3 m away, the technology can even detect very small metallic and non-metallic objects, such as CDs, cell phones or USB drives.
"We're very proud to be using ESA's technology to help businesses and workers continue to be productive, despite the COVID-19 pandemic," adds Colin Evans.
Terahertz and sub-mm waves are employed in space in various ways, to image early galactic evolution and perform temperature and humidity sounding for weather forecasting and research.
Their use down on the ground dates back to the start of this century, when ESA and the UK's Rutherford Appleton Laboratory (RAL) collaborated on shrinking detectors down to an easily portable size, able to image items from a few meters away rather than far away in space.
Figure 3: ThruVision scanning by terahertz camera (image credit: ThruVision)
"Since the early days of terahertz scanning, significant technological steps have been made," explains Peter de Maagt, head of ESA's Antennas and Sub-mm Waves Section, and co-author of the patent. "The scanning technology is now available at commercially affordable prices that allow widespread use."
The ensuing patent is owned jointly by ESA and RAL, subsequently licensed by ThruVision.
"It's a big success for us when a space invention finds wider uses, and this ThruVision's success is a notable example," comments Aude de Clercq, heading ESA's Technology Transfer and Patent Office. "ESA's overall intellectual property rights portfolio consists of around 560 patents, available for licensing by European companies for both space and terrestrial applications."
Figure 4: Developed by UK company ThruVision, the body scanners are non-invasive, passively screening individuals for suspicious objects. They work by detecting the absence of the naturally occurring, extremely high-frequency ‘terahertz' waves, emitted by anything that is warm – including the human body. The terahertz waves can penetrate clothing and thin plastics or ceramics but not metal or liquid water. However, the ThruVision system can also detect plastics guns and ceramic knives (image credit: ThruVision)
1) "Terahertz security for e-shopping centers – and US border," ESA Enabling & Support, 18 December 2020, URL: https://www.esa.int/Enabling_Support/Space_Engineering_Technology
2) Dovil> Čibirait>-Lukenskien>, Kęstutis Ikamas, Tautvydas Lisauskas , Viktor Krozer, Hartmut G. Roskos and Alvydas Lisauskas, "Passive Detection and Imaging of Human Body Radiation Using an Uncooled Field-Effect Transistor-Based THz Detector," Sensors2020, Vol. 20, 4087, Published: 22 July 2020, https://doi.org/10.3390/s20154087
The information compiled and edited in this article was provided by Herbert J. Kramer from his documentation of: "Observation of the Earth and Its Environment: Survey of Missions and Sensors" (Springer Verlag) as well as many other sources after the publication of the 4th edition in 2002. - Comments and corrections to this article are always welcome for further updates (firstname.lastname@example.org).