Rapid Airport Security Screening Using Superconducting Technology - RASSUST

Security at airports now commonly involves full body scanners and new regulations in the UK will require all air-passengers to undergo a full body scan by 2022 as part of the standard security process before boarding an aircraft. Such scanners work by viewing the body at colours not visible to the human eye. These colours occur at so called millimetre wavelengths and in most cases light at this colour in generated in the same way as the optical light we see as humans - heat. Most clothing is transparent to light at millimetre wavelengths whereas many objects that could pose a security risk are not. The heat from our body is a natural source of millimetre light and objects hidden under clothing can block this light from view creating a shadow of the object. However, millimetre wave light is difficult to detect and requires special cameras. The technology in airports to date is not sensitive enough to measure the natural millimetre wave light produced by our body heat but instead illuminates each person with millimetre wave light and measures reflections. This is similar to using a flash on a camera when taking a photograph in a dark room. This process is slow and requires each person to be stationary while the image is taken. Each person takes around 15-20 seconds to be imaged in this way and due to the insensitivity of the system an additional manual search is often required. Moving to a requirement where 100% of passengers are screened in this manner, an increase in the time and cost of security protocols at airports are inevitable.

Using technology originally developed for astronomy, we propose a solution to this problem. We have developed a millimetre wave camera based on superconducting detectors that has the capability of performing the required security imaging while a person simply walks past the camera. In most cases the person would be unaware of this system in the same way we have become unconscious to CCTV at airports. The key to this technology are ultra-sensitive millimetre wave detectors that do not require the "flash" used in current scanners and can work in video mode. The detectors gain their sensitivity by working at extremely low temperatures, in fact, only a fraction of a degree above absolute zero - the coldest temperature physically possible. Realising such a camera in a busy airport may seem impossible but modern technology makes reaching such temperatures routine. To prove this, in November 2018, our group took a generic version of our millimetre-wave camera to Cardiff airport where we conducted a number of successful trials imaging people in a typical airport environment. Our system was able to easily detect a mock gun concealed under a thick coat and was even proven in conjunction with artificial intelligence systems that could recognise and highlight this forbidden object. Such imaging naturally raises concerns regarding privacy and safety. In our system, the image of the person being screened shows up as a silhouette preserving modesty. Furthermore, with no requirement for illumination, our system is completely passive making it the same as taking a normal photograph or video of the person being screened.

This project will address several issues preventing the commercial adoption of this new technology. We wish to adapt our generic camera to enable 24-hour automated operation as well as the ability to image a person from four viewpoints creating a compete security scan as a person walks past. We will also develop new detector arrays providing improved sensitivity to detecting potential concealed threats. We will also develop new electronics that will reduce the overall cost of our system while enhancing performance to meet the challenges of rapid screening in a modern airport.

The overall aim is to produce a full body scanner that is, cheaper, faster, more convenient and overall safer than the technology currently used.