Non-linear acoustic concealed weapons detection (CWD)

In this paper we describe an acoustic weapons detection concept that is based on ultrasonics and nonlinear acoustics. An ultrasonic projector is used to create an acoustic field at the site of inspection. The field is composed of multiple ultrasonic waves interacting at the interrogation site. The ultrasonic field creates acoustic interactions at that site which are used as the primary probe. The acoustic field is tailored to excite the target in an optimum fashion for weapons detection. In this presentation, we present aspects of this approach highlighting its ability to confine the interrogation field, create a narrow-band probing field, and the ability to scan that acoustic field to image objects. Ultrasonic propagation parameters that influence the field will be presented as will data of field characteristics. An image obtained with this system will be shown, demonstrating its capability to achieve high resolution. Effects of cloth over a weapon are shown to alter the image, yet not hide the weapon. Luna will report on its most recent findings as to the nature of this detection technology and its ability to generate information important to CWD.