Magneto-telluric Detection for Metallic Buried IEDs using Superconducting Quantum Interface Device (SQUID),

Improvised explosive devices (IEDs) are the most dangerous risks that the militray forces are currently facing and account for more than 50 percent of daily attacks. Detection of such buried IED is a very challenging task, because the detection task should be performed from a considerable standoff distance. Rapid survey speed is also required.

The magneto-telluric field is created from interaction of natural sources such as the earth’s magnetic field and solar winds. This field is naturally varying and induces electric currents (or telluric currents) under the Earth’s surface in the frequency range of sub-hertz to 10 kHz. Any discontinuity in the soil’s conductivity due to the presence of a buried conducting object will create current gradients which can be measured on the surface. Our group conducted numerical simulation and found that a highly conducting object creates detectable magneto-telluric gradient in the range 3 – 7 p Tesla [16]. The superconducting quantum interference device (SQUID) sensor, well known for providing sufficient sensitivity (hundreds of f Tesla range) to measure such small magneto-telluric gradient, has been applied to build our prototype IED detection platform. Fig. 1a shows the 8-channel SQUID available in our laboratory. In this project, we examine the use of high temperature (Liquid Nitrogen) SQUID sensor to detect disturbance of earth’s magneto telluric field due to the presence of metallic objects. We conduct various scenarios of field (outdoor) experiments to detect metallic targets buried in different type of soil conditions using prototype SQUID system. Fig. 1b shows encouraging results from field tests in the volcanic soil in Hawaii. Limitation and detection performance of the SQUID are being evaluated based on the field experiments.

Deliverables & milestones

  1. Numerical study of the magneto-telluric field at the presence of buried metallic objects.
  2. Analyze the SQUID sensor performance at the outdoor environment.
  3. Development of a prototype IED detection platform using SQUID sensor.
  4. Experimental measurements using the developed system.
  5. Evaluate detection performance of the developed system and provide the optimal configuration.
Fig. 1. (a) High-temperature SQUID sensor and aluminum shielding for reducing environmental noise. (b) X-component of 2D data measured by the SQUID (30 cm elevated from the ground surface).

 

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