MagTag

Next generation passive sensor.

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Inspiration

"The licensee reported to NJDEP on December 3, 2024, that a Ge-68 pin source that they sent for disposal was lost in transit on December 2, 2024. The source is an Eckert & Ziegler model HEGL-0132, with current approximate activity of 0.267 mCi. The shipping container arrived at its destination damaged and empty. The licensee has filed a claim with the shipper. If the source is not located within the 30 days, the licensee will follow-up with a full written report to include root cause(s) and corrective actions."

This isn't an uncommon assurance, within our cities, research labs, and military there is an increasing amount of nuclear material and radioactive waste floating around. Tracking and monitoring the chain of custody and stability of these containers is a major component to national security, public safety, and economic impact.

In one instance at the WIPP plant in New Mexico, a container of nuclear weapon by-product waste had cat litter mixed into it, this caused a chemical reaction inside the container which lead to an increased amount pressure rupturing the drum, causing a radioactive contamination that impact 21 workers and cost $500m to clean up.

What it does

Our project is based off research completed at Sandia National Laboratories. The original research utilized a small radiation hardened sensor. The sensor is comprised of a silicon wafer, then small magnetoelastic resonators are attached the the wafer, the resonators are then coated in different materials for different functions. For example, to detect hydrogen we can coat the resonator in palladium.

What happens is when we expose one of these tags to a low frequency AC magnetic field, each resonator creates a resident frequency, we can monitor those frequencies for shifts in amplitude and magnitude, if we see a shift in frequency we can make the determination that the tag has had exposure to its target.

This processing should happen on some type of IoT device that can deliver this data to a middleware for processing in near realtime, then we apply AI to watch over an array of tags and search for anomalies, then all of this would be visible over some type of GUI.

How we built it

I started out by utilizing components from an old speaker to build the antenna itself. I used the copper coils to generate an AC magnetic field, then I suspended the the coils over the magnetic of the speaker to amplify the excitement of the magneto elastic strip. From there I ran out of components, and turned to building a simulator that enables us to do this digitally, that is then sent to a GUI for displaying.

Challenges we ran into

  • Lack of materials to complete physical prototype

Accomplishments that we're proud of

  • The antenna I created should work when I have all the components
  • Able to test single resonate frequencies
  • Worked through a lot of end user edge cases

What we learned

  • The deep complexities of building the antenna for longer range communications
  • How we are going to run into challenges when it comes to signal amplification and processing

What's next for MagTag

  • Building prototypes of the tag itself in a MEMs facility
  • Building a longer range
  • Improving simulations
  • Improving middleware signal processing

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