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Team “twists” their way to new patents detecting nuclear weapons and more

  • Published
  • DAF T3

WRIGHT-PATTERSON AFB, OHIO – One of the most fascinating aspects of the work done by the scientists and engineers of the Air Force Research Laboratory (AFRL) is how often great discoveries arise out of serendipity. A team can research one thing and, through the process of their hard work, uncover something completely different but still significant. That’s what happened with a team of AFRL scientist which has led to two patents involving the growth of crystals.

Matthew Mann, Maj Thomas Bowen, Lt Col Eric Hunt, and Capt Eric Plummer, all with the AFRL Sensors Directorate (RY) at the time, had been researching Uranium Dioxide (UO2) crystals to discover the capabilities of detecting neutrons for several years. Being able to detect neutrons has a number of uses across many applications. Perhaps the most notable of these is discovering nuclear weapons. During their work, the team began working with Sodium Uranium Oxide (NaUO3) and Rubidium Uranium Oxide (RbUO3).

“The NaUO3 and the RbUO3 fall into a class of materials called perovskites. Perovskites are used in all kinds of technological applications such as solar cells, electronics, and others all across the board,” Mann said.

Named for mineralogist Lev Perovski, perovskites are a family of ABX3 materials that first began with calcium titanium oxide (CaTiO3) minerals. A perovskite structure can have a number of desirable attributes including super conductivity, catalytic properties, magnetic resistance, and more. But Mann said there’s a twist to how the team used perovskites.

“These, however, are a little different simply because we’ve got uranium in a +5-oxidation state versus a typical +4 or +6. This leaves one electron in the outer shell, and this can lead to a lot of different types of magnetic applications.” The oxidation state or number is the total number of electrons an atom gains or loses when forming a chemical bond with another atom.

U.S. Patent #11,346,017 B1 Single Crystalline NAUO3 and Method of Making Same and #11,608,568 B1 Single Crystalline RBUO3 and Method of Making Same detail breaking new ground in crystal growth.

“When we started the UO2 project, we were doing a completely different process that had never been tried before called the hydrothermal growth process. We didn’t understand what type of mineralizer solution – a water-based solution with an additive such as sodium hydroxide – to use. That chemistry was unknown,” Mann explained. “So, we were doing a kind of shotgun approach. We were trying all kinds of different mineralizers. During that process, we came across numerous new materials or new ways to make materials much better.”

Prior to these patents, NAUO3 and RbUO3 were only available in powdered forms and were too small to be useful in detecting neutrons and other important related applications. However, these patented processes can create crystals large enough to be used in the fields of neutron detection, radiation-hardened electronics, , photovoltaics, and magnetic applications.

“From the neutron detection aspect, the uranium inside the material can absorb neutrons and they can cause a fission event inside the crystal. That creates a detectable electric signal,” Mann said. “Neutrons are given off by other radioactive materials. This could be enriched uranium or plutonium used for a nuclear weapon or even in facilities producing these weapons. It can also be used to find other non-nuclear weapons made with material like Californium which can be used in a dirty bomb.”

If serendipity is, as novelist Elizabeth Berg wrote, “just intention unmasked”, these patents are excellent examples of that sentiment.

United States Patent Office Patent: #11,346,017 B1, #11,608,568 B1

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