When energetic protons strike a solid material, they create a burst of secondary particles. These secondary particles can include neutrons, photons, and even other protons. Scientists can use these particles, especially high-energy neutrons, to make valuable isotopes. (Isotopes are variations of a particular type of atom.) Recently, researchers studied these secondary neutrons. They used what they learned to improve the process for producing rare isotopes using these high-energy neutrons.
The Impact
High-energy neutrons produced by proton collisions with dense matter act like tiny wrecking balls. They knock particles out of materials to create rare, valuable isotopes. These secondary neutrons make it possible for scientists to produce unique isotopes vital for an array of purposes. Some isotopes will support discovery science and help us understand the universe. Others will support national security applications by securing a domestic supply chain of these products. Some will support public health applications in the form of new therapies and treatments for cancer. For example, high-purity actinium-225 is a promising radioisotope for advanced cancer therapy. By developing and improving the process for generating secondary neutrons, researchers are establishing a new, reliable, and easier way to produce these essential isotopes.
Summary
Researchers at the Brookhaven Linac Isotope Producer facility studied high-energy secondary neutrons produced during routine proton irradiation of targets. They used real-world data to improve computer simulations of how these interactions (or bombardments) generate secondary neutrons. The comparisons helped improve the accuracy of the simulations and therefore their ability to predict results.
These experiments also allowed the researchers to simulate various scenarios. These scenarios helped them explain the primary factors that influence neutron production. The facility's existing geometry can produce a quantity of isotopes suitable for a wide variety of research applications. In addition, simulation showed that if scientists use target materials comprised of extremely heavy nuclei such as tungsten or tantalum, it could at least double the production of neutrons.
Funding
This work was funded by the Department of Energy Office of Isotope R&D and Production in the Office of Science.