A New Resolution for Nuclear Forensics
Leveraging the Laboratory’s expertise in nuclear forensics—the science of extracting information about the provenance and history of nuclear materials—a team of scientists from Lawrence Livermore and Lawrence Berkeley national laboratories developed a new technique to identify chemical states and material impurities at the scale of individual particles. The research on uranium oxide appears in the May 2025 issue of the Journal of Nuclear Materials, with a subsequent paper on plutonium oxide published in the November 2025 issue of the Journal of Vacuum Science & Technology A.
The team’s method, synchrotron-based scanning transmission x-ray microscopy (STXM), uses a synchrotron-generated x-ray beam focused on a spot only tens of nanometers wide to scan across an actinide sample. Detectors then measure how many x-rays are absorbed at each point in the material for multiple x-ray energies. Since each element has a unique absorption profile, STXM can create detailed images and identify specific elements and their chemical states in very small regions of a sample. “STXM allows us to see details in nuclear materials that traditional methods could not detect,” says lead author and Livermore scientist Rachel Lim. “This ability to pinpoint chemical states and impurities of individual particles marks a major advance for nuclear forensics capabilities.”
Contact: Rachel Lim (925) 423-8914 (lim37 [at] llnl.gov (lim37[at]llnl[dot]gov)).
Reversible 3D Printing
Additive manufacturing typically involves depositing one layer of material at a time and hardening each layer individually. A digital light processing (DLP) printer, for example, projects a structured pattern onto a thin layer of liquid resin to build up a 3D object layer by layer. However, if the print is not exactly right, the entire piece must be reprinted. A Livermore team has developed a resin that enhances traditional 3D printing by introducing dual-wavelength behavior, enabling additive and subtractive manufacturing. The research results were published in the September 2025 issue of Advanced Materials Technologies.
The team designed the resin so that it cures and hardens under blue light and degrades back into liquid form under ultraviolet (UV) light. Chemically, the process leans on blue light causing the molecules to enter a cross-linked network, a standard 3D-printing technique. When exposed to UV light, acid is formed in the resin, which breaks down the molecules into liquid. This unique material enables a hybrid printing system capable of corrective manufacturing, provides improved print resolution, and allows for upcycling and recycling of parts. The patented resin is available for commercialization through Livermore’s Innovation and Partnerships Office. “Ongoing work includes developing an adaptive manufacturing system,” says Livermore scientist and co-author Liliana Dongping Terrel-Perez. “Once we see printing errors, we can adaptively modify the projection images to correct those errors on the fly. Besides DLP printing, we also plan to transfer this method to volumetric additive and subtractive manufacturing.”
Contact: Liliana Dongping Terrel-Perez (925) 423-6981 (terrelperez2 [at] llnl.gov (terrelperez2[at]llnl[dot]gov)).
Rewriting the Moon’s Early History
Apollo 17 astronauts collected rock sample 76535 from the Moon more than 50 years ago, but its influence on understanding lunar history persists today. Formed nearly 50 kilometers underground, the sample has puzzled scientists for decades because it lacks the shock features expected from deep rocks’ violent movement to the surface. The rock was thought to have lifted to the surface as a result of the impact that formed the South Pole–Aitken Basin, the moon’s largest crater. However, new research led by Livermore planetary scientist Evan Bjonnes posits that a different impact in the Serenitatis Basin was the cause of the rock’s relocation. The work is published in the September 28, 2025, issue of Geophysical Research Letters.
The South Pole–Aitken Basin event would have required an additional impact to carry sample 76535 to the Apollo 17 site. Alternatively, the Serenitatis Basin is local to the Apollo 17 site and was the kind of impact capable of lifting the sample to the surface. Using computer simulations of large lunar impacts with models of the Moon’s crust, Livermore showed that during a later collapse stage of giant crater formation, material from tens of kilometers below can be drawn upward gently enough to preserve a rock such as sample 76535. The findings also suggest that impact occurred about 4.25 billion years ago, roughly 300 million years earlier than previously thought. “By pushing Serenitatis back in time, we’re shifting the entire timeline of when big impacts happened across the Solar System,” says Bjonnes.
Contact: Evan Bjonnes (925) 422-8378 (bjonnes1 [at] llnl.gov (bjonnes1[at]llnl[dot]gov)).
