Jacqueline Gates of Lawrence Berkeley National Laboratory isolating livermorium atoms.
Marilyn Sargent/Berkeley Lab 2024 Regents of the University of California
The third heaviest element in the universe has been created in a way that points the way to synthesizing the elusive element 120, the heaviest element in the periodic table.
“We were very shocked, very surprised, and very relieved that we hadn’t made the wrong choice in installing the equipment,” said Jacqueline Gates of the Lawrence Berkeley National Laboratory (LBNL) in California.
She and her colleagues created the element, livermorium, by bombarding pieces of plutonium with beams of charged titanium atoms. Titanium has never been used in such experiments before because it’s hard to turn into a well-controlled beam and it takes millions or trillions of collisions to create just a few new atoms. But physicists think that the titanium beam is essential to making a hypothetical element 120, also known as unbinylium, which has 120 protons in its nucleus.
The researchers first evaporated a rare isotope of titanium in a special oven at 1,650 °C (about 3,000 °F). They then used microwaves to turn the hot titanium vapor into a charged beam, which they sent into a particle accelerator. When the beam reached about 10 percent the speed of light and smashed into a plutonium target, a fragment of it hit a detector, where it detected a trace of just two livermorium atoms.
As expected, each atom rapidly decayed into other elements. The stability of an atomic nucleus decreases as the mass of an atom increases. But the measurements were so precise that there is only about a one in a trillion chance that the result was a statistical fluke, Gates said. The researchers presented their findings on July 23 at the Nuclear Structure 2024 conference at Argonne National Laboratory in Illinois.
Michael Thornesen of Michigan State University says the experiment strengthens the case that creating element 120 is feasible. “We have to do the basics and we have to go in the dark,” he says. “So this is a really important and necessary experiment.”
Toennesen says the creation of unbinylium will have profound implications for our understanding of the strong force, which determines whether heavy elements are stable. Studying unbinylium may also help us understand how exotic elements formed in the early universe.
The heaviest artificial element to date, element 118 (also known as oganesson), has two more protons than livermorium and was first synthesized in 2002. Since then, researchers have been struggling to make atoms heavier, because that requires colliding already-heavy elements with each other, which themselves tend to be unstable. “It’s really, really hard work,” Thornesen says.
But the new experiment has LBNL researchers feeling optimistic: They plan to launch experiments aimed at creating element 120 in 2025 after replacing the plutonium target with the heavier element californium.
“I think we’re pretty close to knowing what to do,” Gates said, “and having the opportunity to add a new element to the periodic table is (very exciting). Very few people get that opportunity.”
topic:
- Chemical /
- Nuclear Physics
