New tool at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) will be taking on some of the periodic table’s latest heavyweight champions to see how their masses measure up to predictions.
Dubbed FIONA, the device is designed to measure the mass numbers of individual atoms of superheavy elements, which have higher masses than uranium.
“Once we have determined those mass numbers, we will use FIONA to learn about the shape and structure of heavy nuclei, guide the search for new elements, and to give us better measurements for nuclear fission and related processes in nuclear physics and nuclear chemistry research,” said Kenneth Gregorich, a senior scientist in Berkeley Lab’s Nuclear Science Division who has been involved in building and testing FIONA.
FIONA’s full name is “For the Identification Of Nuclide A.” The “A” is a scientific symbol representing the mass number—the sum of protons, which are positively charged, and neutrons, which do not have an electric charge— in the nucleus of an atom. The proton count, also known as the atomic number, is unique for each element and is the basis for the arrangement of elements in the periodic table.
FIONA builds on a long history of expertise in heavy element discoveries and nuclear physics research at Berkeley Lab. The Lab’s scientists have been involved in the discovery of 16 elements and also various forms of elements, known as isotopes, which have different numbers of neutrons.
Nuclear physicists have used the known masses of radioactive decay “daughter atoms” as a framework for determining the masses for these heavier “parent” elements.
Previous experiments have also helped to home in on the masses of some of the superheavy elements. But determining the mass number of some of the heaviest elements has remained out of reach because it is challenging to produce isolated atoms and to measure them before they rapidly decay.
FIONA’s measurements are expected to provide a better fundamental understanding of the makeup of these manufactured superheavy atomic nuclei.
“We will be exploring the limits of nuclear stability, answering basic questions such as how many protons you can put in a nucleus,” Gregorich said.