Scientists at the Lawrence Berkeley National Laboratory recently created an isotope called mendelevium-244. It is the 17th form of mendelevium, developed in these same laboratories over sixty years ago, and also the lightest.
“Discovering this new isotope of mendelevium was not easy”
Originally created in 1955 by scientists from Berkeley Lab, the mendelevium is an element whose atomic nucleus contains more or less neutrons (uncharged particles) than other forms of components. To create mendelevium-244, the researchers used a cyclotron 88 inches, type of particle accelerator optimizing the powerful beams of charged particles of the target in order to create atoms of heavier elements. Their work was recently presented in the journal Physical Review Letters.
” Discovering this new isotope of mendelevium was not easy, because all its neighboring isotopes have very similar disintegration properties “Explains the scientist Jennifer pore, who supervised the study. ” Alpha decay describes the process by which a radioactive element like mendelevium breaks down into lighter elements over time. “
” We measured the properties of 10 atoms of mendelevium-244 for the study “, Continues the researcher. ” Each isotope represents a unique combination of protons and neutrons. When a new isotope is discovered, this particular combination of protons [particules chargées positivement] and neutrons have never been observed. The study of these extreme combinations is essential for our global understanding of nuclear matter. “
Thanks to this discovery, the scientists also provided the first direct evidence of an alpha decay process involving berkelium-236, a isotope of the element berkelium, when it becomes americium-232, significantly lighter.
Two separate decay chains
It turned out that the mendelevium-244 consisted of two decay chains separate, each leading to a half-life different: 0.4 seconds and 6 seconds, depending on the different energy configurations of the particles in its nucleus. A half-life representing the time necessary for the number of atoms of a radioactive element to be halved when their nucleus breaks down into other lighter nuclei.
This discovery was made possible thanks to FIONA, 88 inch cyclotron allowing researchers to determine the mass number of an element, i.e. the total amount of protons (positively charged particles) and neutrons (uncharged particles) in the nucleus of a atom. In this case, the mass number of the new isotope was 244.
” The isotope discoveries are cyclical and depend on new accelerators and major progress in the development of experimental equipment. Berkeley’s FIONA and the Facility for Rare Isotope Beams (FRIB), a facility under development by the United States Department of Energy, represent unique means for the discovery of new isotopes in the United States “, valued Michael Thoennessen, professor atMichigan State University.
” In order to ensure that the FIONA measurements were accurate, we first measured the decay properties and the mass numbers of the known isotopes of mendelevium, such as mendelevium-247, 246 and 245 “, Specify the authors of the study.
” Once we were convinced that we knew the properties of these light isotopes of mendelevium well, we tried the experiment to discover the isotope of mendelevium-244, which had not yet been observed. Without direct confirmation that we had produced an isotope with a mass number of 244, it would have been difficult to disentangle the results and prove this discovery. “