New Heavy Isotopes of Calcium
New Heavy Isotopes of Calcium
Some of the heaviest isotopes of common elements are being made right now. For example, just recently, scientists made eight new rare isotopes of the following elements: calcium, phosphorus, sulfur, chlorine, argon, potassium, scandium. They made two new heavy isotopes of calcium: calcium-59, and calcium-60.
Isotopes are heavier or lighter versions of an element. Each element has a unique number of protons but can have different numbers of neutrons. The number of protons plus neutrons determine the atomic mass of that atom. So, calcium 60, for example, has 20 protons and 40 neutrons. This makes calcium-60 much heavier than the most common isotope of calcium, calcium-40 which makes up 97% of the calcium atoms. Calcium-60 has 12 more neutrons than the heaviest “natural” form of stable calcium isotopes, calcium-48. Stable forms of calcium like calcium-48 are called stable because they will last for hundreds of quintillions of years (approximately 40 times the age of the universe). The kinds of heavy isotopes made in the lab like calcium-60 and calcium-59 last for a few thousandths of a second.
Part of the reason scientists make new isotopes is because the scientists are trying to understand how the nucleus of an atom is held together. The nucleus of an atom contains the protons and neutrons and is held together by the “nuclear force”, something we are still trying to fully understand. By making new isotopes, scientists can test theories about how the nuclear force works. There are several models about how the nuclear force functions and looking at the shape and types of isotopes formed can tell us which of the models are correct or close to correct.
In the near future, I see more isotopes being made that may offer more insight into the way the nuclear force holds together the fundamental parts of matter, atoms. If we understand the nuclear force we may be able to harness its power as an energy source. We may also be able to design isotopes for special purposes as each isotope has slightly different properties.
“Researchers from Michigan State University and the RIKEN Nishina Center in Japan have discovered eight new rare isotopes, including the heaviest known calcium atom, calcium-60. The illustration shows a plot used to identify the different nuclei produced in the measurement. Z is the number of protons and A/q is the ratio of the number of protons and neutrons over the charge. The calcium isotopes are indicated from the last stable calcium-48 out to calcium isotopes that can only be reached with FRIB. All nuclei to the right of the red line have been observed for the first time in this measurement. Credit: National Superconducting Cyclotron Laboratory”
Finding new isotopes outside of what theories expect help expand our understanding of nuclear properties. This is a watercolor impression of a re-imagined periodic table.
Michigan State University Facility for Rare Isotope Beams. "Heaviest known calcium atom discovered: Eight new rare isotopes discovered in total." ScienceDaily. ScienceDaily, 12 July 2018. <www.sciencedaily.com/releases/2018/07/180712100555.htm>.
O. B. Tarasov et al, Discovery of Ca60 and Implications For the Stability of Ca70, Physical Review Letters (2018). DOI: 10.1103/PhysRevLett.121.022501
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