A brand new atomic nucleus has just been discovered, claims new study

Introducing the lightest-ever isotope of astatine observed to date.
Tejasri Gururaj
An atom is the smallest level of matter that forms chemical elements.
An atom is the smallest level of matter that forms chemical elements.


Atoms make up everything around us. By studying atomic nuclei, scientists gain a deeper understanding of the universe's fundamental building blocks. Additionally, atomic nuclei have implications for particle physics, nuclear energy, medicine, and astrophysics.

Now, scientists have observed a new type of atomic nuclei in an accelerator; 190astatine (190At) is the lightest isotope of astatine, with 105 neutrons and 85 protons.

This study was conducted in the Accelerator Laboratory at the University of Jyväskylä in Finland by Henna Kokkonen as a part of her master's thesis. 

Speaking about the discovery, Kokkonen said in a press release, "In my thesis, I analyzed experimental data among which the new isotope was found. During my thesis process and summer internships, I got to know the Nuclear Spectroscopy group's work. Now I am very happy to work in the group towards my Ph.D. degree."

Astatine: The elusive element

Astatine is a scarce and radioactive element. Its high radioactivity makes it very unstable, with its most stable isotope, 210astatine, having a half-life of just over eight hours. Most of its isotopes have a half-life of a few seconds. 

Within the periodic table, astatine is placed with halogens, which are highly reactive nonmetallic elements. 

Astatine is the second-rarest naturally-occurring element, with just one gram present on Earth at any moment. Most of its properties are unknown and derived from inference as it is short-lived. It generally undergoes alpha decay into a more stable form, such as radon or bismuth. 

Even though very little is known about this element, some studies have shown that it may have anti-cancer properties, being a potential candidate for radiation therapies. Therefore, gaining a better understanding of this element is vital. 

Discovering the new astatine

The study involved a fusion-evaporation reaction taking place in a gas-filled recoil separator. This apparatus is used in nuclear physics experiments to separate and analyze energetic nuclear reaction products by passing them through a gas medium.

Fusion-evaporation reactions involve the collision of heavy ions with a target nucleus, which fuse to create a compound nucleus. This compound nucleus undergoes alpha decay by ejecting alpha particles, which are particles containing two neutrons and two protons (basically a helium atom), to produce a more stable element.

The research team bombarded 84strontium into silver atoms and studied the decay products. They were not looking for 190At, but that's exactly what they discovered.

The reaction revealed that the alpha particles during the decay of 190At had an energy of around 7750 keV. This measurement provides important insights into the energetics of the decay process.

Additionally, the researchers determined that the half-life of 190At was around one millisecond. The short half-life indicates that 190At is a highly radioactive isotope. These measurements aligned with our predictions from atomic mass models of this isotope.

They further found that the alpha decay of 190At was energetically unhindered, implying that the decay process occurred immediately without delay. The unhindered decay process is notable as it suggests that the spin and parity remain unchanged during the reaction.

The discovery of 190astatine expands our knowledge of the element's isotopic composition and provides valuable data for atomic mass models.

The findings of the study were published in the journal Physical Review C on June 20 and can be found here.

Study abstract:

The α decay of a new isotope 190At has been studied via the 109Ag(84Sr,3n)190At fusion-evaporation reaction by employing a gas-filled recoil separator. An α-particle energy of 7750(20) keV and a half-life of 1.0+1.4−0.4 ms were measured. The measured decay properties correspond to an unhindered α decay, suggesting the same spin and parity of (10) as those of the final state of the decay. The systematics of the nearby nuclei and the predictions of selected atomic mass models were compared with the measured decay properties.

Add Interesting Engineering to your Google News feed.
Add Interesting Engineering to your Google News feed.
message circleSHOW COMMENT (1)chevron
Job Board