# Synopsis: Element $Z=117$ Confirmed

Researchers have independently confirmed the existence of element $117$ and have discovered a new isotope along the way.

Nuclear physicists have invested huge effort in creating superheavy elements, which consist of enough neutrons to provide enhanced stability from nuclear decay. For the past $30$ years, experiments have been marching towards this “island of stability” with a new elemental discovery every $2$ to $3$ years. Part of the discovery process includes the confirmation by an independent experimental collaboration—it is only at this point that an element obtains its official status.

An international team using an intense ${}^{48}\text{Ca}$ beam provided by GSI research facility in Darmstadt, Germany, and a target material of radioactive ${}^{249}\text{Bk}$ supplied by Oak Ridge National Lab in Tennessee has produced two atoms of the superheavy element with atomic number $Z=117$, confirming the initial observation published in 2010 (see 9 April 2010 Viewpoint). In the process, a new isotope ${}^{266}\text{Lr}$ was discovered from the previously unknown alpha-decay branch of ${}^{270}\text{Db}$. With a half-life of $1$ hour, ${}^{270}\text{Db}$ is the longest-lived alpha emitter having an atomic number, $Z$, greater than $102$.

The experiment is a tour de force in superheavy element research and required a detailed reconstruction of a seven-step alpha-decay chain followed by the spontaneous fission of the newly discovered ${}^{266}\text{Lr}$. The difficulty stems from the large variation in decay lifetimes along the alpha chain. The discovery was made feasible by the use of TASCA, a gas-filled recoil separator specifically designed for a high selectivity of superheavy or transactinide elements.

The confirmation by the TASCA team serves as a much-needed step on the long road towards the island of stability. An easier feat will be deciding on a name for $Z=117$. – Kevin Dusling

More Features »

### Announcements

More Announcements »

Nuclear Physics

Astrophysics

Fluid Dynamics

## Related Articles

Gravitation

### Viewpoint: Moiré Effect Could Enhance Neutron Interferometry

A new and more flexible neutron interferometer design relies on the moiré effect, in which two periodic patterns are combined to give a longer-period pattern. Read More »

Nuclear Physics

### Synopsis: Intel on Stellar Element Production from Accelerator Data

Measurements of a nuclear reaction relevant to the synthesis of calcium, potassium, and argon in stars boost the accuracy of models for predicting the elements’ abundances. Read More »

Nuclear Physics

### Viewpoint: Heaviest Element Has Unusual Shell Structure

Calculations of the structure in oganesson—the element with the highest atomic number—reveal a uniform, gas-like distribution of its electrons and nucleons. Read More »