Stepping into the Sea of Instability: The New Sub-μs Superheavy Nucleus ^{252}Rf

Area of Science:

• Nuclear Physics
• Chemistry

Background:

• Superheavy nuclei are elements with atomic numbers greater than 104.
• Understanding the stability and decay properties of superheavy nuclei is crucial for nuclear physics.
• Known superheavy nuclei exhibit a wide range of half-lives, with many decaying in milliseconds or less.

Purpose of the Study:

• To report the synthesis and characterization of a new isotope, Rutherfordium-252 (²⁵²Rf).
• To measure the half-life of ²⁵²Rf and its high-K isomeric state.
• To investigate the trend of spontaneous fission half-lives in neutron-deficient Rutherfordium isotopes.

Main Methods:

• Synthesis of the ²⁵²Rf isotope through nuclear reactions.
• Measurement of the half-life of the ground state and the high-K isomeric state using advanced detection techniques.
• Analysis of decay properties to determine nuclear stability.

Main Results:

• Discovery of the new isotope ²⁵²Rf.
• Measured a ground-state half-life of 60 nanoseconds for ²⁵²Rf, extending the known range by two orders of magnitude.
• Measured a half-life of 13 microseconds for the high-K isomeric state of ²⁵²Rf.
• Confirmed a smooth decrease in spontaneous fission half-lives for neutron-deficient Rf isotopes.

Conclusions:

• The discovery of ²⁵²Rf and its measured half-lives provide critical data for nuclear structure models.
• The findings support the concept of an 'island of stability' for superheavy nuclei.
• This work sets a benchmark for studying high-K states and inverted fission stability in the heaviest elements.