Finnish Physicists Achieve Breakthrough with Astatine-188 Synthesis

Finnish Physicists Synthesize Astatine-188, Advancing Proton Emission Research

In a significant advancement for nuclear physics, researchers at the University of Jyväskylä in Finland have successfully synthesized astatine-188 (^188At), the heaviest known proton-emitting isotope to date. This discovery offers new insights into the stability of atomic nuclei and the forces that govern their behavior.

Synthesis and Identification

The team produced ^188At by bombarding a natural silver target with strontium-84 ions, utilizing a fusion-evaporation reaction. The identification was facilitated by the RITU (Recoil Ion Transport Unit) recoil separator, a specialized detector setup designed for such intricate experiments. Notably, ^188At exhibits a highly deformed, prolate (watermelon-shaped) nucleus and decays via proton emission with a half-life of approximately 190 microseconds.

Understanding Proton Emission

Proton emission is a rare type of radioactive decay in which a proton is ejected from a nucleus. This phenomenon occurs in proton-rich isotopes and provides valuable data on the limits of nuclear stability. The study of proton emission has aided the understanding of nuclear deformation, masses, and structure, and it is a pure example of quantum tunneling.

Implications of the Discovery

The synthesis of ^188At provides valuable data on the limits of nuclear stability, especially concerning proton-rich nuclei. Understanding such isotopes aids in refining theoretical models of nuclear forces and decay processes. Moreover, this discovery underscores the capabilities of modern nuclear research facilities and experimental techniques.

University of Jyväskylä's Contribution

The University of Jyväskylä has a longstanding reputation in nuclear physics research. Their Accelerator Laboratory is equipped with state-of-the-art facilities, including the RITU recoil separator, enabling the production and study of exotic nuclei. This recent achievement adds to their portfolio of significant contributions to the field.

Comparative Discoveries

In January 2025, researchers reported the discovery of a new superheavy nucleus, rutherfordium-252 (^252Rf), with an extremely short half-life of approximately 60 nanoseconds. Such discoveries highlight the ongoing efforts to explore the "sea of instability" in superheavy elements, pushing the boundaries of our understanding of nuclear matter.

Potential Applications

While astatine's isotopes are primarily of interest for theoretical studies, certain isotopes like astatine-211 have shown promise in targeted alpha-particle therapy for cancer treatment. The unique properties of astatine isotopes make them candidates for medical applications, though challenges related to their short half-lives and radioactivity persist.

Conclusion

The synthesis of astatine-188 by the University of Jyväskylä represents a significant advancement in nuclear physics, offering new avenues for research into nuclear stability and the forces at play within atomic nuclei.