Chinese scientists have successfully synthesized "protactinium-210" for the first time, which is the most "neutron deficient" protactinium isotope discovered by humans so far.
This breakthrough has refreshed the understanding of the limits of the existence of atomic nuclei and provided new clues for exploring the origins of elements in the universe.
The experiment was conducted on advanced equipment independently developed by China, demonstrating the country's strong capabilities in heavy and overweight nuclear research, and laying a solid foundation for the future synthesis of new elements. In June 2025 (Beijing time), the Institute of Modern Physics of the Chinese Academy of Sciences reported that its overweight nuclear research team and its collaborators had successfully synthesized a new nuclide, protactinium-210.
This discovery not only fills the gap in the nuclear isotope map, but also marks another milestone achievement in China's cutting-edge research in nuclear physics. The relevant research results have been published in the top international academic journal Nature Communications.

1. Challenge the limits: Annotate new coordinates in the "nuclear universe"
The atomic nucleus is composed of protons and neutrons, like a miniature universe. The theory once predicted the existence of about 7000 different atomic nuclei (nuclides) in the universe, but so far, humans have only discovered over 3300 of them in laboratories. Finding new nuclides, especially in "no man's land" far from the stability line, is one of the holy grails of nuclear physics research, which directly relates to our understanding of the fundamental laws of the material world.
The synthesized protactinium-210 is such a "new star". The nucleus of protactinium element has 91 protons, while the newly discovered protactinium-210 has only 119 neutrons. It is much lighter than the stable protactinium isotope in nature, and is truly an "extreme neutron deficient" nuclide.
The difficulty of synthesizing new nuclides is extremely high in the region of heavy nuclei that are extremely deficient in neutrons, "explained Zhang Mingming, the first author of the study and an associate researcher at the Institute of Modern Physics." Their probability of production is extremely low, like searching for a specific gravel in billions of grains of sand. At the same time, their lifespan is extremely short, often only a few milliseconds or even microseconds, which puts extremely strict requirements on experimental detection technology

2. National treasure: Independent equipment shows hard core strength
This breakthrough experiment relies on China's independently developed "national key equipment" - the China Superheavy Element Research Accelerator (CAFE2) and the new generation inflatable recoil nuclear spectrometer (SHANS2).
The research team used the CAFE2 device to generate a high-intensity calcium-40 ion beam, which acted like a precise "projectile" and rapidly bombarded a specially designed lutetium 175 target. After intense fusion evaporation reactions, the SHANS2 spectrometer, with its ultra-high detection efficiency and precise resolution, successfully "captured" and identified the extremely rare product - protactinium-210 from a massive amount of background particles.
Despite the formation cross-section of protactinium-210 being as low as about 7 picobars (7 × 10-36cm2), we still successfully observed 23 valuable decay events, providing conclusive evidence for the discovery of new nuclides. ”One of the corresponding authors of the paper, Ma Long, a researcher at the Institute of Modern Physics, said, "This fully validates the outstanding performance of our independently developed device in studying heavy and superheavy nuclei, and accumulates valuable experience for future impacts on higher atomic number new elements

3. Profound impact: Expanding cognitive boundaries
The research team accurately measured key properties such as decay energy and half-life of protactinium-210, which expanded our systematic understanding of the nuclear decay patterns in this region. The experimental results are highly consistent with the predictions of existing theoretical models, providing strong experimental support for improving atomic nucleus theory.
The successful synthesis of this new nuclide is not only another important progress made by Chinese scientists in the field of basic research, but also a solid step towards exploring and synthesizing the undiscovered "119" and heavier new elements on the periodic table in the future.
The research was led by the Institute of Modern Physics of the Chinese Academy of Sciences and completed jointly by researchers from Chinese Academy of Sciences University, Guangdong Provincial Laboratory of Advanced Energy Science and Technology, Shandong University and other institutions.