HomeSciencePhysicsExploring the Borders of the Nuclear Landscape

Exploring the Borders of the Nuclear Landscape

• Physics 16, s40

Scientists have exactly measured the lots of 19 neutron-rich nuclei, discovering a brand new isotope of uranium within the course of.

APS/Carin Cain

The properties of heavy, neutron-rich isotopes are poorly identified owing to difficulties in synthesizing these nuclei. Now Toshitaka Niwase on the High Energy Accelerator Research Organization (KEK) in Japan and his colleagues have helped to fill this information hole. The researchers have straight decided the lots of 19 such isotopes, together with a beforehand undetected uranium isotope: 241U [1]. These measurements will each check and refine present nuclear fashions.

Niwase and his colleagues carried out their experiments on the KEK Isotope Separation System (KISS) facility in Saitama, Japan. They accelerated a beam of 238U nuclei right into a rotating goal of 198Pt nuclei. This course of transferred a number of nucleons—protons and neutrons—between the beam and goal nuclei, forming the isotopes of curiosity. The researchers then studied these isotopes utilizing time-of-flight mass spectrometry, a technique wherein an ion’s mass is decided from the time it takes to journey a sure distance via a medium.

The group obtained exact mass values for 19 heavy isotopes that include between 143 and 150 neutrons: 239Pu to 242Pu, 239Np to 242Np, 235U to 242U, and 235Pa to 237Pa. For most of those nuclei, these are the primary direct mass measurements. The researchers say that their use of multinucleon switch reactions mixed with time-of-flight mass spectrometry supplies a brand new option to probe the boundaries of the nuclear panorama. They additionally recommend that different combos of beam and goal nuclei could possibly be used to synthesize and examine nuclei possessing as much as 154 neutrons.

–Ryan Wilkinson

Ryan Wilkinson is a Corresponding Editor for Physics Magazine primarily based in Durham, UK.


  1. T. Niwase et al., “Discovery of new isotope 241U and systematic high-precision atomic mass measurements of neutron-rich Pa-Pu nuclei produced via multinucleon transfer reactions,” Phys. Rev. Lett. 130, 132502 (2023).

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