Nuclear Physics

RIKEN was an early leader in nuclear physics. In 1937, RIKEN scientist Yoshio Nishina built the first cyclotron outside of the United States, where it had been invented. A cyclotron is a device that can be used to accelerate ions—positively charged particles, meaning atomic nuclei—to very strong energies, allowing them to be used in collisions or to produce new isotopes.

Over the years, the facilities grew, and today RIKEN is home to the RI Beam Factory, one of the world’s leading heavy ion accelerator facilities. The cyclotrons are powerful enough to drive a beam of uranium—a heavy nucleus—to up to seventy percent of the speed of light.

Scientists from the RIKEN Nishina Center for Accelerator-Based Science, which operates the RI Beam Factory, are working with partners around the world to study exotic atomic nuclei, contributing to a better understanding of how the universe began and how it is composed at the nuclear level. In 2010, researchers there found a total of 45 new isotopes in just four days of searching, and in 2017, physicists announced that they had used the RI Beam Factory to create 73 new exotic nuclei, adding new species to the 7,000 that are hypothesized to be able to exist. Scientists at RNC continue to search for the “island of stability”—a realm where we can find longer-lived nuclei than those in the area currently explored, and are also looking at the feasibility of using the center’s heavy ion beam to transmute troublesome nuclear waste into more easily managed isotopes.

Another key area of interest at the Nishina Center is the study of superheavy elements--elements that do not exist in nature, and that can only be produced in laboratories. In 2015, a group led by RIKEN research Kosuke Morita was officially recognized as the discoverers of element 113 on the periodic table, which was subsequently named nihonium and given the notation Nh. 

For more information on RIKEN's work in this field, and to see the websites of individual laboratories, see the Nishina Center website.