A joint research group led by Professor Hidetoshi Katori has succeeded in determining for the first time the lifetime of the isomer state of Thorium-229(229Th), which will lead to the realization of a “nuclear clock”. Nuclear clocks are expected to be more accurate than existing atomic clocks because they are based on the resonance frequency of “nuclear” transitions and are less susceptible to environmental noise. In this study, the group developed a device to capture 229Th ions in vacuum and also developed an original technique to selectively detect ions in the nuclear isomer state from the population of 229Th ions captured by the device, and determined the lifetime of the isomer state. The resulting paper was published in the online edition of the scientific journal Nature on April 17.
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