Laser-Microwave Double-Resonance Spectroscopy of Laser-Cooled^<b>9</b><b><i>B</i><i>e</i></b>⁺Ions in a Weak Magnetic Field for Studying Unstable Be Isotopes

Abstract

Laser-microwave double-resonance spectroscopy of laser-cooled 9 Be + ions in a linear Paul trap has been performed aiming at the development of both highly sensitive and precise methods to be applied to the unstable isotopes. By the alternative irradiation of laser and microwave radiation (pulsed-wave method), high accuracy of 4×10 -7 was obtained in the measurement of the ground-state magnetic-dipole hyperfine constant ( A ) of 9 Be + ion in a weak magnetic field. By the continuous-wave method, high sensitive detection of the microwave resonance was demonstrated. These methods can be complementarily applied to the measurements of unknown hyperfine constants of the unstable isotopes for studying the hyperfine anomaly.