In this paper, we report on a laser spectroscopy measurement of 84-87Rb isotopes in superfluid helium (He ii) at 1.8 K using laser-radio-frequency double-resonance spectroscopy. Rb ion beams (>60 MeV/u) provided by the RIKEN projectile fragment separator (RIPS) were injected and trapped into He ii. The stopping position of atoms in He ii was precisely confirmed by laser spectroscopy. By optically pumping the trapped Rb isotopes, large atomic spin polarization (up to 40%) of each observed isotope in the ground state was achieved. The laser-radio-frequency double-resonance spectra were observed for stable 85,87Rb isotopes as well as for unstable isotopes 84,84m,86Rb by scanning a weak magnetic field with a fixed-frequency RF field. From the measured Zeeman splitting, nuclear spin values for 84m,84-87Rb isotopes were determined with reasonable accuracy. The number of ions injected into He ii for the resonance spectra measurement was on the order of 104 particles per second. This work may open new opportunities for the study of various particles trapped in condensed helium in several fields.
|ジャーナル||Physical Review A - Atomic, Molecular, and Optical Physics|
|出版ステータス||出版済み - 11 19 2014|
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