Laser spectroscopy ofBe+7,10in an online ion trap

Abstract

Radioactive beryllium isotope ions ($^{7}\mathrm{Be}^{+}$ and $^{10}\mathrm{Be}^{+}$) that are provided by a projectile fragment separator with $\ensuremath{\approx}1\phantom{\rule{0.3em}{0ex}}\mathrm{GeV}$ beams, as well as stable isotope ions $(^{9}\mathrm{Be}^{+})$ are stored and laser cooled in an online ion trap. Their absolute transition energies of the $2s\phantom{\rule{0.2em}{0ex}}^{2}S_{1∕2}\ensuremath{\rightarrow}2p\phantom{\rule{0.2em}{0ex}}^{2}P_{3∕2}$ transition were measured with an accuracy of $\ensuremath{\sim}{10}^{\ensuremath{-}8}$. In this way isotope shifts of beryllium ions were obtained and the differential mass polarization parameter $\ensuremath{\kappa}=\ensuremath{-}0.286 41(70)\phantom{\rule{0.3em}{0ex}}\mathrm{a.u.}$ as well as the $2s\phantom{\rule{0.2em}{0ex}}^{2}S\ensuremath{\rightarrow}2p\phantom{\rule{0.2em}{0ex}}^{2}P$ transition energy of an infinitely heavy beryllium ion $h{\ensuremath{\nu}}^{\ensuremath{\infty}}=0.145 524 290(42)\phantom{\rule{0.3em}{0ex}}\mathrm{a.u.}$ were determined for the first time.