Magnetic Dipole Hyperfine Constants of 15 Energy Levels in $^{169}$Tm II Determined by Collinear Laser Fluorescence Spectroscopy

Abstract: We present measurements of the hyperfine structure, transition frequencies and relative intensities in 14 lines of 169Tm+ ions starting from the $$4f^{{13}({}^{2!F^{o_{7/2})6s_{1/2}}}} (7/2, 1/2)_{3,4}<sup>o$$ levels. The magnetic dipole hyperfine ($A$) constant of all 15 involved ionic levels are determined, 14 of which have sub-MHz accuracy. For five levels no previous measurements were reported, while all others are in excellent agreement with the literature and improve on the previous accuracy by typically 1 - 2 orders of magnitude. We compare transition strengths and include improved transition frequencies. These results are useful for the quantum computing community, modelling of Tm$<sup>+$ abundances in stellar spectra, as well as for an ongoing measurement program on short-lived Tm isotopes at ISOLDE/CERN.