An improved value for the hyperfine splitting of hydrogen-like²⁰⁹Bi⁸²⁺

Abstract

We report an improved measurement of the hyperfine splitting in hydrogen-like bismuth (209Bi82+) at the experimental storage ring ESR at GSI by laser spectroscopy on a coasting beam. Accuracy was improved by about an order of magnitude compared to the first observation in 1994. The most important improvement is an in situ high voltage measurement at the electron cooler (EC) platform with an accuracy at the 10 ppm level. Furthermore, the space charge effect of the EC current on the ion velocity was determined with two independent techniques that provided consistent results. The result of nm provides an important reference value for experiments testing bound-state quantum electrodynamics in the strong magnetic field regime by evaluating the specific difference between the splittings in the hydrogen-like and lithium-like ions.

High precision hyperfine measurements in Bismuth challenge bound-state strong-field QED

“…Here, the overlap region of laser and ion beam was represented in the time structure of the signal. The comparison of spectra obtained from data of different temporal segments of the ion beam in the overlap region did not show a significant trend34. A conservative estimate of θ =2 mrad was obtained from the largest observed wavelength difference between two beam segments.…”

Studies at the border between nuclear and atomic physics: Weak decays of highly charged ions

“…The electrons are efficiently stripped away from energetic particles while passing through target material [21][22][23]. Fully-ionised and up to 4-electron ions are routinely produced at energies of about 100 − 400 A MeV [24][25][26][27][28][29][30][31][32][33][34][35]. The selection of the atomic charge state is done by optimising the primary projectile energy, target material and its thickness [36].…”

Lifetimes and g-factors of the HFS states in H-like and Li-like bismuth

“…A number of measurements were performed to investigate possible systematic effects on the measured wavelengths of the HFS transitions in 209 Bi 82+ and 209 Bi 80+ [4,7]. By selecting from these runs only those periods when the laser was on resonance, we can also perform checks of systematic effects on the lifetime of the HFS states, albeit with very restricted statistics.…”