Determine the ion-source starting conditions for beam-energy calibration

Determine the precise ion-source conditions and exact starting potential of accelerated 169Tm+ ions in order to eliminate the remaining uncertainty in the beam-energy determination from the applied acceleration voltage.

Background

The transition-frequency analysis requires an accurate determination of the ion-beam energy. Although the acceleration voltage is recorded and stabilized, the ions' initial conditions in the surface-ionization source and their starting potential are not precisely known. The experiment therefore uses a collinear/anticollinear measurement of a hyperfine component of the 384.8 nm transition as an empirical beam-energy reference, rather than relying solely on the recorded acceleration voltage.

References

Though the applied acceleration voltage is recorded and stabilized, we do not know the precise conditions in the ion source and the exact starting potential of the ions.

— Magnetic Dipole Hyperfine Constants of 15 Energy Levels in $^{169}$Tm II Determined by Collinear Laser Fluorescence Spectroscopy  (2609.03997 - Bodnar et al., 3 Sep 2026) in Section 3.2, Transition Frequencies