22nd SPARC Topical Workshop

During the user run 2025 essentially all operation modes of the ESR were used and highlights will be presented: electron cooling, stochastic cooling, stacking, internal experiments and extracted beam experiments with beam delivery to CryRing and HITRAP. The new LSA control system is consolidated in the sense that it offers practically all operation modes covered by the decommissioned legacy...

We briefly report on the first laser excitation of the ground-state hyperfine transition in lithium-like 208Bi80+. The experiment took place at the ESR during the beam-time block at GSI in May 2025 (GPAC-Experiment: G-22-00038). The detection of the transition became possible by combining the laser excitation with dielectronic recombination as (DR) a new detection scheme.

Therefore, the...

The low-lying isomeric state of the $^{229}$Th nucleus has been intensively discussed as a candidate for nuclear clocks. Different approaches are pursued worldwide, either based on Th-doped crystals or lowly charged Th ions. The HITHOR project follows a different approach by utilizing nuclear hyperfine mixing (NHM) in highly-charged hydrogen-like $^{229}$Th$^{89+}$. GSI offers the unique...

For photon energies from several tens of keV up to a few MeV, Compton polarimetry is an indispensable tool to gain insight into subtle details of fundamental radiative processes in atomic physics. Within the SPARC collaboration [1] several segmented semiconductor detectors have been developed that are well suited for application as efficient Compton polarimeters. For photon emission processes...