Sprecher
Beschreibung
Electron cooling is a central beam preparation technique at CRYRING@ESR, and has been employed in all beamtimes since re-commissioning of the storage ring at GSI/FAIR in 2020. With the large variety of ion species available from the UNILAC/SIS18/ESR injector chain and from the local ion source, the electron cooler is required to operate at a wide range of beam parameters. Over the years, beam cooling could be applied successfully for ion energies ranging from $\sim 12~\mathrm{MeV/u}$ down to $\sim 90~\mathrm{keV/u}$. The FAIR control system allows for multi-flattop operation, enabling the cooler to assist with efficient synchrotron acceleration or deceleration of ions in CRYRING@ESR.
In addition to the beam cooling application, the cooler doubles as low-energy internal electron target in some experiments. The latter take advantage of the particularly cold electron beam, created by strong magnetic expansion by factors up to 100. This results in a transverse electron temperature in the order of $1~\mathrm{meV}/k_\mathrm{B}$ and correspondingly high spectroscopic resolution, as recently demonstrated in an experiment on dielectronic recombination of F$^{6+}$.
Since re-installation at GSI/FAIR, several aspects of the cooler hardware have been upgraded and consolidated, including vacuum and high-voltage systems. Further reliability and performance improvements are planned for the upcoming years of CRYRING@ESR operation.
