TUX02
MPI-K, Heidelberg, Germany
ISP, Novosibirsk, Russia
The CSR at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany, is a 35 m circumference cryogenic electrostatic storage ring for positive and negative ions up to 300 keV kinetic energy per charge.* With storage times of typically many minutes for, in particular, molecular and cluster ion beams it enables internal-state sensitive experiments with the stored ions involving lasers, merged particle beams and molecular fragment detection. The electron cooler operates with a p-GaAs negative electron affinity photocathode.** First rotational-state selective dissociative recombination measurements were reported using this device.*** Electron cooling was performed with electron beam energies reaching down to 9 eV (with lower values envisaged in future) and at electron densities down to 105 per ccm. Beam diagnostics included transverse profile imaging with molecular fragments, electronic bunch-signal pickup and in some cases Schottky signals. Electron cooling times in the 1 to few second range were observed for singly-charged ions up to mass 16 u. The limits to the equilibrium beam properties through space charge and intrabeam scattering in the low-energy beams are under study.
* R. von Hahn et al., Rev. Sci. Instr. 87, 063115 (2016)
** D. Orlov et al., J. Appl. Phys. 106, 054907 (2009)
*** O. Novotný et al., Science 10.1126/science.aax5921 (2019)
