Electron-ion collision spectroscopy at heavy-ion storage rings aims at precision measurements of resonance features that occur in the cross sections of electron collision processes such as electron-impact ionization o...Electron-ion collision spectroscopy at heavy-ion storage rings aims at precision measurements of resonance features that occur in the cross sections of electron collision processes such as electron-impact ionization of ions or electron-ion recombination. As part of the international Facility for Antiproton and Ion Research(FAIR)project, the low-energy ion storage ring CRYRING@ESR has been coupled with the heavy-ion accelerators operated by the GSI Helmholtz Center for Heavy-Ion Research in Darmstadt, Germany. This has created a new opportunity for stringent strong field quantum electrodynamics tests through electron-ion collision spectroscopy of heavy few-electron ions. The present contribution provides details of the electron-ion collision spectroscopy setup at CRYRING@ESR and associated data-analysis procedures along with first results for nonresonant and resonant recombination of berylliumlike lead ions. A recombination rate enhancement factor of 3.5 was observed for nonresonant recombination at zero electron-ion collision energy. For resonant recombination excellent agreement with recent theoretical results was obtained when these were shifted by 340 meV in energy.展开更多
基金Supported by the German Federal Ministry for Education and Research (Bundesministerium für Bildung und Forschung, BMBF) via the Collaborative Research Center ErUM-FSP T05—“Aufbau von APPA bei FAIR”(05P19PMFA1, 05P19RGFA1, 05P21PMFA1, 05P21RGFA1, 05P24RG2)supported by the State of Hesse within the Research Cluster ELEMENTS (500/10.006)。
文摘Electron-ion collision spectroscopy at heavy-ion storage rings aims at precision measurements of resonance features that occur in the cross sections of electron collision processes such as electron-impact ionization of ions or electron-ion recombination. As part of the international Facility for Antiproton and Ion Research(FAIR)project, the low-energy ion storage ring CRYRING@ESR has been coupled with the heavy-ion accelerators operated by the GSI Helmholtz Center for Heavy-Ion Research in Darmstadt, Germany. This has created a new opportunity for stringent strong field quantum electrodynamics tests through electron-ion collision spectroscopy of heavy few-electron ions. The present contribution provides details of the electron-ion collision spectroscopy setup at CRYRING@ESR and associated data-analysis procedures along with first results for nonresonant and resonant recombination of berylliumlike lead ions. A recombination rate enhancement factor of 3.5 was observed for nonresonant recombination at zero electron-ion collision energy. For resonant recombination excellent agreement with recent theoretical results was obtained when these were shifted by 340 meV in energy.
