Conference Paper

Physics with colder molecular ions: The Heidelberg Cryogenic Storage Ring CSR


ABSTRACT A novel cryogenic electrostatic storage ring is planned to be built at the Max-Planck Institute for Nuclear Physics in Heidelberg. The machine is expected to operate at low temperatures (similar to 2 K) and to store beams with kinetic energies between 20 to 300 keV. An electron target based on cooled photocathode technology will serve as a major tool for the study of reactions between molecular ions and electrons. Moreover, atomic beams can be merged and crossed with the stored ion beams allowing for atom molecular-ion collision studies at very low up to high relative energies. The proposed experimental program, centered around the physics of cold molecular ions, is shortly outlined.

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    ABSTRACT: Whereas the three‐body Coulomb problem for single excitation and ionization was claimed to be solved in a mathematically correct way during 1999 until 2004 for electron impact on hydrogen and helium, ion‐impact ionization still represents a major challenge for theory. Troubling discrepancies have been observed recently in fully differential cross sections (FDCS) for helium single ionization by fast ion impact and even experimental total cross sections are in striking disagreement with the predictions of all state‐of‐the‐art theories for low‐energy antiproton collisions. Therefore, within the future Facility for Low‐energy Antiproton and Ion Research (FLAIR), it has been proposed to combine state‐of‐the‐art many‐particle imaging methods with a novel electrostatic storage ring for slow antiprotons in order to realize single and multiple ionization cross section measurements for antiprotons colliding with atoms, molecules and clusters. Total, as well as any differential cross sections up to FDCS including ionization‐excitation reactions are envisaged to become available, serving as benchmark data for theory. Here, the present status of experiments in comparison with theory is presented and the layout of an Ultra‐low energy Storage Ring (USR) with its integrated reaction microscope at FLAIR is described. © 2005 American Institute of Physics
    AIP Conference Proceedings. 10/2005; 796(1):266-271.
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    ABSTRACT: The Facility for Low-energy Antiproton and Ion Research (FLAIR) and a large part of the wide physics program decisively rely on new experimental techniques to cool and slow down antiprotons to 20 keV, in particular on the development of an ultra-low energy electrostatic storage ring (USR). The whole research program connected with anti-matter/matter interactions is only feasible if such a machine will be realized. For the USR to fulfil its key role in the FLAIR project, the development of novel and challenging methods and technologies is necessary: the combination of the electrostatic storage mode with a deceleration of the stored ions from 300 keV to 20 keV, electron cooling at all energies in both longitudinal and transverse phase- space, bunching of the stored beam to ultra-short pulses in the nanosecond regime and the development of an in-ring reaction microscope for antiproton-matter rearrangement experiments. In this contribution, the layout and the expected beam parameters of the USR are presented and its role within FLAIR described.
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    ABSTRACT: A new method for time-resolved daughter ion mass spectrometry is presented, based on the electrostatic ion storage ring in Aarhus, ELISA. Ions with high internal energy, e.g., as a result of photoexcitation, dissociate and the yield of neutrals is monitored as a function of time. This gives information on lifetimes in the microsecond to millisecond time range but no information on the fragment masses. To determine the dissociation channels, we have introduced pulsed supplies with switching times of a few microseconds. This allows rapid switching from storage of parent ions to storage of daughter ions, which are dumped into a detector after a number of revolutions in the ring. A fragment mass spectrum is obtained by monitoring the daughter ion signal as a function of the ring voltages. This technique allows identification of the dissociation channels and determination of the time dependent competition between these channels.
    Review of Scientific Instruments 03/2008; 79(2 Pt 1):023107. · 1.60 Impact Factor

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