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HK: Fachverband Physik der Hadronen und Kerne
HK 42: Hauptvorträge
HK 42.4: Hauptvortrag
Freitag, 14. März 2008, 10:00–10:30, 1B/C
Development of a cryogenically cooled liquid beam internal target for FAIR — •Robert Grisenti1,2, Nikos Petridis1, Reinhard Dörner1 und Thomas Stöhlker2 — 1Institut für Kernphysik, J. W. Goethe-Universität, Frankfurt am Main, Germany — 2GSI, Darmstadt, Germany
Most of the internal-target experiments planned at the future FAIR facility at GSI require a high-density, low-spread low-Z target to achieve the highest efficiency in terms of the luminosity. State-of-the-art internal targets realized by expanding a gas through a nozzle into vacuum provide low target densities in the interaction region and a target spatial extension that spreads out over several millimeters. These features make thus gas-jet internal targets not suitable for future storage ring experiments at FAIR. Larger target densities and smaller interaction lengths can be achieved by further cooling the gas to temperatures down into the liquid regime, below 20 K for hydrogen and below 4 K for helium. Producing liquid beams of helium and hydrogen, however, is not straightforward. For instance, in order to make these beams entirely compatible with the high-vacuum conditions in a storage ring the use of sub-10-micrometer diameter nozzles is mandatory. We will discuss the recent advances on the production of micrometer-sized liquid beams and their application in storage-ring experiments. We will also report on the design and development of a prototype cryogenic liquid beam source at the internal-target station at the ESR at GSI.