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RESEARCH PRODUCT

Developments on the 1.4 MeV/u Pulsed Gas Stripper Cell

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The GSI UNILAC in combination with SIS18 will serve as a high-current, heavy-ion injector for the FAIR facility. It must meet high demands in terms of beam brilliance at a low duty factor. As part of an UNILAC upgrade program dedicated to FAIR, a new pulsed gas stripper cell was developed, aiming for increased beam intensities inside the post-stripper. The pulsed gas injection is synchronized with the beam pulse timing, enabling a highly-demanded, increased gas density. First tests using uranium beams on a hydrogen target showed a 60%-increased stripping efficiency into the desired 28+ charge state. In 2015, the setup was improved to be able to deliver increased target thicknesses and enhanced flexibility of the gas injection. In recent beam times, the pulsed gas cell was used with various ion-beam types, to test the capabilities for operation at the GSI UNILAC. The stripping of two ion beams in different gases at different gas densities was successfully tested in mixed-beam operation. Charge fractions, beam emittance, and energy-loss were systematically measured using uranium, bismuth, titanium, and argon beams on hydrogen, helium, and nitrogen targets. Selected results will be presented at the conference.