Tschernajew, M.M.TschernajewGierschke, P.P.GierschkeLin, H.H.LinHilbert, V.V.HilbertKurdal, J.J.KurdalStancalie, A.A.StancalieLimpert, J.J.LimpertRothhardt, J.J.Rothhardt2022-03-062022-03-062020https://publica.fraunhofer.de/handle/publica/26287410.1016/j.vacuum.2020.109443Current laser technology enables table-top high flux XUV sources with photon energies from several tens to several hundreds of eV via high harmonic generation in noble gases. Here we present a compact versatile coupling unit to establish windowless, and thus lossless coupling of such light sources to ultra high vacuum (UHV). The particular coupling unit has been developed to couple a XUV laser source to a heavy ion storage ring. Three-stage differential pumping allows to reduce the input pressure of ~10−6 mbar down to the 10−12 mbar range at the output. The unit particularly reduces the partial pressure of argon, which is used to generate the XUV radiation, by 6 orders of magnitude. Measurements of the pressure distribution inside the different chambers agree well with theoretical simulations. In principle, this unit can also serve for other purposes, where a windowless vacuum coupling is needed, with a transition from High Vacuum (HV) levels to deep UHV, such as coupling to cryogenically cooled detectors, ion traps or to photoelectron emission spectroscopy experiments.encouplingdifferentialGradientLaserUHV620533journal article