Simulations of Space-Charge and Guiding Fields Effects on the Performance of Gas Jet Profile Monitoring

Gas jet based profile monitors inject a usually curtain shaped gas jet across a charged particle beam and exploit the results of the minimally invasive beam-gas interaction to provide information about the beam’s transversal profile. Such monitor will be installed as part of the High Luminosity LHC upgrade at CERN in the Hollow Electron Lens (HEL). The HEL represents a new collimation stage increasing the diffusion rate of halo particles by placing a high intensity hollow electron beam concentrically around the LHC beam. The gas jet monitor will use the fluorescence radiation resulting due to the beam-gas interaction to create an image of the profiles of both hollow electron and LHC beams However, the high beam space-charge and strong guiding magnetic field of the electron beam cause significant displacements of the excited molecules, as they are also ionized, and thus image distortions. This work presents preliminary simulation results showing expected fluorescence images of the hollow electron profile as affected by space-charge and guiding fields using simulation tools such as IPMsim. The influence of the estimated electron beam and gas jet curtain parameters are investigated.