Results on the FCC-hh Beam Screen at the KIT Electron Storage Ring KARA

In the framework of the EuroCirCol collaboration* (work package 4 "Cryogenic Beam Vacuum System"), the fabrication of 3 FCC-hh beam-screen (BS) prototypes has been carried out with the aim of testing them at room temperature at the Karlsruhe Institute of Technology (KIT) 2.5 GeV electron storage ring KARA (KArlsruhe Research Accelerator). The 3 BS prototypes will be tested on a beamline installed by the collaboration, named as BEam Screen TEstbench EXperiment (BESTEX). KARA has been chosen because its synchrotron radiation (SR) spectrum, photon flux and power, match the one foreseen for the 50+50 TeV FCC-hh proton collider. Each of the 3 BS prototypes, 2 m in length, implement a different design feature: 1) baseline design (BD), with electro-deposited copper and no electron-cloud (EC) mitigation features; 2) BD with set of distributed cold-sprayed anti-EC clearing electrodes; 3) BD with laser-ablated anti-EC surface texturing. We present here the results obtained so far at BESTEX and the comparison with extensive montecarlo simulations of the expected outgassing behavior under synchrotron radiation.