SUMMARY OF MODELLING STUDIES ON THE BEAM INDUCED VACUUM EFFECTS IN THE FCC-hh

EuroCirCol is a conceptual design study of a Future Circular Collider (FCC-hh) which aims to expand the current energy and luminosity frontiers that the LHC has established. The vacuum chamber of this 50 TeV, 100 km collider, will have to cope with unprecedented levels of synchrotron radiation power for proton colliders, dealing simultaneously with a tighter magnet aperture. Since the high radiation power and photon flux will release large amounts of gas into the system, the difficulty to keep a low level of residual gas density increases considerably compared with the LHC. This article presents a study of the beam induced vacuum effects for the FCC-hh novel conditions, the different phenomena which, owing to the presence of the beam, have an impact on the vacuum level of the accelerator. To achieve this, a novel beam screen has been proposed, featuring specific mitigating measures aimed at dealing with the beam induced effects. It is concluded that thanks to the new beam screen design, the vacuum level in the FCC-hh shall be adequate, allowing to reach the molecular density requirement of better than 1×1015 H2/m with baseline beam parameters within the first months of conditioning.

[1]  F. Schäfers,et al.  Photo reflectivity and photo electron yield from technical surfaces , 2020 .

[2]  Periodic Reporting for period 3-EuroCirCol ( European Circular Energy-Frontier Collider Study , 2020 .

[3]  R. Kersevan,et al.  RECENT DEVELOPMENTS OF MONTE-CARLO CODES MOLFLOW+ AND SYNRAD+ , 2019 .

[4]  W. Allan Gillespie,et al.  Low secondary electron yield engineered surface for electron cloud mitigation , 2014 .

[5]  Giovanni Iadarola,et al.  Electron cloud studies for CERN particle accelerators and simulation code development , 2014 .

[6]  M. Taborelli,et al.  Carbon coatings with low secondary electron yield , 2013 .

[7]  G. Rumolo,et al.  PyECLOUD and build-up simulations at CERN , 2013, 1309.6773.

[8]  A. Hourd,et al.  Nanosecond pulsed laser blackening of copper , 2012 .

[9]  Mauro Taborelli,et al.  Amorphous carbon coatings for the mitigation of electron cloud in the CERN Super Proton Synchrotron , 2011 .

[10]  O. Malyshev,et al.  A study of the photodesorption process for cryosorbed layers of H2, CH4, CO or CO2 at various temperatures between 3 and 68 K , 1999 .

[11]  V. Baglin,et al.  Photon stimulated desorption of an unbaked stainless steel chamber by 3.75 keV critical energy photons , 1999 .

[12]  O. Malyshev,et al.  Synchrotron radiation induced gas desorption from a Prototype Large Hadron Collider beam screen at cryogenic temperatures , 1996 .

[13]  G. Korn,et al.  Desorption measurements of copper and copper alloys for PEP-II , 1993 .

[14]  G. Sanguinetti,et al.  Measurement of the proton-antiproton total and elastic cross sections at the CERN SPS collider , 1984 .

[15]  F. F. Rieke,et al.  IONIZATION CROSS SECTIONS OF GASEOUS ATOMS AND MOLECULES FOR HIGH-ENERGY ELECTRONS AND POSITRONS. , 1972 .