CERN Proton Synchrotron upgrade

CERN Proton Synchrotron upgrade
Name	Proton Synchrotron upgrade
Location	Meyrin, Switzerland
Institution	CERN
Coordinates	46.233, 6.055
Status	Completed (incremental)
Construction	2020s
Technology	Synchrotron accelerator upgrade

CERN Proton Synchrotron upgrade

The Proton Synchrotron upgrade was a programme of modifications and enhancements to the Proton Synchrotron (PS) at CERN undertaken in the 2020s to extend performance, reliability, and integration with the Large Hadron Collider and the Super Proton Synchrotron. The project involved civil works, magnet refurbishment, radiofrequency improvements, and control system modernisation to support beams for experiments such as ISOLDE, n_TOF, and the Antiproton Decelerator, while aligning with long-term plans including the High-Luminosity Large Hadron Collider and the Future Circular Collider studies. Stakeholders included partner laboratories like Fermilab, DESY, KEK, and funding agencies across European Union member states, with oversight from CERN management and advisory groups such as the CERN Council.

Background and Original Design

The original Proton Synchrotron was commissioned in 1959 as CERN’s second major accelerator, following the Synchro-Cyclotron and preceding the Intersecting Storage Rings. Designed by engineers and physicists influenced by work at Brookhaven National Laboratory and Lawrence Berkeley National Laboratory, the PS served as injector for machines including the Super Proton Synchrotron and later the Large Electron–Positron Collider. The lattice employed combined-function magnets and a four-fold symmetry, with radiofrequency systems developed in collaboration with industry partners and institutes such as STFC Rutherford Appleton Laboratory and Institute of High Energy Physics (IHEP). Early upgrades in the 1970s and 1980s paralleled developments at SLAC National Accelerator Laboratory and TRIUMF, adapting technology from projects like Spallation Neutron Source.

Motivation for the Upgrade

Motivations arose from operational constraints encountered during LHC injection cycles, increasing experimental demand from facilities like ISOLDE and CERN Neutrinos to Gran Sasso proposals, and the need to meet intensity and reliability objectives set by programmes such as European Strategy for Particle Physics and the Particle Physics Project Prioritization Panel. Ageing infrastructure, obsolescent control electronics developed in the era of C-MAC and early digital systems, and beam loss limitations that affected connections to Antiproton Decelerator and n_TOF drove the case. International collaborations and technical reviews by committees including the Scientific Policy Committee and agencies such as Euratom highlighted benefits for synergy with High-Luminosity Large Hadron Collider upgrades and long-baseline proposals like Deep Underground Neutrino Experiment.

Upgrade Components and Technical Enhancements

Major components included refurbishment of main dipole and quadrupole magnet circuits with improved power converters designed with input from ABB and test stands at Laboratoire de l'Accélérateur Linéaire, replacement of ageing radiofrequency cavities with broadband solid-state amplifiers influenced by designs from Helmholtz Association partners, and installation of a modern Experimental Physics and Industrial Control System front-end integrating EPICS paradigms used at Oak Ridge National Laboratory. Beam instrumentation improvements adopted technologies from CERN BE Department, DESY, and Paul Scherrer Institute with new beam position monitors, fast current transformers, and longitudinal diagnostics derived from European XFEL experience. Collimation systems were upgraded with materials and designs tested at The Svedberg Laboratory and Institut Laue–Langevin; vacuum and cryogenic subsystems benefitted from collaboration with ITER suppliers.

Integration with CERN Accelerator Complex

Integration required updated interfaces with the Linear Accelerator 4 project, the Super Proton Synchrotron transfer lines, and timing systems synchronised with White Rabbit networks pioneered by CERN and GSI Helmholtz Centre. The upgrade ensured compatibility with injection patterns demanded by LHC filling schemes and with facilities such as AD and ISOLDE via revised extraction kicker systems and transfer optics modelled using codes from CERN-CTF and verified in partnership with Fermilab simulation teams. Beam dynamics studies referenced results from MAD-X and FLUKA collaborations with IHEP and University of Geneva groups.

Commissioning and Performance Results

Commissioning phases followed a staged approach familiar from projects like Large Electron–Positron Collider refurbishments and the PS Booster upgrades. Early results demonstrated reduced turnaround time consistent with objectives set by the CERN Accelerator School curricula, increased proton intensities for certain cycles comparable to projections from High Luminosity LHC studies, and lower uncontrolled beam loss validated by diagnostics developed with STFC and Czech Technical University partners. Machine availability statistics improved versus historical baselines reported in CERN Yellow Reports, while experiments including n_TOF and ISOLDE reported higher-quality delivered beams.

Radiation Protection and Safety Measures

Safety measures involved upgraded shielding informed by ICRP recommendations and Monte Carlo studies using FLUKA and GEANT4 toolkit collaborations with CERN Radiation Protection Group. Personal dosimetry, access control, and interlock systems were modernised following standards used at Large Hadron Collider sites and in consultation with International Atomic Energy Agency guidelines. Waste management and activation studies coordinated with Paul Scherrer Institute and national regulators addressed long-term decommissioning scenarios analysed in conjunction with the European Commission.

Timeline, Costs, and Project Management

The project followed milestones comparable to other large-scale accelerator undertakings such as High-Luminosity Large Hadron Collider upgrades and drew on project-management practices from European Spallation Source and ITER programmes. Funding combined in-kind contributions from institutes like DESY, Fermilab, KEK, and national agencies coordinated through the CERN Council. Cost control used methodologies from PRINCE2 and joint reviews with advisory bodies including the Scientific Policy Committee and external auditors. The staged implementation reduced operational disruption and aligned with scheduled machine development periods published in CERN timetable documents.

Category:CERN accelerators