Proton Synchrotron Booster

Proton Synchrotron Booster
Landua, Fabienne · CC BY 4.0 · source
Name	Proton Synchrotron Booster
Caption	A section of the accelerator ring.
Institution	CERN
Location	Meyrin, Geneva
Type	Synchrotron
Particle	Proton
Energy	1.4 GeV
Circumference	157 m
Constructed	1968–1972
First beam	1972
Predecessor	Linac 2
Successor	Proton Synchrotron

Proton Synchrotron Booster. It is a key particle accelerator at the CERN laboratory, designed to increase the intensity and energy of proton beams before their injection into the larger Proton Synchrotron. Commissioned in the early 1970s, it was a critical upgrade to the CERN accelerator complex, enabling higher-energy physics experiments. The facility is located underground at the Meyrin site in Switzerland.

History and purpose

The need for the accelerator arose in the 1960s as the Proton Synchrotron approached its intensity limits. Under the leadership of directors like John Adams, CERN approved its construction to overcome the space-charge limit, a phenomenon that restricts beam intensity at low energies. Its primary purpose was to act as an intermediary booster, receiving low-energy protons from Linac 2 and accelerating them to a sufficiently high energy for efficient injection into the Proton Synchrotron. This development was pivotal for the Super Proton Synchrotron research program and subsequent collider projects like the Large Electron–Positron Collider.

Design and technical specifications

The machine consists of four superimposed synchrotron rings housed in a common tunnel, a unique design allowing it to handle four beam batches simultaneously. It accelerates proton beams from an injection energy of 50 MeV, delivered by Linac 2, up to 1.4 GeV. The rings have a circumference of 157 meters and utilize a lattice of dipole and quadrupole magnets for beam steering and focusing. Key systems include radio frequency cavities for acceleration and sophisticated beam diagnostics. Its design directly addressed the space-charge problem by raising the beam's energy before transfer to the Proton Synchrotron.

Operation and performance

In standard operation, the accelerator receives proton pulses from Linac 2, splits them among its four rings, and accelerates the beams over approximately 0.5 seconds. It achieves a cycle repetition rate of up to 1.2 seconds, delivering beams with an intensity exceeding 1.5 × 10^13 protons per pulse. This high-intensity performance was a dramatic improvement, increasing the Proton Synchrotron's beam intensity by a factor of fifty. The beams are then extracted and transferred via the Proton Synchrotron injection line, a process managed by the CERN Control Centre.

Role in the CERN accelerator complex

The facility is a fundamental pre-injector within the CERN accelerator complex. It provides the essential intermediate acceleration stage for all proton-based physics programs at the laboratory. Its beams are not only sent to the Proton Synchrotron but also feed other major machines, including the Super Proton Synchrotron, the Large Hadron Collider, and experiments like ISOLDE. It also supplies protons for the production of antiprotons used in the Antiproton Decelerator and is a source for the CERN Neutrinos to Gran Sasso project.

Upgrades and future developments

The accelerator has undergone several major upgrade programs to meet evolving demands. The LHC Injectors Upgrade project, completed in 2020, significantly enhanced its brightness and reliability for the High-Luminosity Large Hadron Collider era. Key improvements included new radio frequency systems, power supplies for the quadrupole magnets, and a new injection line from Linac 4, which replaced Linac 2. Future developments are aligned with the Physics Beyond Colliders initiative and the Future Circular Collider study, ensuring its continued role as a vital component of CERN's research infrastructure.

Category:CERN