Measuring and optimizing the momentum aperture in a particle accelerator

Area of Science:

• Accelerator Physics
• Particle Beam Dynamics
• Synchrotron Radiation

Background:

• Particle motion in storage rings is constrained by aperture limits, impacting performance metrics like injection efficiency and beam lifetime.
• Intrabeam scattering can cause particles to explore large phase spaces, potentially leading to resonant or chaotic excitation and collisions with the vacuum chamber.

Purpose of the Study:

• To understand the limitations imposed by particle motion within storage rings.
• To precisely correlate beam loss areas with resonance locations using simulations and experiments.
• To provide guidance for avoiding detrimental resonance areas and improve storage ring performance.

Main Methods:

• Conducted studies on on- and off-momentum particle motion at the Advanced Light Source (ALS).
• Employed off-momentum simulations and experimental measurements.
• Utilized frequency map analysis to identify resonance locations and correlate them with beam loss.

Main Results:

• Achieved precise correlation between beam loss areas and resonance locations.
• Demonstrated very good agreement between simulation results and experimental findings.
• Identified predictive improvements for momentum aperture, leading to a 25% increase in beam lifetime at the ALS for high bunch charges.

Conclusions:

• The study provides a clear understanding of limitations in particle motion within storage rings.
• Frequency map analysis is an effective tool for identifying and avoiding detrimental resonance areas.
• Optimizing momentum aperture based on resonance analysis significantly enhances beam lifetime and storage ring performance.