Transverse bunch-by-bunch feedback system for time-resolved experiments at PLS-II.

Area of Science:

• Accelerator Physics
• Synchrotron Radiation Technology

Background:

• The Pohang Light Source II (PLS-II) facility requires an advanced bunch-by-bunch feedback system for time-resolved experiments.
• Previous systems limited the achievable single-bunch current in hybrid fill patterns.

Purpose of the Study:

• To describe the upgraded bunch-by-bunch feedback system at PLS-II.
• To enhance the single-bunch current capability for time-resolved experiments.
• To improve feedback control precision and flexibility.

Main Methods:

• Implemented a single 500 MHz analog-to-digital converter (ADC) replacing four 125 MHz interleaved ADCs.
• Replaced a single 2D feedback loop with two independent 1D feedback loops.
• Integrated tune measurement and single-bunch/stretcher control functionalities.

Main Results:

• Successfully achieved a 400 mA hybrid fill pattern.
• Demonstrated the capability to include a 10 mA single bunch within the hybrid pattern.
• Validated the precision and effectiveness of the upgraded feedback system.

Conclusions:

• The upgraded bunch-by-bunch feedback system significantly enhances PLS-II's capability for time-resolved experiments.
• The system's precision allows for higher single-bunch currents and more flexible operational modes.
• This upgrade, a result of SPring-8 and PLS-II collaboration, advances synchrotron light source technology.