Betatron coupling measurement and optimization in Indus-2 storage ring

Area of Science:

• Accelerator Physics
• Synchrotron Radiation Technology

Background:

• Photon beam brightness is crucial for synchrotron radiation sources.
• Emittance coupling, primarily caused by skew quadrupolar errors, limits brightness in storage rings.

Purpose of the Study:

• To measure and correct betatron coupling in the Indus-2 storage ring.
• To explore advanced methods for further reducing emittance coupling and enhancing beam brightness.

Main Methods:

• Betatron coupling measured using tune split and Linear Optics from Closed Orbit (LOCO) techniques.
• Correction applied using four skew quadrupole power supplies.
• Simulation studies employed the LOCO model and a multi-objective differential evolution algorithm with sixteen power supplies.

Main Results:

• Measured coupling ratio of ~0.8% closely matched the LOCO model.
• LOCO correction reduced coupling to ~0.4%, limited by available degrees of freedom.
• Simulations with sixteen power supplies achieved an emittance ratio <0.04%, increasing brightness by an order of magnitude.

Conclusions:

• The study successfully demonstrated the reduction of emittance coupling in the Indus-2 storage ring.
• Advanced optimization techniques with increased control offer significant potential for brightness enhancement.
• The optimization method provides valuable trade-offs for selecting optimal beam parameters.