Laser beam pointing stabilization using analog position-sensitive diodes

Area of Science:

• Particle accelerators
• Beam diagnostics
• Optics and photonics

Background:

• Laser wire scanners are crucial for ion beam profile and emittance measurements at the Spallation Neutron Source linear accelerator.
• Long propagation distances necessitate robust laser beam stabilization for reliable measurements.
• Previous stabilization systems used digital cameras, limiting bandwidth and radiation tolerance.

Purpose of the Study:

• To present an upgraded laser beam pointing stabilization system.
• To improve radiation tolerance and operational bandwidth for beam diagnostics.
• To enhance the precision of ion beam measurements in accelerators.

Main Methods:

• Implementation of analog position-sensitive diodes (PSDs) as the primary position detector.
• Optimization of the system with an optical diffuser for enhanced performance.
• Utilizing a 60-Hz burst mode laser for dynamic stabilization.

Main Results:

• The upgraded system demonstrates an order-of-magnitude improvement in radiation tolerance compared to previous methods.
• Bandwidth is significantly increased, limited only by the laser's burst repetition rate.
• Suppression of laser beam drifts up to 30 Hz, a substantial improvement over the previous 4 Hz limit.
• Reduction of spectral components below 0.1 Hz by over a factor of 100.

Conclusions:

• The upgraded PSD-based stabilization system offers superior performance for laser wire scanners in accelerator environments.
• Enhanced radiation tolerance and bandwidth enable more reliable and precise ion beam measurements.
• This advancement is critical for optimizing operations and diagnostics at facilities like the Spallation Neutron Source.