Abstract
The Spallation Neutron Source (SNS) at the Oak Ridge
National Laboratory is a high-intensity proton-based
accelerator that produces neutron beams for neutronscattering
research. As the most powerful pulsed neutron
source in the world, the SNS accelerator has experienced an
unprecedented beam instability that has a wide bandwidth
(0 to 300MHz) and fast growth time (10 to100μs). In this
paper, we propose and analyze several FPGA-based designs
for an active feedback damping system. This signal
processing system is the first FPGA-based design for active
feedback damping of wideband instabilities in high intensity
accelerators. It can effectively mitigate instabilities in highintensity
protons beams, reduce radiation, and boost the
accelerator’s luminosity performance. Unlike existing
systems, which are designed using analog components, our
FPGA-based active feedback damping system offers
programmability while maintaining high performance. To
meet the system throughput and latency requirements, our
proposed designs are guided by detailed analysis of resource
and performance tradeoffs. These designs are mapped onto
a reconfigurable platform that includes Xilinx Virtex-II Pro
FPGAs and high-speed analog-to-digital and digital-toanalog
converters. Our results show that our FPGA-based
active feedback damping system can provide increased
flexibility and improved signal processing performance that
are not feasible with existing analog systems.
