Fast BPM data distribution for global orbit feedback using commercial gigabit ethernet technology

Conference · Mon Mar 28 04:00:00 EDT 2011

OSTI ID:1016652

Hulsart, R; Cerniglia, P; Michnoff, R; Minty, M

In order to correct beam perturbations in RHIC around 10Hz, a new fast data distribution network was required to deliver BPM position data at rates several orders of magnitude above the capability of the existing system. The urgency of the project limited the amount of custom hardware that could be developed, which dictated the use of as much commercially available equipment as possible. The selected architecture uses a custom hardware interface to the existing RHIC BPM electronics together with commercially available Gigabit Ethernet switches to distribute position data to devices located around the collider ring. Using the minimum Ethernet packet size and a field programmable gate array (FPGA) based state machine logic instead of a software based driver, real-time and deterministic data delivery is possible using Ethernet. The method of adapting this protocol for low latency data delivery, bench testing of Ethernet hardware, and the logic to construct Ethernet packets using FPGA hardware will be discussed. A robust communications system using almost all commercial off-the-shelf equipment was developed in under a year which enabled retrofitting of the existing RHIC BPM system to provide 10 KHz data delivery for a global orbit feedback scheme using 72 BPMs. Total latencies from data acquisition at the BPMs to delivery at the controller modules, including very long transmission distances, were kept under 100 {micro}s, which provide very little phase error in correcting the 10 Hz oscillations. Leveraging off of the speed of Gigabit Ethernet and wide availability of Ethernet products enabled this solution to be fully implemented in a much shorter time and at lower cost than if a similar network was developed using a proprietary method.

• Research Organization: Brookhaven National Laboratory (BNL) Relativistic Heavy Ion Collider
• Sponsoring Organization: DOE - OFFICE OF SCIENCE
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 1016652
• Report Number(s): BNL--94172-2011-CP; KB0202011
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
ACCELERATORS
AVAILABILITY
COMMUNICATIONS
COMPUTER ARCHITECTURE
DATA ACQUISITION
DISTRIBUTION
FEEDBACK
OSCILLATIONS
RETROFITTING
SWITCHES
TESTING
VELOCITY
relativistic heavy ion collider