Feasibility tests of a new all-digital beam control scheme for LEIR

The new Low Energy Ion Ring (LEIR), to be commissioned at CERN in early 2005, will be a very important element of the LHC lead ions injection chain and will require a new beam control and cavity servoing system. Current plans call for a new all-digital beam control system based on the same technology deployed at Brookhaven National Laboratory (BNL) for the to control the AGS Booster beam. That beam control system, now under development, relies on VME modules and daughter boards based on Digital Signal Processors (DSPs) and Field Programmable Gate Arrays (FPGAs). The DSP provides high throughput processing capabilities and ease of connection with the software layer immediately above, while the daughter boards implement master clock, digital receiver and modulator capabilities. The resulting system is very flexible because is configurable via software and offers multi-processing capabilities and high bandwidth data paths, features that make it very attractive for a beam control implementation. For application to the LEIR beam control system development, a prototype version of the VME modules and daughter boards has been tested in the PS Booster during the summer 2003. A low-intensity proton beam was injected in PS Booster Ring 4 and a simplified beam control and feedback loop was implemented. The resulting system included a phase loop capability and was not integrated within the standard control infrastructure. The overall beam control system performance was satisfactory