LLRF FOR CHOPPER Grgoire Hagmann Philippe Baudrenghien BE/RF/FB February 24th, 2013 Block Diagram LLRF Linac 4, G.Hagmann 2 Chopping pattern Plates delay adjustment Monitoring (Waveform & chopping time) Interlocks Location CDU LLRF Linac 4, G.Hagmann 3 Rack AY01 LLRF Linac 4, G.Hagmann 4 BIS cables arrivals Need of space for transition patch panel : 2U Need 1U Beam permit patch =>TE/MPE/EP Need 1U User permit parch Who? BE/RF or TE/MPE? Position for BIS patch-panels? Transition patch needed No Burndy on VME board Chopper Limitations Max Chopper pulse length : 500us (programmable) => need monitoring (start counter at source on) => Drive off when source off => Drive off when >500us (timeout) from source on => What if timeout? Alarm? User Permit False? OP action? LLRF Linac 4, G.Hagmann 5 accuracy? 1 pattern table for every ring Table switching 1 single synchronization after Source On timing start No Dynamic ring blanking (or more complex => to be studied) 1 accurate synchronization signal 1 pattern table for all rings No distinction if 1 or more ring => just one chopping pattern RF frequencies (L4 & booster) stability? RF Linac4 HW timing T r Fixed implementation => Simple functionality => Robust => Timing always needed Through FPGA => Flexible implementation => Complex functionality possible Timing Hardware? LLRF Linac 4, G.Hagmann 15 New special BI timing LLRF Linac 4, G.Hagmann 16 Chopper ON Chopper OFF Chopper ON (latched) RF Interlock LLRF Linac 4, G.Hagmann 17 Phoenix contact module open (example of a design) Phoenix contact module closed Power side (PLC) : LowLevel side : ST optical receiver on CDU board By-pass input foreseen for debug & tests LLRF Linac 4, G.Hagmann 18