RF and Sequences

Andy Butterworth BE/RFThanks to V. Kain, D. Jacquet, R. Alemany, M.

Lamont, P. Baudrenghien

Outline• System overview• Equipment control and sequencing• Functions• Actions through LHC cycle• Conclusion

LHC 400 MHz (ACS) RF systemSurface building SR4

UX45 cavern

Kly

Antenna

to SUM to SUM

Beam 1

TunnelBeam 2

to SUM to SUM

Transverse(radial)pickup

Longitudinal(phase) pickup

Beam Control beam 1

Beam Control beam 2

RF Synchronization

KlyKly

CavCav

Cav Cav

Kly

Cavity Controller

Cavity Controller

Cavity Controller

Cavity Controller

Antenna

Antenna Antenna

400MHzRF

400MHzRF

RF Voltage SUM• Power system

– 1 klystron per cavity– 1 power converter

serves 4 klystrons (1 cryomodule)

• Low Level– Cavity Controller (2 VME crates): RF control loops around cavity/klystron– Beam Control (5 VME crates): phase, synchro, radial loops around beam– RF Synchro (3 VME crates): Synchronisation with SPS, prepulse generation, reference

clocks for experiments

Control & sequencing• Power system

– klystron, power converter, services (cooling water etc.)– control via PLCs– interface via ACSLine, ACSModule FESA classes

• Cavity controller– ensemble of FESA classes– overall supervision and logic by ALLLine FESA class

• Beam Control– ensemble of FESA classes– overall supervision and logic (foreseen) by ALLBC FESA

class

• RF Synchro– ALLSyncCrate FESA class

Functions

FGC name Channel Device name Units Description Client ModuleRFMDA.UX45.ACSFCA1.B1 0 ACSCA.1B1.VOLTAGE_I MV RF voltage I cavity 1 beam 1 Setpoint  1 ACSCA.1B1.VOLTAGE_Q MV RF voltage Q cavity 1 beam 1 SetpointFCA-right side 2 ACSCA.1B1.COUPLER mm Coupler position cavity 1 beam 1 Tuner Control  3        

RFMDA.SR4.BC.B1 0 ALB.B1.MOMENTUM GeV Momentum beam 1 Beam Param DSP (postponed)  1 ALB.B1.RSTEERING m Radial steering beam 1 Beam Pos Module  2 ALB.B1.PL_GAIN Hz_rad Phase loop gain beam 1 LLLoops DSP  3 ALB.B1.RL_GAIN Hz_m Radial loop gain beam 1 LLLoops DSP  4 ALB.B1.SL_GAIN Hz_rad Synchro loop gain beam 1 LLLoops DSP  5 ALB.B1.SL_A   Synchro loop A beam 1 LLLoops DSP  6 ALB.B1.FPROG_COARSE Hz Coarse frequency program beam 1 LLLoops DSP  7 ALB.B1.NOISE_F_CENT Hz Blowup noise central frequency LLLoops DSP  8 ALB.B1.NOISE_AMPL rad Blowup noise amplitude LLLoops DSP  9 ALB.B1.NOISE_BW Hz Blowup noise bandwidth LLLoops DSP

  10 ALB.B1.SL_TAU sSynchro loop tau beam 1 (no BParams module) LLLoops DSP

  11 ALB.B1.STABLE_PHASE rad Stable phase Beam Phase Module

RFMDA.SR4.BC.COMMON 0        

  1 ALB.B1.FPROG HzFrequency program beam 1 (offset from 400MHz) Dual Freq Prgm Module

  2 ALB.B2.FPROG HzFrequency program beam 2 (offset from 400MHz) Dual Freq Prgm Module

Cavity controllers (per cavity)

Beam control (per beam)

Beam control (common to both beams)

Actions during LHC cycle: injection, ramp• Initial startup (recover from shutdown)

– Switch on power (ACSLine:Setting:mode = ON)– Close cavity LL loops with voltage reference from FGC

(ALLLine:Setting:mode = ON)• Prepare for injection

– Beam control loops state (ALLBCLoops or ALLBC): synchro & phase loops ON, radial loop OFF

– Reset of revolution frequency dividers (ALLSyncCrate:RestartVTU)

• At each injection– Next injected bucket/ring/intensity? from timing/telegram– Next injected bunch pattern (FESA property, ALLBC)

• Ramp, squeeze:– all via functions, no specific actions to be taken

Actions during LHC cycle: flat top• Before physics

– Rephasing between rings• can be large, time consuming in case of ramp with radial loop

– Rephasing to experiments’ bunch clock reference• rapid (few buckets)

– Commute to physics reference generator– All the above (will be) implemented in Beam Control FESA

class• launched using a FESA property

• During physics coast– Frequency trims during physics...?

• commute to frequency program DDS• trim DDS frequency• change reference frequency• rephase to reference• commute to reference

Conclusion• Actions required from sequencer:

– Initial switch on of RF power & Low Level– Setup of synchro and beam control loops before injection– Injection requests giving next injected ring/bucket– Bunch intensity via timing?– Bunch pattern via FESA– Rephasing before physics– Frequency trims during physics?– Function management cf. power converters