llrf for chopper
DESCRIPTION
LLRF for Chopper. Grégoire Hagmann Philippe Baudrenghien BE/RF/FB February 24th, 2013. Block Diagram. Plates delay adjustment Monitoring ( Waveform & chopping time) Interlocks. Chopping «pattern». Location “CDU”. Rack AY01. Rack AY01. BIS cables arrivals - PowerPoint PPT PresentationTRANSCRIPT
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LLRF FOR CHOPPERGrégoire HagmannPhilippe BaudrenghienBE/RF/FB
February 24th, 2013
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LLRF Linac 4, G.Hagmann 2
Block Diagram
Chopping «pattern»
• Plates delay adjustment• Monitoring (Waveform & chopping time)• Interlocks
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LLRF Linac 4, G.Hagmann 3
Location “CDU”
Rack AY01
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LLRF Linac 4, G.Hagmann 4
Rack AY01• BIS cables arrivals• Need of space for
transition patch panel : 2U
• Need 1U Beam permit patch=>TE/MPE/EP
• Need 1U User permit parchWho? BE/RF or TE/MPE?
• Position for BIS patch-panels?DRAFT
Transition patch neededNo Burndy on VME board
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LLRF Linac 4, G.Hagmann 5
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?
<500us
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LLRF Linac 4, G.Hagmann 6
Ring blankingDiscussion with A.Blas• Compatible with booster?
(Magnetic compensation in RF lowlevel…)• Reaction time for ring interlock?
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LLRF Linac 4, G.Hagmann 7
Ring blankingDuring the Linac 4 pulse (window), Can one ring be inhibited?And does it need immediate action?If YES :→ “Dynamic” Ring blanking→ Need timing ring identification→ Need 1 chopping pattern table per ring→ Need accurate HW timing(s) for re-synchronization
If NO :Can 1 ring interlock be interpreted like a change in nb of turn of the ring?If YES:
→ High level software re-compute chopping pattern (new settings)→ Load of the new chopping pattern and played for next cycle/user
If NO:→ No change in chopping pattern table→ Need ppm information for which ring are “played” (Timing or with Software)
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LLRF Linac 4, G.Hagmann 8
L4-Booster synchronizationBeam must be chopped during the 1us PSB ring change
References document : • Synchronization between Linac4 and the PS Booster
CERN-ATS-Note-2010-052
2 solutions :• Synchronization for every Ring
• “Dynamic” ring blanking feasible• Accurate synchronization signals => 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
Tr << TRF
TRF ≈ 2.84ns
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LLRF Linac 4, G.Hagmann 9
L4-Booster synchronization3 Proposals :
Re-synchronization for every ring (Meeting Dec 16th 2011)• 4 timings CTRV (next Ring identifier)
• 1 accurate HW timing at every ring start• Dynamic ring blanking feasible• Safer, consistency between Chopper and PSB
injection Distributor
• 1 timings CTRV (source on)• 1 accurate HW timing at the window start (linac 4 pulse)
• 1 pattern table for 4 rings• No Dynamic ring blanking• Need new setting (at the next cycle) for new pattern
• 4 accurate HW timings, 1 per ring (ring start)• Dynamic ring blanking feasible• HW More complex, More cabling
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LLRF Linac 4, G.Hagmann 10
L4-Booster synchronizationexemple
• 4 timings CTRV (next Ring identifier)• 1 accurate HW timing at every ring start
• Dynamic ring blanking feasible• Safer, consistency between Chopper and PSB
injection Distributor
Ring 1 start
HW timing
Ring 2 start
Ring 3 start
Ring 4 start
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LLRF Linac 4, G.Hagmann 11
CDU details
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LLRF Linac 4, G.Hagmann 12
CDU details
Monitoring, Gating, etc.
From
& T
o B
IS(N
o fib
er a
nym
ore)
RF
Inte
rlock
crat
eStart & Stop independent adjustable
delays for all plates
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LLRF Linac 4, G.Hagmann 13
CDU details• VME board “RF” type• BIS input & output on LEMO
• EPG.0B.304.HLN (or similar)• XXX.1B.308.XXX
• RF Interlock• 1 interlock or 2 interlocks (1 per chopper) ?• From AY01• Optical, Multi-mode, ST • Same for cavity-controller PIMS, CCDTL…)
• TX pulses monitoring• Veto• Diagnostics
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LLRF Linac 4, G.Hagmann 14
BIS «gating»BEAM INTERLOCK SPECIFICATIONS FOR LINAC4, TRANSFER LINES AND PS BOOSTER WITH LINAC4 (L4-CIB-ES-0001 rev.0.3) :
Þ Gating with timing from BE/CO (CTRV) ?Þ Fail safe?Þ Gating rather in the BIS than CDU ?Gating ON
BIS event Latched
Gating OFFChopper forced OFFBIS even unlatched
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LLRF Linac 4, G.Hagmann 15
New special «BI» timing• Addition of a new «CTRV like» timing feasible• Not fail safe
• 2 solutions:• Implemented HW similar to the BIS signal
• => Fixed implementation• => Simple functionality• => “Robust”• => Timing always needed
• Through FPGA• => Flexible implementation• => Complex functionality possible
• Timing Hardware?
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LLRF Linac 4, G.Hagmann 16
New special «BI» timing
Chopper ON Chopper OFF
Chopper ON (latched)
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LLRF Linac 4, G.Hagmann 17
RF Interlock
HFBR-1414
« 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”
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LLRF Linac 4, G.Hagmann 18