Dayle Kotturi LLRF Workshop, CERN [email protected]
October 10-13, 2005
LLRF Control SystemOutline
Scope Requirements Design Considerations Evaluation System drawings How this fits into beam-based longitudinal feedback Conclusions
Dayle Kotturi LLRF Workshop, CERN [email protected]
October 10-13, 2005
Scope
This document summarizes the design of the LCLS LLRF control system design including its interface with the beam-base longitudinal fast feedback.
Dayle Kotturi LLRF Workshop, CERN [email protected]
October 10-13, 2005
ScopeThe low level RF controls system consists of RF phase and amplitude controls at these locations:
LaserGun (Klystron 20-6)L0-A, a.k.a. L0-1 (Klystron 20-7)L0-B, a.k.a. L0-2 (Klystron 20-8)L0 Transverse cavity (Klystron 20-5) L1-S (Klystron 21-1)L1-X (Klystron 21-2)L2 - (Klystrons 24-1,24-2,24-3) to control avg phase/ampl of L2L3 Transverse cavity (Klystron 24-8)L3 - 2 sectors of klystrons, S29+S30
Dayle Kotturi LLRF Workshop, CERN [email protected]
October 10-13, 2005
Requirements (1)Meet phase/amp noise levels shown below:Table 1.RMS tolerance budget for <12% rms peak-current jitter (column 3) or <0.1% rms final e− energy jitter (column 4). The tighter tolerance is in BOLD, underlined text and both criteria, |DI/I0| < 12% and |DE/E0| < 0.1%, are satisfied with the tighter tolerance applied. All tolerances are rms levels and the voltage and phase tolerances per klystron for L2 and L3 are Nk larger, assuming uncorrelated errors, where Nk is the number of klystrons per linac.
Dayle Kotturi LLRF Workshop, CERN [email protected]
October 10-13, 2005
ParameterSymbol|ΔI/I0| < 12%|ΔE/E0| < 0.1%Unitmean L0 rf phase (2 klystrons)00.100.10S-band degmean L1 rf phase (1 klystron)10.100.10S-band degmean LX rf phase (1 klystron)x0.50.5X-band degmean L2 rf phase (28 klystrons)20.070.07S-band degmean L3 rf phase (48 klystrons)30.50.15S-band degmean L0 rf voltage (1-2 klystrons)DV0/V00.100.10%mean L1 rf voltage (1 klystron)DV1/V10.100.10%mean LX rf voltage (1 klystron)DVx/Vx0.250.25%mean L2 rf voltage (28 klystrons)DV2/V20.100.10%mean L3 rf voltage (48 klystrons)DV3/V30.50.08%BC1 chicaneDB1/B10.010.01%BC2 chicaneDB2/B20.050.05%Gun timing jitterΔt00.80.8psecInitial bunch chargeDQ/Q02.04.0%
Dayle Kotturi LLRF Workshop, CERN [email protected]
October 10-13, 2005
Requirements (2)
Achieve 120 Hz feedback to maintain phase/amp stabilityAdhere to LCLS Controls Group standards: RTEMS, EPICS, Channel Access protocol Begin RF processing of high-powered structures May, 2006
Dayle Kotturi LLRF Workshop, CERN [email protected]
October 10-13, 2005
Local feedback loop requirements
At each of these locations, the klystron’s phase and amplitude will be monitored and controlledWhen beam is present, control will be done by beam-based longitudinal feedback (except for T-cavs); when beam is absent, control will be done by local phase and amplitude controller (PAC)
Dayle Kotturi LLRF Workshop, CERN [email protected]
October 10-13, 2005
Design considerationsThrough end of January 2005, various solutions were evaluated, from 100% COTS modules to hybrids of in-house designed boards.
Dayle Kotturi LLRF Workshop, CERN [email protected]
October 10-13, 2005
Options considered Jan/05 (2)
LLRF architecture layout options for feedback signals
Option 1 – ADC with PAD sends 1MB/s normally; 10MB/s peak
CPU
~6', a couple of racks’ distance apart 1 VME Crate
RF I & Q
40 copies
ADCPADPAD
PADPAD
PAD
ADCADC
ADCADC Ethernet, 10 MB/s peak load
For an 119 MHz RF signal, there is 8.4 ns/samplewhich corresponds to 8.4 us/1000 samples. Since each sample is a 2 Byte integer and there are 40 RF signals, this is 80 Bytes, or 80 Kbytes per 1000 samples.Of the 8.4 ms beam pulse duration, 8.4 us is relevant.This means that at 120 Hz, there is 80 Kbytes of data.In 1 second, there is 120*80K=10 MB/s
ProsNo noise in the digital data
transmission
Cons
How to get triggers to ADC?
EVR
Dayle Kotturi LLRF Workshop, CERN [email protected]
October 10-13, 2005
Options considered Jan/05 (3)
PADPAD
PADPAD
Option 2 – “dumb” ADC in VME crate passes raw data to CPU
CPU
ADC
40 analog signals
10
MB/s
ProsCons
Analog noise present
40 copies
EVR
RF I & Q
Dayle Kotturi LLRF Workshop, CERN [email protected]
October 10-13, 2005
Options considered Jan/05 (4)
PADPAD
PADPAD
PADCPU
~6', a couple of racks’ distance apart 1 VME CrateRF I &
Q
40 copies
ADCPADPAD
PADPAD
ADC
ADCADC
ADCMicro
controlleror
FPGA
Ethernet, 10 KB/s + debug data = peak load
ProsLoad is off the VME CPU
ConsHow to get triggers from
ADC?FPGA programming
Option 3 – ADC with PAD sends 1MB/s normally; 10MB/s peak
40 processed values need to be transmitted at 120 Hz.Since each signal is a 2 Byte integer, this corresponds to 80 Bytes at 120 Hz
EVR
Dayle Kotturi LLRF Workshop, CERN [email protected]
October 10-13, 2005
Options considered Jan/05 (5)
PADPAD
PAD
Option 4 – Multiple VME crate solution
CPU
ADC
Fast, but no FPGA
EVR
PADPAD
PADPAD
PAD
RF I & Q
ProsLoad is off the VME CPU
Easier to trigger ADC
ConsMore crates
8 copies
1 VME Crate
triggers
9 copies
Dayle Kotturi LLRF Workshop, CERN [email protected]
October 10-13, 2005
Options considered Jan/05 (6)Option 5 – Multiple VME crate solution with FPGA on board ADC
ProsLoad is off the VME CPU
Easier to trigger ADC
ConsNoise. Ok for Injector, but problem for LINAC where
distances are 160'No/few ADCs available with
on-board FPGACost of FPGA
FPGA programming
PADPAD
PAD
CPU
ADC
Fast, with FPGA
EVR
PADPAD
PADPAD
PAD
RF I & Q
8 copies
1 VME Crate
triggers
9 copies
Dayle Kotturi LLRF Workshop, CERN [email protected]
October 10-13, 2005
Options considered Jan/05 (7)
Option 6 – Everything on a single board
ADC
CPU
EVR
DAC
ethernet
RF I & Q
40 Analog signals
8 copies
PADPAD
PADPAD
PADPAD
PADPAD
triggers
Dayle Kotturi LLRF Workshop, CERN [email protected]
October 10-13, 2005
Options considered Jan/05 (8)
PADPAD
PAD
Preferred Solution: Option 4 – Multiple VME crate solution
CPU
ADC
ADC
Dig I/O
Fast, but no FPGA
Slow, for thermocouples
DAC
For control
EVR
PADPAD
PADPAD
PAD
Place holder dig I/O. maybe not
needed
ProsLoad is off the VME CPU
8 copies
1 VME Crate
CPU
Global feedback VME
Crate
triggersRF I &
Q
Dayle Kotturi LLRF Workshop, CERN [email protected]
October 10-13, 2005
Narrowing down the options May/05Later, the options were narrowed down to two: an Off-the-shelf solution and an in-house solution. This subset of options was presented at the Lehman Review, May 10-12, 2005. Ref: Low Level RF
Dayle Kotturi LLRF Workshop, CERN [email protected]
October 10-13, 2005
Off-the-shelf solution May/05
PAD
Solution 1: Multiple VME crates with COTS modules.
CPU
ADC
fast
ADC
fast
DAC slow
Fast, but no FPGA
Thermocouple system
DAC
fast
EVR
VME Crate
CPU
Global longitudinal beam-based
feedback VME crate
1 trigger for 4 channels of 1k
samples
laser
L0-AL0-B
L1-SL1-XT Cav
gun
Beam-based longitudinal fast feedback gigabit
ethernet
Controls gigabit ethernet (interface to MCC)
RF Reference/4 = 119 MHzstabilized to 50 fs jitter
476 M
Hz R
F Refe
rence
cloc
k dist
ribute
d to a
ll 30 s
ector
s in t
he Li
nac a
nd be
yond
RF Reference*6 = 2856 MHzstabilized to 50 fs jitter
L2: in sector 24, there are 3 stations to adjust in order to accurately control phase and amplitude for long , beam-based fast feedback
10' accelerator
IQ Modulator: a phase shifter
and an attenuator
1 kW 1 kW
100 mW
ADC
slow
RF Reference*6 = 2856 MHzstabilized to 50 fs jitter
Solid State Sub Booster
Klystron
SLED cavity
laser RF
For waveforms e.g. reflected power, beam
voltage
1 trigger to travel up to ½ sector
away
60 MW
HPRF240 MW
60 MW
1 kW
RF Phase and Amplitude correction at 120 Hz for:laser, gun, L0-A, L0-B, L1-S, L1-X, T cav, L2 and S25 Tcav
Slow adjustments to allow rotation
of the reference
phase(inc sensitivity,
dec noise)
All except laser RF
100 mW
119 MHz Laser
Oscillator
Amps
GunNB: For the gun, SLED
cavity is shorted out
119 MHz120 Hz
UV
photodiode
photodiode
Sector 25 T Cav (new 4/2005)
Dayle Kotturi LLRF Workshop, CERN [email protected]
October 10-13, 2005
In-house solution May/05
I and Q Demo-dulator
CPU
FIFOs
ADC
slow
DAC
slow
Thermocouple system
EVR
VME Crate
CPU
laser
L0-AL0-B
L1-SL1-XT Cav
gun
Beam-based longitudinal
fast feedback gigabit
ethernet
Controls gigabit ethernet (interface to MCC)
Eth recvr
Private ethernet8 kBytes at 120 Hz
PAD
ADC
I and Q Modulator
DAC
FIFOs
1 trigger for 4
channels of 1k
samples
Private ethernet4 kBytes at 120 Hz
Solution 2: Multiple VME crates with in-house modules
476 M
Hz R
F Refe
rence
cloc
k dist
ribute
d to a
ll 30 s
ector
s in th
e Lina
c and
beyo
ndRF Reference/4 = 119 MHzstabilized to 50 fs jitter
RF Reference*6 = 2856 MHzstabilized to 50 fs jitter
Controller with
ethernet
Controller with
ethernet
Local trigger
Possibly combined into one module
Slow adjustments to allow rotation of the
reference phase
ADC
fast
Other waveformsFast, but not 119
MHz. 59.5 MHz ok
Global longitudinal beam-based
feedback VME crate
L2: in sector 24, there are 3 stations to adjust in order to accurately control phase and amplitude for long, beam-based fast feedback
PAC
Sector 25 T Cav (new 4/2005)
RF Phase and Amplitude correction at 120 Hz for:laser, gun, L0-A, L0-B, L1-S, L1-X, T cav, L2 and S25 Tcav
10' accelerator
IQ Modulator: a phase shifter
and an attenuator
1 kW 1 kW
100 mW
Solid State Sub Booster
Klystron
SLED cavity
60 MW
HPRF240 MW
60 MW
1 kW
All except laser RF
100 mW
119 MHz Laser
Oscillator
Amps
GunNB: For the gun, SLED
cavity is shorted out
119 MHz120 Hz
UV
photodiode
photodiode
1 trigger to travel up to ½ sector
away
Dayle Kotturi LLRF Workshop, CERN [email protected]
October 10-13, 2005
EvaluationThe Off-the-shelf solution is:
Expensive ($25K per instance * 10 instances) Noisy. ADCs are up to 150’ from what they measure so analog noise levels and ground loop problems would need to be dealt with
The in-house solution is: Possibly longer to develop due to board design and fabrication time.
Dayle Kotturi LLRF Workshop, CERN [email protected]
October 10-13, 2005
Evaluation (2)Characteristics of the Off-the-shelf solution were seen as requiring more effort than those of the in-house solutionPotential offered by the lower cost of the in-house solution to replace 250 klystron controllers in the remainder of the LINAC is attractiveHardware people were available as of 22aug2005 to work on board design if µcontroller was decidedTurned to the EPICS community for ideas and chose a µcontroller
Dayle Kotturi LLRF Workshop, CERN [email protected]
October 10-13, 2005
Evaluation (3)Lower cost alternatives to the $15K VME chassis and IOC were discussed in the session on hardware at the EPICS Collaboration Meeting. April 27-29, 2005Of the options available, only the Coldfire uCdimm 5282 processor had the communication speed and power to meet our data requirements. Cost is $150 per processor plus the development of the board it sits on
Dayle Kotturi LLRF Workshop, CERN [email protected]
October 10-13, 2005
Evaluation (4)By choosing the Coldfire processor, we are able to make use of the port of the operating system, RTEMS, which has already been done.
RTEMS is the standard for the real-time operating system chosen for LCLS by the Controls GroupEPICS, the standard for the control system software for LCLS runs on RTEMSWith these choices, the LLRF control system will be fully integrated into the rest of the LCLS EPICS control system and can speak to other devices and applications such as control panels, alarm handlers and data archivers, using Channel Access protocol, the standard communication protocol for this project.
Dayle Kotturi LLRF Workshop, CERN [email protected]
October 10-13, 2005
I and Q Demo-dulator
CPU
FIFOs
DAC
slow
Temperature monitors
EVR
VME Crate at S20
CPU
Laser and RF ref
L0-AL0-B
L1-SL1-X
T Cav
gun
Controls gigabit ethernet (interface to MCC)
Eth recvr
Private ethernet8 kBytes at 120 HzPAD
ADC
FPGADAC
1 trigger for 4
channels of 1k
samples
Private ethernet4 kBytes at 120 Hz
In-house modules sharing VME crate for timing triggers
476 M
Hz RF
Refer
ence
clock
distrib
uted t
o all 3
0 sec
tors in
the L
inac a
nd be
yond
RF Reference/4 = 119 MHzstabilized to 50 fs jitter
RF Reference*6 = 2856 MHzstabilized to 50 fs jitter
Coldfire CPU
running RTEMS
and EPICS
Coldfire CPU
running RTEMS
and EPICS
Global longitudinal beam-based
feedback VME crate
PAC
RF Phase and Amplitude correction at 120 Hz for:laser, gun, L0-A, L0-B, L1-S, L1-X, T cav
10' accelerator
IQ Modulator gives phase
and amplitude control
1 kW 1 kW
Solid State Sub Booster
Klystron
SLED cavity
60 MW
HPRF240 MW
60 MW
1 kW
All except laser RF
100 mW
119 MHz Laser
Oscillator
Amps
GunNB: For the gun, SLED
cavity is shorted out
119 MHz120 Hz
UV
photodiode
photodiode
1 trigger to travel up to ½ sector
away
Beam-based longitudinal
fast feedback gigabit
ethernet
DAC
slow
VME Crate for longitudinal,
beam-based feedback
Dayle Kotturi LLRF Workshop, CERN [email protected]
October 10-13, 2005
I and Q Demo-dulator
CPU
FIFOs
DAC
slow
Thermocouple system
EVR
VME Crate at S24
CPU
Controls gigabit ethernet (interface to MCC)
Eth recvr
Private ethernet8 kBytes at 120 Hz
PAD
ADC
FPGADAC
1 trigger for 4
channels of 1k
samples
Private ethernet4 kBytes at 120 Hz
In-house modules sharing VME crate for timing triggers
476 M
Hz R
F Refe
rence
cloc
k dist
ribute
d to a
ll 30 s
ector
s in t
he Li
nac a
nd be
yond
RF Reference/4 = 119 MHzstabilized to 50 fs jitter
RF Reference*6 = 2856 MHzstabilized to 50 fs jitter
Coldfire CPU
running RTEMS
and EPICS
Coldfire CPU
running RTEMS
and EPICS
L2: in sector 24, there are 3 stations to adjust in order to accurately control phase and amplitude for long, beam-based
fast feedback
PAC
Sector 25 T Cav (L24-8)
RF Phase and Amplitude correction at 120 Hz for:L2, S25 Tcav and L3
10' accelerator
IQ Modulator gives phase
and amplitude control
1 kW 1 kW
Solid State Sub Booster
Klystron
SLED cavity
60 MW
HPRF240 MW
60 MW
1 kW
100 mW
NB: For the gun, SLED cavity is shorted out
1 trigger to travel up to ½ sector
away
Beam-based longitudinal
fast feedback gigabit
ethernet.Setting only
L24-1
L24-3L24-2
S30S29
DAC
slow
VME Crate for longitudinal,
beam-based feedback
Dayle Kotturi LLRF Workshop, CERN [email protected]
October 10-13, 2005
Eth recvr
EVR
VME Crate at S20
CPU
CPU
Eth recvr
EVR
VME Crate at S24
CPU
PACGun
PADPADPAD
PAC
RF Dist’n
Laser
PACL0-B
PADPAD
PACL1-S
PADPAD
PACL0-Tcav
PADPAD
PACL0-A
PADPAD
PACPAD
PAD
PACL1-X
PADPADPAD
PACL24-1
PACL24-2
PACL24-3
PACTcav L24-8
PACS29
Overview of RF Phase and Amplitude correction at 120 Hz for LCLS LINAC
PACS30
PACPACPAC
PACPAD
PADPAD
VME Crate for longitudinal,
beam-based feedback
Total number of Coldfire processors: 37Total number of PACs: 18Total number of PADs: 19
Total number of VME crates: 3
Dayle Kotturi LLRF Workshop, CERN [email protected]
October 10-13, 2005
How this fits into global feedback (Gun)
TOROID
BUNCH CHARGE
BEAM PHASE CAVITY
GUN RF FEEDBACK
InputsGUN-CELL1-PHAS/AMPLGUN-CELL2-PHAS/AMPL
ActuatorsGUN RF ACTUATORS
2856MHz R ef
GUN RF ACTUATORS
LCLS RF Oscillator
LINAC MDL Ref.
PHAS
GUN RF REF.
LASER RF R EF.
PHAS AMPL
PHASEERROR
ActuatorL0, L1 to L2, L3Phase
AMPL
GUN-CELL2
GUN-CELL1
KLYSTRONAMPLIFIER / SLC CONTROL
LASER OSC
Reference
LASER OSC. PHASE
WATER TEMP
RF GUN
LASER PHASE ACTUATOR
LASER POWERACTUATOR
OUT
2856MHzRF REF.
LASER
GUN
L0A
L0B
L1-X
L1-S
GUN TUNE FEEDBACK
InputsGUN-FOR-PHASGUN-CELL1-PHASGUN-CELL2-PHAS
ActuatorsWATER TEMP
GUN-FOR
LASER OSCILLATOR PHASEand LASER POWERFEEDBACK
InputsLASER OSC. PHASEBUNCH CHARGEGUN-CELL1-AMPL/PHASGUN-CELL2-AMPL/PHASLASER PHASE & AMPLITUDEGUN RF ACTUATORSBEAM PHASE CAVITY
ActuatorsLASER POWERLASER PHASE ACTUATOR
PHASE ERROR BetweenL0, L1 and L 2, L3
LASER PHASE & AMPLITUDE?
LASER AMPLIFIER
Dayle Kotturi LLRF Workshop, CERN [email protected]
October 10-13, 2005
How this fits into global feedback (L0)
L0B LOAD FOR
PHAS
L0B RF REF.
AMPL
L0B RF ACTUATORS
L0B
L0B THREE T HERMOCOUPLEINPUTS
L0B-FOR
KLYSTRONAMPLIFIER / SLC CONTROL
L0A RF ACTUATORS
KLYSTRONAMPLIFIER / SLC CONTROL
L0A R F REF.
L0A
L0 BUNCH ENERGY FEEDBACK
Inputs4 DL1BPMs: BPM10,11,12,13Laser phase, power
Matrixed Information DL1 Energy
Status inputs Flags for what is broken
ActuatorsL0 AMPLITUDE
L0A RF PHAS/AMPL0B RF PHAS/AMP
DL1 BPM 13X Position
DL1 BPM 12X Position
DL1 BPM 11X Position
DL1 BPM 10X Position
L0B RF Feedback
InputsL0B-FOR PHAS/AMPLL0B-LOAD FOR PHAS/AMPL3-THERMOCOUPLES
ActuatorsL0B RF PHAS/AMPL
L0A-FOR
L0A LOAD FOR
L0A T HREETHERMOCOUPLE INPUTS
L0A R F Feedback
InputsL0A-FOR PHAS/AMPLL0A-LOAD FOR PHAS/AMPL3-THERMOCOUPLES
ActuatorsL0A R F PHAS/AMPL
AMPLPHAS
Dayle Kotturi LLRF Workshop, CERN [email protected]
October 10-13, 2005
How this fits into global feedback (L1)
L1D THREET HERMOCOUPLEINPUTS
L1X-FOR
L1X T HREE THERMOCOUPLEINPUTS
PHAS AMPL
L1 RF ACTUATORS
L1 RF REF.
L1 BUNCH ENERGY/LENGTHFEEDBACK
Inputs4 DL1BPMs: BPM10,11,12,133 BC1BPMs: BPMA12,BPMS11,
BPMM12Toroid atBC1: IMBC1OBLM atBC1: BLM11 Laser phase, power
Matrixed Information DL1 EnergyBC1 Energy and Bunch Length
Status inputs Flags for what is broken
ActuatorsL1 RF PHASL1 RF AMPL
L1C THREET HERMOCOUPLEINPUTSL1B THREET HERMOCOUPLEINPUTS
L1X R F Feedback
InputsL1X-FOR PHAS/AMPLL1X-LOAD FOR PHAS/AMPL3-THERMOCOUPLES
ActuatorsL1X R F PHAS/AMPL
KLYSTRONAMPLIFIER / SLC CONTROL
KLYSTRONAMPLIFIER / SLC CONTROL
L1X RF ACTUATORS
AMPLPHAS
L1X R F REF.
L1B-FOR
L1C LOAD FORL1CL1X
L1X LOAD FOR
L1S R F Feedback
InputsL1B-FOR PHAS/AMPLL1B-LOAD FOR PHAS/AMPLL1C-LOAD FOR PHAS/AMPLL1D-LOAD FOR PHAS/AMPLL1B 3 THERMOCOUPLESL1C 3 THERMOCOUPLESL1D 3 THERMOCOUPLES
ActuatorsL1 RF PHAS/AMPL
L1D LOAD FOR
BC1 BPMM12X Position
BC1 BPMS11X Position
BC1 BPMA12X PositionL1D
BC1BUNCHLENGTHL1B LOAD FOR
L1B
Dayle Kotturi LLRF Workshop, CERN [email protected]
October 10-13, 2005
How this fits into global feedback (L2)
L2 24-1
L2 24-1 RF ACTUATORS
PRL RF
PHAS AMPL
KLYSTRONAMPLIFIER / SLC CONTROL
L2 24-2 RF ACTUATORS
L2 24-2
KLYSTRONAMPLIFIER / SLC CONTROL
AMPLPHAS
PRL RF
L2 BUNCH ENERGY/LENGTHFEEDBACK
Inputs4 DL1BPMs: BPM10,11,12,133 BC1BPMs: BPMA12,BPMS11,
BPMM123 BC2BPMs: BPM24401,
BPM24701,BPMS21Toroid atBC1: IMBC1OToroid atBC2: IMBC2OBLM atBC1: BLM11 BLM atBC2: BLM21Laser phase, power
Matrixed Information DL1 EnergyBC1 Energy and Bunch Length BC2 Energy and Bunch Length
Status inputs Flags for what is broken
ActuatorsL2 PHASE AND AMPLITUDE
L2 24-1 R FPHAS ACTUATORL2 24-2 R FPHAS ACTUATOR
BC2 BPM24401X Position
BC2 BPM24701X Position
BC2 BPMS21X Position
BC2 BUNCHLENGTH
Dayle Kotturi LLRF Workshop, CERN [email protected]
October 10-13, 2005
How this fits into global feedback (L3)
DL2 BPMDL3X Position
PRL RF
L3 BUNCH ENERGYFEEDBACK
Inputs4 DL1BPMs: BPM10,11,12,133 BC1BPMs: BPMA12,BPMS11,
BPMM123 BC2BPMs: BPM24401,
BPM24701,BPMS212 DL2BPMs: BPMDL1,BPMDL3Toroid atBC1: IMBC1OToroid atBC2: IMBC2OBLM atBC1: BLM11 BLM atBC2: BLM21Laser phase, power
Matrixed Information DL1 EnergyBC1 Energy and Bunch Length BC2 Energy and Bunch LengthDL2 Energy
Status inputs Flags for what is broken
ActuatorsL3 AMPLITUDE
SECTOR 29PHAS ACTUATORSECTOR 30PHAS ACTUATOR
DL2 BPMDL1X Position
8 KLYSTRONAMPLIFIER / SLC CONTROL
SECTOR 29 PHASE ACTUATOR
PRL RF
8 KLYSTRONAMPLIFIER / SLC CONTROL
SECTOR 30SECTOR 29
SECTOR 30PHASE ACTUATOR
Dayle Kotturi LLRF Workshop, CERN [email protected]
October 10-13, 2005
How this fits into global feedback
*These 10 sectors*8 klystron values are available from the SCP, but may be impossible to read @ 120 Hz. We could provide the corrected values @120 Hz.
L3 RF phase*L3 RF amplitude*
L2 RF phase*L2 RF amplitude*BC-2 energyBC-2 bunch length
LIST OF AVAILABLE PARAMETERSupdated at 120 Hz unless specified otherwise
Laser phaseLaser powerGun RF phaseGun RF amplitudeGun chargeBeam phaseL0A RF phaseL0A RF amplitudeL0B RF phaseL0B RF amplitudeDL1 energyL1 RF phaseL1 RF amplitudeL1-X RF phaseL1-X RF amplitudeBC-1 energyBC-1 bunch length
DL2 energy
Dayle Kotturi LLRF Workshop, CERN [email protected]
October 10-13, 2005
Conclusions
This solution: meets the spec for speed and noise avoids signal noise problems avoids ground loop problems meets LCLS control system requirments and standards running EPICS on RTEMS provides a low cost path for future upgrade in the rest of the LINAC when the rest of the klystron control is replaced
Dayle Kotturi LLRF Workshop, CERN [email protected]
October 10-13, 2005
ConclusionsAt 120 Hz, the LCLS LLRF raw signals must be processed, the phase and amplitude corrections must be sent out, applied and achievedWhen there is beam, this system will integrate with the beam-based longitudinal feedback by accepting the latter’s RF phase and amplitude corrections and passing them on.