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Holger Schlarb, DESY, 16th DESY-MAC 10.11.2010
FLASH
LLRF & Synchronization System+ Roadmap
On behalf of the LLRF and
Laser based Synchronization team
Presented by H. Schlarb
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 2
Outline
• LLRF upgrades and developments at FLASH- Decision to keep MO frequency at 9MHz
=> Software & Hardware will be identical to XFEL
=> Implementation of uTCA based system at FLASH 2011/2012
=> XFEL software development has basically started!
• Highlights from FLASH operation
• Overview on synchronization + some recent results
• Roadmap (Tuesday …)Roadmap (Tuesday …)
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 3
Overview on LLRF systems at FLASH
Gun ACC1 3rd ACC2 ACC3 ACC4 ACC7
~~
Laser
A A A A
BC2BC3
A
Station until 2009 After upgrade 09/10 Shutdown 11/12
RF gun Simcon3.1 SimconDSP uTCA
ACC1 SimconDSP (250kHz)
SimconDSP (250kHz)
uTCA
ACC39 - SimconDSP(54MHz)
uTCA
ACC23 DSP(250kHz)
SimconDSP (250kHz)
uTCA
ACC45 DSP/ATCA(250kHz/54MHz)
SimconDSP (250kHz)
uTCA(semi-dist.)
ACC67 DSP(250kHz)
SimconDSP (250kHz)
uTCA
ACC4 ACC4
LLRF
A
LLRF LLRF LLRF LLRF LLRF
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 4
Upgrade of LLRF system
Upgrade of all RF stations using SimconDSP controller- Gun/ACC23/ACC45/ACC67- IF=250kHz, IQ-sampling scheme- Sampling rate 81MHz (use averaging)
RF control for 3.9GHz - Probe, forward and reflected signals- New RF down converter & LO generation with
IF=54MHz, non IQ-sampling, LO = 3954MHz- Sampling rate 81MHz
10 Channel 14bit ADCs
81 MHz clock rate
8 DAC, 14 bits
2 Gigalinks
FPGA: XILINX Virtex II pro
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 5
Upgrade of LLRF system
Upgrade of all RF stations using SimconDSP controller RF control for 3.9GHz New cabling in injector racks
-MO1 & MO2 cabling completed-New rack & cabling for RF gun-New rack & cabling for ACC1/ACC39-Enclosed racks for better temperature stability-Parallel cabling for development system-Careful noise investigation and power level
adjustment of LO and RF signals
ACC1 ACC39 RF gun
MO ACC39 DWC
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 6
Upgrade of LLRF system
Upgrade of all RF stations using SimconDSP controller RF control for 3.9GHz New cabling in injector racks Upgrade & unified FPGA controller firmware
- Multiple feed forward table (main/beam loading/correction)- Multiple setpoint table (main/beam based correction)- Model based Multiple In Multiple Out (MIMO) controller- Charge correction & intra-train beam based feedback- Exception & Error handling, limiters- Error and status displays
Feed forward table architecture
Scheme of LLRF RF controller
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 7
Upgrade of LLRF system
Upgrade of all RF stations using SimconDSP controller RF control for 3.9GHz New cabling in injector racks Upgrade & unified controller firmware Unified and new control software
- New C++ architecture for front end server- LLRF library based on SysML approach- Unified naming convention- Automatic firmware downloads- Finite State Machine for automation- High level software: diagnostics, calibration…- DAQ integration- Model based learning feed forward (LFF)- Loop phase/gain correction- Piezo control for cavity detuning comp.- …
LFF off
LFF on
Phase [deg]Voltage [MV]
1st bunch
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 8
Upgrade of LLRF system
Upgrade of all RF stations using SimconDSP controller RF control for 3.9GHz New cabling in injector racks Upgrade & unified controller firmware Unified and new control software Beam signals integrated
- Charge signals- Bunch Arrival time- Pyro signal- Real time FB with matrix- Limiter on Ampl/Phase corr.- IIRF filters- Rep. rate adaption- Charge scaling of beam load
compensation table
Control software ~ 90 % completed
Most of features are commissioned
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 9
Upgrade of all RF stations using SimconDSP controller RF control for 3.9GHz New cabling in injector racks Upgrade & unified controller firmware Unified and new control software Beam signals integrated Piezo drivers
- new driver for ACC1 / ACC7- DAQ server for detuning measurements- Several piezo studies performed- Active compensation of ringing- DC voltage added for static detuning
Control software ~ 80 % completedBut many features not fully commissioned
Upgrade of LLRF system
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 10
Upgrade of LLRF system
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 11
LLRF Control Tables – software philosophy -
Controller- + Rot
FF
table
FF_CORR
table
FF_BLC
table
FF-total
table
+
≤
≤≤
DAC
DAC
Operator & FSM & LLRF expert
Setpoints: A, & Parameters: timing, …
Learning
Feed forward≤ Bunch
Pattern
Loop
G/
MPS
Q
ratio
SP_USER
table
+
SP
table≤SP_CORR
table≤
Model based
FF & SP tables
Rota bc d
Field detection
Beam signals -
Q
MPS
SP_BBF
table
Beam based
SP correction
≤
- As larger impact on
cavity/coupler
the more restriction
on table/table generation
- Separation of physics
cause of effect
- Easier exception handling
Static detuning
correction
Dyn. detuning
correction
SP filling correction
Resonance filling
Slow BBF correction
VM offset corr.
DCW calibration
BLC adaptation
Process control via FSM
Slow FB loops for parameter
optimization
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 12
On-crest acceleration phase Definition and adjustment (min. energy spread/ max acceleration) Drifts of down converter + cables (~1-2deg) -> hardware changes 2011 Difference between Setpoint and Vectorsum -> software done To some extend drifts from laser arrival time + conv. -> hardware changes 2011 On-crest phases a dominated by operation set-point (support panel)
Remark:
1% ACC1 gradient change
3.5 phase difference for all
downstream modules
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 13
FLASH results: Learning Feed Forward
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 14
4 ps 0.5 ps
FLASH results: Learning Feed Forward
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 15
FLASH results: with MIMO (ACC39)
Limited by ADC bit noise
Value Repetitive error (aver. 100 macro-pulses)
Abs. Rms PKPKPulse to pulse (each time stamp)
LFF off
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 16
Arrival time measurements
400fs
Typically values
60-100fs rms from injector
60-80fs rms behind BC2
50-60fs rms exit LINAC
Pulse to pulse
about factor of 2 better
than last year
Across bunch train
dA/A~7e-4
(LFF was off
RMS timing jitter
FLASH results: Performance LLRF
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 17
shutdown shutdown
FLASH results: Gradient stability ACC1/ACC39
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011
FLASH results: Performance at 4.5mA operation
Flat gradient solution achieved– 4.5 mA beam
• Characterisation of solution by scanning beam current– model benchmarking
Beam Current (mA)1 2 3 4 5
Gra
dien
t cha
nge
over
400
us (%
)
0
-3
-5
+3
+5
Gradient Tilts vs Beam Current (ACC7)
Intended working
point
~2.5%
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 19
15 consecutive studies shifts (120hrs), and with no downtime
Time to restore 400us bunch-trains after beam-off studies: ~10mins
Energy stability with beam loading over periods of hours: ~0.02%
Individual cavity “tilts” equally stable
Energy stability over 3hrs with 4.5mA
~0.02% pk-pk
9 Feb 2011
Concept with toroid based BLC scaling worked excellent (at least up to 4.5mA)
FLASH results: Performance at 4.5mA operation
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 20
FLASH results: Beam base FB (with MIMO & LFF)
Exit of linac & out-of-loop
• Both intra-train FB on• MIMO controller• Repetitive pkpk deviation < 100fs
< 22 fs
Gun ACC1 3rd ACC2 ACC3 ACC4 ACC7
~ ~Laser
BC2 BC3
Latency of system
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011
Open software developments:
Next steps (till end of FLASH run)• Firmware & Software for RF gun (consistent to SRF)• Automation and permanent usage of DC/AC piezo operation • MIMO controller including BBF• Setpoint correction during filling / resonance filling using phase slopes• Forward peak power reduction• Improved error handling• Rapid VS calibration• Improved DAQ implementation and long term statistics • Error budget management & optimization of loops for LLRF parameters• LO table correction
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 22
1. Project phase (19“ modules, uTCA without backplane)
Complicated cable management - LLRF RTM backplane concept
Layout of uTCA LLRF system
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 23
TT Interne DiskussionFrank Ludwig, Tomasz Jezynski, DESY
Higher risk of signal degradation … (for main linac eventually only)
2. Project phase (19“ modules, uTCA with backplane)
Layout of uTCA LLRF system
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011
Activities and milestones scheduled for Jan. 11 -> Jun. 11
Main components of uTCA based LLRF system:Typically 2-3 revision required for each, 3-6 month per revision
Components With whom Status ExpecteduTCA crate (EMI/PS noise/…)* indu./indu. rev1/prod. Jun/Jan11
ADC board (16bit/10Ch)* with industry revision 1 Mar. 2011
Low noise DCW* in-house/indu. start rev 1. May 2011
Vector modulator* collaboration routing Mar. 2011
AMC controller collaboration production Feb. 2011
LO generation (19’’)* collabr./in-house design May 2011
LO distribution (19’’) collabr./in-house design Mar. 2011
LO generation (RTM)* industry contacted Aug. 2011
Calibration unit (19’’)* collabr./in-house design Apr. 2011
uTCA back plane* collabr./indu. production May 2011
Piezo driver board collabr. design June 2011
* Indicates ultra high performance (<150dBc/Hz , clk ~200fs , <10fs stab., -80dB cx-talk) usually not available in industry (close collaboration / exchange important / few companies)
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011
Software developments uTCA
2011
Most important is the transition from SimconDSP -> uTCA!!! • Firmware & Communication protocols & Front-end server
• Middle layer server can be move to front-end CPU
• Implementation of new Timing/Clock
2012
New software developments feasible• Down-converter calibrations (directly into performance)
• Make us of Pfor/Pref within controller (e.g. real time quench det./model)
• 30Hz operation with 9MHz tables & 96 channels (DSP???)
• AMTF software developments for routine measurements
• Upgrade of beam base feedbacks …
2013/2014• Control software for 25 RF stations XFEL
• Energy management …
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011
uTCA based LLRF Systems & schedule2011•REGAE (May-July) 1 Crate (8)•FLASH ACC1/ACC39 (June-Sep) 1 Crate (24/12) Shutdown 12.09.•PITZ TDS (Aug-Sep) 1 Crate (8)•CMTB (Sep) 1 Crate (24)•FLASH ACC23/ACC45 (Sep-Dec) 2 Crates (48/48) DWC/ADC?
2012•Freeze final LLRF design•FLASH ACC67 1 Crate (48)•FLASH ACC45 1 Crate (48) Semi-distr.•AMTF (March) 3 Crates (24/24/24)•Final revision (Oct.)•Start mass production
2013•XFEL L0 2 Crates (36/36)
2014•XFEL L1-L3 50 Crates (96)
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 27
1) RF distribution
~f ~ 100MHz …GHz
3) Carrier is optically + detection
~f ~ 200 THz
2) Carrier is optically
~MZT
f ~ GHz
4) Pulsed sourcef ~ 5 THz
OXC
Mode locked
Laser
t ft f=
Synchronization system approaches
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 28
Hybrid system for FEL facilities
Performance
Reliability
Costs
RF System
Pulsed systemCW optical
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 29
Layout of XFEL Synchronization System
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 30
Optical synchronization system
NarrowBand.
Direct/Interferometer
EOMs/Seeding
Two color bal. Opt. cross-corr.
End-station
LaserMLO
MO-RF
Laser pulse Arrival beam/laser DWC/Kly
A & cavity
Desired point-to-point stability ~ 10 fs
<5fs
Direct
Distribution
LO-RF
Optical link Optical link
<5fs <5fs
Optical link
FB
EDFL, soliton, t~200fs, f=216MHzSESAM, P > 100mW, phase noise < 5fs (1kHz)
Free space distribution+ EDFA
Dispersion comp.,Polarization contr.,Collinear bal. opt. cross-corr.
Other lasers
Main issue: robustness, stability and maintainability Prototype at FLASH09.12.2010, Daresbury, “Rule of lasers in particle beam research” Holger Schlarb, MSK, DESY
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 31
Optical Synchronization SystemInstallation at FLASH
• Master Laser Oscillator (RF locked to MO)• Free space distribution system to 16 ports• Optical Links: 6 stabilized using OXC & 1 passive • Front-ends
• 4 Bunch arrival time monitors (BAM) • OXC for INJ / TiSA lasers• RF locked for TiSA (HHG) (not yet completed)
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 32
Bunch Arrival MonitorDetector
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 33
Bunch Arrival MonitorsFront-end Electronics
Top view
Bottom view
to LLRF
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 34
Fiber Link Stabilization (RF based)
Time domain Frequency domain
Scheme RF link
Every odd harmonicdestructively interfere
Amplitude detectionwith mixer (sign) ofhigh harmonics (45th)allow to measure link delay variations
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 35
Fiber link stabilization (RF based)
LO generation
Optics section
In-loop Detector branch
Out-of-loop Detector branch
Digital FB loop
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 36
Fiber link stabilization (RF based)Error between in-loop and out of loop ~ 0.8fs rms, 4.8 fs pkpk, (30 m long fiber in laboratory, not stabilized, only monitored)
In-loop / 2
Out-of-loop
difference
overcomes AM-PM conversion in photo-detectors several advantages compared to OXC link (low opt. power, monitoring possible, simple disp. comp.) low cost version link with still high performance
38 hours
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 37
RF generation from optical pulses
Direct conversion with photo detector (PD)– Low phase noise (to be proven at end-station)– Temperature drifts (0.4ps/C°)– AM to PM conversion (0.5-4ps/W)– Potential for improvement (corporation with PSI)
PD BPFlaser pulses
frepf = n*frep
f = n*frep
~~~
Time domain Frequency domain
T = 5ns = 1/frep
Photo DetectorBandwidth PD
frep
100fs Phase noise
Sagnac loop interferometer– balanced optical mixer to lock RF osc.– insensitive against laser fluctuation – Very low temperature drifts Results: f=1.3GHz jitter & drift < 10 fs rms limited by detectionRemark: much easier at hire frequencies …
MZI based balanced RF lock– new scheme, under investigation
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 38
Results double balanced MZI-L2RF
But 0.8 ps/Ktemperature dependence
2fs pkpk
Sensitive to environment
But insensitive to laser power
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 39
Thanks for your attention
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 40
Beam Based FeedbackInstallation
Gun ACC1 3rd ACC2 ACC3 ACC4 ACC7
~ ~BAM BAM BCM BCM BAMBAM
Toroid Toroid Toroid
Laser
LLRF LLRF
LLRF
LLRF LLRF
A A A A
Beam Based Feedbacks:• BAM before BC2 corrects phase in RF-Gun• BAM and BCM after BC2 simultaneously correct amplitude and phase in
ACC1 and 3rd harmonic• BAM and BCM after BC3 correct amplitude and phase in ACC23
Results from BBF running at BC2
BC2 BC3
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 41
Master Laser Oscillator (MLO)Pulse generation and distribution
•Promising: OneFive ORIGAMI-15
• Repetition rate: 216,66MHz
• Average power: > 100mW
• Pulse duration: p < 150 fs
• Integrated timing jitter < 5 fsin the interval [1 kHz; 10MHz]
• Mechanically robust, easy to maintain
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011
Fiber Link Stabilization (optically)
216 MHzEr-dopedfiber laser
J. Kim et al., Opt. Lett. 32, 1044-1046 (2007) Det 1
Det 2 -Balanced optical cross-correlator
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 43
Fiber Link Stabilization (optically) 3 generation of opto-mechanics typical in loop jitter ~ 1-2 fs rms (also smaller)
Experience:
Operate reliablyAmpl. FB to be addSmaller open questions
XFEL:
Dispersion management need to be improvedDelay stage too short for long links and large temp. changes
Courtesy: M. Bock
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 44
LLRF Control Tables
ADC10 PeakDetection
Pyro SPTable
-ChargeCorrection
TransferMatrixQnom
Qtoroid
tsample
Control System
ADC9 Charge Measurement
Gating
OpticalLink
MPS
LLRF SPTable
SP SignalModulation
I Q
I Q
Low Level RF Control SystemsIntra-train BBF Implementation
FPGA
Δt
ΔU
ΔA/A
ΔΦ
Toroid
BCM
BAM
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 45
BBF CalibrationTransfer Matrix Determination
Gun ACC39ACC1
BC2
BAM Pyro
A/ A/ t C/zMonitor systemActuators
?
ACC1 ACC39scanning
extract
measure
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 46
Open issues: observation QL changes
ACC4 ACC5
2.6 -> 3.0 (16%)
Voltage change ACC45 from 67MV to 255MV (~4MV/m -> ~15MV/m)
No change at all
Decay over time
10 min 10 min
2MV/m
17MV/m
Cause need to be investigated (likely main coupler antenna position change due to thermal expansion)
FLASH
Holger Schlarb, MSK, DESY, Advanced Techniques in LLRF control for XFEL, Cracow 18.04.2011 47
Open issues: Cavity pre-detuning using DC piezo voltage
Is accompanied with Ql changes => detuning via Lorenz force detuning
For some cavities orbit changes are observed reduces SASE, but simple corrector sufficient
global orbit FB essential for reproducibility of machine operation
Several studies on detuning compensation during macro-pulse Since 4 weeks PZT for ACC67 in operation (DC/AC)
0V
10V
10V
0V
Successfully used to change pre-detuning Successfully used to change pre-detuning