Wojciech CICHALEWSKI, DMCS_TUL, Seminarium KMiTI 20.06.2011 LLRF in FEL System sterowania...

Wojciech CICHALEWSKI, DMCS_TUL, Seminarium KMiTI 20.06.2011

LLRF in FEL

System sterowania parametrami fali stojącej z zakresu częstotliwości mikrofalowych w akceleratorach liniowych

laserów na swobodnych elektronach

W. Cichalewski w imieniu grupy zaangażowanej w projekty FLASH/XFEL

Wojciech CICHALEWSKI, DMCS_TUL, Seminarium KMiTI 20.06.2011 2

Outline- FEL at DESY

• Free Electron Lasers principles,

• FLASH/XFEL in numbers,

- LLRF system structure and main functionality,

- Cavities operation principles, cavity models,

- Best cavity frequency tuning methods in presence of LFD and microphonics,

- Fast feedbacks design and implementation in LLRF,

- Vector sum control of single and set of modules for FLASH, XFEL, ILC,

- High current beam operation,

- Electron beam acceleration: LLRF control and beam optics adjustment,

- FEL operation procedures for different experiments requirements,

- Beam based feedbacks based on toroid, Beam Arrival Monitor, Beam Position Monitors, and synchrotron radiation detectors signals,

- Global Optical synchronization system description for FLASH and XFEL

- LLRF system at FLASH – current status,

- Accelerator ambient radiation vs. performance of the accelerator electronics,

- Conclusions...


Outline

- FEL at DESY• Free Electron Lasers principles,• FLASH/XFEL in numbers,

- LLRF system structure and main functionality,

- LLRF system at FLASH – current status,- Area of DMCS main activities,- Future (next day, week, month, year....)- Conclusions...


SASE at Free Electron Lasers

Źródło: xfel.eu

Free electron laser light generation using Self Amplified Spontaneous Emission


European X-ray Free Electron Laser at DESY

Źródło: xfel.eu


FLASH

315 m

Bunch Compressor

Bypass

UndulatorssFLASH

Bunch Compressor

5 MeV 150 MeV 450 MeV 1250 MeV

Accelerating StructuresDiagnostics

FEL Experiments

RF stations

LOLARF Gun

Źródło: S. Schreiber


LLRF system structure and main functionality

Źródło:wikipedia MSK DESY



Mission:

Generate RF signal for supplying superconducting cavities in cryomodules,

Optimize RF signal parameters (accelerating field amplitude and phase with respect to the electron beam) according to requested beam acceleration conditions


LLRF system functionality (POV beam operation)

Major issues: Fast feedbacks for field parameters regulation (PID, MIMO, ...) Adaptive algorithms for repetitive errors influence minimization Beam loading compensation, Loop gain and loop phase adjustment, HPAC nonlinearites compensation, Cavities resonance frequency control (piezo-based frequency

regulation), Interfacing to beam based feedbacks,

Additional tasks Modulations imperfections identification and compensation, Calibration of HF signals drifts,


MSK group and DMCS cooperation areas

DMCS and DESY cooperation:

Most of above mentioned LLRF related topics for FLASH, BBF design and implementation, System radiation measurement, Hardware/Software design and test of uTCA based system

for FLASH and XFEL, Continuous wave FEL operation (new), Optical synchronization system (new), Line detector for intra-bunch feedback (new).



1

23

1. Field amplitude & phase regulation 2. Cavity frequency control with piezo actuators3. Qext regulation,


LLRF system structure main hardware components

Upconversion:- Vector Modulator, - up-converter,

Downconversion:- Downconverters,- direct sampling

Field parameters control: - filtering- realization of feedback algorithms, - realization of slow adaptive algorithms, - modulation imperfections reduction,- microwave ampl. nonlinearities compensation.

Digital to analog conversion

Signal discretization:- sampling,- averaging,- I/Q detection...


LLRF hardware systems at FLASH

Źródło: H. Schlarb

10 Channel 14bit ADCs

81 MHz clock rate

8 DAC, 14 bits

2 Gigalinks

FPGA: XILINX Virtex II pro

DSP processor TS


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

Piezo actuators control system



Cavities and Vector Sum diagnostic


Beam Based Feedback implementation

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



High beam operation study towards XFEL/ILC



Continues Wave linac operation

Źródło: J. Sekutowicz


Ongoing developments – ATCA system

New standards under development for telecomunication purposes:

Advanced/Micro Telecommunications Computing Architecture

Main goal:

Build modular, scalable control system suitable for FLASH/ XFEL modules control that follows current telecomunication standards and offers maximal system availability.

ATCA based system development for two years resulted in:

- hardware prototypes has been designed and lab tested (field controller, piezo controller),

- software preparation,

- no meaningful LLRF system operation in accelerator, but:

- experience gained – needed for new uTCA based system development,

- new project ITER.


Ongoing developments – uTCA based system


Future (next week, month, year....)

Next weeks:- debugging of controller board,

- production and debugging of Vector Modulator board,

- firmware download software commissioning,

- front-end server preparation for LLRF controller

- CW operation at CMTB,

Next month:- first uTCA based system measurements at FLASH - KW 30-31(hardware and software has to be debugged by that time),

- installation of uTCA based architecture in different FLASH modules,

- CW operation at CMTB,

Next year:

….....


ConclusionsMain collaboration fields:- design, implementation and commissioning of software for:

- accelerating modules field parameters control,

- beam operation,

- high level control algorithms for system parameters optimization and beam operation ,

- diagnostic of individual cavity and overall system performance,

- fast cavity frequency control,

- Beam based feedbacks,

- optical system synchronization,

- design, implementation and commissioning of hardware for:- piezo control,

- line detectors,

- realization of different controllers,

- different experiments hardware set-up, software preparation and operation support.


To read.....

Sth to read:

- FLASH main page: http://Flash.desy.de

- X-FEL main page: http://xfel.eu

- Collaboration meeting in Cracov:

https://indico.desy.de/conferenceTimeTable.py?confId=4086#20110418

- Long beam operation,

https://indico.desy.de/conferenceOtherViews.py?view=standard&confId=3007


Thank You

THANK YOU FOR YOUR ATTENTION

Wojciech CICHALEWSKI, DMCS_TUL, Seminarium KMiTI 20.06.2011 LLRF in FEL System sterowania...

Documents

Transcript of Wojciech CICHALEWSKI, DMCS_TUL, Seminarium KMiTI 20.06.2011 LLRF in FEL System sterowania...