Overview of Some Feedback & Control Systems at Synchrotron ...

1/33PCAPAC 2016

Overview of some Feedback- & Control systems in Synchrotron SOLEIL

Christer Engblom on behalf of Accelerator & Engineering DivisionChrister Engblom on behalf of Accelerator & Engineering Division

Overview of some Feedback- & Control Systems at Synchrotron SOLEIL


2/33PCAPAC 2016


Context SOLEIL Feedback/Feedforward Systems

Storage Ring Beamline Beamline Endstation

Conclusion



3/33PCAPAC 2016


Context SOLEIL FB/FFW Systems

– Storage Ring• Beam Orbit Stability System• RF Systems• Trajectory Compensation in

Insertion Devices

– Beamline • Fast Attenuation System

– Beamline Endstation• Nanoprobe

Conclusion

4/33PCAPAC 2016


ContextContext

Beam

Detector

Sample

Detector

To increase electron beam stability and

photon energy accuracy

To increase endstationstability

More accurate towards nanopositioning

More stablepermanent static regulation in spite of disturbances

Control & Acquisition Challenges To synchronize

detectors with optics that select photon

energy to acquire only useful data

To perform fastest continuous acquisition to

save time

5/33PCAPAC 2016


ContextContext

Nanoprobe Endstation Challenges– Provide 2D- & 3D tomography scans with nanometric resolution &

mm- range, while maintaining stable photon beam flux and position– Possibility of fast continuous scans with low dynamic errors.

Stability is required for all systems from the electron beam to the endstation.– Machine feedback/feedforward systems (GOFB, RF feedback...)– Beamline feedback systems (FastAtt...)

6/33PCAPAC 2016




Insertion Devices



Conclusion

7/33PCAPAC 2016


Beam Orbit StabilityBeam Orbit Stability

Beam Position Monitors

Beam CorrectorsPower Supplies

LIBERA Module (FPGA)

Feedback loop: Basic idea

8/33PCAPAC 2016



MIMO- Feedback System– BPM – Measure Orbit Errors– Correctors – Correct Orbit

Errors

Singular Value Decomposition

9/33PCAPAC 2016



Global Orbit Feedback (GOFB)– Fast Orbit Feedback (FOFB)– Slow Orbit Feedback (SOFB)

Status– SOFB/FOFB approach– DC250Hz control– Implemented XBPMs into the

feedback photon beam stability improved by factor of 1.3-3

10/33PCAPAC 2016




Insertion Devices



Conclusion

11/33PCAPAC 2016


Storage Ring RF SystemsStorage Ring RF Systems

Power output of 600 kW RF Voltage of 3-4 MV @ 352 Mhz 2 Cryomodules in SR, each holding a 2 superconducting RF cavities Each RF cavity is powered by 180 kW solidstate amplifier.

Cryomodules in Storage Ring180 kW solidstate amplifier

12/33PCAPAC 2016


Orange: Amplitude Loop Green: Phase Loop Red: Direct RF Feedback Grey: Frequency Loop

The amplitude an phase loops are running analog LLRF control

Prototype digital FPGA-based control tested in 2009 for the orange, green, and red loops

Storage Ring RF Systems – Low-level Control SchemeStorage Ring RF Systems – Low-level Control Scheme

13/33PCAPAC 2016


Grey: Frequency Loop– SOLEIL ControlBox– Stepper Motor– Pseudo encoder feedback

Storage Ring RF Systems – Low-level Control SchemeStorage Ring RF Systems – Low-level Control Scheme

14/33PCAPAC 2016




Insertion Devices– Beamline

• Fast Attenuation System


Conclusion

15/33PCAPAC 2016


Trajectory Compensation in Electromagnetic Insertion DevicesTrajectory Compensation in Electromagnetic Insertion Devices

Use of Insertion Devices Close Orbit Distortions (COD) Trajectory Correctors @ entry and exits of ID

– Electromagnetic field variation in horizontal- and vertical orientation

Previous control systems used high- level software via Profibus– Major drawback: difficult to synchronize COD to corrector rate

16/33PCAPAC 2016


Low- Level microcontroller– SPICONTROLLER with SPIDAC

Feedforward Compensation Look-up table– Generate corrections analog signals

in function of main coil current


17/33PCAPAC 2016


SPICONTROLLER archititecture: COD reduced from 25um 8um (2012)


18/33PCAPAC 2016




Insertion Devices



Conclusion

19/33PCAPAC 2016


Fast Attenuation DeviceFast Attenuation Device

SIXS beamline (Pneumatic & piezo actuators), DIFFABS (pneumatic)

Useful for high photon energy scans to avoid detector damage and saturation

Photon flux regulation(3rd gen. Synchrotron 1014 photons/s)– Photon flux < Detector damage

threshold (~109 photons/s)– Photon flux within optimal detector

rangePneumatic FastAtt setup on SIXS

beamline

20/33PCAPAC 2016


CompactCPI board– Measures mean photon flux

• Point detector• 2D XPAD sensor + XPAD intensity

analyser– Multi- actuator control via binary logic

• Moves filters in/out of photon beam

Fast Attenuation DeviceFast Attenuation Device

Detector Damage Range

21/33PCAPAC 2016




Insertion Devices



Conclusion

22/33PCAPAC 2016


Nanoprobe ProjectNanoprobe Project

4- year collaboration project between Synchrotron SOLEIL & MAX IV– Scheduled to finish in 2016

Produce Nanoprobe endstation prototypes capable of 2D- & 3D tomography on the nanometeric scale with mm- range– Beam focusing stages

• Fresnel Zone Plates: 5 DOF/lens• Central Stop: 3 DOF• Order Sorting Aperture: 3 DOF

– Sample Stage: 4 DOF

23/33PCAPAC 2016



4- year collaboration project between Synchrotron SOLEIL & MAX IV– Scheduled to finish in 2016

Produce Nanoprobe endstation prototypes capable of 2D- & 3D tomography on the nanometeric scale with mm- range– Beam focusing stages

• Fresnel Zone Plates: 5 DOF/lens• Central Stop: 3 DOF• Order Sorting Aperture: 3 DOF

– Sample Stage: 4 DOF

24/33PCAPAC 2016



Fresnel Zone Plates– DOF: (X,S,Z,Rx,Rz)– Static positioning stability (8h)– Nanometric- precision– Millimeter- range

Sample Stage– DOF: (X,S,Z,Rz)– Static positioning stability (8h)– Dynamic Positioning stability (Flyscan)– Nanometric- precision– Millimeter- range

25/33PCAPAC 2016


Passive environment stability– Temperature: 1mK difference ~1nm difference– Vibration

Stage Stacking when possible– Modular design

• Simple construction & parts interchangeable• Individually characterize each stage before mounting

– More suitable than parallel structure considering range of motion– Disadvantage: Errors are additive!

Sample stage - Use ”small” Rz rotation stage– Light weight less demanding on lower stages– Disadvantage: Smaller rotation stage higher degree of

eccentricity + wobble

Nanoprobe Project – Approach & Design ChoicesNanoprobe Project – Approach & Design Choices

Passive Stability

Active Stability

Nanometer

26/33PCAPAC 2016



Ex: Sample Stage (X,S,Z,Rz) Cylindrical sample holder (yellow)

27/33PCAPAC 2016



Ex: Sample Stage (X,S,Z,Rz) Cylindrical sample holder (yellow)

28/33PCAPAC 2016



Additive errors from linear stages Rotation eccentricity + wobble

Esample = Ex + Es + Ez

Parasitic errors & in-axis errors

29/33PCAPAC 2016



Additive errors from linear stages Rotation eccentricity + wobble Feedforward Compensation – Reduce repeatable errors (Data from

stage characterization)

30/33PCAPAC 2016



Additive errors from linear stages Rotation eccentricity + wobble Feedforward Compensation – Reduce repeatable errors (Data from

stage characterization) Feedback from Interferometer – reduce all errors

31/33PCAPAC 2016


Nanoprobe Project – Control in Sample Stage/FZP StageNanoprobe Project – Control in Sample Stage/FZP Stage

Sample Stage Delta Tau Controller (with

REVOLUTION Project)– Position Compensation

(Feedforward 1D, 2D, 3D)– Interferometer Feedback– Virtual Axes (Kinematic

Equations)

FZP Stage Galil Controller (SOLEIL ControlBox)

– Control via kinematic equations in python scripts and TANGO

32/33PCAPAC 2016


Nanoprobe Project – Sample Stage Scan ResultsNanoprobe Project – Sample Stage Scan Results

Trajectory errors during 1x1 um XZ-scan: flyscan on X, stepscan on Z.

Encoder feedback, no feedforward, no interferometer feedback

33/33PCAPAC 2016




Encoder feedback, X- feedforward, no interferometer feedback

34/33PCAPAC 2016




Encoder feedback, no feedforward, XZ- interferometer feedback

35/33PCAPAC 2016


Nanoprobe Project – Sample Stage: Rotating...Nanoprobe Project – Sample Stage: Rotating...

XSZ- scans during full 360 degree rotations (30 rot)

Feedforward compensation– Performed and been able to

reduce repeatable position errors

Interferometer feedback– Performed and been able to

reduce position errors (repeatable+non-repeatible)

36/33PCAPAC 2016


Nanoprobe Project – FZP Stability ResultsNanoprobe Project – FZP Stability Results

37/33PCAPAC 2016




Insertion Devices



Conclusion

38/33PCAPAC 2016


Conclusion - Feedback/feedforward systems in SOLEILConclusion - Feedback/feedforward systems in SOLEIL

Beamline Endstation

Nanoprobe

Storage Ring

Beamline

• 2D- & 3D scans with nanometric resolution & mm- range

• Possibility of fast continuous scans with low dynamic errors.

Maintaining stable photon beam flux and position

• 2D- & 3D tomography scans with nanometric resolution & mm-range while maintaining stable photon beam flux and position

• Possibility of fast continuous scans with low dynamic errors.

Overview of Some Feedback & Control Systems at Synchrotron ...

Documents

Transcript of Overview of Some Feedback & Control Systems at Synchrotron ...