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CLIC Meeting April 9, 2010

Stabilization of the quadrupoles of the main linac One of the CLIC feasibility issues C. Hauviller/ EN. CLIC Meeting April 9, 2010. CLIC stabilization requirements. Mechanical stabilization requirements: Quadrupole magnetic axis vibration tolerances:

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CLIC Meeting April 9, 2010

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  1. Stabilization of the quadrupoles of the main linac One of the CLIC feasibility issuesC. Hauviller/ EN CLIC Meeting April 9, 2010

  2. CLIC stabilization requirements • Mechanical stabilization requirements: Quadrupole magnetic axis vibration tolerances: • Main beam quadrupoles to be mechanically stabilized: • A total of about 4000 main beam quadrupoles • 4 types: Type 1 (~ 100 kg), 2, 3 and 4 (~400 kg) • Magnetic length from 350 mm to 1850 mm • Mechanical stabilization might be On at some quads and Off of some others C. Hauviller

  3. How to measure the performances? Compute the integrated r.m.s. displacement at n Herz from the measured PSD (Power Spectral Density) C. Hauviller

  4. Previous performances on stabilization C. Montag, DESY 1996 S. Redaelli, CERN 2004 J. Frisch, SLAC 2001 B. Bolzon, LAPP 2007 C. Hauviller

  5. Mock-up built in 2004 (S. Redaelli) Test set-up used by S. Raedelli

  6. Performance at CERN Stabilisation single d.o.f. with small weight(“membrane”) This is a marble, not a TMC table... 1.2 nm C. Hauviller

  7. C. Hauviller

  8. C. Hauviller

  9. Remarks • Active vibration control is not yet a mature technology. • Activity should be defined as R&D but with CLIC engineering as objective. • It will take time to achieve the final objective but a work plan has been agreed in March 2008 with CDR as an important milestone • Most of the collaborators have background on vibrations but not on the specific field of stabilization. C. Hauviller

  10. Approach • Competency center: understand the subject in depth • Build a knowledgeable team • Use the existing know-how spread in many places: • Previous theses ( in particular Montag, Redaelli, Bolzon,…) • Work done in the labs: Low emittance Light sources, FEL, ILC,… • Work (mainly) in the universities on lithography, satellites and radiotelescopes • Apply to realistic mock-up(s) • Create a reference web site: http://clic-study.web.cern.ch/CLIC-Study/CLIC_Stabilisation/Index.htm C. Hauviller

  11. Precision versus size C. Hauviller

  12. Contents • R & D Actions • Sensors • Characterize vibrations/environmental noise • Actuators • Feedback • Test mock-ups • Integrate and apply to CLIC • CDR and TDR • The team C. Hauviller

  13. Sensors Program of work • State of the art of sensor development and performances (updated on a yearly basis) • Calibrate by comparison. • Interferometer to calibrate other sensors • Create a reference test set-up (at CERN) • Qualification with respect to accelerator environment (EMC, radiation,…) C. Hauviller

  14. State of the art of ground motion sensors Table of Contents • Characteristics • Sensor noise • Noise sources • Noise detection • Sensitivity • Resolution • Sensor types • Geophone • Accelerometer • Feedback seismometer • Capacitive distancemeter • Stretched wire system • Other sensor • Comparison C. Hauviller

  15. Streckeisen STS2 Guralp CMG 3T Guralp CMG 40T Guralp CMG 6T Eentec SP500 PCB 393B31 x,y,z x,y,z x,y,z z z x,y,z 2*1000Vs/m 30s-80Hz electrochemical 2*750Vs/m 2*750Vs/m 2*800Vs/m 2000Vs/m 1.02Vs2/m 120 s -50 Hz 360s -50 Hz 30 s -50 Hz 60 s -70 Hz 10 s -300 Hz 13 kg 13.5 kg 7.5 kg 0.750 kg 0.635 kg Improved performances Lab environment How to measure nanometers and picometers ? Catalogue products • Absolute velocity/acceleration measurements • Seismometers (geophones) • Accelerometers (seismic - piezo) Sensors

  16. Sensors • Relative displacement/velocity • Capacitive gauges : Best resolution 10 pm (PI) , 0 Hz to several kHz • Linear encoders : Best resolution 1 nm (Heidenhain) • Vibrometers (Polytec) ~1nm at 15 Hz • Interferometers • Industrial products (SIOS, Renishaw, Attocube) <1 nm at 1 Hz • (CEA-IRFU) • Low cost “Optical transducer” under development <1nm at 1Hz Compact Straightness Monitor MONALISA atOxford C. Hauviller

  17. Sensors Characterisation commercial devices by comparison Reference test bench Low technical noise lab TT1 (< 2 nm rms 1Hz) Instrument Noise determination C. Hauviller K. Artoos, CLIC-ACE5 03.02.2010

  18. Sensors Characterization for low intensity signals: Which sensor? Quality of its measurement? • Sensitivity + resolution • Cross axis sensitivity • Noise level, « self noise » measurement (ex. blocking the seismic mass or by coherence) • Measuring procedure (influence of the environment) • Signal processing: Resolution, filtering, window, FFT, DSP, • integration, coherence Noise determination by comparison 2 geophones and 2 accelerometers C. Hauviller

  19. Sensors Optical STS-1 GURALP T6D PSD ENDEVCO PCB • Slaathaug • M. Guinchard Guralp : Noise @ 0.1 Hz (catalog) PCB: Noise @ ~10 Hz Endevco+Amplifier: Noise @ ~2 Hz C. Hauviller

  20. Sensors • Present choice: • Guralp T6D seismic Geophone • 0.3-0.4 nm Integrated RMS noise @ 1 Hz • But • sensitive to magnetic field • sensitive to radiation • large dimensions (~ proportional to sensitivity) • Eentec SP500electro chemical seismometer • radiation and magnetic field hard • But • found unstable with time • In the future: • Adapt existing device or develop new ones? • e.g. Michelson interferometer SIOS used for pole tips measurements could be used as reference sensor? C. Hauviller

  21. LEP ground motion during 1 year 300 µm – 1 mm Ground motion due to Lunar cycle (tides) Several µm 7 sec hum 100 nm, CLEX 10 nm, CLEX Accelerometers Cultural noise Geophones Acoustic noise becomes very important Characterize vibrations/environmental noiseEnvironmental vibration levels – orders of magnitude, CERN site Alignment Required vertical stability for all main linac quads for CLIC: 1 nm Required vertical stability for Final Focus quads for CLIC: 0.1 nm Correction with beam-based feedback Mechanical stability of main beam quadrupoles “Slow” motion “Fast” motion C. Hauviller

  22. Characterize vibrations/environmental noise What level of vibrations can be expected on the ground? Several measurement campaigns: LAPP, DESY, CERN.... LHC PSI Effort continued by CERN in 2009 CesrTA AEGIS CLEX CMS Metrology Lab 2009 Lab TT1 M. Sylte, M. Guinchard C. Hauviller

  23. 1nm 5nm 2 nm Vertical Measured on the floor Lateral C. Hauviller M. Sylte, M. Guinchard

  24. Measurements in the LHC tunnel LHC DCUM 1000 ~ 80 m under ground LHC systems in operation, night time Floor building 180 Building 180 Surface No technical systems in operation, night time C. Hauviller

  25. Measurements in the LHC tunnel PSD of all the measurement points (vertical) Technical noise increases next to the experimental hall C. Hauviller

  26. Characterize vibrations/environmental noise Correlation over long distances in LHC tunnel Coherence using a theoretical model (ATL law) Calculated from measurements (2008) C. Hauviller

  27. Characterize vibrations/environmental noise Measurements in the LHC tunnel Ground motion modelling + technical noise modelling Former work A. Seryi, B. Bolzon • Update of 2D power spectral density for LHC tunnel in the vertical and lateral direction • Vertical and lateral models of the technical noise Ref. C. Collette “Description of ground motion” ILC-CLIC LET Beam Dynamics WS 2009 • Reference curves, technical noise Models available integrated in models for stabilisation and BBF Need to characterize precisely the vibration sources C. Hauviller

  28. Characterize vibrations/environmental noise Vertical ground motion Additional technical noise: Reference Reference Ref. : C. Hauviller 28 28

  29. Actuators Program of work • State of art of actuators development and performances (updated on a yearly basis) • Develop and test various damping techniques (passive and active) C. Hauviller

  30. State of art of actuators Table of Contents • Introduction and requirements • Comparison of actuator principles • Different actuators • Piezo electric actuators • Electro-magnetic actuators • Magneto striction • Electro-static plates • Shape memory alloys • Scaling laws • Design of actuators for sub nanometer positioning • Hysteresis free guidance • Non contact direct metrology • X-Y kinematics • Trajectory control and dynamic accuracy + resolution considerations • Limitations • Different configurations of piezo based actuators • Providers of nano actuators and vibration isolation • Nano positioning applications • Bench mark projects • References C. Hauviller

  31. Actuators First selection parameter: Sub nanometre resolution and precision Actuator mechanisms with moving parts and friction excluded (not better than 0.1 μm, hysteresis) Solid state mechanics + Well established - Fragile (no tensile or shear forces), depolarisation Piezo electric materials High rigidity • Rare product, magnetic field, stiffness < piezo, • force density < piezo+ No depolarisation, symmetric push-pull Magneto Strictive materials Risk of break through, best results with μm gaps, small force density, complicated for multi d.o.f. not commercial Electrostatic plates No rigidity, ideal for soft supports Electro magnetic (voice coils) Heat generation, influence from stray magnetic fields for nm resolution Shape Memory alloys Slow, very non linear and high hysteresis, low rigidity, only traction Electro active polymers Slow, not commercial C. Hauviller 31

  32. Selection of piezo actuators Resolution 0.1 nm Positioning and/or stabilisation Range 30 μm Resonance frequency and rigidity As high as possible Up to 100Kg Prestress Force/load capacity (< 20 % mechanical limit) 20 MPa for dynamic behaviour Weight compensating spring, reduces range Assembly Dimensions HVPZT or LVPZT Required power, frequency range controller C. Hauviller 32

  33. Actuators • An example of the integration of piezo actuators PZT in an actual support • - Use of flexural guides against shear forces • - Use of a feedback capacitive sensor 0.1 nm 100 N Calibration bench flexural guides Techniques to be applied for heavier (up to 400Kg) and larger structures (up to 2 meter long)

  34. Feedback Program of work • Develop methodology to tackle with multi degrees of freedom (large frequency range, multi-elements) LAViSTa demonstrated feasibility on models Similar problems elsewhere like the adaptative optics of the European ELT • Apply software to various combinations of sensors/actuators and improve resolution (noise level) High quality acquisition systems at LAViSTa and CERN C. Hauviller

  35. Stabilization strategies C. Hauviller

  36. FeedbackSimilar in size: the ELT project 2952 actuators 5604 sensors A. PREUMONT et al. (Presented to the Smart09 - July 2009) C. Hauviller

  37. How to support the quadrupoles? Comparison control laws and former stabilisation experiments … C. Hauviller

  38. How to support the quadrupoles?  Soft versus rigid ? Soft:+ Isolation in large bandwidth Rigid:- High resolution required actuators But available in piezo catalogues -But more sensitive to external forces + Robust against external forces -Elastomers and radiation + Nano positioning External forces: vacuum, power leads, cabling, water cooling, interconnects, acoustic pressure,…. C. Hauviller

  39. How to support the quadrupoles? Robustness to external force (compliance) C. Hauviller

  40. How to support the quadrupoles? Decision to study two options in parallel: • LAPP option: soft support • CERN option: rigid support C. Hauviller

  41. Option LAPP: Soft support and active vibration control 3 d.o.f. Elastomeric joint • Poles are bolted on supports Actuators positions C. Hauviller

  42. Option LAPP: Status: Construction + tests on elastomer C. Hauviller

  43. Test Mock-ups (CERN) Rigid support and active vibration control (up to 6 dof) • Stabilisation single d.o.f. with small weight (membrane) • Program going on with further improvements 2. Tripod with weight type 1 MBQ with 1 active leg Presently under tests 3. Tripod type 1 MBQ with 3 active legs Inclined leg with flexural joints Two inclined legs with flexural joints Add spring guidance Test equivalent load per leg 4. MOCK-UP Type 4 MBQ on hexapod C. Hauviller

  44. Test Mock-ups (CERN) 1. Stabilisation single d.o.f. with small weight (“membrane”) Theory vs measurement: Transfer function Measurement better< 2 Hz Phase Diff. > 40 Hz Model is good representation 2-40 Hz Differences between theory and Measurements are under investigation C. Hauviller

  45. Test Mock-ups (CERN) 1. Stabilisation single d.o.f. with small weight (“membrane”) Bonus:possibility to nano position the Quadrupole Ref. D. Schulte CLIC-ACE4 : “Fine quadrupole motion” “Modify position quadrupole in between pulses (~ 5 ms) “ “Range 20 μm, precision 2nm » Demonstration nano positioning : S. Janssens open loop Measured with PI capacitive gauge 10 nm, 50 Hz For FREE C. Hauviller

  46. Signal acquisition: the present limitsTo be overcome! • The amplitude of the ground vibrations reduces with frequency. Above some frequency, the participation to the rms integrated value becomes negligible. • The measurement in the quieter zone (TT1) was carried out with an analyzer with a resolution of 24 bit on ± 10 mV. The amplitude of 10 pm at 20 Hz for instance corresponds to voltage amplitude of 2.5 microvolt. To recognize a sine wave we should need at least some points over its amplitude, so we need to be able to measure about 0.1 microvolt on a signal amplitude of about 10 mV. • The signal to noise ratio becomes near to 1 above 10 Hz. Any amplification or ADC should have very low noise. C. Hauviller

  47. Test Mock-ups (CERN) 2. Stabilisation single d.o.f. with type 1 weight (“tripod”) 2 passive feet actuator Tripod 50 kg mass (proportional type 1) Piezo actuator 2 passive feet Feedforward Geophone Feedback Geophone Controller in Labview • Optimise controller design (Tuning, Combine feedback with feedforward) • Improve resolution (actuator, DAQ) • Avoid low frequency resonances in structure and contacts • Noise budget on each step, ADC and DAC noise C. Hauviller

  48. Test Mock-ups (CERN) 2. Stabilisation single d.o.f. with type 1 weight(“tripod”) 2 passive feet actuator S. Janssens Preliminary result First results Feedback @ 10Hz tf ~0.5 Simulation done with transfer function for tt1 -> Close to 1nm up to ~ 1.5 Hz Computer model is being built Expected C. Hauviller

  49. Test Mock-ups (CERN) 3.Stabilisation two d.o.f. with type 1 quadrupole weight (“tripod”) 3a. Inclined leg with flexural joints Status: Launch first prototype flexural hinges 3b. Two inclined legs with flexural joints y x 3c. Add a spring guidance Load compensation (Status: start design) Precision guidance Reduce degrees of freedom Reduce stress on piezo 3d. Test equivalent load/leg C. Hauviller

  50. Test Mock-ups (CERN) 4. Stabilisation of type 4 (and type 1)CLIC MB quadrupole proto type • Lessons learnt step 1 to 3 • Results Tests 1 to 3 • Cost analysis • (number of legs= cost driver) Design for the 4 types • # degrees of freedom • Stress and dynamic analysis • Range nano-positioning • Resolution C. Hauviller

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