News from Stabilisation WG Main Beam Quadrupole Stabilisation

1. News from Stabilisation WG Main Beam Quadrupole Stabilisation News from LAPP News from CEA News from CERN K. Artoos CTC 27/07/2010

2. News from LAPP • Meeting 15th July (Andrea, Claude, Kurt) • MBQ Eigen mode analysis: http://hal.in2p3.fr/in2p3-00480244/fr/ Report: Free-free 279 Hz first bending frequency. Some uncertainties for supported MBQ (depends on boundary conditions). First bending modes around 250 Hz Pole modal measurements ongoing • Active foot : PI capacitive gauges purchased Actuators installed + tested Role and behaviour elastomer not fully understood yet First stabilisation results foreseen in September • Cross check between seismometer and MONALISA • More regular meetings LAPP/CERN planned from September on • Closer collaboration to improve “critical mass” • Decision « baseline stabilisation MBQ » for CDR ? K. Artoos CTC 27/07/2010

3. News from IRFU CEA SACLAY Purchase of SIOS Triple axis interferometer 0.1 nm resolution Borrowed device now available Measurement through 3 mm hole confirmed Preparation measurements started (mirrors etc) Final delivery in September Measurement of pole tip vibrations with respect to yoke Measurements vibrations coil and yoke water cooling Calibration actuators + hexapod Calibration tilt meters K. Artoos CTC 27/07/2010

4. News from CERN Overall approach and work plan : See CTC # 22 Talk C. Hauviller This talk: status, ongoingwork and outlook Claude Hauviller Kurt Artoos Christophe Collette Pablo Fernandez Carmona Michael Guinchard StefJanssens AndreyKuzmin Raphael Leuxe AnstenSlaathaug K. Artoos CTC 27/07/2010

5. Steps toward performance demonstration RIGID option 1. Stabilisation single d.o.f. with small weight(“membrane”) End April CERN 2010 2.5 kg Objective reached Piezo actuator ( PI™): Resolution 0.1 nm Stiffness 24 N/µm Measured vertical resonant frequency ~ 300 Hz K. Artoos IPAC10

6. Input from Pablo Fernandez Carmona: Systematic study and improvement of noise levels: Power supply seismometers Cabling to seismometer Result last week on membrane: Noise level acquisition systems Noise level output 0.6 nm at 1 Hz from 2 nm 1 nm at 1 Hz from 5 nm P. Fernandez Carmona S. Janssens C. Collette K. Artoos CTC 27/07/2010

7. « Nano-positioning » < 1 Hz Beam based feedback: BPM + corrector dipoles Or “Modify position quadrupole in between pulses (~ 5 ms) “ “Range 10 μm, steps 10 to 50 nm, precision 2nm ” Demonstration nano-positioning single d.o.f. : 10 nm, 50 Hz Measured with capacitive gauge 0.1 nm resolution open loop Remark: Measuring < 0.1 nm relative displacement For FREE Catalogue products S. Janssens K. Artoos IPAC10

8. Steps toward performance demonstration RIGID option 2. Stabilisation single d.o.f. with type 1 weight (“tripod”) 2 rigid feet actuator 100 kg S. Janssens Preliminary result in noisy environment No flexural guide yet so can be improved Expected 30 nm at 50 Hz

9. Requirements for the actuating support Natural frequencies > 200 Hz • Stiff • Degrees of freedom: 6 d.o.f. ? • Precise Parallel structure • 0.1 nm resolution vertical • Precision and repeatability 1 – 2 nm Piezo actuators Flexural hinges instead of rotary joints G PI P-225.10 Blocking force 12.5 kN G Stiffness 480 N/μm * G Resolution 0.15 nm G Integrated sensor 0.3 nm Concept drawing K. Artoos IPAC10

10. Design 2 d.o.f. flexuralhinge K axial : ~ 300 N/μm K α : ~ 200 Nm/rad FE model with parameters available Induced stresses in piezo Structural stiffness Difficulty assembly Number and orientation of legs Resolution, structure stiffness, forces Inclination # D.O.F. , COST Resonant frequency Number K. Artoos IPAC10

11. Steps toward performance demonstration RIGID option 3.Stabilisation two d.o.f. with type 1 weight (“tripod”) Test assembly done, this week assembly with real actuators K. Artoos CTC 27/07/2010

12. Block longitudinal Actuator pairs in same plane X- Y guidance Block Roll y v Video modes singularity K. Artoos IPAC10

13. Design x-y guide: status Concept: hyperguided table with 8 flexural beams Type 1 Designing for a low x-y rigidity and high longitudinal and torsional rigidity K. Artoos CTC 27/07/2010

14. Additionalfunctions x-y guide: • Add a direct measurement of the x-y displacement • with respect to intermediateplatform • To replace instrumentation in legs • Has a zero position (reference mark on grating) ! • Sensitivityand noise leveldoes not change with position (unlike capacitive gauges) • Lessstrict alignmentrequirementssensor • Couldbecomelowcost for large serie LIP 281 Linear encoder 1 nm/TTL • Introduce the possibility to protectpiezoactuatorsduring transport • Shouldmakeit possible to reduce the number of actuators. • The x-y guides canbebuilttogether to form a girderaround the magnet as the intermediateplatformbetweenalignment and stabilisation K. Artoos CTC 27/07/2010

15. Stiffness other components: magnet and support Ground broadband excitation amplified at support and magnet resonances • Beam height reduced to 620 mm • Alignment with Eccentric cams at Airy points • Stabilisation actuator pairs above cams Alignment : Eccentric cams. First prototype based on SLS (PSI) F. Lackner K. Artoos IPAC10

16. Steps toward performance demonstration RIGID option 4.Stabilisation two d.o.f. with type 4 weight Type 2 to type 4 willbe an extension/duplicate of type 1. Price enquiry for 6 actuatorsbeingprepared. Toolate for CDR draft end september. K. Artoos CTC 27/07/2010

17. Christophe Collette Stabilisation control strategy Stef Janssens Ongoingwork: Comparisondifferent control/sensorstrategies Contact with seismometer companies to produce a « inertial reference mass » to replace the broadband seismometers or to remove their inconveniences To be presented in September ISMA conference + ref. MEDSI presentation 2010 Force sensing methods at higher frequencies Improvementstability + increase the performance Controller for 2 degrees of freedom for stabilisation and nanopositioning. Model for 6 degrees of freedom type 4 for interaction with BBF. Publication in Physical Review, special topics: accelerator and beam. K. Artoos CTC 27/07/2010

18. C. Collette MEDSI

19. Sensorcharacterisation: Ongoing: « Bungee table » for noise characterisationseismometers Characterisation and research noise and sensitivityseismicaccelerometers, low noise amplifiers, Conditionners,… AnstenSlaathaug Michael Guinchard K. Artoos CTC 27/07/2010

20. Vibration source characterisation: Michael Guinchard AnstenSlaathaug Ongoing: • Ground excitation by shaker with a knownfrequency/spectrum and amplitude and propagation measurement in differentfloors. • Plannedmeasurements surface CMS for final focus • Plannedmeasurements of efficiency passive dampingsystems for pumps etc. • As soon as MBQ prototype isavailablewecan do measurementswith water cooling: vibrometer + LASER interferometerwillbeavailable. • Possibility to do vibration measurements for module, but MeasurementLabhighlyloadedwithother CERN projects: ressource critical. K. Artoos CTC 27/07/2010

21. Conclusions Steadyprogress on stepstowardsdemonstration of feasibility. Not at the same pace as CDR. Importance to have convincing intermediate steps. The schedule is not always in our hands + too many CLIC meetings… (?) The team put in place begins to pay off, important to keepcontinuity long enough (WP). It would help to have a dedicatedworkspaceas canbefound in other places doingthiskind of work: temperature stable, low vibration back ground, « clean » electrical network, cooling water network, lifting and handling,…. *** K. Artoos CTC 27/07/2010