Stabilization of the quadrupoles of the main linacOne of the CLIC feasibility issuesC. Hauviller/ EN CLIC Meeting April 9, 2010 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 Final Focus quadrupoles Main beam quadrupoles Vertical 0.1 nm > 4 Hz 1 nm > 1 Hz Horizontal 5 nm > 4 Hz 5 nm > 1 Hz CLICMeeting100409 C. Hauviller How to measure the performances?
Compute the integrated r.m.s. displacement at n Herz from the measured PSD (Power Spectral Density) Random vibrations (exact term) >> P.S.D.Observation: the level goes down with frequency The summing from infinite frequency down to 1 Hz. Practically we see that from some upper limit the participation can be neglected CLICMeeting100409 C. Hauviller 3 Previous performances on stabilization
C. Montag, DESY 1996 S. Redaelli, CERN 2004 J. Frisch, SLAC 2001 B. Bolzon, LAPP 2007 CLICMeeting100409 C. Hauviller Mock-up built in 2004 (S. Redaelli)
Test set-up used by S. Raedelli Performance at CERN Stabilisation single d.o.f. with small weight(membrane) 1.2 nm This is a marble, not a TMC table... CLICMeeting100409 C. Hauviller 6 CLICMeeting100409 C. Hauviller CLICMeeting100409 C. Hauviller 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. CLICMeeting100409 C. Hauviller 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: CLICMeeting100409 C. Hauviller Precision versus size CLICMeeting100409 C. Hauviller Contents R & D Actions Integrate and apply to CLIC The team Sensors
Characterize vibrations/environmental noise Actuators Feedback Test mock-ups Integrate and apply to CLIC CDR and TDR The team CLICMeeting100409 C. Hauviller 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,) CLICMeeting100409 C. Hauviller 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 CLICMeeting100409 C. Hauviller Sensors How to measure nanometers and picometers ? Catalogue products
Absolute velocity/acceleration measurements Seismometers (geophones) Accelerometers (seismic - piezo) Streckeisen STS2 Guralp CMG 3T CMG 40T 2*750Vs/m 2*800Vs/m 30 s -50 Hz 120 s -50 Hz 360s -50 Hz x,y,z 13 kg 13.5 kg 7.5 kg Eentec SP500 PCB 393B31 2000Vs/m 60 s -70 Hz 1.02Vs2/m z 10 s -300 Hz 0.750 kg 0.635 kg electrochemical CMG 6T 2*1000Vs/m 30s-80Hz Improved performances Lab environment 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) Close to 1nm up to ~ 1.5 Hz Computer model is being built Expected CLICMeeting100409 C. Hauviller 48 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 CLICMeeting100409 C. Hauviller 49 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 CLICMeeting100409 C. Hauviller 50 Apply to CLIC Program of work (as defined in March 2008)
Linac (a demonstrator mock-up will be built) Compatibility of linac supporting system with stabilization (including mechanical design): eigenfrequencies, coupling between girders, coupling of mechanical feedback with beam dynamics feedback, Design of quadrupole (we have to stabilize the magnetic axis) mock-up will have real physical dimensions and all mechanical characteristics but not the field quality required by CLIC CLICMeeting100409 C. Hauviller MB quadrupole Mock-up Module type 4
Overall integration + Liaison with MWG: Artoos Magnet: Modena Modal calculations and poles: Deleglise Stabilisation: see Options Pre-alignment with cams: Lackner Damped floor To be studied Independent measurements: Urner, Fontaine CLICMeeting100409 C. Hauviller A.Jeremie, C.Hauviller September 22, 2009 Main Beam Mock-up Functionalities Parts / Measuring devices
Demonstrate stabilization in operation: Magnet powered, Cooling operating Configurations 1- Stand-alone 2- Integrated in Module 3- Interconnected Accelerator environment Parts / Measuring devices Floor (damping material) Support Pre-alignment Stabilization Magnet Vacuum chamber and BPM Independent measurement CLICMeeting100409 C. Hauviller Main Beam Mock-up Compatibility between functionalities?
Stabilization is better achieved with a rigid support Adjustable re-alignment needs a flexible support To minimize the incompatibility, fix on a rigid ground, minimize the beam height, design rigid movers, rigid girder, magnet with high first eigenfrequency: a challenge! CLICMeeting100409 C. Hauviller Dynamic analysis Lessons learnt from light sources:
Vibrations on the ground Result on magnet Transmissibilty Broadband excitation with decreasing amplitude with increasing frequency. Amplification at resonances Lessons learnt from light sources: Alignment system as rigid as possible Increase natural frequencies ALL components + optionally locking of alignment Maximise rigidity Minimise weight (opposed to thermal stability) Minimise beam height (frequency and Abb error) Optimise support positions CLICMeeting100409 Increase damping C. Hauviller MB quad alignment with excentric cams 55 Main beam quadrupole Under manufacturing
Plain material (incompatible with corrector magnet) Assembly methods to be tested (accuracy of some microns!) CLICMeeting100409 C. Hauviller CLICMeeting100409 C. Hauviller Upgraded in NSRRC 32 Hz for 10 tons CLICMeeting100409 C. Hauviller What should be avoided Avoid flexible floor (damping mass?)
Minimize technical noise: silent pumps, slow speed ventilation, CLICMeeting100409 C. Hauviller Organisation CLIC Stabilisation Working Group (started 2008) Mandate:
(Chairman: C.Hauviller) Collaboration and exchanged information with: IRFU/SIS MONALISA Meetings every 3 months (Stabilization days) Mandate: Demonstrate 1 nm quadrupoles stability above 1 Hz (Linac), in an accelerator environment, with realistic equipment, verify with independent method Demonstrate or provide evidence of 0.1 nm stability above 4 Hz (Final Focus) Characterize vibrations/noise sources in an accelerator Compatibility with pre-alignment STABWG MDI CLICMeeting100409 C. Hauviller 60 CERN- EN LAPP LaViSta CEA-IRFU-SIS OXFORD-MONALISA Claude Hauviller
Kurt Artoos Christophe Collette (fellow) Stef Janssens (PhD student) supervisor Prof. A. Preumont Pablo Fernandez (fellow) Michael Guinchard (Mechanical measurements lab) Andrey Kuzmin Ansten Slaathaug (Technical student) follows up Magnus Sylte Raphael Leuxe LAPP LaViSta LAPP: A. Jeremie, L. Brunetti, G. Deleglise, L. Pacquet, G. Balik SYMME: J. Lottin, R. LeBreton (Phd student) A. Badel, B. Caron CEA-IRFU-SIS F.Ardellier-Desages, M. Fontaine, N. Pedrol Margaley IRFU/SIS OXFORD-MONALISA D. Urner, P. Coe, A. Reichold, M. Warden MONALISA CLICMeeting100409 C. Hauviller 61 When 1nm at 1Hz will be achieved?
CLICMeeting100409 C. Hauviller