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