Nano stabilisation studies for CLIC Overview and status 27/01/2009 Prepared by F. Lackner, K. Artoos

Instrumentation Nanometer reference bench Nanometer reference bench : Characterisation seismic accelerometer Piezo actuator PI : 100N, 25 μm range, 0.1 nm precision capacitive gauge PI 0.1 nm precision (calibrated) Closed loop operation Single membrane flexural guide Tested with Polytec OFV-505 vibrometer Tested with PCB, ENDEVCO 86 seismic accelerometers Measurements: Logarithmic sine sweep (128 s, 0.1 Hz to 100 Hz) Sine fixed frequency, different duration (# averages) 4 seconds FFT block size Test flexural guide + planned improvement

Instrumentation 50 averages (~20 minutes)

Instrumentation Logarithmic sine sweep

Instrumentation Four sec FFT block size How close can we approach time domain (no averaging)? Repeat measurements in noise free place + improve vibrometer support

Instrumentation Next steps reference bench Increase spurious frequencies to be able to measure broadband seismometers Rigid support for vibrometer Repeat tests in low noise environment Place found at CERN Close the loop with new PXI RT hardware Results for next meeting

Instrumentation Different studies ongoing to improve seismic geophones Most interesting: optical systems with quadrature techniques 2004 Since then interferometers are improving rapidly Optical STS-1

Instrumentation Another example from 2008 Optical heterodyne laser encoder with sub-nanometer resolution Chyan-ChyiWu, Cheng-Chih Hsu, Ju-Yi Lee, Hui-Yu Chen and Ching-Liang Dai Meas. Science and Technology 19 (2008) 045305 (8pp) Link to articles will go on website

System Magnet: see afternoon Support (and girder?) and Alignment Tests and simulations alignment system CTF2 MQ alignment system (F. Lackner) PSI mini workshop 4th December 2008 on Girder, component support and alignment design http://fel.web.psi.ch/public/workshop/Girder04.12.08/agendaGW.htm

Analysing the CTF2 support: Plastic deformation on used supports - Entire force transducer not fixed in the longitudinal direction Broken fixation plates - 1mm of axial clearance on the hybrid motor Broken linear roller bearings Further work: Collaboration with midi igénierie, new controller and one state of the art Mialp received for further tests. Bearing points and flexural joints studied in order to reduce mechanical friction and bearing internal clearances. Progress: Will improve stiffness & damping behavior Better understanding of operating Mialp actuators with higher precision. Bearing points and flexural joints Mialp could reach a proposed 10nm resolution after all improvements F. Lackner

Modal analysis on CTF2 setup and the Mialp stepper motor: 1mm clearance Mialp hyprid stepper motor Resolution: 2µm Stroke: 11mm Maximal axial Force: 400N Speed (max): 0.4mm/s 1mm clearance Clamped in longitudinal direction during modal test. Clearance ration of the entire support: ~ 1mm F. Lackner

Mialp modal Analysis using ANSYS: Mode Frequency [Hz] 1. 209.46 2. 210.88 3. 277.14 4. 789.88 5. 791.35 6. 1947.9 1st mode 209 Hz Longitudinal, lateral Found frequencies Simple rigid body model explains the anyway small offset to the measured Mialp. The model does not include details on motor, spindle and bearings. 3rd mode 277 Hz Torsion Frequency [Hz] Animation 1st mode F. Lackner 12

Result Modal Analysis of the Mialp actuator (M. Guinchard): Complete CTF2 set-up: not an elastic structure and not rigid, modal analysis difficult

Reaching µm precision using steppers: Improvement could be done by the implementation of a flexural hinge: Spring force reduces the weight on the actuator as well as a small amount of the internal clearances . Flexural hinge could be realized as thin wall framework next to the stepper motor, would reduce a high amount contact based clearances . Self weight reduction by implementing a spring preload Principle: Flexural hinge frame work to reduce clearances F. Lackner Mialp micro actuator could reach a resolution of about 10nm

System PSI mini workshop 4th December 2008 Girder, component support and alignment design PSI XFEL design New collaboration: CERN to participate in qualification girder support and girder material SLS and DIAMOND Alignment and support system TPS support system Soleil support system Existing experience on micrometer alignment system and supports SLS, SOLEIL, SSRF, NSRRC, ESRF, DIAMOND,... http://clic-stability.web.cern.ch/clic-stability/Alignment_Support_Girder.htm

Proposal for Mockup studies: 16 Reminder Friedrich Lackner, October 16th , 2008 Proposal for Mockup studies: Y Concrete X Z Stabilization System Pre-alignment system Idea: Increasing the stiffness for a stabilization system by clamping the pre-alignment system to concrete support (applying clamping force in non critical Z direction).

System Girder, component support and alignment design SLS: 2 micrometer resolution on ± 2.5 mm Diamond: micrometer resolution on ± 5 mm

System Girder, component support and alignment design NSRRC TPS 6 ball on groove contact (rolling contact) Springs to reduce load on alignment, straighten girder + possibility to add damping Ongoing developments and existing set ups with resolution and range very similar to CLIC + increased natural frequencies

System SOLEIL support + Locking of alignment Locking increases the frequencies to above 45 Hz Springs to decrease load on alignment system Supports GLUED to floor

System Lessons from light sources: Push first resonant frequencies up by making contacts (glued), supports and components rigid. Locking of the structure after alignment At higher frequencies the amplitude of ground excitation is smaller + resulting deformations are smaller The required dynamic range of the stabilisation system also becomes smaller The use of concrete or mineral casts can give rigid but lighter and well damped structures Combining damping and rigid supports is possible by making the support hyperstatic + spring supports can reduce the load on the alignment system

Stabilisation actuator under design Mock-up design : afternoon Thank you