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

2. 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

3. Instrumentation
50 averages (~20 minutes)

4. Instrumentation
Logarithmic sine sweep

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

6. 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

7. 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

8. 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) (8pp)
Link to articles will go on website

9. 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

10. 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

11. 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

12. 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

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

14. 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

15. 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,...

16. 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).

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

18. 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

19. 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

20. 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

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