1. Geometric and Magnetic Measurements
Juan Garcia Perez 1

2. Outline Projects Type of measurements Technologies and Instruments
LTD500
Hardware
Software
Software around Axyz: DIAX & GEAX
Practical examples
AC mole
Stretched wire
SPL cool down monitoring

3. P. Bestmann, H. Mainaud EN-MEF-SU M. Modena, P. Thonet TE-MSC-MNC
Acknowledgments
P. Bestmann, H. Mainaud EN-MEF-SU
M. Modena, P. Thonet TE-MSC-MNC
H. Prin TE-MSC-LMF
S. Russenschuck TE-MSC-MM
A. Vande Craen, W. Zak TE-MSC-CMI
C. Charrondiere EN-ICE-MTA

4. NorMa magnets (AD, LINAC4, ELENA, HIE Isolde)
Projects
NorMa magnets (AD, LINAC4, ELENA, HIE Isolde)
LHC maintenance & upgrades
CLIC
SPL (Superconducting Proton Linac)
FAIR

5. Type of measurements Cold Mass Construction
Cold bore inspection (ovalisation)
Cold bore position (geometric centre)
Alignment of the yoke roll (single aperture)
Extremities positioning
Fiducialisation
Mechanical (shimming)
Magnetic (fiducials measurement)
Alignment of magnets in the tunnel
Monitoring of cool down structures
Mapper 3D (hall sensors position)

6. Technologies and Instruments
Laser Tracker (LTD, AT 402) large range
Stretched wire (optocoupleurs) very short range
Faro/Romer arm (palpeur 3D) medium range
Feed down rotating coils and moles (FAME)
AC mole (static measurement, optic system)
Capacitive sensors
Fibre optic position sensors

7. Laser Tracker (LTD 500) - Hardware
Old LTD 500 stable situation but to be expected laser breakdowns
New AT 402 best replacement (only absolute distance meter, no interferometry, but still tracking)
Good experience in survey team
Not big difference in performance with respect to LTD 500
Price of AT 402 about 80 kSF

8. Laser Tracker (LTD 500) - Software
Axyz obsolete since years, but still working on Windows XP (not network)
Solution with PC-DMIS provided by Leica to upgrade but not optimal choice.
New package more open “Spatial Analizer”
Experience from survey team very good until now.

9. LTD 500- Software around Axyz
DIAX & GEAX. Big effort made by C. Charrondiere to migrate the package (GEAX) to PC-DMIS now finished. New library created. Not good experience to be follow by new projects, but works for old ones.
Best way to go is to move on the new product of Leica and upgrade the old facilities and base the new projects on Spatial Analyzer which is open and oriented to be used by very different systems in different environments.

10. LTD - Conclusion Use as is the old LTD’s and be ready to change
Use PC-DMIS for old applications (license)
Best choice for the future :
AT 402
Spatial Analyzer (license)
Follow the experience of survey team and get training in view of transition

11. AC mole example
Born in Old system with most of its components (hardware & software) obsolete but still working well with the old infrastructure-equipment.
Characteristics: 100 mm length coil. Centred reflector. Optical system (with CCD camera embarked) for cold bore geometry measurements and inspection.
Magnetic axis scan possible, so pitch and yaw angles available for alignment if needed. No big current needed (AC power, from few mA to 1A, 25 Hz). Magnetic angle measurement for any type of magnet.
It was able to measure the axis of LHC dipoles at cold in SM18. It measured all Short Straight Section LHC magnet assemblies automatically.
Difficult to adapt to different bore diameters. Not optimised for field quality.
New ideas & upgrade needed. For instance replace CCD and optical system with a optical fibre endoscope attached to the core of the mole (rotating ring).

12. CBT Reflector Camera 4 LEDs 4 Reflections Acquisition Image CBT
AC mole principles S2 S S1
LED
Image
LED
Image
New idea
Endoscope
Endoscope
CBT
Reflector
Camera
4 LEDs
4 Reflections
Acquisition Image
CBT
Reflector
Camera
4 LEDs
4 Reflections
Acquisition Image

13. FAME New Standard rotating coil system
Mechanics to drive and control the rotation separated
Two reflectors inside the coils shaft for magnetic centre measurement

14. Harmonics (with oscillating wire method)
Stretched wire
Integral measurement of gradient and axis (magnetic centre) by two methods:
Classical stretched wire (flux integral equality vs. movements)
Vibrating wire (no field -> no vibration)
Harmonics (with oscillating wire method)
Alignment and fiducialisation with laser tracker
More precision could be obtained from opto-coupleur support calibration (fraction of µm)
Comparison at small range (~ 1m) between Romer arm and AT402 of a measurement of ‘perfect’ model gives:
Precision AT µm
Precision Romer arm 10 µm

15. Opto-coupleur sensor

16. Single Stretched Wire

17. SPL cool down monitoring
SPL SCM Cavity position monitoring specs:
Static position or slow movements: absolute movements (x,y,z) of each of 4 cavities during steady state operation and cool-down/warm-ups (300-2 K)
Vertical range mm
Precision < 0.05 mm
Resolution < 0.01 mm
Possibly vibration measures (0-1 kHz)
Stretched wire
Opto-coupler sensors
Last cavity support

18. Mapper 3D & Laser Tracker
Monitoring of hall sensors position relies on the mechanical precision of the movement (motors and linear encoders)
It could be improved by direct measurement of the 3D coordinates (and orientation with 2 reflectors) through laser tracker detection of the position of the hall sensor
Portable laser tracker like AT402 could be a very attractive solution

19. Thank you for your attention