Geometric and Magnetic Measurements Juan Garcia Perez 06.03.2014 1

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

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

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

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)

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

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

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.

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.

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

AC mole example Born in 2000. 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).

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

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

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 402 5 µm Precision Romer arm 10 µm

Opto-coupleur sensor

Single Stretched Wire

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 0-2 mm Precision < 0.05 mm Resolution < 0.01 mm Possibly vibration measures (0-1 kHz) Stretched wire Opto-coupler sensors Last cavity support

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

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