1. Alignment systems in ATLAS: Monitoring of the bedplates
ETH Zürich, 02/09/2014
Hélène Mainaud Durand

2. ATLAS

4. HLS = Hydrostatic Levelling System
Based on the principle of the communicating vessels
Free surface of a water network provides the reference frame
Fluid = demineralized water + biocide additive
Different technologies in order to measure the vertical distance to the water surface : capacitive, ultra sonic, optical

5. HLS : capacitive technology
Resolution: 0.2 μm
Range: 5mm
Repeatability: 1 μm
Based on Fogale Nanotech capacitive technology [1], they were developed for ESRF (European Synchrotron Radiation Facility) in France, in 1987, in order to perform the permanent vertical alignment of the Storage Ring. Sensors were then upgraded when used at CERN and KEK.

6. Monitoring of a large infrastructure: ATLAS with HLS

8. Monitoring of a large infrastructure: ATLAS with HLS

9. Origin of seisms perturbing HLS readings in 2005

10. Monitoring of the installation of one detector: calo barrel

11. Monitoring of the installation of calo barrel
USA C M US
BED

16. Alignment systems in LHC: Monitoring of the low beta quadrupoles
ETH Zürich, 02/09/2014
Hélène Mainaud Durand

17. Monitoring of Machine Experiment Interface
Alignment tolerances are getting increasingly tighter
Last genereation and future accelerators ask for monitoring
Most critical area of accelerator are final focus magnets
Limit exposure of personnel to radiation (ALARA)
Sensors need to be radiation hard and to resist high magnetic fields

18. System monitors the co-linearity of focusing magnets
Systems based on capacitive sensors HLS, WPS and DOM
Electronics seperated from sensors
Positioning of one inner triplet to the other at ±0.1 mm
Relative precision inside one triplet few μm level

19. HLS, WPS and DOM Sensors HLS: Monitoring a ‘large’ plane
water surface (communicating vessels)
Resolution : 0.1μm, repeatability : 1 μm
Range: 5 mm or 10 mm
WPS: Monitoring a ‘long’ direction, 2D measurements
conducting stretched wire (carbon peek)
Range: 10 mm by 10 mm
DOM: Monitoring a ‘short’ distance within
distance and calibrated invar rod
Range: 10 mm
100 mm

20. WPS and DOMS

21. Installation in LHC tunnel
Dirk MERGELKUHL

22. Motorized jacks for focus magnets
Manual adjustment is time consuming
ALARA – As Low As Reasonably Achievable
Magnets are adjustable remotely using jacks, stepper motors, reducer, angular encoders, CERN made DAQ system
Load sensors on top of jacks (magnet ~ 15 t)

23. Adjustment of final focus magnet
Short term monitoring during adjustment
Adjustment in two steps
Displacement of 220 μm wthin 5 μm (HLS+WPS)