1. Short range alignment strategy in CLEX and first results CLIC Workshop 2015 26-30 January 2015 on behalf of : Hélène Mainaud-Durand, Mateusz Sosin Mathieu Duquenne Vivien RUDE Contents : CLIC alignment requirements CLEX area Alignment strategy Results

2. CLIC alignment requirements Table 1: CLIC alignment requirements.  Components need to be pre-aligned  Strategy: Fiducialisation of components and girders Initial alignment of the components on the girders  Mateusz Sosin’s presentation Determination of the position of the girder axes in the global coordinate system Adjustment of the position of the girders thanks to actuators To achieve ultra-low emittance and nanometer beam size

3. CLEX CALIFE TBTS TBL X (longitudinal) Y (radial) Z (vertical) Drive Beam Main Beam Module T0 (CLIC) Drive Beam : 2 PETS 2 Drive Beam Quads 2 BPM Main Beam : 2 Superstructures 2 Module T0 (CLIC)

4. Dmitry Gudkov Module T0 Drive Beam Main Beam Goal : Alignment of girder axes (module T0) in the general coordinate system (R CLEX) in real time and remotely with an accuracy of few microns CLEX Drive Beam : 2 PETS 2 Drive Beam Quads 2 BPM Drive Beam Girder Main Beam : 2 Superstructures Main Beam Girder 3

5. Mateusz Sosin Motorization Each girder is equipped with two side interfaces called Master and Slave cradles. Motorization is installed on the Master cradle (3 Degrees of freedom). The Slave cradle is driven by the adjacent girder (ball joint) thanks to the articulation Point (+ 2 Degrees of freedom). Vertical actuator Radial actuator Connection joint 4

6. Fiducialisation x y z C1 C2 x y z 5

7. cWPS (capacitive Wire Positioning System) Variation vertical (mm) In order to align these girders, a straight reference will be used. The stretched wires measured by WPS sensors areactually one of the most accurate systems. cWPS sensors : Range : +/- 5 mm Long term Stability : < 1 μm / 15 days Repeatability system: +/- 1 μm Precision : 1 μm Linearity : 2 μm/mm  Relative calibration Accuracy : 5 μm  Absolute calibration Resolution : << 1 μm Cone Plan Slot 6

8. Sensor Coordinate system Centering Coordinate system Component Coordinate system CLEX Coordinate system Calibration CMM measurement Absolute calculation Coordinates systems Transformation : FROM Component system TO CLEX system Modeling the straight reference (Wires) x y z C1 C2 X Y Z 7

9. A B Horizontal model: Longitudinal (X) Radial (Y) D ΔYΔY M l A B Longitudinal (X) Vertical (Z) D M Vertical model : f l ΔZΔZ The wires, projected on an horizontal plan, are considered as straight lines. The wires are modeled by a catenary and can be approximated by a second order polynomial. (Freddy Becker, Hélène Mainaud-Durand, Thomas Touzé) Modeling of the stretched wires Linear mass Tension 8 Linear function

10. Transformation of Coordinates systems x y z 1 2 3 4 X Y Z Linearization of the rotating matrix (θx, θy, θz <1 mrad) C1 C2 9

11. X Y Z x y z 1 2 3 4 A ΔYΔY Modeling of stretched wiresTransformation of Coordinates system B Observation equation D C1 C2 l 4 unknowns / wire5 unknowns / component 2 observations/sensor 10

12. Method of least squares and results Method to determine the values of the unknowns Principle : Minimize the sum of the squared residuals Unknowns : 13 Observations : 16 A priori accuracy of cWPS : 5 μm Results : Conclusion : There are some mistakes on the observations 11

13. Link girder-cradles : Measurement  Deformation of these links since the CMM measurement x y z Fiducialisation between the cradles and the girder Roll higher than 200 microradians; Radial and vertical translations higher than 50 microns. Fiducialisation in-situ 12

14. Results Unknowns : 13 Observations : 16 A priori accuracy of cWPS : 5 μm Results with new fiducialisation : Precision of the position of the girder in the general coordinate system 12 μm in radial / 17 μm in vertical X (longitudinal) Y (radial) Z (vertical) DB MB 13

15. CLEX CALIFE TBTS TBL X (longitudinal) Y (radial) Z (vertical) Comparison with an other method Calculation of the transformation to go from Rcomponent to RCLEX with a best-fit between common points. Max Residuals : 10 μm Precision of the position of the girder in the general coordinate system : 17 microns in radial / 8 microns in vertical 14

16. Difference between the 2 methods DifferenceRadial (μm)Vertical (μm) DB (C1)727 DB (C2)-752 MB (C1)1532 MB (C2)733 Goal : Alignment of girder axes (module T0) in the general coordinate system (R CLEX) in real time and remotely with an accuracy of few microns The links between the girders and the cradles have to be improved if we want to achieve our goal. 15

17. Summary The link girder-cradles has to be improved or the sensors have to be installed directly on the girder CMM measurements are necessary to provide precise and accurate component fiducialisations The short range alignment strategy proposed is good to achieve our goal (for distances <10m) The stretched wire measured by WPS sensors is curently the most suitable systems to meet the expectations Some comparisons have to be done with beam based alignment method (Wilfried Farabolini).