1. MDI alignment progress The pre-alignment of the QD0’s Niels van Bakel, Bram Bouwens, Hubert Gerwig, Lau Gatignon, Harry van der Graaf, Henk Groenstege, Joris van Heijningen, Jan Koopstra, Helene Mainaud Durand,, Richard Rosing, Vivien Rude CERN, Nikhef IWAA 2012 Fermilab, Sept 13, 2012

3. X Y X Y X Y Alignment of two objects: - omit Z - omit rotZ Measure: - translation X - translation Y - rotX -rotY -Equivalent to -4 points (X,Y)

4. Momentum Measurement of charged particles in the L3 experiment: Chamber Position Monitoring Lorentz Force: Track Curvature measurement Detector Muon Particle Track Detector

5. Direct measurement: two anti // Rasniks: light source + image sensor lens … would only require path of sight of 20 mm 2 …. …. along beampipe…..!

7. Monitor X,Y of (both) QD0 end ref’s with respect to RR (with Rasniks) to be calibrated on 3D measuring machine

8. Rasnik Lines-of Sight spokes

9. Reference Ring RR

10. Spoke - length 3.5 m; - has only one function: to transfer radial position better than 1 μm Material: Zerodur: thermal expansion coefficient < 0.2 x 10 -6

11. Alignment is NOT influented by: - (common) deformation of RRs (sag, spoke load) - temperature of individual RR - (common) deformation of spoke wheel (spoke weight compression) - temperature of individual spoke wheel

12. Spoke tip on RR side: contact definition < 0.1 μm Steel ball Zerodur rod (6 mm x 6 mm x 3500 mm spoke support tube: flexo suspension

17. Inner spoke detailOuter spoke detail Precision ring QD0 support tube

18. Volume reserved for support plate of Rasnik/Rasdif Radial retraction for endcap opening

25. 1983: 4QD Red Alignment System Nikhef (Rasnik) 1993: CCD Rasnik 2003: RasDif: long distance

26. Comparison Stretched Wire System versus RasDif (TT1) RasChain: interconnected Rasnik systems for basic CLIC units of 2010 mm MDI/QD0 alignment: vibrations - new (green) semiconductor lasers - shielding - image analysis software

27. diffraction plate simulated measured Thermal shielding of light path