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H. MAINAUD DURAND on behalf of the CLIC active pre-alignement team with 3D views and data from Hubert Gerwig, Richard Rosing and Juha Kemppinen Pre-alignment status MDI meeting, 02/09/2011
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2 SUMMARY Monitoring of QD0 Study on cam movers on a 5 DOF setup
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3 Monitoring of QD0 Concept 4 Reference Rings (RR) located at each extremity of QD0, supported from outer tube 6 radial spokes per RR RR spoke Line of sight for alignment systems In two steps: A monitoring of the position of QD0 w.r.t RR thanks to proximity sensors. (initial calibration of their position performed on a CMM) A transfer of the position of RR thanks to 6 spokes to alignment systems. By combination of redundant information, the position of the center of 4 RR is computed.
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4 Monitoring of QD0 Concept: alignment systems RasNik RasCLIC laser + beam expander diffraction plate pixel image sensor
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5 Monitoring of QD0 Latest results: choice of material RR and spokes in Zerodur
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6 Monitoring of QD0 Latest results : design of RR RR: 6 gage blocks with flat surface, glued between the 2 rings Simulations concerning RR : deformation ~ 1 μm. As we will perform relative measurements, no impact
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7 Monitoring of QD0 Latest results : design of spokes Squares rods in zerodur (6 mm x 6 mm), with a length of 200 mm, glued together (final length 1 m) At the RR extremity of spoke: a hard stainless steel precision ball, pressed against the reference surface of gage block of RR (a screwing concept using torque screw is being studied. Each spoke is supported by a square aluminium pipe. Flexo, made of silicon rubber will be the link between spoke and pipe, allowing that no radial force is applied, except the load of the bar itself.
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8 Monitoring of QD0 Latest results : status At the « non-RR » extremity of spoke: RasCLIC and RasNik system will be tested on two beam test modules (169/S-029)
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9 Monitoring of QD0 Latest results : status First tests will concern the assembly of 1m of zerodur rods: guiding, then heating / thermal expansion behavior
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10 Monitoring of QD0 Integration
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11 SUMMARY Monitoring of QD0 Study on cam movers on a 5 DOF setup
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12 Monitoring of QD0 Why a 5 DOF mock-up to validate cam movers? In order to have a better knowledge of cam movers and algorithms of repositioning For the MB quads of Main linac and BDS, we are looking for a resolution and repeatability of adjstument never reached before (below 1 μm). These requirements are not fulfilled on other facilities where cam movers are installed (LCLS @ SLAC, SLS @ PSI). Cam movers were validated on a 1 DOF setup (where a repeatibility below 1 μm) was reached, but the setup was too rigid to measure resonant frequencies. (Target on the 5 DOF mock-up: first resonant frequency > 50 Hz, in order to be compatible with stabilization requirements).
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13 Monitoring of QD0 Description of 5 DOF mock-up
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14 Monitoring of QD0 Cam movers Configuration: 5 cam movers in order to provide 5 DOF A kinematic mount interface below the common support of MB quad support providing a unique solution of interface 4 interface with ground for higher stiffness Cam movers from SLS Upgraded SLS cam movers: (optimization of clearances and links between parts) Cam movers from ZTS vvu Kosice: A more rigid structure Higher gear ratio (Worm gearbox ratio = 60, bearing reducer ratio = 85) Different worm gear and stepper motor The stepper motor and the worm gear unit are coupled to the cam shaft via a zero backlash bearing reducer instead of a planetary gear A high resolution absolute rotary angle encoder from Renishaw is directly mounted on the cam shaft
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15 Monitoring of QD0 Latest results Blank assembly of the setup Resolution of displacements: According to the manufacturer, the cam mover’s movement resolution is 3.8’’. Based on this, the 5 DOF setup theoretical resolution in translations is below 1µm and in rotations below 1µrad. The cam movers were not calibrated before the blank assembly of the 5 DOF setup so the control algorithm cannot be fully exploited. Therefore it was not possible to test the resolution of re- adjustment of all translations and rotations separately. First tests do however indicate that the re-adjustment resolution of translations are below 2 µm. But area very noisy: standard deviation of WPS measurements ~ 1.3 μm. Eigenfrequencies measurements: Before concrete is added around the plates Several natural frequencies were measured below 50 Hz, coming from the mechanical plates and their anchoring screws (see edms report n°1152988 from Mechanical Measurement Lab). A RMS integrated level close to 9 nm at 1 Hz was computed; this confirmed that the area is too noisy for our measurements.
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16 Monitoring of QD0 Next steps Find a new area Calibration of cam movers Remounting of 5 DOF setup, with higher rigidity of mechanical plates Determination of the first resonant frequencies of the support Extrapolation at MDI case
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