CLIC Survey and alignment: status and plans

1. CLIC Survey and alignment: status and plans • OUTLINE • Short review of the activity • Objectives and milestones for 2013 • Report of outstanding / unresolved issues CTC, 15/01/2013 Edms n° 1261487 H. MAINAUD DURAND on behalf of the CLIC active pre-alignement team

2. Short review of the activity • Main objective: towards absolute measurements for the sensors • A lot of improvements on the cWPS linearity bench, allowing: • A linearity along ± 4 mm within 1 μm • An interchangeability within 5 μm • Absolute measurements within 8 μm • Tests on the oWPS on their linearity bench and in 169 have shown: • A linearity within 1 μm • An interchangeability within 6-8 μm • Absolute measurements ~ 15 μm • Short range systems from NIKHEF: • 6 chainplates ready to be installed on TBTM • An absolute calibration bench is under design @ NIKHEF • Main objective: towards micrometric displacements for the actuators • Linear actuators: validation on TBTM within the requirements • Cam movers: validation ok for standard cam movers • In both cases: a short displacement is achieved in 2-3 iterations (target < 1 μm) • Small cam mover: problem of pinion of gearbox that broke during first series of tests

3. Short review of the activity • Development of laser based alternatives: • Validation of the concept on short range (3 m) with low cost components under progress. First results are promising. • Complementary tests to validate further system parameters using motorized displacement tables. • Consolidation and inter-comparison: • Huge problem of humidity in the TT1 tunnel (> 90%!), with a lot of difficulties met to re-install stretched wires and NIKHEF laser system. Everything seems ok now. • Tests of inter-comparison foreseen beginning of January.

4. Short review of the activity • Validation of the fiducialisation strategy on TBTM: • Combination of CMM & AT401 measurements: alignment of the components within 15-20 μm • Pre-alignment using 2 independent strategies was coherent within 10 μm. • Control of the alignment of the components: • Methods developed (AT401, micro-triangulation, Romer arm) allow measurements better than 10μm. A few components controlled and fiducialized: PETS, DB quad, AS. • Active alignment: • All mechanical tests performed successfully when no constraints are applied on the girders (no vacuum, no waveguides) • Active alignment checked with success: alignment in less than 3 iterations within 1μm

5. Short review of the activity • Spokes: • A setup has been built with 1m zerodur spokes, with semi spheres as contact and RasNik sensors on extremities: • Repeatability of contact with semi sphere: ~ 0.1 μm • Temperature expansion of zerodur very small • Young’s modulus of Zerodur checked • A setup with 3m zerodur spokes under design to prepare their calibration procedure

6. Objectives for 2013 Task 1 Tasks 2, 3 & 4 • Laser based alternatives: • Development of a compact lambda sensor • Validation of Raschain sensors on short and long range through inter-comparison tests with WPS. • Precision and accuracy of a metrological network over 140 m (re-calculation using cWPS with improved absolute measurements) • Fiducialisation, control of alignment of TBTM during T° and transport tests • Validation of micrometric repositioning with additional constraints (vacuum and waveguides) • Design and manufacture of a calibration setup for spokes

7. Outstdanding / unresolved issues • Development of a compact cam mover to be validated on 5DOF • Long term space in ISR • Collaboration with JINR • TZ32 • Safety in TT1 • All staff members (=experts) will work 100% of their time for LHC during LS1 • PACMAN