H. MAINAUD DURAND on behalf of the CLIC active pre-alignment team Status on CLIC pre-alignment studies

2 OUTLINE Problem and solution proposed Review of the 4 WP created: o Description o Status o Next steps Summary

3 Problem and solution proposed Problem Within +/- 0.1 mm (1  ) Active pre-alignment Beam based alignment Beam based feedbacks Within a few microns Active pre-alignment = Determination of the position of the components in a general coordinate system thanks to alignment systems Re-adjustment thanks to actuators + The zero of each component will be included in a cylinder with a radius of a few microns:  14 µm (RF structures & MB quad BPM)  17 µm (MB quad) Adjustment required: step size below 1 µm Mechanical pre-alignment PRE-ALIGNMENT (beam off)

4 Problem and solution proposed Solution proposed Several components will be pre-aligned on supports or girders: Configuration of girders and supports: Reference of alignment: overlapping reference lines

5 Problem and solution proposed Solution proposed Sensors & actuators are associated to each support / articulation point of girder: As a summary: For CDR:- straight reference = stretched wires - sensors = Wire Positioning Sensors (WPS)

6 Problem and solution proposed Priorities One solution feasible From the performance point of view Compatibility with other systems & integration Affordable Alternative solutions To qualify the first solution To replace the first solution Criteria: -Cost -Easy to integrate -Performant -Easy to install -Easy to maintain -Low sensitivity to environment (humidity, pressure, T°) -High resistance to radiation -High resistance to magnetic fields -Low sensitivity to EMC

7 Problem and solution proposed Description of WP

8 Task 1 : development of sensors and actuators Sensors (introduction) Requirements: Biaxial measurements (radial & vertical) Range : > 3 mm Resolution < 0.2 μm Repeatability: < 1 μm Accuracy: < 5 μm over the whole range 3 solutions under development: cWPS = capacitive Wire Positioning Sensors oWPS = optical Wire Positioning Sensors RasDif / RasNik Strategy in all cases: Validation on individual setups and calibration benches Inter-comparison on two beam modules in lab & accelerator environment

9 Task 1 : development of sensors and actuators Sensors : cWPS Main characteristics (from the manufacturer) Resolution: 0.1 μm Range : +/- 5 mm (along two axes) Repeatability: 1 μm Wire: carbon peek Not so simple to verify these characteristics !!! Improvement of the mechanical interface Development of a very accurate linearity bench Development of an « absolute » bench Trying to have a place with a temperature stable within ± 1ºC Status Linearity depends of the generation of carbon peek wire used: < 5μm over the whole range (better in middle range) Repeatability in installation < 1 μm Interchangeability < 1μm Accuracy not better than 50 µm Next steps Improve linearity and accuracy Perform studies concerning the impact of temperature on the sensor

10 Task 1 : development of sensors and actuators Sensors : oWPS Main characteristics (from the manufacturer) Resolution: < 0.1 μm Range : +/- 5 mm (along two axes) Repeatability: 1 μm Accuracy : < 5μm Wire: Vectran Not so simple to verify these characteristics !!! Development of a very accurate linearity bench Vectran wire used invisible to infra red light and not anti-static Status Qualification of the Vectran wire with irradiation tests Development of a silver plasma coated Vectran wire Development of a very accurate linearity bench to be qualified through CMM measurements Next steps Determine linearity & accuracy of oWPS Develop Rad hard version

11 Task 1 : development of sensors and actuators Sensors : RasChain 2 possibilities: RasNik versus RasDif Status: Test setup to validate RasNik & Rasdif on 4 m First results: jitter and refractive bending of light  thermal shielding needed Preparation of sensors for two beam modules Next steps Installation at CERN and inter-comparison

12 Task 1 : development of sensors and actuators Actuators Validation on individual setups Validation on mock- ups Requirements: Stroke : > 3 mm Resolution < 0.5 μm Repeatability: < 1μm Latest results, next steps: see presentation on cam movers, AWG8, 28/09/11 Development of specific actuators = linear actuators = cam movers

13 Task 2 : tunnel metrology Development of laser based alternatives In collaboration with NIKHEF : o Design of a long range solution RasDif o Inter-comparison in TT1 (140 m) / TZ32 tunnels (500 m)  Relative comparison this autumn LAMBDA project (Laser Alignment Multipoint Based – Design Approach) o First simulations performed: angular orientation & repeatability of shutter should be better than 0.2 mrad & 12 µm, in order to detect a micrometric displacement o Next steps: validate the concept on short distance, without vacuum

14 Task 2 : tunnel metrology Consolidation of stretched wire solution Knowledge of static geoid A theoretical study demonstrated that a determination of gravity field with an accuracy of 0.01 mm over 200 m was possible provided dense astro-geodetic and gravimetric measurements Confirmed by measurements performed every 10 m but extremely fastidious Deflectometer under validation on 12 m, to be extended on 100 m Other issues Modelization of the sag of a stretched wire Impact of air currents How to install easily and rapidly a wire stretched over 500 m?

15 Task 3 : active pre-alignment of two beam modules Validation of the whole strategy of pre-alignment on short distances CMM measurements (dimensional control, pre-alignment of components on their supports, fiducialisation), but STATIC Issue: measure 2 m long objects within a few microns In combination with measurements from Laser Tracker, measurements arm or micro triangulation in lab and tunnels (control after transport, during tests,…) Laser tracker: AT 401 Micro triangulation Romer arm Simulations, based on real performance of AT401: Each fiducial of one module determined at a precision of 6.5 μm Each component of one module determined at a precision of 6.8 μm Next steps Validate the strategy on two beam module prototypes

16 Task 3 : active pre-alignment of two beam modules Validation of the whole strategy of pre-alignment on short distances Design of articulation point, and associated sensors interfaces See presentation by Mateusz Sosin AWG7+ AWG8, 29/09/11

17 Task 4 : active pre-alignment & monitoring in MDI See presentation “BDS alignment progress”, AWG8, 28/09/11

18 Summary 4 WP proposed concerning R&D for Survey and alignment of CLIC : oDevelopment of sensors and actuators oDevelopment of alignment systems on long distance for tunnel metrology oQualification on two beam modules oCase of MDI area Even if feasibility issues are nearly demonstrated, a lot remains to be done: oWorking at the micron level is non standard, and requires to solve a lot of problem before tackling the measurements themselves:  Stable environment conditions  Etalon or references oAmong the priorities:  Improve the performance of different types of sensors and perform their qualification according to pre-defined criteria  Consolidate the stretched wire method  Develop alternatives to qualify the stretched wire and/or to replace it  Validate the fiducialisation strategy on the two beam modules prototypes as well as short range pre-alignment

19 Thank you very much for your attention!