Author: griffet, S.
Paper Title Page
WEPPD073 Strategy and Validation of Fiducialization for the Pre-alignment of CLIC Components 2693
  • S. griffet, A. Cherif, J. Kemppinen, H. Mainaud Durand, V. Rude, G. Sterbini
    CERN, Geneva, Switzerland
  The feasibility of the high energy e+ e linear collider CLIC (Compact Linear Collider) is very dependent on the ability to accurately pre-align its components. There are two 20-km-long Main Linacs which meet in an interaction point (IP). The Main Linacs are composed of thousands of 2 m long modules. One of the challenges is to meet very tight alignment tolerances at the level of CLIC module: for example, the center of a Drive Beam Quad needs to be aligned within 20 μm rms with respect to a straight line. Such accuracies cannot be achieved using usual measurement devices. Thus it is necessary to work in close collaboration with the metrology lab. To test and improve many critical points, including alignment, a CLIC mock-up is being assembled at CERN. This paper describes the application of the strategy of fiducialization for the pre-alignment of CLIC mock-up components. It also deals with the first results obtained by performing measurements using a CMM (Coordinate Measuring Machine) to ensure the fiducialization, using a Laser Tracker to adjust or check components’ positions on a girder and finally using a Measuring Arm to perform dimensional control after assembling steps.  
WEPPD074 Issues and Feasibility Demonstration of Positioning Closed Loop Control for the CLIC Supporting System Using a Test Mock-up with Five Degrees of Freedom 2696
  • M. Sosin, M. Anastasopoulos, N. Chritin, J. Kemppinen, H. Mainaud Durand, V. Rude, G. Sterbini, S. griffet
    CERN, Geneva, Switzerland
  Since several years, CERN is studying the feasibility of building a high energy e+ e linear collider: the CLIC (Compact LInear Collider). One of the challenges of such a collider is the pre-alignment precision and accuracy requirement on the transverse positions of the linac components, which is typically 14 μm over a window of 200 m. To ensure the possibility of positioning within such tight constraints, CERN Beams Department’s Survey team has worked intensively at developing the methods and technology needed to achieve that objective. This paper describes activities which were performed on a test bench (mock-up) with five degrees of freedom (DOF) for the qualification of control algorithms for the CLIC supporting system active-pre-alignment. Present understanding, lessons learned (“know how”), issues of sensors noise and mechanical components nonlinearities are presented.