Author: Artoos, K.
Paper Title Page
MOPO027 Status of a Study of Stabilization and Fine Positioning of CLIC Quadrupoles to the Nanometre Level* 538
 
  • K. Artoos, C.G.R.L. Collette, M. Esposito, P. Fernandez Carmona, M. Guinchard, C. Hauviller, S.M. Janssens, A.M. Kuzmin, R. Leuxe, R. Moron Ballester
    CERN, Geneva, Switzerland
 
  Funding: The research leading to these results has received funding from the European Commission under the FP7 Research Infrastructures project EuCARD, grant agreement no.227579
Mechanical stability to the nanometre and below is required for the CLIC quadrupoles to frequencies as low as 1 Hz. An active stabilization and positioning system based on very stiff piezo electric actuators and inertial reference masses is under study for the Main Beam Quadrupoles (MBQ). The stiff support was selected for robustness against direct forces and for the option of incrementally repositioning the magnet with nanometre resolution. The technical feasibility was demonstrated by a representative test mass being stabilized and repositioned to the required level in the vertical and lateral direction. Technical issues were identified and the development programme of the support, sensors, and controller was continued to increase the performance, integrate the system in the overall controller, adapt to the accelerator environment, and reduce costs. The improvements are implemented in models, test benches, and design of the first stabilized prototype CLIC magnet. The characterization of vibration sources was extended to forces acting directly on the magnet, such as water-cooling induced vibrations. This paper shows the achievements, improvements, and an outlook on further R&D.
 
 
MOPO028 Modal Analysis and Measurement of Water Cooling Induced Vibrations on a CLIC Main Beam Quadrupole Prototype* 541
 
  • K. Artoos, C.G.R.L. Collette, M. Esposito, P. Fernandez Carmona, M. Guinchard, S.M. Janssens, R. Leuxe, M. Modena, R. Moron Ballester, M. Struik
    CERN, Geneva, Switzerland
  • G. Deleglise, A. Jeremie
    IN2P3-LAPP, Annecy-le-Vieux, France
 
  Funding: The research leading to these results has received funding from the European Commission under the FP7 Research Infrastructures project EuCARD, grant agreement no. 227579.
To reach the Compact Linear Collider (CLIC) design luminosity, the mechanical jitter of the CLIC main beam quadrupoles should be smaller than 1.5 nm integrated root mean square (r.m.s.) displacement above 1 Hz. A stiff stabilization and nano-positioning system is being developed but the design and effectiveness of such a system will greatly depend on the stiffness of the quadrupole magnet which should be as high as possible. Modal vibration measurements were therefore performed on a first assembled prototype magnet to evaluate the different mechanical modes and their frequencies. The results were then compared with a Finite Element (FE) model. The vibrations induced by water-cooling without stabilization were measured with different flow rates. This paper describes and analyzes the measurement results.
 
 
TUPC014 System Control for the CLIC Main Beam Quadrupole Stabilization and Nano-positioning* 1021
 
  • S.M. Janssens, K. Artoos, C.G.R.L. Collette, M. Esposito, P. Fernandez Carmona, M. Guinchard, C. Hauviller, A.M. Kuzmin, R. Leuxe, J. Pfingstner, D. Schulte, J. Snuverink
    CERN, Geneva, Switzerland
 
  The conceptual design of the active stabilization and nano-positioning of the CLIC main beam quadrupoles was validated in models and experimentally demonstrated on test benches. Although the mechanical vibrations were reduced to within the specification of 1.5 nm at 1 Hz, additional input for the stabilization system control was received from integrated luminosity simulations that included the measured stabilization transfer functions. Studies are ongoing to obtain a transfer function which is more compatible with beam based orbit feedback; it concerns the controller layout, new sensors and their combination. In addition, the gain margin must be increased in order to reach the requirements from a higher vibration background. For this purpose, the mechanical support is adapted to raise the frequency of some resonances in the system and the implementation of force sensors is considered. Furthermore, this will increase the speed of repositioning the magnets between beam pulses. This paper describes the improvements and their implementation from a controls perspective.  
 
TUPC023 Status of Ground Motion Mitigation Techniques for CLIC 1048
 
  • J. Snuverink, K. Artoos, C.G.R.L. Collette, F. Duarte Ramos, A. Gaddi, H. Gerwig, S.M. Janssens, J. Pfingstner, D. Schulte
    CERN, Geneva, Switzerland
  • G. Balik, L. Brunetti, A. Jeremie
    IN2P3-LAPP, Annecy-le-Vieux, France
  • P. Burrows
    Oxford University, Physics Department, Oxford, Oxon, United Kingdom
  • B. Caron
    SYMME, Annecy-le-Vieux, France
  • J. Resta-López
    IFIC, Valencia, Spain
 
  The Compact Linear Collider (CLIC) accelerator has strong stability requirements on the position of the beam. In particular, the beam position will be sensitive to ground motion. A number of mitigation techniques are proposed - quadrupole stabilisation and positioning, final doublet stabilisation as well as beam based orbit and interaction point (IP) feedback. Integrated studies of the impact of the ground motion on the CLIC Main Linac (ML) and Beam Delivery System (BDS) have been performed, which model the hardware and beam performance in detail. Based on the results future improvements of the mitigation techniques are suggested and simulated. It is shown that with the current design the tight luminosity budget for ground motion effects is fulfilled and accordingly, an essential feasibility issue of CLIC has been addressed.