Author: Costa Pinto, P.
Paper Title Page
THPFI044 NEG Thin Film Coating Development for the MAX IV Vacuum System 3385
  • M.J. Grabski, J. Ahlbäck, E. Al-Dmour, P.F. Tavares
    MAX-lab, Lund, Sweden
  • S. Calatroni, P. Chiggiato, P. Costa Pinto, M. Taborelli
    CERN, Geneva, Switzerland
  The new synchrotron radiation facility of the MAX IV laboratories is under construction and expected to deliver the first light beam in 2016. To cope with the small aperture, the intense photon bombardment and the low-pressure requirement, most of the beam pipes for the 3-GeV ring are going to be coated with Ti-Zr-V non-evaporable getter (NEG) thin films. To take advantage from the experience acquired during the construction of the Large Hadron Collider (LHC), collaboration between CERN and MAX IV Laboratories has been set up. The choice of the extruded Cu tubes, the preliminary surface treatments, the coating configuration, and the performance validation of the small-diameter vacuum chambers have been addressed. In parallel, an intense development has been tackled at CERN for the coating of vacuum chambers where photon and electron beams circulate in separate pipes. The most important results of the collaboration are presented and future perspectives pointed out.  
THPFI051 Radio-Frequency Multipacting as Quality Control of Coatings for e-Cloud Suppression 3403
  • P. Costa Pinto, J. Bauche, S. Calatroni, F. Caspers, P. Edwards, M. Holz, M. Taborelli
    CERN, Geneva, Switzerland
  To mitigate electron clouds in particle accelerators, a carbon coating with low SEY has been developed. In the case of the SPS (Super Proton Synchrotron), which belongs to the LHC injector chain, testing the performance of coated beam pipes directly in the accelerator must cope with the schedule of the regular machine operation. For this reason an alternative instrument based on RF induced multipacting in a coaxial configuration has been designed for ex-situ characterization of the main bending dipoles of the SPS. In this contribution we report the results obtained before and after coating for two 6.4 meter dipoles with different cross sections of the vacuum chambers. The multipacting is monitored by measuring the pressure rise and the RF reflected power. After coating, the power threshold to induce multipacting is strongly reduced indicating a lower propensity for electron cloud. The impact of the RF coupling on the sensitivity of the technique is discussed.  
THPFI057 Development of Vacuum Chamber in Low Z Material 3421
  • C. Garion, P. Costa Pinto, M.A. Gallilee, J. Perez Espinos
    CERN, Geneva, Switzerland
  Highly transparent vacuum chambers are more and more required in high energy particle physics. In particular, vacuum chambers in the experiments should be as transparent as possible to minimize the background to the detectors while reducing also the material activation. Beryllium is, so far, the most performing material for this application, but it presents some drawbacks such as brittleness, manufacturing issues, toxic hazard, high cost and low availability. A development work to obtain alternative material to the beryllium with similar performance is being carried out at CERN. Three categories have been defined and considered: raw bulk material, material and structural composites. Main requirements are the vacuum compatibility: leak tightness, low outgassing rate, temperature resistance (in the range 200-230 °C), transparency, and mechanical stiffness and strength. Carbon is the element with the lowest atomic number after beryllium and that is appropriate for this application. Therefore carbon based materials have been considered in a variety of options. In this paper, several technologies are presented and discussed. Results of preliminary tests on samples are also shown.