Author: Pojer, M.
Paper Title Page
MOPPD062 Aperture Measurements in the LHC Interaction Regions 508
 
  • S. Redaelli, M.C. Alabau Pons, R.W. Assmann, R. Bruce, M. Giovannozzi, G.J. Müller, M. Pojer, J. Wenninger
    CERN, Geneva, Switzerland
 
  The aperture of the LHC interaction regions is crucial for the LHC performance because it determines the smaller β* that can be achieved. The aperture has been measured at a maximum energy of 3.5 TeV and at different β* values, following optimized procedure to allow safe measurements at high energy. In this paper, the results of these aperture measurements, which are used as a reference for β* reach and crossing scheme estimates at the LHC interaction points, are presented.  
 
THPPD028 Studies on the LHC Superconducting Circuits and Routine Qualification of Their Functionalities 3563
 
  • M. Pojer, G. D'Angelo, R. Mompo, R. Schmidt, M. Solfaroli Camillocci
    CERN, Geneva, Switzerland
 
  The Large Hadron Collider (LHC) is systematically undergoing periods of maintenance stop (either 4-5 days stops or longer Christmas breaks), after which some of the superconducting circuits (or the totality of them) have to be re-commissioned to check the correct functionality of all powering and protection systems. Detailed procedures have been developed during the past few years and they have been optimized to increase powering tests efficiency, thus reducing beam downtime. The approach to the routine qualification of the LHC powering systems is described in this paper. During 2011 technical stops, some particular studies on the superconducting circuits were performed, to assess the quality of the superconducting splices of individually powered magnets and to study the quench propagation in the main magnet bus-bars. The methodology of these tests and some results are also presented.  
 
THPPD029 Machine Availability at the Large Hadron Collider 3566
 
  • M. Pojer, R. Schmidt, M. Solfaroli Camillocci, S. Wagner
    CERN, Geneva, Switzerland
 
  One of the most important parameters for a particle accelerator is its uptime, the period of time when it is functioning and available for use. In its second year of operation, the Large Hadron Collider (LHC) has experienced very high machine availability, which is one of the ingredients of its brilliant performance. Some of the strategies followed to increase MTBF are described in the paper. The approach of periodic maintenance stops, often questioned, is also discussed. Some considerations on the ideal length of a physics fill are also drawn.  
 
THPPP009 Automated Execution and Tracking of the LHC Commissioning Tests 3743
 
  • K. Fuchsberger, V. Baggiolini, M. Galetzka, R. Gorbonosov, M. Pojer, M. Solfaroli Camillocci, M. Zerlauth
    CERN, Geneva, Switzerland
 
  To ensure the correct operation and prevent system failures, which can lead to equipment damage in the worst case, all critical systems in the Large Hadron Collider (LHC), have to be tested thoroughly during dedicated commissioning phases after each intervention. In view of the around 7,000 individual tests to be performed each year after a Christmas stop, a lot of effort was already put into the automation of these tests at the beginning of LHC hardware commissioning in 2005, to assure the dependable execution and analysis of these tests. To further increase the productivity during the commissioning campaigns and to enforce amore consistent workflow, the development of a dedicated testing framework was launched. This new framework is designed to schedule and track the automated tests for all systems of the LHC and will also be extendable, e.g., to beam commissioning tests. This is achieved by re-using different, already existing execution frameworks. In this paper, we outline the motivation for this new framework and the related improvements in the commissioning process. Further, we sketch its design and present first experience from the re-commissioning campaign in early 2012.  
 
THPPP018 Operation of the LHC at High Luminosity and High Stored Energy 3767
 
  • J. Wenninger, R. Alemany-Fernandez, G. Arduini, R.W. Assmann, B.J. Holzer, E.B. Holzer, V. Kain, M. Lamont, A. Macpherson, G. Papotti, M. Pojer, L. Ponce, S. Redaelli, M. Solfaroli Camillocci, J.A. Uythoven, W. Venturini Delsolaro
    CERN, Geneva, Switzerland
 
  In 2011 the operation of the Large Hadron Collider LHC entered its first year of high luminosity production at a beam energy of 3.5 TeV. In the first months of 2011 the number of bunches was progressively increased to 1380, followed by a reduction of the transverse emittance, an increase of the bunch population and a reduction of the betatron function at the collision points. The performance improvements steps that were accumulated in 2011 eventually brought the peak luminosity to 3.6·1033 cm-2s−1. The integrated luminosity delivered to each of the high luminosity experiments amounted to 5.6 fb-1, a factor of 5 above the initial target defined in 2010. The operational experience with high intensity and high luminosity at the LHC will be presented here, together with the issues that had to be tackled on the road to high intensity and luminosity.