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Venturini Delsolaro, W.

Paper Title Page
WEPD028 Performance of the Superconducting Corrector Magnet Circuits during the Commissioning of the LHC 2470
 
  • W. Venturini Delsolaro, V. Baggiolini, A. Ballarino, B. Bellesia, F. Bordry, A. Cantone, M. P. Casas Lino, C. CastilloTrello, N. Catalan-Lasheras, Z. Charifoulline, C. Charrondiere, G. D'Angelo, K. Dahlerup-Petersen, G. De Rijk, R. Denz, M. Gruwe, V. Kain, M. Karppinen, B. Khomenko, G. Kirby, S. L.N. Le Naour, A. Macpherson, A. Marqueta Barbero, K. H. Mess, M. Modena, R. Mompo, V. Montabonnet, D. Nisbet, V. Parma, M. Pojer, L. Ponce, A. Raimondo, S. Redaelli, V. Remondino, H. Reymond, A. Rijllart, R. I. Saban, S. Sanfilippo, K. M. Schirm, R. Schmidt, A. P. Siemko, M. Solfaroli Camillocci, H. Thiesen, Y. Thurel, A. Vergara-Fernández, A. P. Verweij, R. Wolf, M. Zerlauth
    CERN, Geneva
  • A. Castaneda, I. Romera Ramirez
    CIEMAT, Madrid
  • SF. Feher, R. H. Flora
    Fermilab, Batavia, Illinois
  
  The LHC is a complex machine requiring more than 7400 superconducting corrector magnets distributed along a circumference of 26.7 km. These magnets are powered in 1380 different electrical circuits with currents ranging from 60 A up to 600 A. Among the corrector circuits the 600 A corrector magnets form the most diverse and differentiated magnet circuits. About 60000 high current connections had to be made. A minor fault in a circuit or one of the superconducting connections would have severe consequences for the accelerator operation. All magnets are wound from various types of Nb-Ti superconducting strands, and many contain resistors to by-pass the current in case of the transition to the normal conducting state in case of a quench, and hence reduce the hot spot temperature. In this paper the performance of these magnet circuits is presented, focussing on the quench current and quench behaviour of the magnets. Quench detection and the performance of the electrical interconnects will be dealt with. The results as measured on the entire circuits will be compared to the test results obtained during the reception tests of the individual magnets.  
WEPD031 Dependence of the Static and Dynamic Field Quality of the LHC Superconducting Dipole Magnets on the Pre-cycle Ramp Rate 2479
 
  • N. J. Sammut, L. Bottura, G. Deferne, W. Venturini Delsolaro, R. Wolf
    CERN, Geneva
  • N. J. Sammut
    University of Malta, Faculty of Engineering, Msida
  
  The allowed multipoles in the Large Hadron Collider (LHC) superconducting dipole magnets decay whilst on a constant current plateau. It is known that the decay amplitude is largely affected by the powering history of the magnet, and particularly by the pre-cycle flat top current and duration and the pre-injection preparation duration. Recently, it was observed that the decay amplitude is also highly dependent on the pre-cycle ramp rate, which has an indirect effect also on the sample of data taken at constant field along the magnet loadlines. This is an important consideration to be included in the Field Description for the LHC (FiDeL), to cope with the difference between the test procedure followed for series tests and the expected cycles during the machine operation. This paper presents the results of the measurements performed to investigate this phenomenon and describes the method included in FiDeL to represent this dependence.  
WEPD033 A Demonstration Experiment for the Forecast of Magnetic Field and Field Errors in the Large Hadron Collider 2482
 
  • N. J. Sammut, R. Alemany-Fernandez, L. Bottura, G. Deferne, M. Lamont, J. Miles, S. Sanfilippo, M. Strzelczyk, W. Venturini Delsolaro, P. Xydi
    CERN, Geneva
  • N. J. Sammut
    University of Malta, Faculty of Engineering, Msida
  
  In order to reduce the burden on the beam-based feedback, the Large Hadron Collider (LHC) control system is embedded with the Field Description for the LHC (FiDeL) which provides a forecast of the magnetic field and the multipole field errors. FiDeL has recently been extensively tested at CERN to determine main field tracking, multipole forecasting and compensation accuracy. In this paper we describe the rationale behind the tests, the procedures employed to characterize and power the main magnets and their correctors, and finally, we present the results obtained. We also give an indication of the prediction accuracy that the system can deliver during the operation of the LHC and we discuss the implications that these will have on the machine performance.  
WEPD034 Main Field Tracking Measurement in the LHC Superconducting Dipole and Quadrupole Magnets 2485
 
  • P. Xydi, R. Alemany-Fernandez, L. Bottura, G. Deferne, M. Lamont, J. Miles, R. Mompo, M. Strzelczyk, W. Venturini Delsolaro
    CERN, Geneva
  • N. J. Sammut
    University of Malta, Faculty of Engineering, Msida
  
  One of the most stringent requirements during the energy ramp of the Large Hadron Collider (LHC) is to have a constant ratio between dipole-quadrupole and dipole-dipole field so as to control the variation of the betatron tune and of the beam orbit throughout the acceleration phase, hence avoiding particle loss. To achieve the nominal performance of the LHC, a maximum variation of ±0.003 tune units can be tolerated. For the commissioning with low intensity beams, acceptable bounds are up to 30 times higher. For the quadrupole-dipole integrated field ratio, the above requirements translate in the tight windows of 6 ppm and 180 ppm, while for dipole differences between sectors the acceptable error is of the order of 10-4. Measurement and control at this level are challenging. For this reason we have launched a dedicated measurement R&D to demonstrate that these ratios can be measured and controlled within the limits for machine operation. In this paper we present the techniques developed to power the magnets during the current ramps, the instrumentation and data acquisition setup used to perform the tracking experiments, the calibration procedure and the data reduction employed.  
WEPP005 Measurements and Effects of the Magnetic Hysteresis on the LHC Crossing Angle and Separation Bumps 2530
 
  • N. J. Sammut, H. Burkhardt, C. Giloux, W. Venturini Delsolaro, S. M. White
    CERN, Geneva
  • N. J. Sammut
    University of Malta, Faculty of Engineering, Msida
  
  The superconducting orbit corrector magnets (MCBC and MCBY) in the Large Hadron Collider (LHC) at CERN will be used to generate parallel separation and crossing angles at the interaction points during the different phases that will bring the LHC beams into collision. However, the field errors generated by the inherent hysteresis in the operation region of the orbit correctors may lead to unwanted orbit perturbations that could have a critical effect on luminosity. This paper presents the results obtained from dedicated cryogenic measurements on the orbit correctors from the simulated results on the impact of the hysteresis on the LHC orbit.  
WEPD029 Performance of the Main Dipole Magnet Circuits of the LHC during Commissioning 2473
 
  • A. P. Verweij, V. Baggiolini, A. Ballarino, B. Bellesia, F. Bordry, A. Cantone, M. P. Casas Lino, A. Castaneda, C. CastilloTrello, N. Catalan-Lasheras, Z. Charifoulline, G.-J. Coelingh, G. D'Angelo, K. Dahlerup-Petersen, G. De Rijk, R. Denz, M. Gruwe, V. Kain, B. Khomenko, G. Kirby, S. L.N. Le Naour, A. Macpherson, A. Marqueta Barbero, K. H. Mess, M. Modena, R. Mompo, V. Montabonnet, D. Nisbet, V. Parma, M. Pojer, L. Ponce, A. Raimondo, S. Redaelli, H. Reymond, D. Richter, A. Rijllart, I. Romera, R. I. Saban, S. Sanfilippo, R. Schmidt, A. P. Siemko, M. Solfaroli Camillocci, H. Thiesen, Y. Thurel, W. Venturini Delsolaro, A. Vergara-Fernández, R. Wolf, M. Zerlauth
    CERN, Geneva
  • SF. Feher, R. H. Flora
    Fermilab, Batavia, Illinois
  
  During hardware commissioning of the Large Hadron Collider, 8 main dipole circuits and 16 main quadrupole circuits are tested at 1.9 K and up to their nominal current. Each dipole circuit contains 154 magnets of 15 m length, and has a total stored energy of up to 1.1 GJ. Each quadrupole circuit contains 47 or 51 magnets of 5.4 m length, and has a total stored energy of up to 20 MJ. All magnets are wound from Nb-Ti superconducting Rutherford cables, and contain heaters to quickly force the transition to the normal conducting state in case of a quench, and hence reduce the hot spot temperature. In this paper the performance of these circuits is presented, focusing on the quench current and quench behaviour of the magnets. Quench detection, heater performance, operation of the cold bypass diodes, cryogenic recovery time, electrical joints, and possible magnet-to-magnet quench propagation will be dealt with. The results as measured on the entire circuits will be compared to the test results obtained during the reception tests of the individual magnets.