| Paper |
Title |
Page |
| WEPD033 |
A Demonstration Experiment for the Forecast of Magnetic Field and Field Errors in the Large Hadron Collider
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2482 |
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- 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
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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.
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| WEPD034 |
Main Field Tracking Measurement in the LHC Superconducting Dipole and Quadrupole Magnets
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2485 |
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- 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
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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.
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| WEPP059 |
Automatic Post-operational Checks for the LHC Beam Dump System
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2653 |
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- E. Gallet, J. Axensalva, V. Baggiolini, E. Carlier, B. Goddard, V. Kain, M. Lamont, N. Magnin, J. A. Uythoven, H. Verhagen
CERN, Geneva
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In order to ensure the required level of reliability of the LHC beam dump system a series of internal post-operational checks after each dump action must be performed. Several data handling and data analysis systems are required internally and at different levels of the LHC control system. This paper describes the data acquisition and analysis systems deployed for post-operational checks, and describes the experience from the commissioning of the equipment where these systems were used to analyse the dump kicker performance.
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| WEPP065 |
Beam Commissioning of the SPS-to-LHC Transfer Line TI 2
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2668 |
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- J. A. Uythoven, G. Arduini, R. W. Assmann, N. Gilbert, B. Goddard, V. Kain, A. Koschik, T. Kramer, M. Lamont, V. Mertens, S. Redaelli, J. Wenninger
CERN, Geneva
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The transfer line for the LHC Ring 1 was successfully commissioned with beam in the autumn of 2007. After extraction from the SPS accelerator and about 2.7 km of new transfer line, the beam arrived at the temporarily installed beam dump, about 50 m before the start of the LHC tunnel, without the need of any beam threading. This paper gives an overview of the hardware commissioning period and the actual beam tests carried out. It summarises the results of the beam test optics measurements and the performance of the installed hardware.
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