A demonstration experiment for the forecast of magnetic field and field errors in the Large Hadron Collider

LHC Project Report 1128 CERN, CH-1211 Geneva 23 Switzerland 1) University of Malta & CERN 2) Paul Scherrer Institut, Switzerland CERN, Geneva, Switzerland Presented at EPAC'08, 11th European Particle Accelerator Conference, Genoa, Italy June 23-27, 2008 A DEMONSTRATION EXPERIMENT FOR THE FORECAST OF MAGNETIC FIELD AND FIELD ERRORS IN THE LARGE HADRON COLLIDER* N. Sammut, P. Xydi, R. Alemany Fernandez, L. Bottura, G. Deferne, M. Lamont, J. Miles, S. Sanfilippo, M. Strzelczyk, W. Venturini Delsolaro; 1-CERN, Geneva CH-1211, Switzerland; 2-University of Malta, Msida MSD 2080, Malta; 3-Paul Scherrer Institut, 5232 Villigen Switzerland Abstract In order to reduce the burden on the beam-based feedback, the Large Hadron Collider control system is equipped 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. This paper describes the rationale behind the tests, the procedures employed to 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.In order to reduce the burden on the beam-based feedback, the Large Hadron Collider control system is equipped 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. This paper describes the rationale behind the tests, the procedures employed to 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.