Cargando…

Mathematical formulation to predict the harmonics of the superconducting Large Hadron Collider magnets; 3, Precycle ramp rate effects and magnet characterization

The Large Hadron Collider (LHC) at CERN is equipped with a feed-forward control system known as the field description for the LHC (FiDeL) which is designed to predict the magnetic field and its multipoles, hence reducing the burden on beam based feedback. FiDeL consists of a physical and empirical p...

Descripción completa

Detalles Bibliográficos
Autores principales: Sammut, Nicholas, Bottura, Luca, Deferne, Guy, Venturini Delsolaro, Walter
Lenguaje:eng
Publicado: 2009
Materias:
Acceso en línea:https://dx.doi.org/10.1103/PhysRevSTAB.12.102401
http://cds.cern.ch/record/1233194
_version_ 1780918497100955648
author Sammut, Nicholas
Bottura, Luca
Deferne, Guy
Venturini Delsolaro, Walter
author_facet Sammut, Nicholas
Bottura, Luca
Deferne, Guy
Venturini Delsolaro, Walter
author_sort Sammut, Nicholas
collection CERN
description The Large Hadron Collider (LHC) at CERN is equipped with a feed-forward control system known as the field description for the LHC (FiDeL) which is designed to predict the magnetic field and its multipoles, hence reducing the burden on beam based feedback. FiDeL consists of a physical and empirical parametric field model based on magnetic measurements at warm and in cryogenic conditions. It is particularly critical during beam injection when the field decays and at the beginning of acceleration when the field snaps back. It is known that the decay amplitude is largely affected by the powering history of the magnet, particularly by the precycle flattop current and duration and the preinjection preparation duration. Recently, we have collected data that quantify the dependence of the decay amplitude on the precycle ramp rate. This paper presents the results of the measurements performed to investigate this effect, and the method included in FiDeL to model the precycle dependence. With this complete picture of dynamic changes, we finally discuss the effect on the data taken at nominally constant field, along the magnet loadline. We show that a correction for dynamic changes is required for adequate magnet characterization.
id cern-1233194
institution Organización Europea para la Investigación Nuclear
language eng
publishDate 2009
record_format invenio
spelling cern-12331942019-09-30T06:29:59Zdoi:10.1103/PhysRevSTAB.12.102401http://cds.cern.ch/record/1233194engSammut, NicholasBottura, LucaDeferne, GuyVenturini Delsolaro, WalterMathematical formulation to predict the harmonics of the superconducting Large Hadron Collider magnets; 3, Precycle ramp rate effects and magnet characterizationAccelerators and Storage RingsThe Large Hadron Collider (LHC) at CERN is equipped with a feed-forward control system known as the field description for the LHC (FiDeL) which is designed to predict the magnetic field and its multipoles, hence reducing the burden on beam based feedback. FiDeL consists of a physical and empirical parametric field model based on magnetic measurements at warm and in cryogenic conditions. It is particularly critical during beam injection when the field decays and at the beginning of acceleration when the field snaps back. It is known that the decay amplitude is largely affected by the powering history of the magnet, particularly by the precycle flattop current and duration and the preinjection preparation duration. Recently, we have collected data that quantify the dependence of the decay amplitude on the precycle ramp rate. This paper presents the results of the measurements performed to investigate this effect, and the method included in FiDeL to model the precycle dependence. With this complete picture of dynamic changes, we finally discuss the effect on the data taken at nominally constant field, along the magnet loadline. We show that a correction for dynamic changes is required for adequate magnet characterization.oai:cds.cern.ch:12331942009
spellingShingle Accelerators and Storage Rings
Sammut, Nicholas
Bottura, Luca
Deferne, Guy
Venturini Delsolaro, Walter
Mathematical formulation to predict the harmonics of the superconducting Large Hadron Collider magnets; 3, Precycle ramp rate effects and magnet characterization
title Mathematical formulation to predict the harmonics of the superconducting Large Hadron Collider magnets; 3, Precycle ramp rate effects and magnet characterization
title_full Mathematical formulation to predict the harmonics of the superconducting Large Hadron Collider magnets; 3, Precycle ramp rate effects and magnet characterization
title_fullStr Mathematical formulation to predict the harmonics of the superconducting Large Hadron Collider magnets; 3, Precycle ramp rate effects and magnet characterization
title_full_unstemmed Mathematical formulation to predict the harmonics of the superconducting Large Hadron Collider magnets; 3, Precycle ramp rate effects and magnet characterization
title_short Mathematical formulation to predict the harmonics of the superconducting Large Hadron Collider magnets; 3, Precycle ramp rate effects and magnet characterization
title_sort mathematical formulation to predict the harmonics of the superconducting large hadron collider magnets; 3, precycle ramp rate effects and magnet characterization
topic Accelerators and Storage Rings
url https://dx.doi.org/10.1103/PhysRevSTAB.12.102401
http://cds.cern.ch/record/1233194
work_keys_str_mv AT sammutnicholas mathematicalformulationtopredicttheharmonicsofthesuperconductinglargehadroncollidermagnets3precycleramprateeffectsandmagnetcharacterization
AT botturaluca mathematicalformulationtopredicttheharmonicsofthesuperconductinglargehadroncollidermagnets3precycleramprateeffectsandmagnetcharacterization
AT deferneguy mathematicalformulationtopredicttheharmonicsofthesuperconductinglargehadroncollidermagnets3precycleramprateeffectsandmagnetcharacterization
AT venturinidelsolarowalter mathematicalformulationtopredicttheharmonicsofthesuperconductinglargehadroncollidermagnets3precycleramprateeffectsandmagnetcharacterization