doi:10.1109/TASC.2003.812641engBottura, LLeroy, DModena, MPojer, MPugnat, PRossi, LSanfilippo, SSiemko, AVlogaert, JWalckiers, LWyss, CPerformance of the First LHC Pre-series Superconducting DipolesAccelerators and Storage RingsLHC-Project-Report-619CERN-LHC-Project-Report-619Within the LHC magnet program, a preseries production of final design, full-scale superconducting dipoles has presently started in industry and magnets are being tested at CERN. The main features of these magnets are: two-in-one structure, 56 mm aperture, six-block two layer coils wound from 15.1 mm wide graded NbTi cables, and all-polyimide insulation. This paper reviews the main test results of magnets tested to date in both supercritical and superfluid helium. The results of the quench training, conductor performance, magnet protection, sensitivity to ramp rate, and magnetic field quality are presented and discussed in terms of the design parameters and the aims of the LHC magnet programme.2002-12-12http://cds.cern.ch/record/59938110.1109/TASC.2003.812641http://cds.cern.ch/record/599381oai:cds.cern.ch:599381 doi:10.1109/TASC.2003.812643engAmet, SBottura, LGranata, VLe Naour, SMishra, R KOberli, L RRichter, DSanfilippo, SVerweij, A PWalckiers, LWolf, RPersistent and Coupling Current Effects in the LHC Superconducting DipolesAccelerators and Storage RingsLHC-Project-Report-620CERN-LHC-Project-Report-620One of the main issues for the operation of the LHC accelerator at CERN is the field errors generated by persistent and coupling currents in the main dipoles at injection conditions, i.e., 0.54 T dipole field. For this reason we are conducting systematic magnetic field measurements to quantify the above effects and compare them to the expected values from measurement on strands and cables. We discuss the results in terms of DC effects from persistent current magnetization, AC effects with short time constant from strand and cable coupling currents, and long-term decay during constant current excitation. Average and spread of the measured field errors over the population of magnets tested are as expected or smaller. Field decay at injection, and subsequent snap-back, show for the moment the largest variation from magnet to magnet, with weak correlation to parameters that can be controlled during production. For this reason these effects are likely to result in the largest spread of field errors over the whole dipole production.2002-12-12http://cds.cern.ch/record/59938210.1109/TASC.2003.812643http://cds.cern.ch/record/599382oai:cds.cern.ch:599382 doi:10.1109/TASC.2003.812658engGiloux, CMompo, RSiemko, ATaylor, T MVenturini-Delsolaro, WWalckiers, LYamamoto, AShintomi, TNakamoto, TOhuchi, NOgitsu, TTsuchiya, KTest Results of a Variant-Design LHC Twin-Aperture Dipole MagnetAccelerators and Storage RingsLHC-Project-Report-621CERN-LHC-Project-Report-621Since 1989, KEK and CERN carried out jointly an experimental program in the frame of the R&D work for the LHC main dipole. The mechanical structure of this design is based on a separate coil/collar and "horizontally split iron" concept. A total of four single aperture and two twin-aperture 1 m long dipole magnets were built. The last twin-aperture magnet was tested at CERN, reaching a maximum field of 9.55 T at 1.9 K. This paper reports the magnet training performance and quench localization at 1.9 K and 4.5 K. The performance as a function of current ramp rate and measurements of the field quality are also reported.2002-12-12http://cds.cern.ch/record/59938310.1109/TASC.2003.812658http://cds.cern.ch/record/599383oai:cds.cern.ch:599383 doi:10.1109/TASC.2003.812655engLa China, MCavallari, GiorgioFerracin, PGarcía-Pérez, JTodesco, EzioScandale, WalterA Method to Determine the Flexural Rigidity of the Main Dipole for the Large Hadron ColliderAccelerators and Storage RingsLHC-Project-Report-622CERN-LHC-Project-Report-622The Large Hadron Collider (LHC) superconducting dipole cold mass is a cylindrical structure 15 m long, made of a shrinking cylinder which contains iron laminations and collared coils. This structure, weighing about 28 ton is horizontally bent by 5 mrad. Its shape should be preserved from the assembly phase to the operational condition at cryogenic temperature. Hence an accurate comprehension of the mechanical behaviour of the cold mass is required. In particular the flexural rigidity in horizontal and vertical directions represents one of the foremost properties to be aware of. To determine the flexural rigidity, deformations of the cold mass induced by the self weight have been measured and compared with the predictions of an analytical structural model. A particular care has been taken in reducing the experimental error by an appropriate fitting procedure.2002-12-12http://cds.cern.ch/record/59938810.1109/TASC.2003.812655http://cds.cern.ch/record/599388oai:cds.cern.ch:599388 engRossi, LThe LHC Main Dipoles and Quadrupoles toward Series ProductionAccelerators and Storage RingsLHC-Project-Report-623CERN-LHC-Project-Report-623The Large Hadron Collider (LHC) is under construction at CERN. Most of its 27 km underground tunnel will be filled with superconducting magnets, mainly 15 m long dipoles and 3.3 m long quadrupoles. In total 1248 dipole and 400 quadrupole magnets will be built (including spares), all wound with copper stabilized NbTi Rutherford cables and designed to operate in superfluid helium at 1.9 K. The dipoles operative field is 8.3 T, the system being designed for possible operation up to 9 T (ultimate field). The pre-series dipole production has started in 2000 in three companies while the series dipole construction will start at the beginning of 2003. As far as quadrupoles are concerned, the prototypal phase (carried out at CEA - Saclay, F) is followed directly by the series construction, started in March 2002. In the paper the magnet main characteristics are reviewed and the special tooling, put in place to fulfill the mass production with the suitable accuracy and safety margin, is described. The results obtained on the first fifteen pre-series magnets as well as the effect of the corrective actions taken to meet the necessary field quality are discussed. Finally a realistic plan of the Project, foreseeing that last dipoles are delivered in summer 2006, is presented.2002-12-12http://cds.cern.ch/record/599389http://cds.cern.ch/record/599389oai:cds.cern.ch:599389 doi:10.1109/TASC.2003.812865engBottura, LBreschi, MFabbri, M GAnalytical Calculation of Current Distribution in Multistrand Superconducting CablesAccelerators and Storage RingsCERN-LHC-2002-021-MTAIn recent years the problem of current distribution in multistrand superconducting cables has received increasing attention for large scale superconductivity applications due to its effect on the stability of fusion magnets and the field quality of accelerator magnets. A modelling approach based on distributed parameters has revealed to be very effective in dealing with long cables made of some tens or hundreds of strands. In this paper we present a fully analytical solution equation for a distributed parameters model in cables made of an arbitrary number of strands, whose validity is subjected to symmetry conditions generally satisfied in practical cables. We give in particular analytical formulae of practical use for the estimation of the maximum strand currents, time constants and redistribution lengths as a function of the cable properties and the external voltage source.2002-12-20http://cds.cern.ch/record/59903110.1109/TASC.2003.812865http://cds.cern.ch/record/599031oai:cds.cern.ch:599031