Paul, C Preis, K Russenschuck, Stephan Siegel, N dipole field calculation field errors saturation effects 1997 1997 The program package ROXIE has been developed at CERN for the design and optimization of the coil geometries for the superconducting magnets for the Large-Hadron-Collider, LHC. It has been extended to the calculation of iron induced effects applying a reduced vector potential formulation. The method allows accurate computation of the multipole errors in the magnets and allows the distinction between the effects resulting from the coil geometry and the yoke geometry. The aim of this report is to describe the computational method as well as to give the newest estimates on the multipole errors to be expected in the LHC main dipoles. Boschmann, H Dubbeldam, R L Kirby, G A Lucas, J Ostojic, R Russenschuck, Stephan Siemko, A Vanenkov, I Weterings, W 1997 1997 In the framework of the LHC magnet development programme, a large bore single aperture 1-meter long superconducting dipole has been built in collaboration with HOLEC. The magnet features a single layer coil wound using the LHC main dipole outer layer cable, phenolic inserts, and a keyed two part structural iron yoke. This paper presents the magnetic and mechanical design and optimisation of the magnet. We describe the coil winding and curing, and present the construction and assembly procedures. Finally we report on the mechanical behaviour during assembly and cooling, and present the magnet training behaviour. Delikaris, D Dauvergne, J P Passardi, Giorgio Lottin, J C Lottin, J P Lyraud, C 1998 1998 The design concept of the CMS experiment, foreseen for the Large Hadron Collider (LHC) project at CERN, is based on a superconducting solenoid magnet. The large coil will be made of a four layers winding generating the 4 T uniform magnetic induction required by the detector. The length of the solenoid is 13 m with an inner diameter of 5.9 m. The mass kept at liquid helium temperature totals 220 t and the electromagnetic stored energy is 2.7 GJ. The windings are indirectly cooled with a liquid helium flow driven by a thermosyphon effect. The external cryogenic system consists of a 1.5 kW at 4.5 K (entropy equivalent) cryoplant including an additional liquid nitrogen precooling unit and a 5000 litre liquid helium buffer. The whole magnet and cryogenic system will be tested at the surface by 2003 before final installation in the underground area of LHC. Siegel, N Tommasini, D Vanenkov, I 1998 1998 Capacitive force transducers have been developed and used for monitoring the coil pre-stress during assembly and excitation of several dipole models for LHC. Typically these gauges are strips several tenths of millimeter thick that can be made according to a large variety of geometries. Inserted between two surfaces, they allow to measure the distribution of contact pressures up to 200 MPa from am bient temperature to superfluid helium also in presence of a static magnetic field. The sequence and quality of the manufacturing steps are determining factors in the performance of this kind of gauge s. The paper describes the basic principles, possible configuration geometries, fabrication and calibration procedures of these gauges. Finally the applications of capacitive gauges in the framework o f the R&D programme of superconducting short dipole models for LHC are reviewed and discussed. Bóna, M Perin, R Rossi, L 1998 1998 CERN and INFN are jointly building the first full-size superconducting dipole prototype for the LHC. This magnet, whose construction was launched in spring 1995, is completely manufactured in industry . Its fabrication required the upgrade of the tooling which was used to build three 10-m long prototypes under a previous CERN-INFN Collaboration. The construction is being completed and the cryostate d magnet is expected to be at CERN for testing by the end of 1997. In this paper we discuss the results of the measurements carried out at 4.2 K and 2 K to determine the conductor properties (Ic of wi res and cables, magnetization), as well as the short sample limit. The main features of the coil construction are presented, together with the results of the main fabrication phases. In particular, th e validity of the fabrication techniques is assessed based on the obtained results. Wolf, R 1998 1998 The field integral in superconducting accelerator magnets wound with Rutherford cable decays slowly when the magnet current is constant. This is believed to be caused by the decrease of the filament m agnetization of the cable strands due to current redistribution. In this paper the decrease is calculated for changes of the self-field of the strand and for changes of the external field due to the o ther strands. It is shown that the self field can only contribute significantly if the current change redistributes homogeneous by over the strand cross-section. However, none of the current redistrib ution mechanisms studied, including the quality index number of the critical current transition, gave a sufficiently large redistribution. Only the external field changes can explain the large decreas e (about 20%) of the filament magnetization observed on LHC prototype dipole magnets. An analytical model shows that the average decrease always lies between 1 and 2 times the absolute value of the av erage external field change in the windings, provided that the field is periodic over the length of the cable. Leroy, D Oberli, L R Perini, D Siemko, A Spigo, G 1998 1998 A twin-aperture superconducting (sc) dipole model has been designed in collaboration with Finnish and Swedish Institutions and built at CERN. The cable critical current was attained at a central field of 10.5 T at a temperature of 1.77 K after three training quenches only. This model has shown a very good quench performance as well as a robust mechanical behavior over several thermal cycles. This p aper will discuss the design, the innovations of the mechanical structure, and the results obtained during the intensive campaigns of tests. Andreyev, N I Artoos, K Kurtyka, T Leroy, D Oberli, L R Perini, D Russenschuck, Stephan Siegel, N Siemko, A Tommasini, D Vanenkov, I Walckiers, L Weterings, W 1998 1998 The LHC model program for main dipoles is based on the design, fabrication and testing at CERN of a number of single and twin aperture 1m long magnets. So far, a number of single aperture models, each with specific characteristics, were tested at 2 K at a rate of about one per month. These magnets are the main tool used to check coil performance as a function of design and assembly options in view of optimizing and finalizing choices of components and procedures. Initial quenching field levels of 8.8 T were obtained and the short sample limit of the cable at 1.9 K was reached corresponding to a central bore field of 10 T. A few twin aperture dipole models were also built and tested, using the same structural components as for the long magnets which are now being built in industry. The paper discusses the main characteristics of the models built so far, the instrumentation developed to date and the experience obtained. Finally it describes the plans aimed at continuing a vigorous program to provide input to the long magnet program in industry. Bottura, L Pagano, O Perin, R Perini, D Savary, F Siemko, A Spigo, G Vlogaert, J Walckiers, L 1998 1998 A number of twin aperture, 10 m long, model dipole magnets for the LHC Project have been built and tested. With regard to the models of the first generation, the inner coil diameter and the intra-beam distance were increased from 50 to 56 mm and from 180 to about 194 mm, respectively. Also with regard to the previous models, a 5-block (instead of a 6-block) coil cross-section was chosen and the wid th of the Rutherford cable was reduced from 17 mm to 15 mm. The coils were manufactured and collared in Industry, the assembly of their magnetic circuit and cold mass were carried out at CERN. The ind ividual design and manufacturing features of each of these magnets are described and the results of their warm and cold magnetic measurement are presented and discussed. Andreyev, N I Artoos, K Casarejos, E Kurtyka, T Rathjen, C Perini, D Siegel, N Tommasini, D Vanenkov, I 1998 1998 A series of single and twin aperture 1 metre magnet models has been built and tested in the framework of the R&D program of main superconducting dipole magnets for the Large Hadron Collider project. The se models, designed for a nominal field of 8.3 T at 1.8 K, have been constructed to test the performance of SC coils and to optimise various design options for the full length 15 metre long dipoles. T he models have been extensively equipped with a specially developed mechanical instrumentation, enabling both the control of main assembly parameters - like coil azimuthal and axial pre-load, stress i n the outer shrinking cylinder - and also the monitoring of magnet behaviour during cooling and energising, under the action of electromagnetic forces. The instrumentation used, mainly based on strain gauge transducers, is described and the results of mechanical measurements obtained during power tests of the models are discussed and compared with the design predictions based on Finite Element calc ulations. Rifflet, J M Peyrot, M Rohmig, P Tortschanoff, Theodor Védrine, P 1998 1998 In the framework of the LHC (Large Hadron Collider) R&D program, CERN and CEA-Saclay have collaborated to develop and construct two quadrupole magnet prototypes which have been successfully cold-teste d. This collaboration has been extended as part of French special contribution to the LHC project. The previous design has been adapted to meet the new LHC parameters and two new cold masses are being constructed. This paper describes the new cold masses, their assembly process and the foreseen organization for the industrial production of about 470 units. Salminen, J Ijspeert, Albert Ang, Z Billan, J Walckiers, L Bapna, S Karmarkar, M Puntambekar, A Thipsay, A García-Tabarés, L 1999 1999 The LHC main dipoles will be equipped with sextupole corrector magnets with a field strength of 1700 x2 (T,m) and a magnetic length of 110 mm to correct sextupole field errors. Within the LHC magnet programme CERN has developed in collaboration with CAT a cosine-q type of design where much emphasis has been put on the cost reduction. The magnet features a two-layer racetrack coil, without end spacers, wound from a rectangular NbTi-wire. The two layers are wound simultaneously turning in opposite directions. The yoke is made of a scissor-type of lamination, which allows bringing the iron close to the coil for field enhancement. In this paper we review the manufacturing experiences with the first 12 prototypes built at CERN and CAT. The results of the training at 4.2 K and 1.9 K are presented along with the magnetic field quality measured at room temperature and at 1.9 K. Bajko, M Ijspeert, Albert Pérez, J C García-Tabarés, L Calero, J Toral, F 1999 1999 The precompression of the coils is considered to be one of the most important parameters to achieve good training performance in a superconducting magnet. In order to better understand and optimise precompression, a test device has been created that allows to test individual coils in a cryostat at 4.2 K exerting a variable precompression in situ. The paper describes the design, construction and calibration of the testing device, the test instrumentation and the results of the first experiments with sextupolar coils. This work was realised in the framework of a collaboration between CERN and CEDEX/Spain. Kirby, G A Nakamoto, T Ostojic, R Taylor, T M Terashima, A Higashi, N Higashi, H Kawamata, H Ogitsu, T Shintomi, T Tanaka, K Tsuchiya, K Vanenkov, I Yamamoto, A 1999 1999 A superconducting insertion quadruple is being developed by KEK in collaboration with CERN for the Large Hadron Collider (LHC) project. The mechanical design of the magnet in which the pre-stress is applied to the coil through thin stainless steel collars inside the yoke, the two halves of which are held together by means of keys, has been validated experimentally by measurements on a short model. The 140 mm long model was assembled from real magnet components in order to simulate the magnet assembly and to evaluate the change in coil pre-stress during assembly and cool-down. A new technique using capacitance pressure transducers was used, which has enabled measurements of the stress distributions in the coil with high accuracy. This paper describes the mechanical design of the quadrupole magnet and results obtained from the short mechanical model. Karppinen, M Ijspeert, Albert Hauge, N Nielsen, B R 1999 1999 A prototype of the MCBX correction dipole magnet is being built in industry. It features a horizontal dipole nested inside a vertical dipole The coils of the 0.6 m long single-bore magnet are wound with 7 or 9 rectangular superconducting wires pre-assembled as flat cables. As the end fields contribute for more than 50 % to the field integral an optimisation in 3D was required. The impregnated coils containing CNC-machined end spacers are pre-compressed with an aluminium shrinking cylinder. The yoke consists of scissor-laminations to back up the coil rigidity and to centre the coil assembly. These laminations move inward during the cooldown and the movement is blocked at a pre-defined temperature building-up a circumferential stress in the stainless steel outer shell. This paper describes the magnetic and mechanical design of this magnet. The expected performance from the calculations is presented. The assembly procedure is reviewed and the experience with the 250 mm long mechanical model is reported. Ang, Z Bottura, L Tommasini, D Walckiers, L 1998 1998 A series of 1-m long, 56 mm aperture dipole models has been built and tested at CERN within the scope of the R&D program for LHC. Here we report a summary of results of warm and cold steady state field measurements in these models, concentrating on the contribution of the coil geometry. The first allowed harmonics are clearly correlated to the coil azimuthal size, and the slope of the correlation can be predicted accurately.