The planned upgrade of the LHC collimation system includes additional collimators to be installed in the dispersion suppressor areas of points 2, 3 and 7. To provide the necessary longitudinal space ...for the collimators, a replacement of 8.33 T Nb-Ti LHC main dipoles with 11 T dipoles based on rm Nb 3 rm Sn superconductor compatible with the LHC lattice and main systems is being considered. To demonstrate this possibility FNAL and CERN have started a joint program to develop a 2 m long single-aperture dipole magnet with the nominal field of 11 T at similar to 11.85 kA current and 60 mm bore. This paper describes the demonstrator magnet magnetic and mechanical designs and analysis, coil fabrication procedure. The rm Nb 3 rm Sn strand and cable parameters and test results are also reported.
Training of accelerator magnets is a costly and time consuming process. The number of training quenches must therefore be reduced to a minimum. We investigate training of impregnated Nb3Sn Rutherford ...cable in a small-scale experiment. The test involves a Rutherford cable impregnated in a meandering channel simulating the environment of a canted-cosine-theta (CCT) coil. The sample is powered using a transformer and the Lorentz force is generated by an externally applied magnetic field. The low material and helium consumption enable the test of a larger number of samples. In this article, we present training of samples impregnated with alumina-filled epoxy resins, a modified resin with paraffin-like mechanical properties, and a new tough resin in development at ETH Z\"urich. These new data are compared with previous results published earlier. Compared to samples with unfilled epoxy resin, those with alumina-filled epoxy show favorable training properties with higher initial quench currents and fewer training quenches before reaching 80% of the critical current.
Purpose To introduce a Whitneyelement based coupling of the Finite Element Method FEM and the Boundary Element Method BEM to discuss the algebraic properties of the resulting system and propose ...solver strategies. Designmethodologyapproach The FEM is interpreted in the framework of the theory of discrete electromagnetism DEM. The BEM formulation is given in a DEMcompatible notation. This allows for a physical interpretation of the algebraic properties of the resulting BEMFEM system matrix. To these ends we give a concise introduction to the mathematical concepts of DEM. Findings Although the BEMFEM system matrix is not symmetric, its kernel is equivalent to the kernel of its transpose. This surprising finding allows for the use of two solution techniques regularization or an adapted GMRES solver. Research limitationsimplications The programming of the proposed techniques is a work in progress. The numerical results to support the presented theory are limited to a small number of test cases. Practical implications The paper will help to improve the understanding of the topological and geometrical implications in the algebraic structure of the BEMFEM coupling. Originalityvalue Several original concepts are presented a new interpretation of the FEM boundary term leads to an intuitive understanding of the coupling of BEM and FEM. The adapted GMRES solver allows for an accurate solution of a singular, unsymetric system with a righthand side that is not in the image of the matrix. The issue of a gridtransfer matrix is briefly mentioned.
In this paper we elaborate on the nature and challenges for the magnet
systems of a muon collider as presently considered within the scope of the
International Muon Collider Collaboration (IMCC). We ...outline the structure of
the work proposed over the coming period of five years to study and demonstrate
relevant magnet technology. The proposal, which is part of the overall work
planned to establish feasibility of a muon collider, is in direct response to
the recent recommendations received from the Laboratories Directors Group
(LDG). The plan is to profit from joint activities, within the scope of the
IMCC and beyond, implemented through direct and EU-funded contributions.
In this paper we present the co-simulation of a PID class power converter controller and an electrical circuit by means of the waveform relaxation technique. The simulation of the controller model is ...characterized by a fixed-time stepping scheme reflecting its digital implementation, whereas a circuit simulation usually employs an adaptive time stepping scheme in order to account for a wide range of time constants within the circuit model. In order to maintain the characteristic of both models as well as to facilitate model replacement, we treat them separately by means of input/output relations and propose an application of a waveform relaxation algorithm. Furthermore, the maximum and minimum number of iterations of the proposed algorithm are mathematically analyzed. The concept of controller/circuit coupling is illustrated by an example of the co-simulation of a PI power converter controller and a model of the main dipole circuit of the Large Hadron Collider.
Colliders are built on a foundation of superconducting magnet technology that provides strong dipole magnets to maintain the beam orbit and strong focusing magnets to enable the extraordinary ...luminosity required to probe physics at the energy frontier. The dipole magnet strength plays a critical role in dictating the energy reach of a collider, and the superconducting magnets are arguably the dominant cost driver for future collider facilities. As the community considers opportunities to explore new energy frontiers, the importance of advanced magnet technology - both in terms of magnet performance and in the magnet technology's potential for cost reduction - is evident, as the technology status is essential for informed decisions on targets for physics reach and facility feasibility.
For the FAIR-project at GSI a model dipole was built at BNL with the nominal field of 4 T and a nominal ramp rate of 1 T/s. The magnet design was similar to the RHIC dipole, with some changes for ...loss reduction and better cooling. The magnet was already successfully tested in a vertical cryostat, with good training behaviour. Cryogenic losses were measured and first results of field harmonics were published. However, for a better understanding of the cooling process, quench currents at several ramp rates were investigated. Detailed measurements of the field harmonics at 2 T/s between 0 and 4 T were performed.
FNAL and CERN are developing a 5.5-m-long twin-aperture Nb3Sn dipole suitable for installation in the LHC. A 2-m-long single-aperture demonstrator dipole with 60 mm bore, a nominal field of 11 T at ...the LHC nominal current of 11.85 kA and 20% margin has been developed and tested. This paper presents the results of quench protection analysis and protection heater study for the Nb3Sn demonstrator dipole. Extrapolations of the results for long magnet and operation in LHC are also presented.
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