Hybrid magnets are currently under consideration as an economically viable option towards 20 T dipole magnets for next generation of particle accelerators. In these magnets, High Temperature ...Superconducting (HTS) materials are used in the high field part of the coil with so-called "insert coils", and Low Temperature Superconductors (LTS) like Nb 3 Sn and Nb-Ti superconductors are used in the lower field region with so-called "outsert coils". The attractiveness of the hybrid option lays on the fact that, on the one hand, the 20 T field level is beyond the Nb 3 Sn practical limits of 15-16 T for accelerator magnets and can be achieved only via HTS materials; on the other hand, the high cost of HTS superconductors compared to LTS superconductors makes it advantageous exploring a hybrid approach, where the HTS portion of the coil is minimized. We present in this paper an overview of different design options aimed at generating 20 T field in a 50 mm clear aperture. The coil layouts investigated include the Cos-theta design (CT), with its variations to reduce the conductor peak stress, namely the Canted Cos-theta design (CCT) and the Stress Management Cos-theta design (SMCT), and, in addition, the Block-type design (BL) including a form of stress management and the Common-Coil design (CC). Results from a magnetic and mechanical analysis are discussed, with particular focus on the comparison between the different options regarding quantity of superconducting material, field quality, conductor peak stress, and quench protection.
This work aims at contributing to the development of superconducting Nb3Sn thin films for possible applications, as for instance in superconducting radio frequency (SRF) cavities. The synthesis of ...Nb–Sn coatings was carried out on copper substrates by electrodeposition from 1-butyl-3-methylimidazolium chloride (BMIC) ionic liquids containing SnCl2 and NbCl5. Cyclic voltammetric curves were recorded to identify the reduction potentials of Nb and Sn ionic species. Electrodeposition was performed at 40 and 400mA/cm2 and 130°C. The CV demonstrated that BMIC has a suitable potential window for co-deposition of Nb and Sn. The electrodeposited coatings showed a cubic Nb3Sn phase with (211) preferred orientation, a disordered orthorhombic NbSn2 phase and Sn–Cu phases. Film thickness was from 200 to 750nm. These results suggest that electrodeposition of Nb–Sn coatings on copper substrates could be a suitable route to one day replace the current expensive Nb SRF cavities.
•Reproducible electrochemical process to synthesize Nb3Sn films onto Cu.•BMIC ionic liquids containing Sn and Nb chlorides.•Nb–Sn coatings containing the cubic Nb3Sn phase were obtained.•A maximum coating thickness of 750nm was obtained.
A 100-TeV-scale Hadron Collider (HC) with a nominal operation field of at least 15 T is being considered for the post-LHC era, which requires using the Nb 3 Sn technology. Practical demonstration of ...this field level in an accelerator-quality magnet and substantial reduction of the magnet costs are important requirements for realization of such a machine. Fermilab has started the development of a 15 T Nb 3 Sn dipole demonstrator for a 100-TeV-scale HC. The magnet design is based on optimized 60-mm-aperture four-layer shell-type coils, graded between the inner and outer layers to maximize the performance and reduce the cost. The experience gained during the Nb 3 Sn magnet R&D is applied to various aspects of the magnet design. This paper describes the magnetic and structural designs and parameters of the 15 T Nb 3 Sn dipole demonstrator and the steps toward its fabrication.
Keystoned Rutherford cables made of 28 strands and with a stainless steel core were developed and manufactured using 1-mm Nb 3 Sn composite wires produced by Oxford Superconducting Technology with ...127 and 169 restacks using the Restacked-Rod-Process. The performance and properties of these cables were studied to evaluate possible candidates for 15-T accelerator magnets.
The 11 T Dipole for HL-LHC: Status and Plan Savary, F.; Barzi, E.; Bordini, B. ...
IEEE transactions on applied superconductivity,
06/2016, Letnik:
26, Številka:
4
Journal Article
Recenzirano
Odprti dostop
The upgrade of the Large Hadron Collider (LHC) collimation system includes additional collimators in the LHC lattice. The longitudinal space for these collimators will be created by replacing some of ...the LHC main dipoles with shorter but stronger dipoles compatible with the LHC lattice and main systems. The project plan comprises the construction of two cryoassemblies containing each of the two 11-T dipoles of 5.5-m length for possible installation on either side of interaction point 2 of LHC in the years 2018-2019 for ion operation, and the installation of two cryoassemblies on either side of interaction point 7 of LHC in the years 2023-2024 for proton operation. The development program conducted in conjunction between the Fermilab and CERN magnet groups is progressing well. The development activities carried out on the side of Fermilab were concluded in the middle of 2015 with the fabrication and test of a 1-m-long two-in-one model and those on the CERN side are ramping up with the construction of 2-m-long models and the preparation of the tooling for the fabrication of the first full-length prototype. The engineering design of the cryomagnet is well advanced, including the definition of the various interfaces, e.g., with the collimator, powering, protection, and vacuum systems. Several practice coils of 5.5-m length have been already fabricated. This paper describes the overall progress of the project, the final design of the cryomagnet, and the performance of the most recent models. The overall plan toward the fabrication of the series magnets for the two phases of the upgrade of the LHC collimation system is also presented.
Fermilab and CERN have started the development of 11 T Nb 3 Sn dipoles to replace a number of Large Hadron Collider (LHC) NbTi dipole magnets and free space for the additional collimators anticipated ...for the LHC luminosity upgrades. An essential step in the design of these magnets is the development of the 40-strand, high aspect ratio cable needed to achieve the nominal field of 11 T at the LHC operating current of 11.85 kA. To investigate conductors suited for this and other high-field magnet applications, a larger Superconducting Strand and Cable R&D lab was established at FNAL's Technical Division. Keystoned cables with and without a stainless steel core were developed and produced using 0.7 mm Nb 3 Sn strands made by Oxford Superconducting Technology with 127 (baseline) and 169 (advanced) restacks using the Restacked-Rod-Process. The electrical performance of these two strands is compared in cables made with different processes and geometries. Some of the effects of a cross-over in the cable were measured. Finally, it is shown how finite element modeling can be used as an aid in Rutherford-type cable design.
PDF
