The 42+ T Hybrid Magnet Project at CNRS-LNCMI-Grenoble (original) (raw)
Related papers
Status of the 43 T Hybrid Magnet of LNCMI-Grenoble
IEEE Transactions on Applied Superconductivity, 2016
Based on a close collaboration between CEA and CNRS, a new hybrid magnet is being built at LNCMI-Grenoble. By combining a resistive insert, made of Bitter and polyhelix coils, with a large bore superconducting outsert, an overall continuous magnetic field of at least 43 T will be produced in a 34 mm warm bore aperture. The superconducting coil relies on the novel development of a Nb-Ti/Cu Rutherford Cable On Conduit Conductor (RCOCC) cooled down to 1.8 K by a bath of superfluid helium at atmospheric pressure and will produce a nominal magnetic field of 8.5 T in a 1.1 m cold bore diameter. After thorough reviews of the hybrid magnet design, which have anticipated possible upgrades of the maximum magnetic field produced, the project has entered in its production phase. The status and the next steps of the project will be reviewed highlighting the remaining technical challenges.
Recent Progress of the Series-Connected Hybrid Magnet Projects
IEEE Transactions on Applied Superconductivity, 2010
The National High Magnetic Field Laboratory (NHMFL) in Tallahassee, Florida has designed and is now constructing two Series Connected Hybrid (SCH) magnets, each connecting a superconducting outsert coil and a resistive Florida Bitter insert coil electrically in series. The SCH to be installed at the NHMFL will produce 36 T and provide 1 ppm maximum field inhomogeneity over a 1 cm diameter spherical volume. The SCH to be installed at the Helmholtz Center Berlin (HZB) in combination with a neutron source will produce 25 T to 30 T depending on the resistive insert. The two magnets have a common design for their cable-in-conduit conductor (CICC) and superconducting outsert coils. The CICC outsert coil winding packs have an inner diameter of 0.6 m and contribute 13.1 T to the central field using three grades of CICC conductors. Each conductor grade carries 20 kA and employs the same type of Nb 3 Sn superconducting wire, but each grade contains different quantities of superconducting wires, different cabling patterns and different aspect ratios. The cryostats and resistive insert coils for the two magnets are different. This paper discusses the progress in CIC conductor and coil fabrication over the last year including specification, qualification and production activities for wire, cable, conductor and coil processing.
Progress in the design of the superconducting magnets for the EU DEMO
Fusion Engineering and Design
In the framework of the DEMOnstration fusion power plant (DEMO) design coordinated by the EUROfusion consortium, a pre-conceptual design of the superconducting magnet system has been developed. For the toroidal field coils (TFCs), three winding pack (WP) options have been proposed; exploring different winding approaches (pancakes vs. layers), and manufacturing techniques (react & wind vs. wind & react Nb 3 Sn). Thermal-hydraulic and mechanical analyses on the three WPs have produced encouraging results, with some critical issues to be solved in future studies and optimizations. The experimental tests on TF prototype short sample conductors have demonstrated a limited performance degradation with electromagnetic cycles and significantly lower effective strains than most of the large-size Nb 3 Sn conductors reported in literature. The toroidal field quench protection circuit has been studied, starting from different topologies and focusing on the most promising one. Two designs are also presented for the central solenoid magnet, with preliminary evaluations on the AC losses during the plasma breakdown. Finally, the design of a TF winding pack based on HTS conductors and the experimental tests on "fusion-relevant" HTS cables are illustrated.
2013
In view of the development and demonstration of high field (~ 12 T), a hybrid magnet consisting of the main outer Low Temperature Superconductor coil made from NbTi and High Temperature Superconductor (HTS) insert is developed using commercially available Bi2223/Ag tape. The performance tests were carried out both at 77 and 4.2 K. The HTS-based current lead for the HTS insert is developed and tested considering the diameter of the existing port in the cryostat. Prior to coil manufacturing several measurements were performed on HTS tape under various conditions. Here we describe the design, construction and test results of HTS insert coil.
2018
Uncertain performance and extensive training are characteristic of the accelerator magnets needed for high energy particle accelerators, particularly the Nb3Sn magnets planned for future high energy proton colliders, making high-temperature superconductor (HTS) magnets a potential option, even though there are many concerns about protection of such magnets during quench. Here we describe the performance of two recent racetrack coils made with state-of-the-art Bi-2212 wires in a 17-strand Rutherford cable that enable very high wire current density up to 1000 A/mm2 at 30 T in optimally processed wires. The coils carried up to 8.6 kA while generating a peak field of 3.5 T at 4.2 K, at a wire current density of 1020 A/mm2. Quite different from Nb-Ti and Nb3Sn magnets, these magnets showed no early quenching indicative of training, showed virtually no dependence of quench current on ramp rate and gave clear signs of entering the flux flow state in a stable manner before thermal runaway a...
2018
Uncertain performance and long training with many unpredictable quenches and slowly increasing quench currents are characteristic of the accelerator magnets needed for high energy particle accelerators, particularly the Nb3Sn magnets planned for future high energy proton colliders. This behavior makes high-temperature superconductor (HTS) magnets a potential option, even though there are many concerns about protection of such magnets during quench. Here we describe the performance of two recent racetrack coils made with a 17-strand Rutherford cable with state-of-theart Bi-2212 wires capable of delivering current density up to 1000 A/mm at 27 T. The coils carried up to 8.6 kA while generating a peak field of 3.5 T at 4.2 K, at a wire current density of 1020 A/mm. Quite differently from Nb-Ti and Nb3Sn magnets, these Bi-2212 magnets showed no early quenching indicative of training, showed virtually no dependence of quench current on ramp rate, and entered the flux flow state in a stab...
Design of a Superconducting 32 T Magnet With REBCO High Field Coils
IEEE Transactions on Applied Superconductivity, 2000
The design and fabrication of a 32 T, 32 mm cold bore superconducting magnet with high field REBCO inner coils is underway at the NHMFL. In support of the design, conductor characterization measurements have been made including critical current as a function of field, field orientation, temperature, and strain on conductors and joints. Various conductor and turn insulation systems were examined. The selected coil fabrication method for the 32 T magnet is pancake wind, dry wind coils with sol-gel insulation on a stainless steel co-wind. Quench protection of the REBCO coils by distributed heaters is under development. Small REBCO coils have been made and tested in a 20 T background field to demonstrate performance of the technology. The design of the 32 T magnet is described, including coil configuration and conductor lengths, fraction of critical current, selection of conductor copper content for protection, and stress in the windings.
Fabrication and Testing of a Combined Superconducting Magnet for the TESLA Test Facility
IEEE Transactions on Applied Superconductivity, 2006
An international collaboration at DESY is currently studying the possibilities of a new type of particle accelerator: the superconducting linear collider, developed under the project name TESLA. The TESLA Test Facility is trying to establish a well-developed collider design, which will also be helpful for the design of a superconducting X-ray Free Electron Laser facility (XFEL), a project approved by the German Government and now in its initial stage. Besides, XFEL will be the ideal workbench to improve the necessary components for the next International Linear Collider (ILC). This paper is about the fabrication and testing of the first prototype of a combined superconducting magnet for focusing and steering purposes, in the framework of the Spanish contribution to the TESLA project. It consists of a quadrupole and two dipole concentric coils, one horizontal and another one, vertical. The double pancake winding technique with a ribbon of eight pre-glued wires has been used in order to develop a cheap method for the quadrupole coils in industrial scale, as the accelerator would need about 800 magnets. The coils were fully instrumented with voltage taps to study the quench propagation. The magnet has been successfully tested at DESY and the results are reported in this paper.
Scientific Reports, 2019
High-temperature superconductors (HTS) could enable high-field magnets stronger than is possible with Nb-Ti and Nb 3 Sn, but two challenges have so far been the low engineering critical current density J e , especially in high-current cables, and the danger of quenches. Most HTS magnets made so far have been made out of REBCO coated conductor. Here we demonstrate stable, reliable and training-quenchfree performance of Bi-2212 racetrack coils wound with a Rutherford cable fabricated from wires made with a new precursor powder. These round multifilamentary wires exhibited a record J e up to 950 A/ mm 2 at 30 T at 4.2 K. These coils carried up to 8.6 kA while generating 3.5 T at 4.2 K at a J e of 1020 A/ mm 2. Different from the unpredictable training performance of Nb-Ti and Nb 3 Sn magnets, these Bi-2212 magnets showed no training quenches and entered the flux flow state in a stable manner before thermal runaway and quench occurred. Also different from Nb-Ti, Nb 3 Sn, and REBCO magnets for which localized thermal runaways occur at unpredictable locations, the quenches of Bi-2212 magnets consistently occurred in the high field regions over a long conductor length. These characteristics make quench detection simple, enabling safe protection, and suggest a new paradigm of constructing quench-predictable superconducting magnets from Bi-2212.