The high luminosity LHC (HL-LHC) project is aimed at studying and implementing the necessary changes in the LHC to increase its luminosity by a factor of five. Among the magnets that will be upgraded ...are the 16 superconducting low-β quadrupoles placed around the two high luminosity interaction regions (ATLAS and CMS experiments). In the current baseline scenario, these quadrupole magnets will have to generate a gradient of 140 T/m in a coil aperture of 150 mm. The resulting conductor peak field of more than 12 T will require the use of Nb 3 Sn superconducting coils. We present in this paper the HL-LHC low-β quadrupole design, based on the experience gathered by the US LARP program, and, in particular, we describe the support structure components to pre-load the coils, withstand the electro-magnetic forces, provide alignment and LHe containment, and integrate the cold mass in the LHC IRs.
The forward hadron magnets of the planned electron-ion collider (EIC) at Brookhaven National Laboratory (BNL) present a set of unique challenges. In addition to the typical magnet requirements in ...terms of aperture, gradient, and field quality, the field leakage from the hadron magnets to the electron apertures must be negligible. Due to the close proximity of the two apertures the shielding solution for the electron beam can affect the field quality of the hadron magnets.
In this paper, a design for the Q1ApF/Q1BpF low beta quadrupoles based on NbTi Rutherford cable operating at 2K is presented. In this design the electron beam shielding and the required field quality in the hadron magnets are achieved using a set of cutouts in the iron yoke solely without resorting to active shielding. The chosen layout along with the key parameters are presented and their effect on hadron magnets in term of field quality and operational margins are also discussed.
In the context of high-energy physics, the use of Nb 3 Sn superconducting magnets as a cost-effective and reliable technology depends on improvements in the following areas: long development and ...manufacturing cycles, conductor degradation after thermal cycling, long training, as well as a demonstration in accelerator magnets with a beam aperture of the full potential of modern Nb 3 Sn conductors. In short, performance, robustness, and cost are the three issues to be addressed. The Magnet Development project (MagDev) of the Swiss Accelerator Research and Technology initiative (CHART) at the Paul Scherrer Institute (PSI) aims to contribute to the solutions to each of these issues, re-thinking the manufacturing and design process. In our program, every innovation is to be validated by means of a panoply of fast-turnaround tools: from non-powered and powered samples and coils, tested under background field, to low-field subscale magnets and high field short prototypes. This work presents one element in this panoply of R&D vehicles: a stress-managed Nb 3 Sn coil called BigBOX, impregnated with paraffin wax, and tested, through a collaboration with the Magnet Development Program of the United States (US-MDP), in the background field of Brookhaven National Laboratory (BNL)'s common coils dipole DCC17.
The Electron-Ion Collider (EIC), planned for construction at Brookhaven National Laboratory, will consist of two intersecting beams of intense electrons and high-energy protons or heavier atomic ...nuclei. The collider will need many demanding components, including high field superconducting magnets for the Interaction Region (IR). It has been decided that a prototype of one such magnet, the B1pF dipole, shall be built, to validate design choices common to all Rutherford cable dipole and quadrupole IR magnets. B1pF is one of several high field magnets in the interaction region whose design is based on the 15.1 mm wide NbTi cable, a cable like the one used in the main dipole coil of the Large Hadron Collider (LHC) at CERN. The current design is based on a single layer coil with an inner diameter of 300 mm and magnetic length of ∼3 m which generates a magnetic field at the center of the magnet of about 3.7 T at a current of ∼11 kA at design. This paper presents the mechanical design of the B1pF dipole magnet, and the R&D effort associated with the development of the prototype, including tests for successfully winding and curing coils of the needed configuration into proper structural and magnetic elements, and including a multilayer magnetic return yoke which meets field requirements while providing an initial reduced structure suitable for operational testing in an existing test facility.
The MQXFA production series quadrupoles being built for the Hi-Lumi (HL) LHC upgrade by the US Accelerator Upgrade Project (US-HL-LHC AUP) will have very limited voltage instrumentation for ...characterizing quench events that occur during magnet training and performance validation testing. In order to understand the origin of the quenches, and whether they have some implication for ongoing magnet fabrication, a full-length Quench Antenna Array (QAA) was built with axial resolution of 50 mm to be employed during cold testing in the anti-cryostat. The goal is to have fine-resolution, full-length coverage detection of quench events axially, as well as to have azimuthal resolution on the order of the cable width (about 1 degree for the cross-section), in a device that can be used both for vertical and horizontal testing. To achieve this, a 5 m long QAA with 128 channels of high-speed data acquisition has been designed and fabricated. The array features full-length radially positioned antennas for azimuthal localization, and short, high-sensitivity, antennas for axial detection. This paper discusses the design, construction and analysis of the MQXFA QAA, and first results from its use during quench testing in the production magnets.
A block coil geometry is appealing in the body of particle accelerator dipole or quadrupole magnets, but less so in the ends of conventional designs, because conductors near the midplane of the beam ...tube must be bent in the hard direction to cross over to the other side of the tube. To avoid damage to brittle conductors such as Nb 3 Sn or HTS, the bend must be very gradual, resulting in undesirably long magnet ends. An alternative design - "overpass/underpass" or "cloverleaf" - can ramp the conductor within a short length with bending only in the easy direction. Described here is a proof-of-principle design and analysis of an "overpass/underpass" coil geometry for a block coil dipole of 11 T or more.
This paper presents the design, construction, and test results of a high-energy-density coil for a superconducting magnetic energy storage system (SMES). The coil was designed to reach 25 T at 4 K in ...a 100-mm bore under a program funded by ARPA-E. The coil used over 6 km of 12-mm-wide second-generation high-temperature superconductors (HTS) provided by SuperPower. Such high fields and large aperture in a coil built with a new and still-developing conductor and magnet technology created several challenges, which included large stresses and quench protection. This paper summarizes an ambitious research program that resulted in an SMES coil reaching 12.5 T at 27 K. This is the first time that such high fields and such high energy densities have been generated at a temperature over 10 K, and it opens the door for the possible use of HTS magnets in energy storage and other applications.
An important step toward the advent of nuclear fusion as a future power source is the development of plasma-facing materials that can function as designed for a long period of time. While ITER and ...other devices including Wendelstein 7-X and the Joint European Torus will provide insight into divertor and first wall performance, a dedicated device to advance the understanding of material performance in the representative plasma environments is needed. The Material Plasma Exposure eXperiment has been proposed as a linear plasma device to generate and to direct fusion reactor-like plasma energy and particle flux at the target materials with electron temperatures of 1-15 eV and electron densities of <inline-formula> <tex-math notation="LaTeX">10^{20} </tex-math></inline-formula>-<inline-formula> <tex-math notation="LaTeX">10^{21}\,\,\text{m}^{-3} </tex-math></inline-formula>. Given that the requirements for radio frequency (RF) heating on-axis field are no greater than 2.5 T and the warm bore diameters must be between 60 cm and 1.5 m, the conceptual design was developed for the experiments on a set of superconducting magnets carried out using commercially available NbTi superconductors. This conceptual design evaluated the cryogenic heat loads, mechanical loads, and quench protection to ensure that the current design is compatible with current technologies. In addition, an alternative evaluation of this design relative to ReBCO high-temperature superconducting magnets determined the conditions under which these technologies could be advantageous.
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.
Magnets in the fragment separator region of the Facility for Rare Isotope Beams (FRIB) would be subjected to extremely high radiation and heat loads. The critical elements of FRIB are the dipole ...magnets, which are used to select the desired isotopes. Since conventional NiTi and Nb 3 Sn superconductors must operate at ~ 4.5 K, the removal of the high heat load generated in these magnets using these superconductors would be difficult. High-temperature superconductors have been shown to be radiation resistant and can operate in the 40 K temperature range where heat removal is an order of magnitude more efficient than at 4.5 K. The coils of this magnet must accommodate the large curvature from the 30° bend that the magnet will subtend. This paper will describe the magnetic and conceptual design for these magnets.
PDF
