Canted-Cosine-Theta (CCT) magnet is an accelerator magnet that superposes fields of nested and tilted solenoids that are oppositely canted. The current distribution of any canted layer generates a ...pure harmonic field as well as a solenoid field that can be cancelled with a similar but oppositely canted layer. The concept places windings within mandrel's ribs and spars that simultaneously intercept and guide Lorentz forces of each turn to prevent stress accumulation. With respect to other designs, the need for pre-stress in this concept is reduced by an order of magnitude making it highly compatible with the use of strain sensitive superconductors such as Nb 3 Sn or HTS. Intercepting large Lorentz forces is of particular interest in magnets with large bores and high field accelerator magnets like the one foreseen in the future high energy upgrade of the LHC. This paper describes the CCT concept and reports on the construction of CCT1 a "proof of principle" dipole.
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.
We report on the progress in our R&D program, targeted to develop the technology for the application of (Bi-2212) in accelerator magnets. The program uses subscale coils, wound from insulated cables, ...to study suitable materials, heat treatment homogeneity, stability, and effects of magnetic field and thermal and electro-magnetic loads. We have addressed material and reaction related issues and report on the fabrication, heat treatment, and analysis of subscale Bi-2212 coils. Such coils can carry a current on the order of 5000 A and generate, in various support structures, magnetic fields from 2.6 to 9.9 T. Successful coils are therefore targeted towards a hybrid -HTS magnet which will demonstrate the feasibility of Bi-2212 for accelerator magnets, and open a new magnetic field realm, beyond what is achievable with .
We summarize the status of Nb3Sn development in the USA. The US conductor development program (CDP), initiated in 1999, has resulted in commercial wires that carry more than 3 kAmm-2 at 12 T and 4.2 ...K. These high current Nb3Sn wires have successfully been cabled and used in accelerator magnets that achieved record magnetic fields. This article describes the CDP, its achievements, and the manufacturers involved. We discuss low magnetic field instability in magnets that re-emerged through the use of very high current density Nb3Sn wires, and solutions that address these stability problems. It is shown how cabling of high current wires is a balance between edge deformation and mechanical stability of the cable, and an empirical cable recipe is described. The article concludes with an outlook for possible future methods to optimize, and further increase, the current carrying capacity in Nb3Sn at medium magnetic fields. The article describes how record current density Nb3Sn wires have to be implemented in accelerator type magnets, to achieve magnetic fields that approach the performance limitations of Nb3Sn.
In this paper, we outline the present status of the design studies for the high-luminosity Large Hadron Collider, focusing on the choice of the aperture of the inner triplet quadrupoles. After ...reviewing some critical aspects of the design such as energy deposition, shielding, heat load, and protection, we present the main tentative parameters for building a 150-mm-aperture Nb 3 Sn quadrupole, based on the experience gathered by the LARP program in the past several years.
As part of the Large Hadron Collider (LHC) Luminosity upgrade program, the U.S.-LHC Accelerator Research Program collaboration and CERN are working together to design and build a 150-mm aperture Nb 3 ...Sn quadrupole for the LHC interaction regions. A first series of 1.5-m-long coils was fabricated and assembled in a first short model. A detailed visual inspection of the coils was carried out to investigate cable dimensional changes during heat treatment and the position of the windings in the coil straight section and in the end region. The analyses allow identifying a set of design changes which, combined with a fine tune of the cable geometry and a field quality optimization, were implemented in a new second-generation coil design. In this paper, we review the main characteristics of the first generation coils, describe the modification in coil layout and discuss their impact on parts design and magnet analysis.
In 2004, the US DOE established the LHC Accelerator Research Program (LARP) with the goal of developing a technology base for future upgrades of the LHC. The focus of the magnet program, which is a ...collaboration of three US laboratories, BNL, FNAL and LBNL, is on development of high gradient quadrupoles using Nb 3 Sn superconductor. Other program components address issues regarding magnet design, radiation-hard materials, long magnet scale-up, quench protection, fabrication techniques and conductor and cable R&D. This paper presents an overall view of the program with emphasis on the current quadrupole project and outlines the long-term goals of the program
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