Construction of block-coil high-field model dipoles for future hadron colliders

Abstract

Abstract-A family of high-field dipoles is being developed at Texas A&M University, as part of the program to improve the cost-effectiveness of superconducting magnet technology for future hadron colliders. The TAMU technology employs stress management, flux-plate control of persistent-current multipoles, conductor optimization using mixed-strand cable, and metalfilled bladders to provide pre-load and surface compliance. Construction details and status of the latest model dipole will be presented.

Fabrication of ‘TAMU3’, a ‘Wind/React’ stress-managed 14T Nb3Sn block coil design

“…This third developmental phase incorporates, internal coil stressmanagement, relaxed tolerances, and a simple construction via bladder preloading, reduction of ac losses and snap-back via field/conductor orientation, and the inclusion of flux plates (for injection field harmonic suppression, not applicable for phases 2 and 3) of the earlier phases [1,2]. TAMU3 will additionally utilize "high J c (12T, 4.2K) Nb 3 Sn Rutherford type performance cable" in the range of 2.5 to 3.0 kA/mm 2 . There have been major improvements in materials and their properties resulting in simplification of several of the third phase processes.…”

Test Results of a ${\rm Nb}_{3}{\rm Sn}$ Wind/React “Stress-Managed” Block Dipole

“…This paper presents and discusses data obtained from the testing and operation of TAMU2. The construction details were presented in previous papers [1,2]. The main objective in building and testing TAMU2 was to validate the stress management strategy [3] in which a support matrix is integrated with the windings and pressurized metal filled bladders [4] are used to preload the external structure and to transmit stress to the flux return yoke and ultimately to the aluminum retaining cylinder.…”

“…The side bladders provide uniform stress transfer of horizontal Lorentz stress from the coil to the flux return. The top/bottom bladders friction-lock the beam elements of the stress management structure at the ends of the winding so that axial Lorentz force is transferred directly to the flux return [1,2].…”

Rapid-cycling dipole using block-coil geometry and bronze-process Nb₃Sn superconductor

“…The Texas A&M group is developing a high-field dipole technology for future colliders, with a near-term goal of 16 T using Nb 3 Sn windings [3] and a long-term goal of 25 T using Bi-2212 windings [4]. The design uses a block-coil geometry to convey several key benefits: facilitation of stress management within windings, natural suppression of persistent-current magnetization, modular construction of coils, and expansion-bladder preload.…”