Construction of a Mirror-Configuration Stress-Managed<tex>$rm Nb_3rm Sn$</tex>Block-Coil Dipole

Abstract

The second phase of development of a new high-field dipole technology has been completed. A model dipole employing wind/react Nb 3 Sn cable and stress-managed block coil geometry was fabricated and will soon be tested at LBNL. The dipole features stress-strain management in its internal windings and metal-filled bladder preload. Pending validation of performance of these new features, the new technology should result in improved cost-effective fabrication of dipoles for 16 T and beyond. Construction experience and plans for the next phase of development are presented.

50 tesla superconducting solenoid for fast muon cooling ring

“…The division of shells was chosen to limit Lorentz stress in each shell to ~120 MPa. A new development was employed to manage stress within each shell, which has emerged from our development of high-field dipoles [11]. An outer stainless-steel stress shell is placed on each vacuum-impregnated winding, and an expansion bladder is located between the winding and the stress shell.…”

Improved S-2 Glass Fabric Insulation for $\hbox{Nb}_{3}\hbox{Sn}$ Rutherford Cable

“…The above requirements upon the insulation system have increasingly become a pacing constraint for high-field dipole development, as the current density within the non-Cu subelements of the strand has improved (currently 3 kA/mm at 12 T, 4.2 K); the design field has pushed to 16 Tesla and beyond; and Lorentz stresses have increased to 200 MPa and beyond [1]. Current-generation model dipoles with such parameters utilize either S-2 glass fabric [2], [3] m/side or pre-impregnated ceramic fabric [4] m/side for insulation. The volume fraction of insulation in the windings ranges from 12-22% of the winding, which costs 2-4 Tesla when projected along the working line of a dipole.…”

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

“…The Texas A&M University Accelerator Research Lab continues the development of a new approach to the design and construction of Nb 3 Sn magnets with the next phase prototype for high field (>10T) wind & react based magnet coils. 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].…”