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

Abstract

Abstract-A second phase of a high field dipole technology development has been tested. A Nb 3 Sn block-coil model dipole was fabricated, using magnetic mirror geometry and wind/react coil technology. The primary objective of this phase was to make a first experimental test of the stress-management strategy pioneered at Texas A&M. In this strategy a high-strength support matrix is integrated with the windings to intercept Lorentz stress from the inner winding so that it does not accumulate in the outer winding. The magnet attained a field that was consistent with short sample limit on the first quench; there was no training. The decoupling of Lorentz stress between inner and outer windings was validated. In ramp rate studies the magnet exhibited a remarkable robustness in rapid ramping operation. It reached 85% of short sample(ss) current even while ramping 2-3 T/s. This robustness is attributed to the orientation of the Rutherford cables parallel to the field in the windings, instead of the transverse orientation that characterizes common dipole designs.Test results are presented and the next development phase plans are discussed.

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

“…The suppression of ac losses was evident in the testing of the model dipole TAMU2 [5]. This model Nb 3 Sn dipole attained short-sample field on its first quench, and 85% of short-sample field even at a ramp rate of 4 T/s!…”

Block-Type Nb3Sn Dipole R&D at Texas A&M University

“…a b Fig. 10.1 (a) Coil cross-section; and (b) a 3D sketch of a block-type dipole magnet 1999-2001 Nb-Ti 6.6 T/8.1 kA 6.5 T/8.0 kA Battle et al (2001) TAMU2 2002-2006 Nb 3 Sn (ITER) a 6.9 T/9.4 kA 6.6 T/8.9 kA Noyes et al (2006) and McInturff et al (2007 ) TAMU3 2007-2013 Nb 3 Sn (RRP) b 13 T/13.6 kA 6.6 T/7.6 kA Blackburn et al (2008a), Holik et al (2011Holik et al ( , 2014 1. How to manage the accumulation of Lorentz stress so that it does not produce strain in the windings beyond the limit for degradation of critical current density J c ?…”

Progress with High-Field Superconducting Magnets for High-Energy Colliders

“…At the same time, the magnet group at TAMU proposed [30] and studied [31] a concept of stress management in high-field dipoles based on block-type coils. Table 3 lists the design parameters of the single-aperture dipole magnets developed and tested at LBNL and FNAL, and Fig.…”