Final Technical Report
This document presents an annual report on our long-term R&D grant for development of new technology for future colliders. The organizing theme of our development is to develop a compact high-field collider dipole, utilizing wind-and-react Nb3Sn coil fabrication, stress man-agement, conductor optimization, bladder preload, and flux plate suppression of magnetization multipoles . The development trail for this new technology began over four years ago with the successful testing of TAMU12, a NbTi model in which we put to a first test many of the construction details of the high-field design. We have built TAMU2, a mirror-geometry dipole containing a single coil module of the 3-module set required for the 14 Tesla design. This first Nb3Sn model was built using ITER conductor which carries much less current than high-performance conductor but enables us to prove in practice our reaction bake and impregnation strategies with ‘free’ su-perconductor. TAMU2 has been shipped to LBNL for testing. Work is beginning on the con-struction of TAMU3, which will contain two coil modules of the 14 Tesla design. TAMU3 has a design field of 13.5 Tesla, and will enable us to fully evaluate the issues of stress management that will be important to the full design. With the completion of TAMU2 and the construction of TAMU3 the Texas A&M group ‘comes of age’ in the family of superconducting magnet R&D laboratories. We have completed the phase of developing core technologies and fixtures and entered the phase of building and testing a succession of TAMU3 model dipoles that each build incrementally upon a proven core design. TAMU3 provides a testbed in which we can build a succession of model dipoles in which each new model uses one new winding module coupled with one module from the previ-ous model, and uses all of the same structural elements in successive models. This incremental development should enable us to keep to a minimum the time between the completion and test-ing of successive models. Each new model will incorporate a particular design element that we wish to evaluate: first the basic TAMU3 structure, then substitute one pancake using high-performance superconductor (3,000 A/mm2 @ 12 T, 4.2 K), then substitute one pancake using mixed-strand cable, then insert a steel nose to reduce the peak field in the end region of a single-pancake coil. While we are building and testing this succession of TAMU3 models we will de-velop the tooling and evaluate strategies for flaring the ends of the center double-pancake coil needed for.TAMU4. TAMU4 is a full implementation of the design, culminating in 14 Tesla performance. Pending the proposed increase of budget from the present 3-year-flat budget and providing that the tests of each model dipole do not lead to substantial modifications of the de-sign, the time to build and test each succeeding model could be ~9 months. During the present funding year we made a sequence of innovations that have major poten-tial benefit for the commissioning of LHC, upgrade of its luminosity, and its long-term future: • An electrode assembly, suitable for integration within the existing LHC dipoles, ca-pable of killing the electron cloud effect – an effect that threatens to limit the lumi-nosity that could be attained in LHC; • A Nb3Sn structured cable, which makes it possible to design very high gradient quadrupoles for upgrade of the interaction regions of LHC to enhance its luminosity; • A Nb3Sn/NbTi levitated-pole dipole for use in the D1 bends that combine and sepa-rate the beams at the intersection regions. The levitated-pole design uniquely solves the problems of radiation damage and heating from particles swept from the beam. • A hybrid dipole technology, in which inner windings of Bi-2212 are integrated in a Nb3Sn block-coil dipole to push to 24 Tesla, opening the possibility of a future trip-ler upgrade of LHC .
- Research Organization:
- Texas A & M Univ., College Station, TX (United States). Texas A & M Engineering Experiment Station
- Sponsoring Organization:
- USDOE - Office of Energy Research (ER)
- DOE Contract Number:
- FG02-04ER41292
- OSTI ID:
- 889404
- Report Number(s):
- DE/ER/41292.1; TRN: US0703122
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BLADDER
COMMISSIONING
DIPOLES
ELECTRODES
FABRICATION
FLARING
HEATING
IMPLEMENTATION
IMPREGNATION
LUMINOSITY
MAGNETIZATION
MODIFICATIONS
MULTIPOLES
OPTIMIZATION
ORGANIZING
QUADRUPOLES
RADIATIONS
STEELS
SUPERCONDUCTING MAGNETS
SUPERCONDUCTORS
dipole
magnet
superconductor
Nb3Sn
accelerator
storage ring
collider