33. HIGH-FIELD SUPERCONDUCTOR AND SUPERCONDUCTING MAGNET TECHNOLOGIES FOR HIGH ENERGY PARTICLE COLLIDERS
The Department of Energy High Energy Physics program supports a broad research and development (R&D) effort in the science, engineering, and technology of charged particle accelerators, storage rings, and associated apparatus. Advanced R&D is needed in support of this research in high-field superconductor and superconducting magnet technologies. This topic addresses only those superconductor and superconducting magnet development technologies that support dipoles, quadrupoles, and higher order multipole corrector magnets for use in accelerators, storage rings, and charged particle beam transport systems. Grant applications are sought only in the following subtopics:
a. High-Field Superconductor Technology—Grant applications are sought to develop new or improved superconducting wire technologies for magnets that operate at a minimum of 12 Tesla (T) field, with increases up to 15 to 20 T sought in the near future (three to five years). Vacuum requirements in accelerators and storage rings favor operating temperatures of 1.8 to 20 K. Stability requirements for magnets dictate that the effective filament diameter should be less than 30 micrometers. Upgrades of existing particle accelerators will require some magnets that operate under a high radiation (and thermal) load. New or improved technologies must demonstrate: (1) property improvements such as higher critical current densities and higher upper critical fields, (2) the manageable degradation of these properties as a function of applied strain, and (3) low losses in changing transverse magnetic fields, such as for twisted round multifilamentary wires. Any proposed process improvements must result in equivalent performance at reduced cost. All grant applications must focus on conductors that will be acceptable for accelerator magnets, especially with regard to the operating conditions mentioned above, and must address plans to physically deliver a sufficient amount of material of 1 km minimum length for winding and testing in small dipole or quadrupole magnets.
Grant applications are also sought to develop improvements in the starting raw materials and the basic superconducting materials for niobium-titanium (Nb-Ti) alloys, A-15 compounds (such as Nb3Sn and Nb3Al), high-temperature superconductors (HTS; such as Bi2Sr2CaCu2O8 and YBa2Cu3O7-δ), and magnesium diborides (MgB2 and its alloyed variants). Regarding Nb-Ti alloys: High performance Nb-Ti alloys operating above 8 T continue to be required for focusing quadrupole magnets or for graded windings in the low-field portions of high-field magnets; therefore, grant applications are sought to develop Nb-Ti composite superconductors with properties optimized at 8 T fields and higher at 4.2 K. Regarding A-15 compounds: A minimum current density of 1800 A mm-2 at 15 T and 4.2 K must be achieved in the superconductor itself. Regarding HTS: A minimum current density of 1200 A mm-2 (not A cm-2) must be achieved in the superconductor itself, and a minimum current density of 250 A mm-2 must be achieved over the total conductor cross section at 12 T minimum and 4.2 K. Regarding MgB2: present wires are characterized by a filling factor that is too low, wire cross-sections that have too few filaments, and upper critical and irreversibility fields that are too low therefore, grant applications should seek to improve the current density over the wire cross-section, implement restacked round-wire multifilamentary designs, and extend the field at which a critical current density can be attained over the superconductor cross-section of 1200 A mm-2 in the 12-16 T range at 4.2 K.
Grant applications are also sought to develop: (1) innovative wire processing technologies, and (2) innovative insulating materials that are compatible with the use of intermetallic superconductors in practical devices. Innovative wire processing technologies of interest include methods to utilize stranded conductors with high aspect ratio, such as Rutherford cables, or low-loss tape geometries in particle accelerator applications; technologies to improve wire piece length and increase billet mass also are of interest. Innovative insulating materials should enable the use of intermetallic superconductors, such as the A-15, HTS, or MgB2 types, in practical devices. Insulating systems must: be compatible with high temperature reactions in the 750-900 ºC range; be capable of supporting high mechanical loads at both room and cryogenic temperatures; have a high coefficient of thermal conductivity; be resistant to radiation damage; and exhibit low creep and low out-gassing rates when irradiated.
Questions - contact Bruce Strauss (bruce.strauss@science.doe.gov)
b. Superconducting Magnet Technology—Grant applications are sought to develop: (1) improved instrumentation to measure properties (such as local strain, temperature, and magnetic field) which are directly applicable to the testing of superconducting magnets; (2) improved current leads based on high-temperature superconductors for application to high-field accelerator magnets, which have requirements that include an operating current level of 5 kA or greater, stability, low heat leak, and good quench performance; (3) alternative designs, to traditional "cosine theta" dipole and "cosine two-theta" quadrupole magnets, that may be more compatible with the more fragile A-15, and the HTS, high-field superconductors; (4) designs for bent (e.g., bending radius in the range 0.75 to 1.25m) solenoids (e.g., 2 T, 30 cm inside diameter) with superimposed dipole fields (e.g., 1 T) for dispersion generation in large emittance beams; (5) improved industrial fabrication methods for magnets such as welding and forming; or (6) improved cryostat and cryogenic techniques.
Questions - contact Bruce Strauss (bruce.strauss@science.doe.gov)
References:
1. Balachandran, U., et al., eds., “Advances in Cryogenic Engineering Materials,” Proceedings of the Cryogenic Engineering Conference, Keystone, CO 2005, Vol. 52 A & B, New York: American Institute of Physics (AIP), 2006. (ISBN: 0-7354-0316-3)*
2. Cifarelli, L. and Mariatato, L., eds., “Superconducting Materials for High Energy Colliders,” Proceedings of the 38th Workshop of the INFN Eloisatron Project, Erice, Italy, October 19-25, 1999, River Edge, NJ: World Scientific, 2001. (ISBN: 981-02-4319-7)
3. Duggan, J. L. and Morgan, I. L., eds., “Application of Accelerators in Research and Industry,” Proceedings of the 17th International Conference on the Application of Accelerators in Research and Industry, Denton, TX, November 12-13, 2002, New York: American Institute of Physics, August 2003. (AIP Conference Proceedings No. 680) (ISBN: 0-7354-0149-7)*
4. Chew, J., et al., eds., “Proceedings of the 2003 Particle Accelerator Conference,” Portland, Oregon, May 12-16, 2003, Institute of Electrical and Electronics Engineers (IEEE), 2003. (ISBN: 0-7803-7739-9)
5. Mess, K. H., et al., “Superconducting Accelerator Magnets,” River Edge, NJ: World Scientific, 1996. (ISBN: 981-02-2790-6)
6. “The 2000 Applied Superconductivity Conference,” Virginia Beach, VA, September 17-22, 2000, IEEE Transactions on Applied Superconductivity, 3 Parts, 11(1), March 2001. (ISSN: 1051-8223)
7. “The 2002 Applied Superconductivity Conference,” Houston, TX, August 4-9, 2002, IEEE Transactions on Applied Superconductivity, 3 parts, 13(2), June 2003. (ISSN: 1051-8223)
8. “The 2004 Applied Superconductivity Conference,” Jacksonville, FL, October 3-8, 2004, IEEE Transactions on Applied Superconductivity, 3 parts, 15(2), June 2003. (ISSN: 1051-8223)
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* Abstracts and ordering information available at: http://proceedings.aip.org/proceedings/
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