A major problem of state-of-the-art Nb 3 Sn accelerator magnets is their long training due to thermo-mechanical perturbations. Increasing the specific heat, C p , of the Rutherford cable would reduce ...and/or eliminate training by limiting the coils temperature rise. This paper studies feasibility of increasing the C p of Rutherford-type cables by using thin composite Cu/Gd 2 O 3 and Cu/Gd 2 O 2 S tapes produced by Hyper Tech Research, Inc. The tape can be either wrapped around the cable, placed on the cable wide faces under the insulation, and/or inserted as a core. Wire samples outfitted with these high- C p ribbons, or tapes, were prepared and tested at FNAL for their Minimum Quench Energy ( MQE ). At 90% I c and 15 T, the average gain of MQE of the Nb 3 Sn wire soldered to the Cu/Gd 2 O 2 S 55 μm thick ribbon was 2.5, and further increased at larger transport currents.
High-field accelerator magnets made of state-of-the-art Nb 3 Sn Rutherford cables demonstrate relatively long trainings due to sudden heat depositions originated by thermo-mechanical perturbations in ...the magnet coils. Coil sensitivity to these perturbations can be reduced by increasing the specific heat, C p , of major coil components - strands, or whole cable, or epoxy. The R&D on all these three approaches is in progress. This paper studies feasibility of increasing the C p of Rutherford-type cables by using a thin composite Cu/Gd 2 O 3 tape. The tape can be either wrapped around the cable, placed on the cable wide faces under the insulation, and/or inserted as a core. Cu/Gd 2 O 3 ribbons with ∼30% of Gd 2 O 3 powder and two different thicknesses were produced by Hyper Tech Research, Inc. Wire and cable samples outfitted with these high- C p ribbons, or tapes, were prepared and tested at FNAL for the Minimum Quench Energy ( MQE ). At 80% I c , the MQE gain average over the tested magnetic field range of the NbTi cable with high- C p tape on both sides was ∼1.3. The MQE gain average of the NbTi wire wrapped with the high- C p ribbon was 3.1.
In December 2009 during its first cold test, LQS01, the first Long Nb 3 Sn Quadrupole made by LARP (LHC Accelerator Research Program, a collaboration of BNL, FNAL, LBNL and SLAC), reached its target ...field gradient of 200 T/m. This target was set in 2005 by the US Department of Energy, CERN and LARP, as a significant milestone toward the development of Nb 3 Sn quadrupoles for possible use in LHC luminosity upgrades. LQS01 is a 90 mm aperture, 3.7 m long quadrupole using Nb 3 Sn coils. The coil layout is equal to the layout used in the LARP Technological Quadrupoles (TQC and TQS models). Pre-stress and support are provided by a segmented aluminum shell pre-loaded using bladders and keys, similarly to the TQS models. After the first test the magnet was disassembled, reassembled with an optimized pre-stress, and reached 222 T/m at 4.5 K. In this paper we present the results of both tests and the next steps of the Long Quadrupole R&D.
In 2004, the US DOE established the LHC Accelerator Research Program (LARP) with the goal of developing a technology base for future upgrades of the LHC. The focus of the magnet program, which is a ...collaboration of three US laboratories, BNL, FNAL and LBNL, is on development of high gradient quadrupoles using Nb 3 Sn superconductor. Other program components address issues regarding magnet design, radiation-hard materials, long magnet scale-up, quench protection, fabrication techniques and conductor and cable R&D. This paper presents an overall view of the program with emphasis on the current quadrupole project and outlines the long-term goals of the program
The U.S. LHC Accelerator Research Program (LARP) has started the fabrication of 3.7-m long Nb 3 Sn quadrupole models. The Long Quadrupoles (LQ) are ldquoProof-of-Principlerdquo magnets which are to ...demonstrate that Nb 3 Sn technology is mature for use in high energy particle accelerators. Their design is based on the LARP Technological Quadrupole (TQ) models, developed at FNAL and LBNL, which have design gradients higher than 200 T/m and an aperture of 90 mm. The plans for the LQ R&D and a design update are presented and discussed in this paper. The challenges of fabricating long accelerator-quality Nb 3 Sn coils are presented together with the solutions adopted for the LQ coils (based on the TQ experience). During the fabrication and inspection of practice coils some problems were found and corrected. The fabrication at BNL and FNAL of the set of coils for the first Long Quadrupole is in progress.
The test of the first LARP (LHC Accelerator Research Program) Long Quadrupole is a significant milestone toward the development of Nb 3 Sn quadrupoles for LHC (Large Hadron Collider) Luminosity ...Upgrades. These 3.7-m long magnets, scaled from the 1-m long Technological Quadrupoles, are used to develop our capabilities to fabricate and assemble Nb 3 Sn coils and structures with lengths comparable to accelerator magnet dimensions. The long quadruples have a target gradient of 200 T/m in a 90-mm aperture. Pre-stress and support are provided by an Al-shell-based structure pre-loaded using bladders and keys. The coils were fabricated at BNL and FNAL, the shell-based structure was designed and assembled at LBNL, the test is performed at FNAL. In this paper we present the final steps of the development of the first model (LQS01), several upgrades to the test facility, the test results of witness cables, and the short sample limit.
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