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FNAL and CERN are carrying out a joint R&D program with the goal of building a 5.5-m-long twin-aperture 11-T \Nb3\Sn dipole prototype that is suitable for installation in the LHC. An important part of the program is the development and test of a series of short single-aperture and twin-aperture dipole models with a nominal field of 11 T at the LHC operation current of 11.85 kA and 20% margin. This paper presents the results of magnetic measurements of a 1-m-long single-aperture \Nb3\Sn dipole model fabricated and tested recently at FNAL, including geometrical field harmonics and effects of coil magnetization and iron yoke saturation. [ABSTRACT FROM PUBLISHER]

FNAL and CERN are performing an R&D program with the goal of developing a 5.5 m long twin-aperture 11 T \Nb3\Sn dipole suitable for installation in the Large Hadron Collider (LHC). An important part of the program is the development and test of a series of short single-aperture and twin-aperture models with a nominal field of 11 T at the LHC nominal current of 11.85 kA and 20% margin. This paper describes design and fabrication features, and test results of a 1 m long single-aperture \Nb3\Sn dipole model tested at FNAL. [ABSTRACT FROM PUBLISHER]

A program to develop model magnets for a helical cooling channel is under way at Fermilab. In the first steps of a planned sequence of magnets, two four-coil helical solenoid models with 300 mm aperture have been fabricated and tested. These two models, HSM01 and HSM02, used insulated NbTi Rutherford cable wound onto stainless steel rings with spliceless transitions between coils. Strip heaters were included for quench protection of each coil, and the coils were epoxy-impregnated after winding inside the support structures. Based on the results of the first model the second model was made using a cable with optimized cross-section, improved winding and epoxy-impregnation procedures, enhanced ground insulation, and included heat exchange tubing for a test of conduction cooling. We report on the results and lessons learned from fabrication and tests of these two models. [ABSTRACT FROM PUBLISHER]

The planned upgrade of the LHC collimation system includes additional collimators to be installed in the dispersion suppressor areas of points 2, 3 and 7. To provide the necessary longitudinal space for the collimators, a replacement of 8.33 T Nb-Ti LHC main dipoles with 11 T dipoles based on Nb3Sn superconductor compatible with the LHC lattice and main systems is being considered. To demonstrate this possibility FNAL and CERN have started a joint program to develop a 2 m long single-aperture dipole magnet with the nominal field of 11 T at \sim11.85 kA current and 60 mm bore. This paper describes the demonstrator magnet magnetic and mechanical designs and analysis, coil fabrication procedure. The Nb3Sn strand and cable parameters and test results are also reported. [ABSTRACT FROM PUBLISHER]

The LHC collimation upgrade foresees two additional collimators installed in the dispersion suppressor regions of points 2, 3 and 7. To obtain the necessary longitudinal space for the collimators, a solution based on an 11 T dipole as replacement of the 8.33 T LHC main dipoles is being considered. CERN and FNAL have started a joint development program to demonstrate the feasibility of Nb3Sn technology for this purpose. The program started with the development and test of a 2-m-long single-aperture demonstrator magnet. The goal of the second phase is the design and construction of a series of 2-m-long twin-aperture demonstrator magnets with a nominal field of 11 T at 11.85 kA current. This paper describes the electromagnetic design and gives a forecast of the field quality including saturation of the iron yoke and persistent-current effects in the Nb3Sn coils. The mechanical design concepts based on separate collared coils, assembled in a vertically split iron yoke are also discussed. [ABSTRACT FROM PUBLISHER]

The US-LARP collaboration is developing a new generation of large-aperture high-field quadrupoles based on Nb3Sn superconductor for the LHC upgrades. The development and implementation of this new technology involves the fabrication and testing of series of model magnets, coils and other components with various design and processing features. New 120-mm HQ coils made of Rutherford cable, one with an interlayer resistive core, and both with optimized reaction processes, were fabricated and tested using a quadrupole mirror structure under operating conditions similar to those in a real magnet. The coils were instrumented with voltage taps and strain gauges to study the mechanical and quench performance. Quench antenna and temperature gauges were installed in the mirror structure to measure the coil temperature and locate quench origins. This paper presents details of the coil design and fabrication procedures, coil assembly and pre-stress in the quadrupole mirror structure, and coil test results. [ABSTRACT FROM PUBLISHER]

Conceptual designs of a superconducting dipole magnet for a storage ring of a muon collider with a 1.5 TeV center of mass (c.o.m.) energy and an average luminosity of 10^34\ cm^-2s^-1 are presented. In contrast to proton machines, the dipoles for the muon collider should be able to handle \sim0.5 kW/m of dynamic heat load from the muon beam decays. The magnets are based on Nb3Sn superconductor and designed to provide an operating field of 10 T in the 20-mm aperture with the critical current margin required for reliable machine operation. The magnet cross-sections were optimized to achieve the best possible field quality in the aperture occupied by beams. The developed mechanical structures provide adequate coil prestress and support at the maximum level of Lorentz forces in the coil. Magnet parameters are reported and compared with the requirements. [ABSTRACT FROM AUTHOR]

A series of 90-mm TQC quadrupole models with a collar-based mechanical structure has been fabricated and tested within the framework of the US-LHC Accelerator Research Program (LARP) using quadrupole-symmetric stainless steel collar laminations. This paper describes the design features, construction and test of TQC02Eb, the first TQC made with dipole-type collar and collaring techniques. Magnet test includes quench performance and field quality measurements at 4.5 and 1.9 K. Results of model performance for TQC quadrupoles based on dipole-type and quadrupole-type collars are compared and discussed. [ABSTRACT FROM AUTHOR]

This paper presents magnetic and mechanical designs of the quadrupole mirror structure to test single shell-type quadrupole coils. Three quadrupole coils made of different Nb3Sn strands, cable insulation and pole materials were tested using this structure at 4.5 and 1.9 K. The coils were instrumented with voltage taps, spot heaters, temperature sensors and strain gauges to study their mechanical and thermal properties and quench performance. The quadrupole mirror model assembly and test results are reported and discussed. [ABSTRACT FROM AUTHOR]

Two Cu stabilized Nb3Al strands, F1 (Nb matrix) and F3 (Ta matrix), fabricated at NIMS were wound into Rutherford cables at Fermilab in collaboration with NIMS. A Small Race-track magnet using F! Rutherford cable, the first Nb3Al dipole magnet in the world, was constructed and tested to full current at Fermilab. This magnet was tested extensively to full short sample data and its quench characteristics were studied and reported. The 3-D magnetic field calculation was done with ANSYS to find the peak field. The quench characteristics of the magnet are explained with the characteristics of the Nb3 Al strand and Rutherford cable. The Small Racetrack magnet built using Ta matrix F3 strand was constructed and will be tested in the near future. The advantages and disadvantages of these Nb3Al cables are briefly discussed. [ABSTRACT FROM AUTHOR]

Fermilab is working on the development of Nb3 Sn accelerator magnets using shell-type dipole coils and the wind-andreact method. As a part of the first phase of technology development, Fermilab built and tested six 1 m long dipole model magnets and several dipole mirror configurations. The last three dipoles and two mirrors reached their design fields of 10-11 1. The technology scale up phase has started, by building 2 m and 4 m dipole coils and testing them in a mirror configuration in which one of the two coils is replaced by a half-cylinder made of low carbon steel. This approach allows for shorter fabrication times and extensive instrumentation preserving almost the same level of magnetic field and Lorentz forces in the coils as in a complete dipole model magnet. This paper presents details on the 2 m (HFDM07) and 4 m long (HFDM08) Nb3 Sn dipole mirror magnet design and fabrication technology, as well as the magnet test results which are compared with 1 m long models. [ABSTRACT FROM AUTHOR]

Test results are reported on four quadrupole magnet model tests (TQS01a, TQS01b, TQS01c, TQS02) in support of the development of a large-aperture Nb3 Sn superconducting quadrupole for the US LHC Accelerator Research Program (LARP). All four magnet assemblies used key and bladder technology to compress and support the coils within an iron yoke and an aluminum shell. The first three models tested different magnet assemblies of several coils, having MJR conductor, and gapped segmented bronze pole-islands. TQS02's coils utilized improved (RRP) Nb3 Sn conductor, and addressed TQS01's quench-training pattern, by utilizing titanium alloy (TiA16V4) pole-islands, with no axial gaps during reaction. This paper summarizes the assembly, cool-down and performance of TQS01a, TQS01b, TQS01c, and TQS02 and compares measurements with design expectations. [ABSTRACT FROM AUTHOR]

This paper describes the development and test of TQC01b and TQC02E, the second and third models in the TQC series. ANSYS analysis of the mechanical structure, its underlying assumptions, and changes based on experience with TQC01 are presented and discussed. Construction experience, in-process measurements, and modifications to the assembly since TQC01 are described. The test results presented here include magnet strain and quench performance during training of TQC01b and TQC02E. [ABSTRACT FROM AUTHOR]

The high performance Nb3Sn strand produced by Oxford Superconducting Technology (OST) with the Restack Rod Process (RRP) is presently considered as a baseline conductor for the Fermilab's accelerator magnet R&D program. To improve the strand stability in the current and field range expected in magnet models, the number of subelements in the strand was increased by a factor of two (from 54 to 108), which resulted in a smaller effective filament size. The performance of the 1.0 and 0.7 mm strands of this design was studied using virgin and deformed strand samples. 27-strand Rutherford cables made of 1 mm strand were also tested using a superconducting transformer, small race-track and 1-m shell-type dipole coils. This paper presents the RRP strand and cable parameters, and reports the results of strand, cable and coil testing. [ABSTRACT FROM AUTHOR]

Feasibility study of Cu stabilized Nb3AI strand and Rutherford cable for the application to high field accelerator magnets are being done at Fermilab in collaboration with NIMS. The Nb3A1 strand, which was developed and manufactured at NIMS in Japan, has a non-copper Jc of about 844 A/mm² at 15 Tesla at 4.2 K, a copper content of 50%, and filament size of about 50 microns. Rutherford cables with 27 Nb3Al strands of 1.03 mm diameter were fabricated and tested. Quench tests on a short cable were done to study its stability with only its self field, utilizing a high current transformer. A pair of 2 meter long Nb3Al cables was tested extensively at CERN at 4.3 and 1.9 K up to 11 Tesla including its self field with a high transport current of 20.2 kA. In the low field test we observed instability near splices and in the central region. This is related to the flux-jump like behavior, because of excessive amount of Nb in the Nb3Al strand. There is possibility that the Nb in Nb3Al can cause instability below 2 Tesla field regions. We need further investigation on this problem. Above 8 Tesla, we observed quenches near the critical surface at fast ramp rate from 1000 to 3000 A/sec, with quench velocity over 100 m/sec. A small racetrack magnet was made using a 14 m of Rutherford cable and successfully tested up to 21.8 kA, corresponding to 8.7 T. [ABSTRACT FROM AUTHOR]

In support of the development of a large-aperture Nb3Sn superconducting quadrupole for the Large Hadron Collider (LHC) luminosity upgrade, two-layer quadrupole models (TQC and TQS) with 90 mm aperture are being constructed at Fermilab and LBNL within the framework of the US LHC Accelerator Research Program (LARP). This paper describes the construction and test of model TQC01. ANSYS calculations of the structure are compared with measurements during construction. Fabrication experience is described and in-process measurements are reported. Test results at 4.5 K are presented, including magnet training, current ramp rate studies and magnet quench current. Results of magnetic measurements at helium temperature are also presented. [ABSTRACT FROM AUTHOR]

In support of the development of a large-aperture Nb3Sn superconducting quadrupole for the Large Hadron Collider luminosity upgrade, two models (TQS and TQC) with a 90-mm aperture are being constructed at LBNL and FNAL within the framework of the US LHC Accelerator Research Program (LARP). These models use two identical Nb3Sn coils but have different coil support structures. This paper describes the fabrication, assembly, cool-down and test of TQS01—a model based on key and bladder technology with supporting iron yoke and an aluminum shell. Comparison of the test measurements with design expectations is also reported. [ABSTRACT FROM AUTHOR]

A helical cooling channel has been proposed to quickly reduce the six-dimensional phase space of muon beams for muon colliders, neutrino factories, and intense muon sources. A novel superconducting magnet system for a muon beam cooling experiment is being designed at Fermilab. The inner volume of the cooling channel is filled with liquid helium where passing muon beam can be decelerated and cooled in a process of ionization energy loss. The magnet parameters are optimized to match the momentum of the beam as it slows down. The results of 3D magnetic analysis for two designs of magnet system, mechanical and quench protection considerations are discussed. [ABSTRACT FROM AUTHOR]

After successful testing of a 1 m long dipole mirror magnet and three dipole models based on two-layer Nb3Sn coils, Fermilab has started a Nb3Sn technology scale-up program using the dipole mirror design and the developed Nb3Sn coil fabrication technology based on the wind-and-react method. The scale-up will be performed in several steps starting from a 2 m long coil made of Powder-in-Tube (PIT) strand. This will be followed by 4 m long Nb3Sn coils made of PIT and RRP strands that will be fabricated into dipole mirror magnets and tested. This paper presents a summary of Fermilab's wind-and-react short model program. It includes details on the 2 m and 4 m long, 2 layer Nb3Sn dipole mirror magnet design, mechanical structure, and fabrication infrastructure. [ABSTRACT FROM AUTHOR]

As a first step toward the development of a large-aperture Nb3Sn superconducting quadrupole for the Large Hadron Collider (LHC) luminosity upgrade, two-layer technological quadrupole models (TQS01 at LBNL and TQC01 at Fermilab) are being constructed within the framework of the US LHC Accelerator Research Program (LARP). Both models use the same coil design, but have different coil support structures. This paper describes the TQC01 design, fabrication technology and summarizes its main parameters. [ABSTRACT FROM AUTHOR]

As part of the High Field Magnet program at Fermilab three cos (Θ) magnets—two mirror dipole magnets utilizing RRP cable and one dipole magnet utilizing PIT cable—have been designed, fabricated and tested recently. Both mirror magnets with RRP strands only reached ∼5–60% of their estimated critical current limit. The PIT conductor based dipole however reached its critical current limit producing over 10 T magnetic field in the bore of the magnet. This paper describes the parameters of superconducting strands and cable, the details of magnet design and fabrication procedure, and reports the results. [ABSTRACT FROM AUTHOR]

As part of the High Field Magnet program at Fermilab simple magnets have been designed utilizing small racetrack coils based on a sound mechanical structure and bladder technique developed by LBNL. Two of these magnets have been built in order to test Nb3 Sn cables used in cos-theta dipole models. The powder-in-tube strand based cable exhibited excellent performance. It reached its critical current limit within 14 quenches. Modified jelly roll strand based cable performance was limited by magnetic instabilities at low fields similar to previously tested dipole models which used similar cable. [ABSTRACT FROM AUTHOR]

Fermilab is involved in the development of new generation high-field accelerator magnets using state-of-the-art Nb3Sn strands produced using different technologies. Two 1-m long models—mirror configuration and dipole magnet—were fabricated recently at Fermilab based on powder-in-tube (PIT) Nb3Sn strands with small effective filament size. This paper describes the parameters of superconducting strands and cable, the details of magnet design and fabrication procedure, and reports the results of PIT coil testing. [ABSTRACT FROM AUTHOR]

Fermilab is developing and investigating different high-field magnets (HFM) for present and future accelerators. The HFM R&D program focused on the 10-12 T magnets based on Nb3Sn superconductor and explored both basic magnet technologies for brittle superconductors-wind-and-react and react-and-wind. Magnet design studies in support of LHC upgrades and VLHC were conducted. A series of 1-m long cos-theta dipole models based on the wind-and-react technique was fabricated and tested. Three 1-m long flat racetracks and the common coil dipole model, based on a single-layer coil and react-and-wind technique, were also fabricated and tested. Extensive theoretical and experimental studies of electro-magnetic instabilities in Nb3Sn strands, cables and magnets were performed and led to a successful 10 T dipole model. This paper presents the details of Fermilab's HFM program, reports its status and major results, and formulates the next steps for the program. [ABSTRACT FROM AUTHOR]

The first one-meter long common coil dipole model (HFDC-01) has been fabricated and tested at Fermilab. This magnet has several innovative features such as: single-layer racetrack coils, a 22-mm wide 60-strand Rutherford type cable made of 0.7-inm Nb3Sn strands, and a stainless steel coil-support structure reinforced by horizontal bridges inserted between coil blocks. The model was instrumented with voltage taps, quench heaters, temperature sensors and strain gauges in order to monitor the quench origin, and to study mechanical and quench protection issues. This paper summarizes the model design parameters, the fabrication procedures and the test results. [ABSTRACT FROM AUTHOR]

A short model of single-layer Nb3 Sn common coil dipole magnet has been fabricated and tested at Fermilab. The paper summarizes results of magnetic measurements in the common coil model. The geometrical harmonics, coil magnetization and iron saturation effects, ramp-rate dependence, field decay and the "snap-back" effect at injection are presented. [ABSTRACT FROM AUTHOR]

A racetrack magnet, using Nb[sub 3]Sn superconducting cable reacted before winding, has been fabricated and tested at Fermilab. It consists of two flat racetrack coils, connected in a common-coil configuration, separated by a 5 mm thick fiberglass plate. Synthetic oil was used to prevent sintering of the strands during the heat treatment. The coils were wound and vacuum impregnated in the mechanical structure. The turn-to-turn insulation, consisting of Kapton® and pre-impregnated fiberglass tapes as wide as the cable, was wound together with the bare cable in order to form a continuous inter-turn spacer. The coils were instrumented with voltage taps, temperature sensors, spot heaters and quench heaters. The maximum current achieved was 12 675 A which is 78% of the short sample limit at 5.1 K (minimum temperature in the coil during 75 A/s ramp). Measurement of the temperature margin revealed a low degradation in the innermost turns. Quench performances at different temperatures and ramp rate effects have been measured and are presented and discussed. [ABSTRACT FROM AUTHOR]

Conceptual designs of 90-mm aperture high-gradient quadrupoles based on the Nb[sub 3]Sn superconductor, are being developed at Fermilab for possible 2nd generation IRs with the similar optics as in the current low-beta insertions. Magnet designs and results of magnetic, mechanical, thermal and quench protection analysis for these magnets are presented and discussed. [ABSTRACT FROM AUTHOR]

Examines the quench and mechanical performance of high gradient superconducting quadrupole magnet for use in the interaction regions of Large Hadron Collider. Magnetic field harmonics; Mechanical behavior in several thermal cycles; Design of the magnet.

Examines the design and fabrication of a common coil dipole magnet made from niobium tin alloy superconductors. Application of the dipole for Very Large Hadron Collider; React-and-wind fabrication method; Coil winding.

Describes a single-layer common coil dipole being developed for the Very Large Hadron Collider at the Fermi Accelerator Laboratory in Batavia, Illinois. Design concept which allows a large bending radius at the coil ends and is well suited for use of the react-and-wind technique with brittle superconductors.

Presents results of thermal studies of a high gradient quadrupole magnet cooled with pressurized stagnant superfluid. Measurement of magnet quench performance in superfluid as a function of helium temperature and heat deposition in the coil; Alternating current loss measurements; Correlation between current ramp rate and heat deposition in the coil; Thermal design parameters; Operation margin in the Large Hadron Collider.

Describes the development of react and wind common coil dipoles for the Very Large Hadron Collider at the Fermi Accelerator Laboratory in Batavia, Illinois. Selection of Nb[sub 3]Sn wound after reaction to reduce costs; Horizontally split yoke design for the hybrid common coil; Magnetic design optimization.

Investigates the quench performance of model magnets for the Large Hadron Collider inner triplet quadrupoles at the Fermilab in Batavia, Illinois. Refining of mechanical and magnetic design; Optimization of fabrication and assembly tooling; Quench tests for several thermal cycles; Excitation current ramp rate; Temperature dependence studies; Ramp rate sensitivity.

Reports on the achievement of field quality in Fermilab-built models of quadrupole magnets for the Large Hadron Collider (LHC) interaction region. Development of the models by the United States LHC Accelerator Project; Planned operation of the magnets in superfluid helium; Design of the magnets; Measurement system; Field quality analysis; Reference harmonics table.