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Conductor fabrication for ISABELLE dipole magnets

Description: Fabrication techniques and specifications are discussed for the composite superconductor braids to be used in the dipole magnets of the ISABELLE Storage Rings. Properties of the NbTi and Cu composite superconductor are given, the braid parameters are presented, and the fabrication processes are shown in photographs. (PMA)
Date: January 1, 1975
Creator: McInturff, A.D.
Partner: UNT Libraries Government Documents Department

Scaling laws for modeling large superconducting solenoids

Description: The neutrino factory cooling system will consist of a long series of superconducting solenoids with a warm bore of 1.2 meters. In order to minimize the cost of the 200 to 300-meter long solenoid muon-cooling channel, the solenoids must be fabricated so that their mass is minimized. This report discusses how one can model the stress, strain and quench behavior of these large solenoid sections by building one-third to one-half scale models of the magnets. The cost of building and engineering the scale model magnets is a small fraction of the cost of fabricating a full-scale magnet section. This report discusses the limitations of the scaling approach as well as the types of superconducting solenoids for which the modeling technique is suitable.
Date: August 16, 2000
Creator: Green, M.A. & McInturff, A.D.
Partner: UNT Libraries Government Documents Department

Collider scenario implications of ASST Operation

Description: After the achievement of the SSCL`s Congressionally Mandated milestone, the Accelerator System String Test (ASST) half cell under went a series of power tests. These tests involved quenches induced in various configurations and in power levels up to the maximum operation point. These tests have produced data which has defined various parameters and requirements for the individual elements and system.
Date: May 1, 1993
Creator: McInturff, A.D.; Burgett, W. & Christianson, M.
Partner: UNT Libraries Government Documents Department

The SSC full cell prototype string test

Description: At the conclusion of the SSC half cell magnet string testing program in February, 1993, the preliminary data analysis revealed that several substantive technical questions remained unresolved. These questions were: (1) could the high voltages to ground (>2 kV) measured during fault (quench) conditions be substantially reduced, (2) could the number of magnetic elements that became resistive (quenched) be controlled and 3) did the cryostats of the magnetic elements provide adequate insulation and isolation to meet designed refrigeration loads. To address these and other existing questions, a prototypical fall cell of collider magnets (ten dipoles and two quadrupoles) was assembled and tested. At the conclusion of this testing there were definitive answers to most of the questions with numerical substantiation, the notable exception being the beat leak question. These answers and other results and issues are presented in this paper.
Date: October 17, 1994
Creator: McInturff, A. D.; Kraushaar, P.; Burgett, W. & Cromer, L.
Partner: UNT Libraries Government Documents Department

Superfluid Performance of Tevatron IR Quad Heaters

Description: A collaborative team from the two laboratories measured the performance of a Tevatron Interaction region (IR) quadrupole at temperatures from 1.8 K to 4.4 K. These studies included measurement of their performance as a function of temperature as well as measurement of the effectiveness of the protection heaters. Heater diffusion times were measured for various temperatures, current levels, and power densities. These results and their implications on the design of magnet protection systems and magnet design operating in this temperature range will be discussed.
Date: December 12, 1996
Creator: Lietzke, A.; McInturff, A.D. & Scanlan, R.M.
Partner: UNT Libraries Government Documents Department

ISABELLE full scale dipoles

Description: Data are presented on the various cosine theta type magnet models constructed at BNL in the development of ring magnets for ISABELLE, a pair of intersecting 200 GeV proton accelerating storage rings. The rings are to be filled with 30 GeV protons from the AGS and then accelerated to 200 GeV. The acceleration period is a 120 sec ramp from approximately 0.5 T to 4 T. The effect of mechanical precompression on training was studied by varying the interference fit between the coil (ISA IV) and its iron shield. The results were used to optimize the mechanical design of the full-size magnet models. (auth)
Date: January 1, 1975
Creator: McInturff, A. D.; Dahl, P. F.; Kassner, D.; Lasky, C.; Robins, K. & Sampson, W. B.
Partner: UNT Libraries Government Documents Department

Low temperature quench performance of Fermilab Low-{Beta} insertion quadrupoles

Description: The recently revived superconducting magnet program at Fermilab is currently focused on the development of high gradient quadrupoles for possible use in the Large Hadron Collider (LHC) interaction regions at CERN. In order to provide input for the new quadrupole design which will operate in superfluid helium, we have tested a Fermilab Tevatron low-{beta} quadrupole cold mass and compared its low temperature performance to a newly assembled heavily instrumented version which was mechanically modified to take advantage of the gain in critical current.
Date: April 1, 1997
Creator: Bossert, R.; Lietzke, A.; McInturff, A.D.; Scanlan, R. & Collaboration, LHC
Partner: UNT Libraries Government Documents Department

Two Alternate High Gradient Quadrupoles; An Upgraded Tevatron IR and A"Pipe" Design

Description: With the U.S. cancellation of the SSC project, the only large approved hadron accelerator project is CERN's LHC. One of the more critical elements in the performance of a collider is the quadrupole lens at the beam collision points. These quadrupoles, usually referred to as the 'insertion quads' normally form a set of triplets around the interaction region. Their focal power directly affects the luminosity available at the crossing point In order to achieve as high a gradient as possible, the CERN design team has proposed a very efficient high gradient quadrupole which is based on a graded four-layer winding structure. At Fermilab's Tevatron, an upgraded two layer winding quadrupole has been in operation since 1989, and has provided a 50% higher gradient than its predecessor. The quadrupole was basically state of the art when it was designed in 1985. Since then however, improvements have been made in cabling, conductor perfonnance, etc. Naturally, operation of a modernized version of this .design can provide higher capabilities. This improved two layer design can serve as an alternative to the more intricate graded four layer design now envisioned for the LHC, provided it can obtain the proposed gradient. A high gradient quadrupole with a 'pipe' layout can be considered as a possible candidate for future large collider insertion regions. It is possible to fine-tune the design to obtain a good field-quality, the conductor is well cooled in case of a large radiation heat load, and the overall structure is smaller than a conventional quadrupole with a comparable field gradient.
Date: April 1, 1995
Creator: McInturff, A.D.; Oort, J.M. van & Scanlan, R.M.
Partner: UNT Libraries Government Documents Department

Fabrication and component testing results for a Nb{sub 3}Sn dipole magnet

Description: At present, the maximum field achieved in accelerator R&D dipoles is slightly over 10T, with NbTi conductor at 1.8 K. Although Nb{sub 3}Sn has the potential to achieve much higher fields, none of the previous dipoles constructed from Nb{sub 3}Sn have broken the 10T barrier. We report here on the construction of a dipole with high current density Nb{sub 3}Sn with a predicted short sample limit of 13T. A wind and react technique, followed by epoxy impregnation of the fiberglass insulated coils, was used. The problems identified with the use of Nb{sub 3}SD in earlier dipole magnets were investigated in a series of supplemental tests. This includes measurement of the degradation of J{sub c} with transverse strain, cabling degradation, joint resistance measurements, and epoxy strength tests. In addition, coff assembly techniques were developed to ensure that adequate prestress could be applied without damaging the reacted Nb{sub 3}Sn cable. We report here the results of these tests and the construction status of this 50 mm bore dipole.
Date: October 1, 1994
Creator: Dell`Orco, D.; Scanlan, R.M.; Taylor, C.E.; Lietzke, A.; Caspi, S.; van Oort, J.M. et al.
Partner: UNT Libraries Government Documents Department

The use of a permanent magnet for water content measurements ofwood chips

Description: The Lawrence Berkeley National Laboratory has developed a device that measures the water content of wood chips, pulp and brown stock for the paper industry. This device employs a permanent magnet as the central part of a NMR measurement system. This report describes the magnet and the NMR measurement system. The results of water content measurements in wood chips in a magnetic field of 0.47 T are presented.
Date: September 20, 2001
Creator: Barale, P.J.; Fong, C.G.; Green, M.A.; Luft, P.A.; McInturff,A.D.; Reimer, J.A. et al.
Partner: UNT Libraries Government Documents Department

Heat leak performance of SSC collider dipole magnets

Description: The large number of superconducting dipoles in the SSC results in a stringent heat leak budget for each dipole. Ensuring that the dipoles meet this budget is vital to the successful operation or the collider. This work surveys heat leak measurements taken during 4 different magnet string tests. These tests involved both 40 mm and SO mm aperture dipoles. In these experiments the heat leak to the 80 K shield, 20 K shield and cold mass are measured. The results are compared to predictions from a computational thermal model of the dipole cryostat. Discrepancies are seen between the predicted and measured values. Possible explanations for these discrepancies are given.
Date: September 1, 1993
Creator: Weisend, J.G. II; Levin, M.; Franks, D.; Pletzer, R.; Augustynowicz, S.; McInturff, A.D. et al.
Partner: UNT Libraries Government Documents Department

Design of Racetrack Coils for High Field Dipole Magnets

Description: The magnet group at LBNL is currently in the process of developing high-field accelerator magnets for use in future colliders. One of the primary challenges is to provide a design which is cost-effective and simple to manufacture, at the same time resulting in good training performance and field quality adequate for accelerator operation. Recent studies have focused on a racetrack geometry that has the virtues of simplicity and conductor compatibility. The results have been applied to the design of a series of prototype high-field magnets based on Nb{sub 3}Sn conductor.
Date: September 8, 2000
Creator: Sabbi, G.; Caspi, S.; Gourlay, S.A.; Hafalia, R.; Jackson, A.; Lietzke, A. et al.
Partner: UNT Libraries Government Documents Department

Mechanical Design of HD2, a 15 T Nb3Sn Dipole Magnet with a 35 mm Bore

Description: After the fabrication and test of HD1, a 16 T Nb{sub 3}Sn dipole magnet based on flat racetrack coil configuration, the Superconducting Magnet Program at Lawrence Berkeley National Laboratory (LBNL) is developing the Nb{sub 3}Sn dipole HD2. With a dipole field above 15 T, a 35 mm clear bore, and nominal field harmonics within a fraction of one unit, HD2 represents a further step towards the application of block-type coils to high-field accelerator magnets. The design features tilted racetrack-type ends, to avoid obstructing the beam path, and a 4 mm thick stainless steel tube, to support the coil during the preloading operation. The mechanical structure, similar to the one used for HD1, is based on an external aluminum shell pretensioned with pressurized bladders. Axial rods and stainless steel plates provide longitudinal support to the coil ends during magnet excitation. A 3D finite element analysis has been performed to evaluate stresses and deformations from assembly to excitation, with particular emphasis on conductor displacements due to Lorentz forces. Numerical results are presented and discussed.
Date: June 1, 2006
Creator: Ferracin, P.; Bartlett, S.E.; Caspi, S.; Dietderich, D.R.; Gourlay, S.A.; Hafalia, A.R. et al.
Partner: UNT Libraries Government Documents Department

Developmentof the 15 T Nb3Sn dipole HD2

Description: The Superconducting Magnet Program at Lawrence Berkeley National Laboratory (LBNL) is continuing the development of HD2, a 1 m long Nb{sub 3}Sn dipole generating a dipole field of 15 T in a 36 mm clear bore. With tilted (flared) ends to avoid obstructing the beam path, HD2 represents a step towards the development of cost effective accelerator quality magnets. The design has been optimized to minimize geometric harmonics and to address iron saturation and conductor magnetization effects. The support structure is based on an external aluminum shell, pre-tensioned with pressurized bladders and interference keys. Aluminum axial rods and stainless steel end plates provide longitudinal support to the coil ends during magnet excitation. This paper reports on field quality optimization and magnet parameters. The design and fabrication of the coil and structure components, and results from coil winding, reaction, and potting are also presented.
Date: June 1, 2008
Creator: Caspi, S.; Cheng, D.W.; Dietderich, D.R.; Hafalia, A.R.; Hannaford, C.R.; Higley, H. et al.
Partner: UNT Libraries Government Documents Department

Nb3Sn Quadrupole Magnets for the LHC IR

Description: The development of insertion quadrupoles with 205 T/m gradient and 90 mm bore represents a promising strategy to achieve the ultimate luminosity goal of 2.5 x 10{sup 34} cm{sup -2}s{sup -1} at the Large Hadron Collider (LHC). At present, Nb{sub 3}Sn is the only practical conductor which can meet these requirements. Since Nb{sub 3}Sn is brittle, and considerably more strain sensitive than NbTi, the design concepts and fabrication techniques developed for NbTi magnets need to be modified appropriately. In addition, IR magnets must provide high field quality and operate reliably under severe radiation loads. The results of conceptual design studies addressing these issues are presented.
Date: August 1, 2001
Creator: Sabbi, G.; Caspi, S.; Chiesa, L.; Coccoli, M.; Dietderich, D.r.; Ferracin, P. et al.
Partner: UNT Libraries Government Documents Department

MAGNETIC FIELD MEASUREMENTS OF HD2, A HIgh Nb3Sn DIPOLE MAGNET

Description: The Superconducting Magnet Program at Lawrence Berkeley National Laboratory has designed and tested HD2, a 1 m long Nb{sub 3}Sn accelerator-type dipole based on a simple block-type coil geometry with flared ends. HD2 represents a step toward the development of cost-effective accelerator quality magnets operating in the range of 13-15 T. The design was optimized to minimize geometric harmonics and to address iron saturation and conductor magnetization effects. Field quality was measured during recent cold tests. The measured harmonics are presented and compared to the design values.
Date: May 4, 2009
Creator: Wang, X.; Caspi, S.; Cheng, D. W.; Felice, H.; Ferracin, P.; Hafalia, R. R. et al.
Partner: UNT Libraries Government Documents Department

Test Results for RD3c, A Nb3Sn Common-Coil Racetrack Dipole Magnet

Description: The Superconducting Magnet Group at Lawrence Berkeley Laboratory has been developing racetrack technology for economical, high-field accelerator magnets from brittle superconductor. Recent tests have demonstrated (1) robust, reusable, double-layer, flat racetrack, wind and react Nb{sub 3}Sn coils, (2) a reusable, easily assembled, coil-support structure that can minimize conductor movement, and (3) 15T dipole fields, with no degradation. RD3c is our first attempt to compare measured and calculated field harmonics. A single-layer, Nb{sub 3}Sn, flat racetrack inner-coil was wound on both sides of a bore-plate, and then reacted and potted (as previously). Hard spacers were wound into the inner coils, to adjust the geometric field harmonics, and identify any problems from hard-spacers. Harmonic measurements with a warm rotating coil also required a considerably thicker bore-plate (for the 35mm OD anti-cryostat). The inner coil-module was sandwiched between two existing outer-coil modules, and pre-stressed within the reusable yoke and shell loading structure. The magnet's performance is discussed, and compared with calculations.
Date: August 1, 2002
Creator: Lietzke, A.F.; Caspi, S.; Coccoli, M.; Dietderich, D.R.; Ferracin, P.; Gourlay, S.A. et al.
Partner: UNT Libraries Government Documents Department

Test Results on Nb3Sn Dipole Magnets

Description: A cosine theta type dipole magnet using Nb{sub 3}Sn conductor have been designed, built and tested. D19H is a two-layer dipole magnet with a Nb{sub 3}Sn inner layer and a NbTi outer layer. Coil-pairs are connected with two of the four Nb{sub 3}Sn splices in a high field region, and compressed by a ring and collet system. It trained well at 4.4K, but poorly at 1.8K. Strain gages revealed that the coil-ends were not loaded well enough for high field operation (after cool-down), so another thermal cycle is planned. The low end-load is believed to be the cause of several mysteries observed during operation. Except for the outer-layer 1.8 K training difficulty, the magnet's operation was encouraging.
Date: December 12, 1996
Creator: Lietzke, A.F.; Benjegerdes, R.; Caspi, S.; Dell'Orco, D.; Harnden, W.; McInturff, A.D. et al.
Partner: UNT Libraries Government Documents Department

Performance Comparison of Nb3Sn Magnets at LBNL

Description: The Superconducting Magnet group at Lawrence Berkeley National Laboratory has been successfully developing Nb{sub 3}Sn high-field dipole magnet technology for the last ten years. Noteworthy magnet tests include D20 (50mm bore, 4-layer cos{theta}, 12.8 T, accelerator quality dipole), and recent racetrack dipoles: (1) RTI (2-layer, 12 T, no bore, no training), (2) RD3b (3-layer, 14.7 T, 10mm bore), (3) RD3c (3-layer, 10 T, low-harmonics 35mm bore), and (4) some small Nb{sub 3}Sn magnets that utilized new technology. The performance of these magnets is summarized, comparing (1) cable and magnet geometry parameters, (2) training behavior, (3) ramp rate sensitivity, (4) RRR measurements, (5) peak temperatures and voltages, and (6) fast flux adjustments that occur during ramping.
Date: August 1, 2002
Creator: Chiesa, L.; Caspi, S.; Coccoli, M.; Dietderich, D.R.; Ferracin, P.; Gourlay, S.A. et al.
Partner: UNT Libraries Government Documents Department

Fabrication and Test Results of a Nb3Sn Superconducting Racetrack Dipole Magnet

Description: A 'proof-of-principle' Nb{sub 3}Sn superconducting dual-bore dipole magnet was built from racetrack coils, as a first step in a program to develop an economical, 15 Tesla, accelerator-quality magnet. The mechanical design and magnet fabrication procedures are discussed. No training was required to achieve temperature-dependent plateau currents, despite several thermal cycles that involved partial magnet disassembly and substantial pre-load variations. Subsequent magnets are expected to approach 15 Tesla with substantially improved conductor.
Date: February 6, 2000
Creator: Chow, K.; Dietderich, D.R.; Gourlay, S.A.; Gupta, R.; Harnden, W.; Lietzke, A. F. et al.
Partner: UNT Libraries Government Documents Department

Fabrication and Test Results of a Nb3Sn Superconducting Racetrack Dipole Magnet

Description: A 'proof-of-principle' Nb{sub 3}Sn superconducting dual-bore dipole magnet was built from racetrack coils, as a first step in a program to develop an economical, 15 Tesla, accelerator-quality magnet. The mechanical design and magnet fabrication procedures are discussed. No training was required to achieve temperature-dependent plateau currents, despite several thermal cycles that involved partial magnet disassembly and substantial pre-load variations. Subsequent magnets are expected to approach 15 Tesla with substantially improved conductor.
Date: March 22, 1999
Creator: Chow, K.; Dietderich, D.R.; Gourlay, S.A.; Gupta, R.; Harnden, W.; Lietzke, A.F. et al.
Partner: UNT Libraries Government Documents Department

Fabrication and Test Results of a Prototype, Nb3Sn Superconducting Racetrack Dipole Magnet

Description: A prototype, Nb{sub 3}Sn superconducting magnet, utilizing a racetrack coil design has been built and tested. This magnet represents the first step in a recently implemented program to develop a high field, accelerator quality magnet. This magnet was constructed with coils wound from conductor developed for the ITER project, limiting the magnet to a field of 6-7 Tesla. Subsequent magnets in the program will utilize improved conductor, culminating in a magnet design capable of producing fields approaching 15 Tesla. The simple geometry is more suitable for the use of brittle superconductors necessary to eventually reach high field levels. In addition, fewer and simpler parts are used in fabricating these coils compared with the more conventional cosine theta cross section coils. The general fabrication steps, mechanical design and quench performance are discussed.
Date: September 1, 1998
Creator: Gourlay, S. A.; Chow, K.; Dietderich, D.R.; Gupta, R.; Hannaford, R.; Harnden, W. et al.
Partner: UNT Libraries Government Documents Department