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Quench Protection and Magnet Supply Requirements for the MICEFocusingand Coupling Magnets

Description: This report discusses the quench protection and power supply requirements of the MICE superconducting magnets. A section of the report discusses the quench process and how to calculate the peak voltages and hotspot temperature that result from a magnet quench. A section of the report discusses conventional quench protection methods. Thermal quench back from the magnet mandrel is also discussed. Selected quench protection methods that result in safe quenching of the MICE focusing and coupling magnets are discussed. The coupling of the MICE magnets with the other magnets in the MICE is described. The consequences of this coupling on magnet charging and quenching are discussed. Calculations of the quenching of a magnet due quench back from circulating currents induced in the magnet mandrel due to quenching of an adjacent magnet are discussed. The conclusion of this report describes how the MICE magnet channel will react when one or magnets in that channel are quenched.
Date: June 8, 2005
Creator: Green, Michael A. & Witte, Holger
Partner: UNT Libraries Government Documents Department

The Role of Reluctance in PM Motors

Description: The international research community has lately focused efforts on interior permanent magnet (IPM) motors to produce a traction motor for hybrid electric vehicles (HEV). One of the beneficial features of this technology is the additional torque produced by reluctance. The objective of this report is to analytically describe the role that reluctance plays in permanent magnet (PM) motors, to explore ways to increase reluctance torque without sacrificing the torque produced by the PMs, and to compare three IPM configurations with respect to torque, power, amount of magnet material required (cost), and percentage of reluctance torque. Results of this study will be used to determine future research directions in utilizing reluctance to obtain maximum torque and power while using a minimum amount of magnet material.
Date: June 16, 2005
Creator: Otaduy, P.J.
Partner: UNT Libraries Government Documents Department

Finite Element Model of Training in the superconducting quadrupole magnet SQ02

Description: This paper describes the use of 3D finite element models to study training in superconducting magnets. The simulations are used to examine coil displacements when the electromagnetic forces are cycled, and compute the frictional energy released during conductor motion with the resulting temperature rise. A computed training curve is then presented and discussed. The results from the numerical computations are compared with test results of the Nb{sub 3}Sn racetrack quadrupole magnet SQ02.
Date: November 1, 2007
Creator: Caspi, Shlomo & Ferracin, Paolo
Partner: UNT Libraries Government Documents Department

The Inductive Coupling of the Magnets in MICE and its Effect onQuench Protection

Description: The inductive coupling between various MICE magnet circuits is described. The consequences of this coupling on magnet charging and quenching are discussed. Magnet quench protection is achieved through the use of quench-back. Calculations of the quenching of a magnet due to quench-back resulting from circulating currents induced in the magnet mandrel due to quenching of an adjacent magnet are discussed. This report describes how the MICE magnet channel will react when magnets in that channel are quenched.
Date: September 8, 2005
Creator: Green, Michael A. & Witte, Holger
Partner: UNT Libraries Government Documents Department

How the Performance of a Superconducting Magnet is affected by theConnection between a small cooler and the Magnet

Description: As low temperature cryocoolers become more frequently used to cool superconducting magnets, it becomes increasingly apparent that the connection between the cooler and the magnet has an effect on the design and performance of the magnet. In general, the use of small coolers can be considered in two different temperature ranges; (1) from 3.8 to 4.8 K for magnet fabricated with LTS conductor and (2) from 18 to 35 K for magnets fabricated using HTS conductor. In general, both temperature ranges call for the use of a two-stage cooler. The best method for connecting a cooler to the magnet depends on a number of factors. The factors include: (1) whether the cooler must be used to cool down the magnet from room temperature, (2) whether the magnet must have one or more reservoirs of liquid cryogen to keep the magnet cold during a loss of cooling, and (3) constraints on the distance from the cooler cold heads and the magnet and its shield. Two methods for connecting low temperature coolers to superconducting magnets have been studied. The first method uses a cold strap to connect the cold heads directly to the loads. This method is commonly used for cryogen-free magnets. The second method uses a thermal siphon and liquid cryogens to make the connection between the load being cooled and the cold head. The two methods of transferring heat from the magnet to the cooler low temperature cold head are compared for the two temperature ranges given above.
Date: September 8, 2005
Creator: Green, Michael A.
Partner: UNT Libraries Government Documents Department

Towards Integrated Design and Modeling of High Field Accelerator Magnets

Description: The next generation of superconducting accelerator magnets will most likely use a brittle conductor (such as Nb{sub 3}Sn), generate fields around 18 T, handle forces that are 3-4 times higher than in the present LHC dipoles, and store energy that starts to make accelerator magnets look like fusion magnets. To meet the challenge and reduce the complexity, magnet design will have to be more innovative and better integrated. The recent design of several high field superconducting magnets have now benefited from the integration between CAD (e.g. ProE), magnetic analysis tools (e.g. TOSCA) and structural analysis tools (e.g. ANSYS). Not only it is now possible to address complex issues such as stress in magnet ends, but the analysis can be better detailed an extended into new areas previously too difficult to address. Integrated thermal, electrical and structural analysis can be followed from assembly and cool-down through excitation and quench propagation. In this paper we report on the integrated design approach, discuss analysis results and point out areas of future interest.
Date: June 1, 2006
Creator: Caspi, S. & Ferracin, P.
Partner: UNT Libraries Government Documents Department

The Role of Quench-back in the Passive Quench Protection of Uncoupled Solenoids in Series with and without Coil Sub-division

Description: This paper is the final paper in a series of papers that discusses passive quench protection for high inductance solenoid magnets. This report describes how passive quench protection system may be applied to superconducting magnets that are connected in series but not inductively coupled. Previous papers have discussed the role of magnet sub-division and quench back from a conductive mandrel in reducing the hot-spot temperature and the peak coil voltages to ground. When magnets are connected in series, quench-back from a conductive mandrel can cause other magnets in a string to quench even without inductive coupling between magnets. The magnet mandrels must be well coupled to the magnet circuit that is being quenched. When magnet circuit sub-division is employed to reduce the voltages-to-ground within magnets, the resistance across the subdivision becomes the most important factor in the successful quenching of the magnet string.
Date: October 15, 2010
Creator: Guo, Xing Long; Green, Michael A; Wang, Li; Wu, Hong & Pan, Heng
Partner: UNT Libraries Government Documents Department

Fabrication and test results of a high field, Nb3Sn superconducting racetrack dipole magnet

Description: The LBNL Superconducting Magnet Program is extending accelerator magnet technology to the highest possible fields. A 1 meter long, racetrack dipole magnet, utilizing state-of-the-art Nb{sub 3}Sn superconductor, has been built and tested. A record dipole filed of 14.7 Tesla has been achieved. Relevant features of the final assembly and tested results are discussed.
Date: June 15, 2001
Creator: Benjegerdes, R.; Bish, P.; Byford, D.; Caspi, S.; Dietderich, D.R.; Gourlay, S.A. et al.
Partner: UNT Libraries Government Documents Department

TF Inner Leg Space Allocation for Pilot Plant Design Studies

Description: A critical design feature of any tokamak is the space taken up by the inner leg of the toroidal field (TF) coil. The radial build needed for the TF inner leg, along with shield thickness , size of the central solenoid and plasma minor radius set the major radius of the machine. The cost of the tokamak core roughly scales with the cube of the major radius. Small reductions in the TF build can have a big impact on the overall cost of the reactor. The cross section of the TF inner leg must structurally support the centering force and that portion of the vertical separating force that is not supported by the outer structures. In this paper, the TF inner leg equatorial plane cross sections are considered. Out-of- Plane (OOP) forces must also be supported, but these are largest away from the equatorial plane, in the inner upper and lower corners and outboard sections of the TF coil. OOP forces are taken by structures that are not closely coupled with the radial build of the central column at the equatorial plane. The "Vertical Access AT Pilot Plant" currently under consideration at PPPL is used as a starting point for the structural, field and current requirements. Other TF structural concepts are considered. Most are drawn from existing designs such as ITER's circular conduits in radial plates bearing on a heavy nose section, and TPX's square conduits in a case, Each of these concepts can rely on full wedging, or partial wedging. Vaulted TF coils are considered as are those with some component of bucking against a central solenoid or bucking post. With the expectation that the pilot plant will be a steady state machine, a static stress criteria is used for all the concepts. The coils are assumed to be ...
Date: September 6, 2012
Creator: Zolfaghari, Peter H. Titus and Ali
Partner: UNT Libraries Government Documents Department

A protype dipole septum magnet for fast high current kicker systems

Description: A dipole "septum" magnet without a material septum has been designed and tested as part of a fast beam kicker system for use in intense, electron-beam induction accelerators. This septum magnet is a simple, iron-based electromagnet with two static, oppositely oriented dipole field regions used to provide further separation of beam centroids given a small angle kick by a fast beam kicker. The magnet geometry includes removable pole pieces to allow experimental flexibility. Field errors experienced by the beam depend crucially on the magnitude of the initial kick that provides displacement of the beam centroids from the transition region between the two dipole field regions. Results of simulations are reported.
Date: March 29, 1999
Creator: Wang, L F; Caporaso, G J; Chen, Y J; Lund, S M; Poole, B R & Brown, T F
Partner: UNT Libraries Government Documents Department

Correction magnets for the Fermilab Recycler Ring

Description: In the commissioning of the Fermilab Recycler ring the need for higher order corrector magnets in the regions near beam transfers was discovered. Three types of permanent magnet skew quadrupoles, and two types of permanent magnet sextupoles were designed and built. This paper describes the need for these magnets, the design, assembly, and magnetic measurements.
Date: May 27, 2003
Creator: al., James T Volk et
Partner: UNT Libraries Government Documents Department

Nb3Sn accelerator magnet development around the world

Description: During the past 30 years superconducting magnet systems have enabled accelerators to achieve energies and luminosities that would have been impractical if not impossible with resistive magnets. By far, NbTi has been the preferred conductor for this application because of its ductility and insensitivity of Jc to mechanical strain. This is despite the fact that Nb{sub 3}Sn has a more favorable Jc vs. B dependence and can operate at much higher temperatures. Unfortunately, NbTi conductor is reaching the limit of it usefulness for high field applications. Despite incremental increases in Jc and operation at superfluid temperatures, magnets are limited to approximately a 10 T field. Improvements in conductor performance combined with future requirements for accelerator magnets to have bore fields greater than 10 T or operate in areas of large beam-induced heat loads now make Nb{sub 3}Sn look attractive. Thus, laboratories in several countries are actively engaged in programs to develop Nb{sub 3}Sn accelerator magnets for future accelerator applications. A summary of this important research activity is presented along with a brief history of Nb{sub 3}Sn accelerator magnet development and a discussion of requirements for future accelerator magnets.
Date: June 23, 2003
Creator: Lamm, Michael J.
Partner: UNT Libraries Government Documents Department

Towards a new LHC interaction region design for a luminosity upgrade

Description: After the LHC operates for several years at nominal parameters, it will be necessary to upgrade it for higher luminosity. Replacing the low-{beta} insertions with a higher performance design based on advanced superconducting magnets is one of the most straightforward steps in this direction. Preliminary studies show that, with magnet technology that is expected to be developed by early in the next decade, a factor of 2 to 5 reduction in {beta}* could be achieved with new insertions, as part of an upgrade aimed at a factor of 10 luminosity increase. In this paper we survey several possible second generation LHC interaction regions designs, which address the expected limitations on LHC performance imposed by the baseline insertions.
Date: May 29, 2003
Creator: al., James Strait et
Partner: UNT Libraries Government Documents Department

High Field Magnet R&D in the USA

Description: Accelerator magnet technology is currently dominated by the use of NbTi superconductor. New and more demanding applications for superconducting accelerator magnets require the use of alternative materials. Several programs in the US are taking advantage of recent improvements in Nb{sub 3}Sn to develop high field magnets for new applications. Highlights and challenges of the US R and D program are presented along with the status of conductor development. In addition, a new R and D focus, the US LHC Accelerator Research Program, will be discussed.
Date: October 1, 2003
Creator: Gourlay, S.A.
Partner: UNT Libraries Government Documents Department

Design issues for cryogenic cooling of short periodsuperconducting undulators

Description: Superconducting insertion devices, which produce periodic magnetic fields, have been built and installed in a number of synchrotron-light source storage-rings. For the most part, these devices have been wigglers, which have relatively long period lengths. This report concerns itself with the special cryogenic issues associated with short period undulators. The motivation for considering the incorporation of superconducting technology in insertion device designs is to achieve higher magnetic fields than can be achieved with more conventional permanent magnet technology. Since the peak field decreases sharply with increased magnet gap to period ratio, the cryogenic design of the magnet system is crucial. In particular, the insulation required for a warm vacuum bore device is impractical for short period undulators. This report describes the issues that are related to a cold bore ({approx}4 K) and an intermediate temperature bore (30 to 70 K) designs. The criteria for the use of small cryocoolers for cooling a short period undulator are presented. The problems associated with connecting small coolers to an undulator at 4.2 K are discussed.
Date: September 15, 2003
Creator: Green, M.A.; Dietderich, D.R.; Marks, S.; Prestemon, S.O. & Schlueter, R.D.
Partner: UNT Libraries Government Documents Department

Passive temperature compensation in hybrid magnets with application to the Fermilab stacker and recycler ring dipole design

Description: Design theory of hybrid (permanent magnet plus iron) accelerator magnets with application to the proposed permanent magnet recycler and stacker rings at the Fermi National Laboratory is presented. Field stability in such devices requires that changes in the strength of the permanent magnet material with temperature be compensated. Field tuning techniques, including those employing variable capacitance between energized pole and magnet yoke and those employing variable energization of magnet pole pieces, are described. Mechanical configurations capable of achieving temperature compensation passively, including use of expanding liquids/gases and bimetallic springs are outlined. Active configurations, relying on a actuator, in addition to temperature compensation, have the additional benefit of enabling magnet tuning about a nominal operating field level.
Date: June 1, 1995
Creator: Schlueter, R.D.; Marks, S.; Loper, C. & Halbach, K.
Partner: UNT Libraries Government Documents Department

INSERTION DEVICES R AND Ds FOR NSLS-II.

Description: NSLS-II is a medium energy storage ring of 3GeV electron beam energy with sub-nm.rad horizontal emittance and top-off capability at 500mA. Damping wigglers will be used not only to reduce the beam emittance but also for broadband sources for users. Cryo-Permanent Magnet Undulators (CPMUs) are considered for hard X-ray linear device, and permanent magnet based Elliptically Polarized Undulators (EPUs) are for polarization control. Rigorous R&D plans have been established to pursue the performance enhancement of the above devices as well as building new types of insertion devices such as high temperature superconducting wiggler/undulators. This paper describes the details of these activities and discuss technical issues.
Date: June 25, 2007
Creator: TANABE,T.; HARDER, D.A.; RAKOWSKY, G.; SHAFTAN, T. & SKARITKA, J.
Partner: UNT Libraries Government Documents Department

Magnet options for sensors for the pulp and paper industry

Description: The Lawrence Berkeley National Laboratory (LBNL) has been developing sensors for the pulp and paper industry that uses a magnetic field. The applications for magnetic sensors that have studied include (1) sensors for the measurement of the water and ice content of wood chips entering the pulping mill, (2) sensors for measuring the water content and other constituents of the black liquor leaving the paper digester, and (3) sensors for measuring paper thickness and water content as the paper is being processed. These tasks can be done using nuclear magnetic resonance (NMR). The magnetic field used for doing the NMR can come from either permanent magnets or superconducting magnets. The choice of the magnet is dependent on a number of factors, which include the size of the sample and field strength needed to do the sensing task at hand. This paper describes some superconducting magnet options that can be used in the pulp and paper industry.
Date: May 5, 2001
Creator: Green, M.A.; Barale, P.J.; Fong, C.G.; Luft, P.A.; Reimer, J.A. & Yahnke, M.S.
Partner: UNT Libraries Government Documents Department

BNL Direct Wind Superconducting Magnets

Description: BNL developed Direct Wind magnet technology is used to create a variety of complex multi-functional multi-layer superconducting coil structures without the need for creating custom production tooling and fixturing for each new project. Our Direct Wind process naturally integrates prestress into the coil structure so external coil collars and yokes are not needed; the final coil package transverse size can then be very compact. Direct Wind magnets are produced with very good field quality via corrections applied during the course of coil winding. The HERA-II and BEPC-II Interaction Region (IR) magnet, J-PARC corrector and Alpha antihydrogen magnetic trap magnets and our BTeV corrector magnet design are discussed here along with a full length ILC IR prototype magnet presently in production and the coils that were wound for an ATF2 upgrade at KEK. A new IR septum magnet design concept for a 6.2 T combined-function IR magnet for eRHIC, a future RHIC upgrade, is introduced here.
Date: September 12, 2011
Creator: Parker, B.; Anerella, M.; Escallier, J.; Ghosh, A.; Jain, A.; Marone, A. et al.
Partner: UNT Libraries Government Documents Department

Specification and R and D Program on Magnet Alignment Tolerances for NSLS-II

Description: The NSLS-II light source is a proposed 3 GeV storage ring, with the potential for ultra-low emittance. Despite the reduced emittance goal for the bare lattice, the closed orbit amplification factors are on average >55 in both planes, for random quadrupole alignment errors. The high chromaticity will also require strong sextupoles and the low 3 GeV energy will require large dynamic and momentum aperture to insure adequate lifetime. This will require tight alignment tolerances ({approx} 30{micro}m) on the multipole magnets during installation. By specifying tight alignment tolerances of the magnets on the support girders, the random alignment tolerances of the girders in the tunnel can be significantly relaxed. Using beam based alignment to find the golden orbit through the quadrupole centers, the closed orbit offsets in the multipole magnets will then be reduced to essentially the alignment errors of the magnets, restoring much of the dynamic aperture and lifetime of the bare lattice. Our R&D program to achieve these tight alignment tolerances of the magnets on the girders using a vibrating wire technique, will be discussed and initial results presented.
Date: May 4, 2009
Creator: Kramer,S.L. & Jain, A. K.
Partner: UNT Libraries Government Documents Department