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Structural and magnetic properties of SmCo5 thin films grown on glass substrates with a Cr underlayer were investigated. The nanocrystalline SmCo5 film with a (1120) texture exhibited high in-plane intrinsic coercivity up to 26.5 kOe and a large in-plane magnetic anisotropy. The crystallinity of the SmCo5 layer plays an important role, which is strongly dependent on the texture and the morphology of the Cr underlayer. A smooth Cr underlayer with a (200) texture and a good crystallinity is desired for the SmCo5 film with a good magnetic performance. This work demonstrates a process to achieve high intrinsic coercivity and large in-plane magnetic anisotropy SmCo5 films on glass substrates deposited at a relatively low temperature (400 °C). [ABSTRACT FROM AUTHOR]

Structure and magnetic properties of mechanically alloyed Cu-doped SmCo6.7-xCuxCr0.3 (x=0.1–0.7) magnets have been systematically studied. The magnetically hard main phase is found to be of Th2Ni17 type in the SmCo6.7-xCuxCr0.3 alloys. A small amount of Cu addition is favorable for the formation of the 2:17 phase/Co nanocomposite structure in the alloys. The increase of Cu doping results in more Cu precipitating in the alloys with separating the grains, which significantly enhances the intrinsic coercivity iHc of the alloys and weakens the exchange coupling between the magnetically hard and soft phases. The magnetization reversal processes of the magnets have been discussed, upon the measurement of the recoil curves. [ABSTRACT FROM AUTHOR]

Some results concerning the magnetic and structural properties of [NdFeBNbCu/Co]·n thin films in view of their utilization for manufacturing permanent magnets are presented. As compared to Ta/NdFeBNbCu/Ta magnetic single layer, the multilayer Ta/[NdFeBNbCu/Co]·3/Ta films exhibit good hard magnetic properties and an increase in the Curie temperature due to Nb–Cu addition and stratification effect using Co as spacer layer. The influence of the additions content and the stratification effect on the microstructural and hard magnetic properties of multilayer [NdFeBNbCu/Co]·n thin films, when the total thickness of NdFeBNbCu layers was 540 nm and the thickness of the Co spacer layers was varied successively from 0 to 6 nm for different annealing conditions, are discussed. [ABSTRACT FROM AUTHOR]

Fe-MoS2 heterostructures are synthesized in simple hydrothermal method. Different concentrations of Fe precursor are used to grow different thickness of Fe thin sheets placing MoS2 as a template surface. Different characterization techniques are done to confirm the desired phases present in the samples. After that their magnetic characterization is carried out to measure its magnetic property. The hysteresis loop obtained is different from the conventional transition metal nanoparticles. Due to charge transfer from transition metal 3d orbital to 3p orbital of sulfur, the magnetic property of the as grown nanostructure is changed. Magnetic hysteresis loops reveal high amount of exchange bias which changes with temperature. At very low temperature ferromagnetic hysteresis loop is observed. With increasing temperature magnetic saturation dies away due to presence of antiferromagnetic interaction. This antiferromagnetic interaction comes due to charge transfer from Fe to MoS2. The transferred charges at MoS2 surface creates an induced spin moment which is in antiferromagnetic coupling with the Fe spins. [ABSTRACT FROM AUTHOR]

This paper presents a new method for cancellation cogging torque by magnet shaping. First, the conditions to be met by the induction space wave for the total cancellation of cogging torque are analytically established. These results are then used to determine the shape of the magnets. The approach followed is inverse to that used by traditional methods, whereby, based on a predetermined shape of the magnets, the cogging torque is calculated. As a result, the proposed method enables optimum results to be obtained directly and it is generalizable to any motor configuration. The methodology has been first validated by means of finite elements and then tested experimentally on a dc motor and on an ac motor for both radial and parallel magnetization. [ABSTRACT FROM AUTHOR]

In the 1990s, for Nuclotron, the pioneer accelerator using fast ramped superconducting magnets, a novel cable with superconducting strands wrapped around a cooling tube was developed. Such cable fabrication technology was advanced and adopted for the SIS100 or NICA project. In parallel with major application for fast ramped superferric magnets, application for high field magnets with a cosine–theta type is investigated. In this paper, we give an overview of the history of Nuclotron-type cables, list its advantages, and outline its applicability far beyond the original usage field. [ABSTRACT FROM PUBLISHER]

High-field superconducting accelerator magnets are a key technology of the future circular collider. In order to master the technical challenges and achieve the performance targets, CERN has launched a technology development program. The first step of the program is to explore the Nb3Sn performance limits at 18 T field level and high stress, simplifying to the maximum the coil geometry. The first magnet to be built, the enhanced racetrack model coil (ERMC), aims at a mid-plane field of 16 T with 10% margin on the load line at 4.2 K. The ERMC is composed of two flat racetrack coils with no bore. To further develop the block-coil geometry, a second magnet, the racetrack model magnet (RMM), will be composed of two ERMC coils and a middle coil with a 50-mm closed cavity, addressing the issue of the design of an inner support to compensate for the preload forces. The RMM aims at a central field of 16 T in a 50-mm cavity, with 10% margin at 4.2 K. The next step is to develop a more compact and cost-effective design using two cable sizes, and therefore two different current densities. The coils will be assembled in a shell-based support structure using bladders and keys, which allows a precise control of the stress with minimal spring back and conductor overstress. This paper describes the magnetic and mechanical design of the ERMC and the RMM. [ABSTRACT FROM PUBLISHER]

Within the future circular collider study, a 100-km long circular hadron collider is being designed for 100 TeV center-of-mass collision energies. The design of the 16 T Nb3Sn bending dipole magnets is carried out within the EuroCirCol collaboration. Three different type of dipole designs have been developed, each aiming to be as compact as possible, accounting for the design criteria. Quench protection a critical aspect of the magnet design and potentially limits the magnet compactness. The EuroCirCol magnets were designed assuming a protection system with significantly improved efficiency compared to the present LHC dipole protection. In this paper, we consider present state-of-the-art quench protection technologies, such as quench heaters and CLIQ, and apply them into the designed 16 T Block-type dipole. Two different simulation models are used to estimate the magnet hotspot temperature and voltages after a quench and consequently estimate the suitability of the different methods. [ABSTRACT FROM PUBLISHER]

Transient effects occurring in a superconducting accelerator circuit can be correctly simulated only if the models consistently account for the electrothermodynamic coupling between the magnets, the protection systems, and the remaining network. We present a framework based on the idea of cosimulation. The core component is a coupling interface exchanging information between the independent models. Within the framework, we simulate selected parts of a magnet and the electrical network, combining appropriately different commercial tools. This modularity gives the possibility of integrating new tools in the framework, to provide further insights on different physical domains as mechanics or fluid dynamics. The workflow is applied to the field-circuit coupling of an LHC main dipole magnet. [ABSTRACT FROM PUBLISHER]

High-field superconducting magnets are the key components of the high-energy particle accelerators. The Institute of High Energy Physics, Beijing, China, has been working on the related R&D since 2014. In parallel with the baseline R&D roadmap with common coil configuration, preliminary electromagnetic design of a 20-T 2-in-1 dipole magnet with cos-theta configuration has been carried out as an option for the model magnet R&D in future. Totally six layers of coils are required for each aperture of this dipole with the high temperature superconductor for the inner two layers and the low temperature superconductor for the outer four layers. Graded coil design is selected to increase the efficiency of the conductor utilization. For each aperture, the clear bore diameter is 50 mm. Asymmetric coil configuration has been adopted to obtain a good geometrical field quality. After optimization, the field uniformity of 10−4 within 2/3 of the aperture is achieved. The coil ends of the dipole magnet have also been designed and optimized. The detailed magnetic analysis and the main characteristics of this magnet are presented. [ABSTRACT FROM PUBLISHER]

The HTS insert for the 32 T superconducting magnet is comprised of two dry wound, double pancake REBCO coils of different lengths, nested within an LTS outsert. The high fields present within the HTS coils create large axial compression forces and significant radial expansion. The mechanical solutions implemented to account for the effects of axial and radial coil movement are described. These solutions are applied throughout many of the mechanical subsystems in and between the HTS coils, including electrical terminations, electrical bussing, external reinforcing of the windings, and suspension of the HTS coils within the outsert. Experiences from the assembly in preparation for the initial operation of the magnet are also shared. [ABSTRACT FROM PUBLISHER]

A superconducting flux pump based on a high-temperature superconducting (HTS) dynamo has been demonstrated which employs rotating permanent magnets and a ReBCO conductor stator wire. This device is capable of injecting large dc currents (>100 A) into industrial superconducting magnet coils. Dynamic resistance, due to the interaction of the dc current with the ac magnetic field at the stator, provides a performance limit for this type of HTS dynamo exciter. It has been shown for a given device, the output of the HTS dynamo can be described by a simple circuit model linking short-circuit current (Isc), dynamic resistance (Rd), and open-circuit voltage (Voc). Isc represents the maximum dc current that can be delivered by the dynamo to a series-connected superconducting circuit and is found to be independent of rotational frequency for a fixed device geometry. We have recently demonstrated that this dynamo effect can be applied to excite a closed superconducting circuit through the cryostat wall, such that all active components of the dynamo are located outside of the cryogenic envelope. Here, we report experimental results which explore the relationship between rotor magnet geometry and ReBCO stator wire width on the output performance of a simple HTS dynamo. We characterize the effect of magnet orientation, aspect ratio and shape, at fixed flux gap, on I sc, Rd, and Voc. [ABSTRACT FROM PUBLISHER]

The FRESCA2 Dipole Magnet is developed within the framework of a collaboration between CEA Saclay and CERN, in the continuity of the European project EuCARD. The goal is to manufacture a dipole magnet providing a 13 T magnetic field in a 100 mm aperture for a superconducting cable test station at CERN. The magnet is composed of four double-layer Nb3Sn coils, arranged in a block-type configuration, with flared ends. Four Nb3Sn coils have been fabricated at CEA Saclay and CERN. This paper reports on the coil fabrication, describing the process, the issues encountered, and the solutions implemented. A series of geometrical and electrical characterizations were also performed on the coils in order to validate their quality. The coils are finally validated and ready to be assembled at CERN to form the magnet. The magnet assembly process is also described: the coils are assembled to form a coil pack, the coil pack is inserted in a shell-based support structure and pre-loaded at room temperature. The margins, expected in the different operation cases, are finally presented. [ABSTRACT FROM PUBLISHER]

This paper describes the development of detector magnets from the mid-1960s to the LHC detector magnets. The discovery of cryogenic stability in March, 1965, made large detector magnets possible. A number of bubble chamber magnets were built as a result. In the 1970s, the quest for thin magnets started. This led to the development of quench protection through quench-back and the development of indirect cooling with two-phase helium in tubes. The late 1970s and 1980s led to the development of a conductor with ultrapure aluminum as a stabilizer. This led to large coils that were wound inside a strong aluminum mandrel. The LHC saw the development of magnets that are open and they return their own flux without iron. This paper describes the development of detector magnets that have been used in high-energy physics. [ABSTRACT FROM PUBLISHER]

At the Instititue of Electrical Engineering of the Chinese Academy of Sciences, a central field of up to 24 T was achieved with a ReBCO insert in a 15-T LTS magnet at 4.2 K. The reali-zation of a 24-T magnetic field with an all superconducting magnet makes our program more ambitious. A 30-T all superconducting magnet program composed of a 15-T 35-mm ReBCO insert and a 15-T LTS background magnet is our next goal. The design of the insert is performed first in this paper. The 15-T insert consists of two stacks of ReBCO double pancake coils connected in series. The operation current is designed as 123.5 A, and the operation margins for these two ReBCO coils are both 53%, which is a good approach to improve the operation stability of the insert. Stress analysis is also performed. Methods to improve poor cooling conditions are presented in this paper for regions where helium bubbles are trapped due to the diamagnetic susceptibility of helium. New technologies for fabricating a high-field ReBCO insert with a solid structure are introduced. A multichannel data acquisition system for high-field insert research is under construction. This program is planned to be finished and tested in 2017. [ABSTRACT FROM PUBLISHER]

A key challenge for a future circular collider (FCC) with centre-of-mass energy of 100 TeV and a circumference in the range of 100 km is the development of high-field superconducting accelerator magnets, capable of providing a 16 T dipolar field of accelerator quality in a 50 mm aperture. This paper summarizes the strategy and actions being undertaken in the framework of the FCC 16 T Magnet Technology Program and the Work Package 5 of the EuroCirCol. [ABSTRACT FROM PUBLISHER]

For the upgrade of the LHC during the long shutdown 2 and for the HL-LHC upgrade during the long shutdown 3, a few 15 m 8.3 T Nb–Ti main dipole magnets are foreseen to be replaced by two 11 T Nb3Sn dipoles, 5.5 m long each. After the production and test of three single aperture models at CERN, the first 2-m-long twin-aperture model has been tested. The model was used to exploit the limits of the model in terms of quench performance and protection. The protection studies included the heater efficiency studies and hotspot temperature studies. In this paper, the performance of the magnet DP101 in terms of training behavior, detection, and protection, and other cold powering test will be presented and discussed. [ABSTRACT FROM PUBLISHER]

A 1.3-GHz/54-mm LTS/HTS NMR magnet, assembled with a three-coil (Coils 1-3) 800-MHz HTS insert in a 500-MHz LTS NMR magnet, is under construction. The innermost HTS insert Coil 1 has a stack of 26 no-insulation (NI) double pancake (DP) coils wound of 6-mm-wide and 75-\mu m-thick REBCO tapes. In order to keep the hoop strains on REBCO tape <0.6% at an operating current Iop of 250\; A and in a field of 30.5$\;$T, we overbanded each pancake in Coil 1 with a 6-mm-wide, 76-μm-thick 304 stainless steel strip: 7-mm-thick radial build for the central 18 pancakes, while 6-mm-thick for the outer 2 × 17 pancakes. In this paper, Coil 1 was successfully tested at 77\;$K and 4.2 \;$K. In the 77-K test, the measured critical current was 35.7\;$A, determined by an E$-field criterion of 0.1 \;\mu increased from 5 \;$ to 40\;$ A. The field distribution at different along the $z$ -axis was measured. The residual field distributions discharged from 10 and 20 $\;$A were recorded. In the 4.2-K test, Coil 1 successfully generated a central field of 8.78$\;$T at 255 $\;$A. The magnet constant is 34.4 $\;$mT/A, which is same as our designed value. The field homogeneity at the coil center within a $\pm 15$ -mm region is around 1700$\;$ ppm. This large error field must be reduced before field shimming is applied. [ABSTRACT FROM PUBLISHER]

The U.S. large hadron collider (LHC) Accelerator Research Program, in close collaboration with The European Organization for Nuclear Research (CERN), has developed three generations of high-gradient quadrupole (HQ) Nb $_3$Sn model magnets, to support the development of the 150 mm aperture Nb$_3$Sn quadrupole magnets for the high-luminosity LHC. The latest generation, HQ03, featured coils with better uniformity of coil dimensions and properties than the earlier generations. The HQ03 magnet was tested at fermi national accelerator laboratory (FNAL), including the field quality study. The profiles of low-order harmonics along the magnet aperture observed at 15 kA, 1.9 K can be traced back to the assembled coil pack before the magnet assembly. Based on the measured harmonics in the magnet center region, the coil block positioning tolerance was analyzed and compared with earlier HQ01 and HQ02 magnets to correlate with coil and magnet fabrication. To study the capability of correcting the low-order nonallowed field errors, magnetic shims were installed in HQ03. The expected shim contribution agreed well with the calculation. For the persistent-current effect, the measured $a_4$ can be related to 4% higher in the strand magnetization of one coil with respect to the other three coils. Finally, we compare the field errors due to the interstrand coupling currents between HQ03 and HQ02. [ABSTRACT FROM PUBLISHER]

A whole-body high-field MRI magnet is being constructed. A compensation solenoid method was employed to design the coil configuration for the magnet. In order to manage the mechanical stress, we sectioned the long solenoid into six windings, and they were wound on five aluminum alloy mandrels. Four compensation coils were wound outside of the long solenoid windings to compensate the field inhomogeneity of imaging region. Preliminary analysis used by a simplified method has been conducted to estimate the stress levels and coil deformations. Furthermore, a finite-element method (FEM) was used to obtain the stress distribution of the magnet structure fully. The electromagnetic stresses, the sliding behavior, and the quench dynamic stresses were simulated by these FEM models. The cumulative stresses caused by winding pretension and thermal contractions were used as initial stresses to calculate the frictional stresses for the interface contact analysis. The quench-induced stresses and deformations of thermal shields are also discussed. The results are exploited to conduct mechanical design and construction of the magnet. [ABSTRACT FROM PUBLISHER]

In synchrotron light sources the radiation is emitted from bending magnets and insertion devices (undulators, wigglers) placed on the storage ring by accelerating charged particles radially. The frequencies of produced radiation can range over the entire electromagnetic spectrum and have polarization characteristics. In synchrotron machines, the electron beam is forced to travel on a circular trajectory by the use of bending magnets. Quadrupole magnets are used to focus the beam. In this paper, we present the design studies for bending, quadrupole, and sextupole magnets for the storage ring of the Turkish synchrotron radiation source (TURKAY), which is in the design phase, as one of the subprojects of the Turkish Accelerator Center Project. [ABSTRACT FROM AUTHOR]

Purpose: The expansion of the electric vehicle (EV) market will bring changes in the type of environmental impact generated by the transport sector. This will be partially associated to the introduction of new technologies for energy storage and powertrains, including electric motors technology, which can play a critical role for the EV. To assure its optimal performance, key components and innovative materials are integrated in current motor designs. Such is the case of permanent magnets (PM), commonly made of rare-earth elements, which have a history of ecological concerns related to its mining. The goal of the paper is to study novel traction e-motors and to assess the influence of its components, in the environmental performance of the motor and the electric vehicle. Methods: In this study, a life cycle assessment (LCA) is performed, including the manufacturing, use, and end of life stages of a traction electric motor for EV applications. A comparison is presented, where the rare-earth magnets are replaced by ferrite magnets, under several efficiency scenarios. Average European conditions are considered for framing the modeling. A functional unit of 1 km driven by the vehicle is used. Results and discussion: Twelve impact categories were selected to present the potential environmental impact of the motors. Energy consumption during the use stage was identified as a hotspot responsible for an important share of the impact. The amount of energy consumed is highly dependent on the efficiencies of the powertrain, which is why improving efficiency should be regarded as crucial for decreasing the environmental damage produced by the motor. The use of rare-earth magnets during manufacturing does not represent a significant share of the impact, as they only take 2 % of the total mass. Other components, including laminations, housing and windings were instead recognized as more significant than the mangets, mainly for climate change, toxicity of humans, soil and water bodies, as well as metal depletion. The use of alternative materials for rare-earth magnets can contribute in the reduction of the potential impact, as long as the overall efficiency of the motor remains the same or increases. Conclusions: Based on the study results, it can be concluded that the environmental performance of traction motor is closely tight to its efficiency. Selection of materials during design should focus more on preserving or improving the efficiency of the motor, than on materials with low environmental impact during production. [ABSTRACT FROM AUTHOR]

Next generation of dipole magnets with a field higher than 16 T are considered for future particle colliders. To do so, combined-technology magnets, made of Nb–Ti, \Nb3\Sn and high-temperature superconductor (HTS) materials, have to be developed to reduce the cost of such a magnet. Therefore, in the framework of the European Coordination for Accelerator Research and Development (EuCARD-2) project, many HTS dipole magnet designs have to be investigated to find the most effective design for the HTS insert in a graded magnet. This paper discusses the $\cos\theta$ option. A 5-T stand-alone configuration of the HTS accelerator magnet (the first goal of EuCARD-2) appears to be achievable, whereas mechanical stress distribution shows that its use as an insert in a graded magnet is very challenging. This paves the way for alternative designs as the so-called slot or motor-like design, which is briefly introduced here. [ABSTRACT FROM PUBLISHER]

A light weight, simple design NMR apparatus consists of 24 identical magnets arranged in Halbach array was designed and built. The homogeneity of the magnetic field B0 can be improved by dividing a long magnets into several rings. The size of the useful volume depends on both the gap between each ring and some others shim magnets. Our aim is to enhance the sensitive volume and to maintain the highest magnetic static field (B0). This apparatus generates a B0 field strength of about 0.1 T. This work focuses on the magneto-static simulation of NdFeB magnets arrangement and on the comparison with the measurement of the magnetic field strength and homogeneity in three dimensions (3D). The homogeneity of the magnetic field B0 is optimized with the help of CAD and mathematical software. Our results were also validated with a Finite Element Method (FEM). The simulation results of the strength and of the homogeneity of B0 field were compared to those obtained with a digital gaussmeter. The homogeneity in the magnet longitudinal axis and the field B0 strength are similar. However, the homogeneity in transverse plane differs from simulation and measurement because of the quality of the magnets. In order to improve the homogeneity, we propose a new shim method. [ABSTRACT FROM AUTHOR]

In order to optimize the preformation of the field free line (FFL) for human-targeted clinical magnetic particle imaging, an advanced design for the generation of FFL with two pairs of concentric circular coils is proposed in this paper. Simulation study using FEM software was performed to study the relationship between the coil geometric parameters and the FFL quality. Particle-swarm optimization algorithm was performed to optimize the coil topology to gain a highly homogenous gradient field. The results demonstrated that high quality FFL can be generated by the concentric circular coil pairs and the topology of the concentric circle coils is also promising for the human target clinical usage, with the rotation of the FFL just perpendicular to the movement direction of patients inside. [ABSTRACT FROM AUTHOR]

A hybrid magnet is under construction at the High Magnetic Field Laboratory, Chinese Academy of Sciences (CHMFL). The hybrid magnet consists of a superconducting magnet and a resistive magnet. The superconducting magnet is wound with \Nb3\Sn Cable-in-Conduit Conductors. The resistive magnet is made of Bitter type conductors. The superconducting magnet and the resistive magnet will be charged by two separate power supplies. A trip of the resistive magnet due to a power supply or other fault will result in the increment of the magnetic field, current, and temperature in the superconducting magnet and consequentially influence the stable operation of the superconducting magnet. The thermal-hydraulic performance analysis of the superconducting magnet during a trip of the resistive magnet was performed and will be discussed in this paper. [ABSTRACT FROM PUBLISHER]

Various solenoids must be developed for different machines of the FAIR-Project. A solenoid design environment (SDE) has been developed to reduce expenditure of design time and work. The design environment is based on an Opera-2d input text file. Most significant physical and technical parameters of a solenoid are considered. Due to the axial symmetry, a two-dimensional solenoid model describes well the main characteristics of a real magnet. The first use of the SDE was the design of a solenoid for an emittance transfer experiment at GSI. The 36 cm long magnet creates a flux density of 1 Tesla at the center. The coil of the solenoid is separated in two halves to allow placing a movable stripping foil on the beam axis. Nevertheless, the magnet design avoids a local flux minimum in the center, since it might act as a trap of electrons. Creating a SDE and a solenoid with this tool takes a little more manpower than designing one solenoid without environment system. But in the future the SDE will help to decrease development time significantly. [ABSTRACT FROM PUBLISHER]

The Canted–Cosine–Theta (CCT) magnet design offers significant reductions in conductor stress by using mandrels to prevent the accumulation of operating Lorentz forces. Each mandrel consists of a cylindrical spar with ribs guiding the conductor. These ribs intercept the turn-to-turn accumulation of forces by transferring them to the spar. Design studies of a layered CCT coil pack coupled to a shell-based structure are shown. The use of a 3-D periodic symmetry region to reduce the problem size for finite element modeling is detailed along with a discussion of axial boundary conditions. ANSYS calculation results for a two layer NbTi dipole being constructed at LBNL (CCT1) are presented. ANSYS calculations show the Lorentz force induced stress in CCT1 at the single turn level, demonstrating interception and suggesting investigation of CCT design with minimal structure external to the coil pack. [ABSTRACT FROM PUBLISHER]

A 100-T magnetic field has heretofore been available only in pulse mode. This first-cut design demonstrates that a 100-T DC magnet (100 T) is possible. We base our design on: Gadolinium-based coated superconductor; a nested-coil formation, each a stack of double-pancake coils with the no-insulation technique; a band of high-strength steel over each coil; and a 12-T radial-field limit. The 100 T, a 20 mm cold bore, 6-m diameter, 17-m height, with a total of 12 500-km long superconductor, stores an energy of 122 GJ at its 4.2-K operating current of 2400 A. It requires a 4.2-K cooling power of 300 W. [ABSTRACT FROM AUTHOR]

A capacitor bank power supply of 14.8 MJ is built in Wuhan National Pulsed High Magnetic Field Center (WHMFC). Another pulse generator power supply of 100 MJ/100 MVA is expected to be finished by the end of August, 2012. These power supplies can drive pulsed magnets with a magnetic field of 50 T to 80 T and a pulse duration of 15 ms to 1000 ms (Li et al. in IEEE Trans. Appl. Supercond. 18:596, ). In addition to that, a new battery bank power supply system is also designed. This system can output a maximum voltage of 1000 V, a maximum current of 40 kA and a pulse duration of 2 s to feed pulsed flat-top magnets of 40 T/2 s. This power supply consists of battery bank and its charger, thyristor DC switch and its forced commutation, DC breaker, control system, Crowbar, PWM controller and magnet. The battery bank uses 945 lead-acid batteries and its modular design makes it easy to modify the voltage and current of the power supply by changing the connections of the batteries based on the requirement of single-coil, double-coil and triple-coil magnets. The design and primary tests of the battery power supply system will be introduced in this paper (Schillig et al. in IEEE Trans. Appl. Supercond. 10:526, ). [ABSTRACT FROM AUTHOR]

The first 80 T dual-coil magnet was manufactured and tested at the Wuhan National High Magnetic Field Center (WHMFC). The inner coil consists of 8 layers of 2.8 mm × 4.3 mm CuNb microcomposite wire developed in China; the bore diameter is 14 mm and the outer diameter 135 mm. The outer coil was wound directly on the inner coil with 12 layers of 3 mm × 6 mm soft copper. Each conductor layer of both coils was reinforced by Zylon/epoxy composite. The inner and outer coil were driven by a 1.6 MJ/5.12 mF capacitor bank and by eight 1 MJ/3.2 mF modules, respectively. At the voltage of 14.3 kV for the inner coil and 22 kV for the outer coil, the inner and outer coils produced peak fields of 48.5 T and 34.5 T respectively, which gave a total field of 83 T. This was the first combined operation of the new capacitor banks installed at the WHMFC. We present details of the design, manufacture and test of the dual-coil magnet and discuss crucial material properties. Based on this experience, a second dual-coil magnet will be designed; the enhanced design will be discussed. With the total energy of 12.6 MJ, peak field up to 90 T is expected. [ABSTRACT FROM AUTHOR]

The Dresden High Magnetic Field Laboratory (HLD) is a user facility which provides scientists with the possibility to perform a broad range of experiments in pulsed magnetic fields. Recent progress in the magnet-technology development at the HLD has led to significant advances in achieving non-destructive pulsed magnetic fields close to the megagauss mark. Using 9.5 MJ dual-coil magnets with 16 mm bore, in 2011 a world-record field of 91.4 T has been achieved. Later 94.2 T have been reached. We report on the magnet design and performance of these magnets as well as on the design for the next generation of dual-coil magnets characterized by interchangeable inner sub-coils and improved control of the axial preload. [ABSTRACT FROM AUTHOR]

A 40 tesla long pulse magnet and a battery bank as the power supply have been designed. This is now under construction at the Wuhan National High Magnetic Field Center. The 22 mm bore magnet will generate smooth pulses with duration 1 s and rise time 0.5 s. The battery bank consists of 945 12V/200 Ah lead-acid battery cells. The magnet and battery bank were optimized by codes developed in-house and by ANSYS. The coil was made from soft copper with internal reinforcement by fiber-epoxy composite; it is divided into two sections connected in series. The inner section consists of helix coils with each layer reinforced by Zylon composite. The outer section will be wound from copper sheet and externally reinforced by carbon fiber composite. [ABSTRACT FROM AUTHOR]

The Laboratoire National des Champs Magnétiques Intenses (LNCMI) develops different types of coils suited to specific experiments. We present some recent developments on magnet design. Several coils are dedicated to experiments in large scale facilities in France and Switzerland. A 30 T split-pair coil for X-rays diffraction and one 40 T coil for plasma physics at the LULI, two 30 T coils with axial access (one with an conical bore) for X-ray diffraction and absorption experiments. A 40 T wide angle conical access solenoid with a high duty-cycle for neutron scattering at the ILL is being constructed. For use at the installation in Toulouse we have developed, apart from our standard 60 and 70 T coils, several special coils: a coil with a long optical path with 30 T transverse magnetic field and a 90 T long pulse dual coil system. [ABSTRACT FROM AUTHOR]

At the Wuhan National High Magnetic Field Center (WHMFC) a 50 T/100 ms flat-top long-pulse magnet consisting of two coaxially nested coils is designed. The power and energy to operate the magnet is provided by a 100 MVA/185 MJ inertial energy storage motor-generator set. To accommodate the needs of this and future magnets, two 67.5 MW power supply modules based on 12-pulse converters are designed to convert the ac-power produced by the generator into controlled dc-power. The modules can operate independently as well as in parallel or in series. Each module consists of a combined input disconnect/grounding switch, two rectifier transformers, two parallel-connected 6-pulse rectifiers, a crowbar circuit, and a reversing switch. Two different transformer tap settings allow the module to provide no-load voltages of 3.2 kV and 2.7 kV and full-load voltages of 2.7 kV and 2.25 kV at the rated current of 25 kA for a 2 second pulse once every half hour. All components of the power supply modules are now under construction, with complete delivery and installation expected in early 2012. The design of the power supply components is described in detail. Digital simulation results of the power supply driving the 50 T/100 ms magnet are presented. [ABSTRACT FROM PUBLISHER]

A tunable hybrid quadrupole magnet design has been proposed for the final focus in the Compact Linear Collider (CLIC) that is currently under study. The proposed design is a combination of an iron dominated electromagnetic quadrupole with a bore diameter of 8.25 mm with permanent magnet blocks placed between the poles made of soft magnetic CoFe alloy “Permendur”. The possibility of using Sm2Co17 and Nd2Fe14B as material for the permanent magnet blocks has been investigated. It is shown that a very high field gradient of 530 T/m (Sm2Co17) and 590 T/m (Nd2Fe14B) can be achieved. [ABSTRACT FROM PUBLISHER]

Future accelerator magnets will need to reach higher field in the range of 20 T. This field level is very difficult to reach using only Low Temperature Superconductor materials whereas High Temperature Superconductors (HTS) provide interesting opportunities. High current densities and stress levels are needed to design such magnets. YBCO superconductor indeed carries large current densities under high magnetic field and provides good mechanical properties especially when produced using the IBAD approach. The HFM EUCARD program studies the design and the realization of an HTS insert of 6 T inside a \ Nb3{\ {Sn}} dipole of 13 T at 4.2 K. In the HTS insert, engineering current densities higher than 250 \ MA/m^2 under 19 T are required to fulfill the specifications. The stress level is also very severe. YBCO IBAD tapes theoretically meet these challenges from presented measurements. The insert protection is also a critical because HTS materials show low quench propagation velocities and the coupling with the \ Nb3{\ {Sn}} magnet makes the problem even more challenging. The magnetic and mechanical designs of the HTS insert as well as some protection investigation ways will be presented. [ABSTRACT FROM PUBLISHER]

As part of participation in project FAIR, IHEP has been developing designs of fast-cycling superconducting corrector magnets for the SIS 300 ring. There will be four types of corrector magnets: a steering dipole with vertical and horizontal dipole coils, a chromaticity sextupole, a resonance sextupole and a multipole magnet, consisting of quadrupole, sextupole and octupole coils. The paper presents requirements for the magnets, optimizations of the cross-section and 3D geometries, main magnetic characteristics, selection of the mechanical structure of the magnet to confine all forces affecting the coil. Since the magnets are fast-cycling, special attention is given to the choice of the current-carrying element by taking into account quench processes. Numerical analysis of AC losses and magnet temperature margin will also be presented. [ABSTRACT FROM PUBLISHER]

The Main Beam Quadrupole (MBQ) magnets represent one of the most populated families of Compact Linear Collider (CLIC) magnets. In total more than 4000 units of 4 different types with the same bore radius of 5 mm and field gradient of 200 T/m but with different magnetic length are needed. An extremely high precision and mechanical stability are necessary in order to fulfill the magnetic and stabilization requirements as defined in the beam optics studies. A magnet design has been proposed and several quadrupole prototypes of different length have been produced targeting a high mechanical precision. Magnetic calculation, constructional design and the first test results are presented. [ABSTRACT FROM PUBLISHER]

Integrable non-linear accelerator lattices are regarded as one potential option for the next generation of high-intensity accelerators. In particle tracking studies non-linear integrable lattices have shown to be effective in suppressing machine resonances, tune shifts and instabilities. This paper gives an update on the magnet design for a 150 MeV electron test facility. The required magnetic field is difficult to generate with conventional multipole magnets; we outline a potential solution and discuss the implications for a high energy proton driver. [ABSTRACT FROM PUBLISHER]

Korea Institute of Radiological & Medical Sciences (KIRAMS) has started the development of a superconducting cyclotron for carbon therapy. The goal of the development is to produce a 430 MeV/u carbon beam for medical use. The magnet system is composed of one set of NbTi superconducting coils and four spiral sectors with a return yoke. The hill angular widths, hill gaps, and spiral angles with radius have been designed for the isochronous magnetic field. The spiral sector shape and the beam characteristics of the designed magnetic field have been presented. [ABSTRACT FROM PUBLISHER]

The NHMFL has developed a high-field split resistive magnet for use in far-infrared photon scattering experiments. The magnet includes four large scattering ports of elliptical shape at the mid-plane amounting to a total solid angle of 0.5 steradians of available user space. Such a magnet configuration results in unique design challenges being especially severe for the windings in the mid-plane region of the innermost coils. Consequently, the NHMFL developed, tested and employed a new technology called Split Florida-Helix. Next, the coil design of the split user magnet, to be operated at our own facility, has been completed in 2009. This user magnet consist of 5 resistive coils consuming a total of less than 28 MW of dc power and providing a flux-density of 25 T available to the user space. To meet the unique design challenges, Split Florida-Helix technology is used around the mid-plane of the two inner most coils and state-of-the-art Florida-Bitter technology is used for all the regular winding in all 5 coils. [ABSTRACT FROM PUBLISHER]

In his De Magnete William Gilbert claims that it is possible to make a magnet by hammering a red-hot bar of wrought iron arranged north-south on an anvil. This is contrary to modern ideas concerning the 'Curie temperature' (770°C for carbon steel), and to the recognized susceptibility of steel magnets to mechanical abuse. It has proved impossible to replicate Gilbert's technique experimentally. Only lengthy cold hammering of hardened carbon steel specimens on a large ferrous anvil produced weak permanent magnets. [ABSTRACT FROM AUTHOR]

NMR magnets using high-Tc superconductors (HTS) to generate high magnetic fields exceeding 25 T are currently being designed by several organizations. In these designs, the HTS is used for the inner coils, and the other coils consist of NbTi and Nb3Sn wires. The YBCO wire, which is a typical HTS, has excellent critical current performance over a wide range of magnetic fields and tolerates high tensile stress of up to 700 MPa. These properties make it possible to realize a high-field NMR magnet. In particular, the superior mechanical strength allows for the high-stress criterion of the electromagnetic force to be applied to the design of the magnets. In this study, we show the conceptual design of 1.3 GHz (30.5 T) NMR magnets under the condition of high hoop stress of 500 MPa. To achieve high magnetic field homogeneity in these designs, we propose three magnet design plans that have different arrangements of the compensation coils. We assumed that the magnet would be operated by the driven mode at 4.2 K. We also considered the strong angular dependence of the critical current of the YBCO wires to design the magnet. [ABSTRACT FROM AUTHOR]

An optimum design of a water-cooled Bitter magnet was investigated for containerless melting experiments under a magnetic levitation condition. In order to minimize the vertical movement of a levitating sample due to the magnetic susceptibility change during a heating process, the gradient of B(∂B/∂z) along the center axis of a magnet must be large around the levitating position. Concerning the modification of an existing double Bitter magnet with 52 mm warm bore at the HFLSM, lager gradient of B(∂B/∂z) is obtained by shortening the inner coil and making the outer coil longer. [ABSTRACT FROM AUTHOR]

Modern high-Jc Nb3Sn strands and cables used in high field accelerator magnet models suffer from flux jump-related instabilities at low magnetic fields, these instabilities are exacerbated by enhanced magnetization and/or reduced RRR. Such instabilities and their response to deff and RRR in individual strands have been widely reported. In this work, we look at the influence of strand deformation during cabling on RRR and magnetization for strands extracted from Nb3Sn Rutherford cables. Seven separate cable types were used for this study, a number which had been previously used in both racetrack and quadrupole magnets. In the present experiments, longitudinal variations of RRR were estimated from multiple-tap measurements along the length of strands extracted from the various cables and then reacted in a special fixture. Magnetization measurements were then performed on cable sections to examine the effect of edge deformation. The implications of these measurements for stability are discussed. [ABSTRACT FROM AUTHOR]

n-value of the superconductor is key parameter in the persistent magnet design, affecting cost and performance. Analysis is presented that shows that a few mK overheat from the nonlinear index loss during standard Ic measurement of NbTi and Nb3Sn conductors in the helium bath can significantly affect the measurements and produce artificially high n-values. The error increases in conductors with higher n. Effect of low heat transfer, Eref criterion and index stability crisis are discussed. Analytical correlation is presented between the apparent and actual n-values. [ABSTRACT FROM AUTHOR]

A focusing lens R&D program is close to completion and industrial production of magnets has begun. Two types of magnets are being built for use in the room temperature RF section at the front end of a superconducting H-minus linac of a High Intensity Neutrino Source. All of the magnets are designed as a solenoid with bucking coils to cancel the field in the vicinity of adjacent RF cavities, and one type incorporates steering dipole corrector coils. We present a summary of the predicted and measured quench and magnetic properties for both R&D and production device samples that have been tested at Fermilab. [ABSTRACT FROM AUTHOR]

The Muon Ionization Cooling Experiment (MICE) will demonstrate ionization cooling in a short section of a realistic cooling channel using a muon beam at Rutherford Appleton Laboratory in the UK. The coupling magnet is a superconducting solenoid mounted around four 201 MHz RF cavities, which produces magnetic field up to 2.6 T on the magnet centerline to keep muons within the iris of RF cavities windows. The coupling coil with inner radius of 750 mm, length of 285 mm and thickness of 102.5 mm will be cooled by a pair of 1.5 W at 4.2 K small coolers. This paper will introduce the updated engineering design of the coupling magnet made by ICST in China. The detailed analyses on magnetic fields, stresses induced during the processes of winding, cool down and charging, and cold mass support assembly are presented as well. [ABSTRACT FROM AUTHOR]