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Sample records for nb-ti accelerator magnets

  1. Comparison of the costs of superconducting accelerator dipoles using NbTi, Nb3Sn and NbTiTa

    International Nuclear Information System (INIS)

    Hassenzahl, W.

    1981-03-01

    The present study, which is based on the assumption that future, high-energy accelerators will use superconductors, is a comparison of the costs of 5 to 12 Tesla NbTi, Nb 3 S/sub n/, and NbTiTa accelerator magnets operating at 4.2 K or 1.8 K. The object of this evaluation is not to determine the actual cost of future accelerators, rather, its purpose is to provide some rationale for research on the next generation of superconducting accelerator magnets. Thus, though the actual costs of accelerator magnets may be different from those given here, the comparisons are valid

  2. Effect of Cu4Ti compound formation on the characteristics of NbTi accelerator magnet wire

    International Nuclear Information System (INIS)

    Garber, M.; Suenaga, M.; Sampson, W.B.; Sabatini, R.L.

    1985-01-01

    High critical current density, J/sub c/ > 2500 A/mm 2 , and small filament diameter, d approx. 3 μm, are required in multifilamentary NbTi wire used for superconducting accelerator magnets. Wires obtained from various commercial sources had J/sub c/'s in the range 1000 to 2800 A/mm 2 amd d's in the range 1 to 23 μm. The filaments were examined by means of scanning electron microscopy in order to determine the reason for the variation in J/sub c/. It was found that the filaments in high J/sub c/ wires had clean smooth surfaces and uniform cross section along their lengths. Filaments in low J/sub c/ wires show formation of Cu 4 Ti compound particles on their surfaces and large variations in cross section. The lower critical current measured in these wires is believed to be largely due to this effect. The superconducting-normal state transition is relatively wide in these wires

  3. 40 mm bore Nb-Ti model dipole magnet

    International Nuclear Information System (INIS)

    Taylor, C.; Gilbert, W.; Hassenzahl, W.; Meuser, R.; Peters, C.; Rechen, J.; Scanlan, R.

    1984-01-01

    Preliminary R and D has been started on magnets for a next-generation high-energy-physics accelerator, the 20 TeV Superconducting Supercollider (SSC). One design now being developed at LBL is described in this paper. The design is based on two layers of flattened Nb-Ti cable, a 40 mm ID winding with flared ends, and an operating field of 6.5 T. Experimental results are presented on several one-meter-long models tested at both He I and He II temperature. Measurement of field, residual magnetization, quench propagation velocity, and winding prestress are presented. (A 2-in-1 magnet based on this coil design is being jointly developed by LBL and Brookhaven National Laboratory, and 15 ft. long models are being constructed at BNL)

  4. Magnetization and critical currents of NbTi wires with fine filaments

    International Nuclear Information System (INIS)

    Ghosh, A.K.; Sampson, W.B.

    1985-01-01

    In high energy accelerators such as the SSC, the magnetization of the superconductor is an important component in determining the harmonic fields at injection (approx.0.3T). In an effort to reduce these residual fields, interest has focused on NbTi conductors with fine filaments which are expected to have a reduced magnetization as dictated by the critical state model. With this in view, the magnetization and critical currents were measured at 4.3K for a set of NbTi wires with filament diameters, d, ranging from 1.0 to 5.0 microns. The data show that, although the magnetization scales linearly with d, it does not do so with the product J/sub c/d for d less than 3 μm. However, at these d values, the critical transport current density, J/sub c/ of NbTi was observed to decrease rapidly as a function of d. The origin of this J/sub c/ degradation and its effect on the scaling of magnetization within the framework of the critical state model is explored. We also examine the question of the observed asymmetry of the hysteretic magnetization

  5. Critical current studies on fine filamentary NbTi accelerator wires

    International Nuclear Information System (INIS)

    Garber, M.; Sabatini, R.L.; Sampson, W.B.; Suenaga, M.

    1986-01-01

    The magnets for the Superconducting Super Collider, a high energy proton colliding beam accelerator, require a superconductor with very high current density (> 2400 A/mm 2 at 5 T) and very small filaments ( about 2μ m in diameter). Previous work has shown that by controling the formation of Cu 4 Ti compound particles on the filament surfaces it is possible to make fine filamentary NbTi wire with high critical current density. The performance of multi-filamentary wire is characterized by the current density and the quantity ''n'' which describes the superconducting-normal transition. Micrographs of wires having high J /SUB c/ and high n show smooth, uniform filaments. Recently wires of very high critical current and high n have been produced in experimental quantities by commercial manufacturers

  6. Critical current studies on fine filamentary NbTi accelerator wires

    International Nuclear Information System (INIS)

    Garber, M.; Suenaga, M.; Sampson, W.B.; Sabatini, R.L.

    1985-01-01

    The magnets for the Superconductig Super Collider, a high energy proton colliding beam accelerator, require a superconductor with very high current density (>2400 A/mm 2 at 5 T) and very small filaments (approx. 2μm in diameter). Previous work has shown that by controlling the formation of Cu 4 Ti compound particles on the filament surfaces it is possible to make fine filamentary NbTi wire with high critical current density. The performance of multi-filamentary wire is characterized by the current density and the quantity ''n'' which describes the superconducting-normal transition. Micrographs of wires having high J/sub c/ and high n show smooth, uniform filaments. Recently wires of very high critical current and high n have been produced in experimental quantities by commercial manufactures

  7. Magnetic field profiles of NbTi tapes

    International Nuclear Information System (INIS)

    Migliori, A.; Taylor, R.D.; Bartlett, R.D.

    1976-01-01

    Magnetic field profile measurements were performed on stabilized NbTi tapes in zero applied field carrying large transport current densities. Field profile data were taken on large diameter superconducting sample loops at temperatures between 2 0 K and T/sub c/ (about 9.2 0 K) and several persistent currents up to I/sub c/(T), the maximum. The field profiles scaled with current, independent of temperature, at temperatures below 8.5 0 K and were well described by an elliptical shell approximation which left a current-free, field-free central region. Critical state models applied to this self-field situation proved inadequate. Complex profiles produced by trapped flux in the tape loop were described quantitatively by assuming concentric elliptical shells each with a different current density. The maximum current which could be persisted in the loop at each temperature was linear from 4 to 8.5 K. The effective resistance of the superconducting loop including its joint was less than 10 -13 ohms

  8. The optimization of NbTi-Nb/sub 3/Sn high field superconducting magnet used for physics experiments

    International Nuclear Information System (INIS)

    Han, B.; Han, S.; Feng, Z.X.

    1989-01-01

    The approach to the optimum cost design of multigraded NbTi-Nb/sub 3/Sn high field superconducting magnet is proposed. Investigation shows that by reasonably choosing the contribution of NbTi and Nb/sub 3/Sn coils to the central field required and properly increasing the parameters β of both NbTi and Nb/sub 2/Sn coils, the optimum cost design of the NbTi-Nb/sub 3/Sn solenoid magnet can be obtained. This is the base on which the minimum cost design of multi-graded NbTi-Nb/sub 3/Sn high field superconducting magnet is reached. As an example, a calculation of a 14T three graded NbT-Nb/sub 3/Sn superconducting magnet with a bore of 31mm in diameter is given

  9. Models and experimental results from the wide aperture Nb-Ti magnets for the LHC upgrade

    CERN Document Server

    Kirby, G.; Bajko, M.; Charrondiere, M.; Bourcey, N.; Datskov, V.I.; Fessia, P.; Feuvrier, J.; Galbraith, P.; Tabares, A. Garcia; Garcia-Perez, J.; Granieri, P.; Hagen, P.; Lorin, C.; Perez, J.C.; Russenschuck, S.; Sahner, T.; Segreti, M.; Todesco, E.; Willering, G.

    2013-01-01

    MQXC is a Nb-Ti quadrupole designed to meet the accelerator quality requirements needed for the phase-1 LHC upgrade, now superseded by the high luminosity upgrade foreseen in 2021. The 2-m-long model magnet was tested at room temperature and 1.9 K. The technology developed for this magnet is relevant for other magnets currently under development for the high-luminosity upgrade, namely D1 (at KEK) and the large aperture twin quadrupole Q4 (at CEA). In this paper we present MQXC test results, some of the specialized heat extraction features, spot heaters, temperature sensor mounting and voltage tap development for the special open cable insulation. We look at some problem solving with noisy signals, give an overview of electrical testing, look at how we calculate the coil resistance during at quench and show that the heaters are not working We describe the quench signals and its timing, the development of the quench heaters and give an explanation of an Excel quench calculation and its comparison including the ...

  10. Performance Limits and IR Design Challenges of a Possible LHC Luminosity Upgrade Based on Nb-Ti SC Magnet Technology

    CERN Document Server

    Brüning, Oliver Sim; Ostojic, R; Rossi, L; Ruggiero, F; Scandale, Walter; Taylor, T

    2004-01-01

    We investigate the maximum LHC performance for a standard IR design based on classical NbTi insertion magnets. We include in our analysis a ternary Nb-based ductile allow such as NbTi(Ta), a less developed but relatively cheap superconducting material which may allow to gain about 1 T in the peak field in the coils, and discuss the corresponding luminosity reach for a possible LHC upgrade compared to that based on Nb$_{3}$Sn magnets.

  11. 9.1-T iron-free Nb-Ti dipole magnet with pancake windings

    International Nuclear Information System (INIS)

    Gilbert, W.; Caspi, S.; Hassenzahl, W.; Meuser, R.; Peters, C.; Rechen, J.; Schafer, R.; Taylor, C.; Wolgast, R.

    1983-03-01

    An eight-pancake Nb-Ti dipole magnet, with bent up ends, called D-108B has been built and tested. This magnet is a Nb-Ti version of a Nb 3 Sn magnet designed to produce a 10-tesla dipole field in a 40 mm diameter aperture. The pancack design is used for the heavy 12,000 ampere Nb 3 Sn cable because of the mechanical difficulty in winding such a heavy cable into the conventional nested cylindrical shell configuration with a 2'' inner winding diameter. The Nb-Ti version operates at 1.8K, in He II, has superconducting cable half as thick as the Nb 3 Sn cable, and operates at half the operating current: 6000 A rather than 12,000 A at 10 tesla. Both magnets are approximately one meter long. D-10B was tested from January 26 to February 2, 1983 and reached short-sample performance in both He I and He II after moderate training. The central field at 4.3K is 7.0 (+- 0.1) tesla, and at 1.8K is 9.1 (+- 0.2) tesla. Ramp rate sensitivity and cyclic heating data were also measured

  12. A 9.1-T iron-free Nb- Ti dipole magnet with pancake windings

    International Nuclear Information System (INIS)

    Gilbert, W.; Caspi, S.; Hassenzahl, W.; Meuser, R.; Peters, C.; Rechen, J.; Schafer, R.; Taylor, C.; Wolgast, R.

    1983-01-01

    An eight-pancake Nb-Ti dipole magnet with bent-up ends and called D-10B has been built and tested. This magnet is a Nb-Ti version of a Nb 3 Sn magnet designed to produce a 10-tesla dipole field in a 40 mm diameter aperture. The pancake design is used for the heavy 12,000 ampere Nb 3 Sn cable because of the mechanical difficulty in winding such a heavy cable into the conventional nested cylindrical shell configuration with a 2'' inner winding diameter. The Nb-Ti version operates at 1.8 K in helium II, has superconducting cable half as thick as the Nb 3 Sn cable, and operates at half the current (6,000 amperes) at 10 tesla. Both magnets are approximately one meter long. D-10B was tested from January 26 to February 2, 1983, and reached short-sample performance in both helium I and helium II after moderate training. The central field at 4.3 K is 7.0 tesla and at 1.8 K is 9.1 tesla. Ramp rate sensitivity and cyclic heating data were also measured

  13. Alternating magnetic field losses in ATLAS type aluminium stabilized NbTi superconductors

    CERN Document Server

    Boxman, E W; ten Kate, H H J

    2002-01-01

    During ramping up- and down of the current in large-scale magnets the ramp losses are an important factor affecting the thermal and electro-magnetic stability of the system. The calculation of the losses is not straightforward due to the large dimensions of the conductor (~600 mm/sup 2/) implying that diffusion effects have to be taken into account. The AC-losses of the Al stabilized NbTi cable conductors used in the ATLAS magnet system were measured in 0.5 m long samples, using an inductive method with pick-up coils as well as the calorimetric method. External varying magnetic fields up to 2 tesla amplitude were applied parallel and perpendicular to the conductor wide surface. The results are compared to theory. It is found that hysteresis loss, eddy current loss in the Aluminum cladding and cable-to-cladding coupling loss contribute most to the AC loss. (5 refs).

  14. Conductors for commercial MRI magnets beyond NbTi: requirements and challenges

    Science.gov (United States)

    Parizh, Michael; Lvovsky, Yuri; Sumption, Michael

    2017-01-01

    Magnetic resonance imaging (MRI), a powerful medical diagnostic tool, is the largest commercial application of superconductivity. The superconducting magnet is the largest and most expensive component of an MRI system. The magnet configuration is determined by competing requirements including optimized functional performance, patient comfort, ease of siting in a hospital environment, minimum acquisition and lifecycle cost including service. In this paper, we analyze conductor requirements for commercial MRI magnets beyond traditional NbTi conductors, while avoiding links to a particular magnet configuration or design decisions. Potential conductor candidates include MgB2, ReBCO and BSCCO options. The analysis shows that no MRI-ready non-NbTi conductor is commercially available at the moment. For some conductors, MRI specifications will be difficult to achieve in principle. For others, cost is a key barrier. In some cases, the prospects for developing an MRI-ready conductor are more favorable, but significant developments are still needed. The key needs include the development of, or significant improvements in: (a) conductors specifically designed for MRI applications, with form-fit-and-function readily integratable into the present MRI magnet technology with minimum modifications. Preferably, similar conductors should be available from multiple vendors; (b) conductors with improved quench characteristics, i.e. the ability to carry significant current without damage while in the resistive state; (c) insulation which is compatible with manufacturing and refrigeration technologies; (d) dramatic increases in production and long-length quality control, including large-volume conductor manufacturing technology. In-situ MgB2 is, perhaps, the closest to meeting commercial and technical requirements to become suitable for commercial MRI. Conductor technology is an important, but not the only, issue in introduction of HTS/MgB2 conductor into commercial MRI magnets. These

  15. Ternary superconductor ''NbTiTa'' for high field superfluid magnets

    International Nuclear Information System (INIS)

    McInturff, A.D.; Carson, J.; Larbalestier, D.; Lee, P.; McKinnel, J.; Kanithi, H.; McDonald, W.; O'Larey, P.

    1990-06-01

    The possibility exists to obtain a higher 'Hc 2 ' upper critical field in the NbTi system which is normally limited by a spin-orbit coupling term. The introduction of scattering reduces this coupling. The spin-orbit scattering rate is proportional to Z 4 and therefore leads logically to the introduction of a high atomic number element which is more or less similar with respect to all of the other properties, i.e., Tc. Previous studies have shown Tantalum to be an excellent choice. The present work represents an attempt to obtain a high current density, high field ternary magnet conductor (Jc (10T, 2K, ρeff = 10 -12 Ω-cm)) > 2000A/mm 2 . This goal was met, but the conductor was clearly not optimized

  16. Magnetization measurements on multifilamentary Nb3Sn and NbTi conductors

    International Nuclear Information System (INIS)

    Ghosh, A.K.; Robins, K.E.; Sampson, W.B.

    1984-01-01

    The effective filament size has been determined for a number of high current Nb 3 Sn multifilamentary composites. In most cases it is much larger than the nominal filament size. For the smallest filaments (approx. 1 micron) the effective size can be as much as a factor of forty times the nominal size. Samples made by the internal tin, bronze route, and jelly roll methods have been examined with filaments in the range one to ten microns. Rate dependent magnetization and flux jumping have been observed in some cases. NbTi composites ranging in filament size from nine to two hundred microns and with copper to super-conductor ratios between 1.6:1 and 7:1 have been examined in the same apparatus. Low field flux jumping was only observed in conductors with very large filaments and relatively little stabilizing copper. 9 references, 6 figures, 3 tables

  17. Magnetic hysteresis and complex susceptibility as measures of ac losses in a multifilamentary NbTi superconductor

    International Nuclear Information System (INIS)

    Goldfarb, R.B.; Clark, A.F.

    1985-01-01

    Magnetization and ac susceptibility of a standard NbTi superconductor were measured as a function of longitudinal dc magnetic field. The ac-field-amplitude and frequency dependences of the complex susceptibility are examined. The magnetization is related to the susceptibility by means of a theoretical derivation based on the field dependence of the critical current density. Hysteresis losses, obtained directly from dc hysteresis loops and derived theoretically from ac susceptibility and critical current density, were in reasonable agreement

  18. Evaluation of APC NbTi superconductor in a model dipole magnet

    International Nuclear Information System (INIS)

    Scanlan, R.M.; Lietzke, A.; Royet, J.; Wandesforde, A.; Taylor, C.E.; Wong, J.; Rudziak, M.K.

    1993-01-01

    The artificial pinning center (APC) approach to NbTi superconductor fabrication offers the potential benefits of higher current density and lower cost than the conventional process for NbTi. We have been evaluating several approaches for fabricating NbTi via the APC approach to determine whether these advantages can be realized in a practical conductor. The study began with the fabrication by several vendors of 10kg size samples which were evaluated as short samples. This was followed by the scale-up of one process to 150mm diameter billets. This material was evaluated first in a solenoid configuration and recently in a one-meter long dipole. We will report here on the results of these coil tests and other characterization results for this new material. We will also describe the plans to continue the scale-up to full size billets and we will discuss the potential cost savings of this approach compared with conventional NbTi fabrication

  19. Magnetization and loss measurements on Nb3Sn and NbTi strands for ITER and LHC

    International Nuclear Information System (INIS)

    Foitl, M.

    2001-05-01

    Recent developments in high energy physics have led to a demand for high magnetic fields which cannot be generated permanently by conventional magnets wound from Cu cables. The acceleration of protons in a ring accelerator up to particle energies of several TeVs or the magnetic confinement of fusion plasmas of sufficient pressure to generate ∼1 GW of fusion power, or even more, are only two examples. To reach beam to beam collision energies of several TeV for hadrons or heavy ions, accelerator magnets have to provide very high magnetic fields which can only be produced by superconducting magnets. In the case of the Large Hadron Collider (LHC), which is planned to be commissioned in the year 2005, the circumference of the beam line is given by the dimensions of the 27 Km Large Electron Positron (LEP) Collider tunnel. Consequently each superconducting arc dipole has to provide a field of 8.36 T to bend 7 TeV protons around the ring. Apart from the total magnitude of the bending field, which necessitates to operate the superconducting NbTi magnets at 1.9 K, very strict demands have to be drawn to the quality of the field components of the guiding field. Actually, any kind of random field error would dilute the 7-on-7 TeV counter-rotating proton beams and degrade their nominal luminosity of 1034 cm -1 s -2 . The main contributions to random field errors are random displacements of the coil positions with respect to nominal design, persistent current magnetization stemming from current imbalances in the superconducting cables and variations of the strand magnetization which come from irregularities in the strand manufacturing process. Since there will be more than one cable manufacturer, there will certainly be a difference between average magnetization values for each of them. Interfilament proximity coupling could make the magnetization higher at low fields, which could also have an influence on the performance of certain magnets in the machine. In the first part of

  20. Future Accelerator Magnet Needs

    International Nuclear Information System (INIS)

    Devred, Arnaud; Gourlay, Stephen A.; Yamamoto, Akira

    2005-01-01

    Superconducting magnet technology is continually evolving in order to meet the demanding needs of new accelerators and to provide necessary upgrades for existing machines. A variety of designs are now under development, including high fields and gradients, rapid cycling and novel coil configurations. This paper presents a summary of R and D programs in the EU, Japan and the USA. A performance comparison between NbTi and Nb 3 Sn along with fabrication and cost issues are also discussed

  1. Low Gradient, Large Aperture IR Upgrade Options for the LHC compatible with Nb-Ti Magnet Technology

    CERN Document Server

    Brüning, Oliver Sim; Ostojic, R

    2007-01-01

    The paper presents three different layout and optics solutions for the upgrade of LHC insertions using Nb-Ti superconducting quadrupoles. Each solution is the outcome of different driving design criteria: a) a compact triplet using low gradient quadrupoles; b) a triplet using low gradient quadrupoles of modular design, and c) a layout minimizing the B-max while using modular magnets. The paper discusses the different strategies and design criteria for the three solutions. It also discusses their relative advantages and disadvantages and identifies outstanding studies that need to be addressed in order to develop the solutions further. All cases assume that the first quadrupole magnet requires a smaller minimum aperture and therefore, can feature a slightly larger gradient than the remaining final focus quadrupole magnets.

  2. Pulsed critical current measurements of NbTi in perpendicular and parallel pulsed magnetic fields using the new Cryo-BI-Pulse System

    International Nuclear Information System (INIS)

    Stehr, V; Tan, K S; Hopkins, S C; Glowacki, B A; Keyser, A De; Bockstal, L Van; Deschagt, J

    2006-01-01

    Rapid transport current versus high magnetic field characterisation of high-irreversibility type II superconductors is important to maximise their critical parameters. HTS conductors are already used to produce insert coils that increase the fields of conventional magnets made from NbTi (Nb, Ta) 3 Sn and Nb 3 Al wires. There is fundamental interest in the study of HTS tapes and wires in magnetic fields higher than 21T, the current limit of superconducting magnets producing a DC field. Such fields can be obtained by using pulse techniques. High critical currents cannot be routinely measured with a continuous current applied at liquid helium, hydrogen or neon temperatures because of thermal and mechanical effects. A newly developed pulsed magnetic field and pulsed current system which allows rapid J c (B, T) measurements of the whole range of superconducting materials was tested with a multifilamentary NbTi wire in perpendicular and parallel orientations

  3. Acoustic emission in a superconductor (Nb-Ti) during magnetic field and current sweep

    International Nuclear Information System (INIS)

    Nomura, Harehiko

    1980-01-01

    Though superconducting magnets are indispensable in the fields of nuclear fusion, MHD power generation, high energy technology, and the trains using magnetic levitation, the safety of the magnets used for those fields is required to be fully investigated because their accumulating energy reaches up to several GJ. For this purpose, the improvement of monitoring techniques is extremely important to grasp exactly the magnetization of such large energy magnets. Although the detection of the terminal voltage of the magnets has been mainly used so far, the purpose has not yet been fulfilled because various phenomena appear in the form of noises in the terminal voltage. The authors have found the monitoring method using acoustic emission in a system completely independent from voltage observation. From this viewpoint, the experiments have been performed aiming at the generation of acoustic emission in conjunction with magnetization out of the fine structure of super-conductors, taking notice of the emitted sound frequency ranging over several hundred kHz. The results and investigation revealed that the superconductor itself emitted ultrasonic sound. It was found that the observation of this acoustic power intensity was able to monitor not only the magnetization of superconductors but also its current sweep. Since the motion of the magnetic flux is converted into the signal of acoustic field, this measuring method is less affected by noise disturbance from electromagnetic systems, and is expected to be useful for the researches on analyzing superconductor characteristics. (Wakatsuki, Y.)

  4. Quench development in magnets made with multifilamentary NbTi cable

    International Nuclear Information System (INIS)

    Flora, R.H.; Kuchnir, M.; Tollestrup, A.V.

    1976-01-01

    An experimental study of the normal zone propagation and total resistance as a function of time is described. The normal zone propagation velocity in a single strand was measured as a function of both current and magnetic field with particular interest in the neighborhood of the short sample limit. The study proceeded from measurements in single multifilamentary strands to measurements in 23 strand cables under different cooling environments to final measurements in actual ramping dipole magnets made with this cable. Interpretation of the results led to the determination of safety limits for the Energy Doubler/Saver magnets and to safeguards implemented by an energy dumping circuit which effectively protects these magnets from self-destruction

  5. NbTi Superferric Corrector Magnets for the LHC Luminosity Upgrade

    CERN Document Server

    Volpini, G; Bellomo, G; Broggi, F; Paccalini, A; Pedrini, D; Leone, A; Quadrio, M; Somaschini, L; Sorbi, M; Todero, M; Uva, C; Fessia, P; Todesco, E; Toral, F

    2015-01-01

    CERN and INFN, Italy, have signed an agreement for R&D activities relating to high-luminosity LHC superconducting magnets, which include the design, construction, and cryogenic test of a set of five prototypes, one for each type foreseen, from the skew quadrupole to the dodecapole. The reference layout of these magnets is based on a superferric design type, which allows reaching the required integrated field strength with a relatively simple design. Since the number of magnets of all the types required for the series is 36, emphasis has been put on modularity, reliability, ease of construction, and on the use of an available superconducting wire. This paper presents the status of the development work being performed at INFN, LASA Laboratory, and at CERN, focusing on the following issues: the electromagnetic 2- and 3-D design including harmonic component study; the fringe field analysis; the magnet powering and quench protection; mechanical and construction main choices.

  6. Feasibility study of parallel conduction cooling of NbTi magnet and sample probe in a cryogen-free magnet system

    Science.gov (United States)

    Catarino, I.; Soni, V.; Barreto, J.; Martins, D.; Kar, S.

    2017-02-01

    The conduction cooling of both a 6 T superconducting magnet along with a sample probe in a parallel configuration is addressed in this work. A Gifford-McMahon (GM) cryocooler is directly cooling the NbTi magnet, which aims to be kept at 4 K, while a gas-gap heat switch (GGHS) manages the cooling power to be diverted to the sample probe, which may be swept from 4 K up to 300 K. A first prototype of a GGHS was customized and validated for this purpose. A sample probe assembly has been designed and assembled with the existing cryogen-free magnet system. The whole test setup and components are described and the preliminary experimental results on the integration are presented and discussed. The magnet was charged up to 3 T with a 4 K sample space and up to 1 T with a sweeping sample space temperature up to 300 K while acting on the GGHS. Despite some identified thermal insulation problems that occurred during this first test, the overall results demonstrated the feasibility of the cryogen-free parallel conduction cooling on study.

  7. Superconducting materials for particle accelerator magnets

    International Nuclear Information System (INIS)

    Larbalestier, D.C.

    1983-01-01

    Present accelerator designs are clustered around a field of 5 Tesla with several future studies looking at the 8-to-10 Tesla range. There has also been some recent interest in low-field iron-dominated dipoles in which the superconductor will see a field of about 2 Tesla. The demands of this present range of interest can still be met, with the upper limit at about 10 Tesla, by the use of Nb-Ti (or Nb-Ti-Ta) or Nb 3 Sn. Both of these conductors are available in multifilamentary form from industrial sources and are suitable for accelerator magnets. The upper critical field and transition temperature of both types of composite cover the foreseeable range of demand for such magnets. There is no magical new composite on the horizon that is likely to replace Nb-Ti or Nb 3 Sn. One class of materials which has a potentially exciting prospect is that of the ternary molybdenum sulfides. These can have an upper critical field of greater than 50 T, which extends their superconductivity into field ranges unattainable with A15 compounds; the two drawbacks to such materials, however, are the amount of development needed to produce superconductors from them with useful current densities and the fact that it does not appear that they would offer any features not already possessed by Nb-Ti or Nb 3 Sn in the field range presently of interest to accelerator designers. Using this pragmatic approach, this paper addresses these and other superconducting composites in terms of their fabrication, their testing, the measurement aspects of their critical current densities, and other properties which are pertinent to their selection for particle accelerator magnet use

  8. Recent status of superconductors for accelerator magnets

    International Nuclear Information System (INIS)

    Greene, A.F.

    1992-01-01

    A survey is given of superconductor wire and cable which has been or will be used for construction of dipole magnets for all of the large European and US superconducting accelerator rings. Included is a simplified view of the construction methods and operating requirements of an accelerator dipole magnet, with emphasis on required superconductor performance. The methods of fabricating Nb-Ti superconductors are described, including the critical parameters and materials requirements. The superconductor performance requirements are summarized in an effort to relate why these are important to accelerator designers. Some of the recently observed time dependent effects are covered briefly

  9. Superconducting Magnets for Accelerators

    Science.gov (United States)

    Brianti, G.; Tortschanoff, T.

    1993-03-01

    This chapter describes the main features of superconducting magnets for high energy synchrotrons and colliders. It refers to magnets presently used and under development for the most advanced accelerators projects, both recently constructed or in the preparatory phase. These magnets, using the technology mainly based on the NbTi conductor, are described from the aspect of design, materials, construction and performance. The trend toward higher performance can be gauged from the doubling of design field in less than a decade from about 4 T for the Tevatron to 10 T for the LHC. Special properties of the superconducting accelerator magnets, such as their general layout and the need of extensive computational treatment, the limits of performance inherent to the available conductors, the requirements on the structural design are described. The contribution is completed by elaborating on persistent current effects, quench protection and the cryostat design. As examples the main magnets for HERA and SSC, as well as the twin-aperture magnets for LHC, are presented.

  10. Magnetization and loss measurements on Nb$_{3}$Sn and NbTi strands for ITER and LHC

    CERN Document Server

    Foitl, M

    2001-01-01

    Recent developments in high energy physics have led to a demand for high magnetic fields which cannot be generated permanently by conventional magnets wound from Cu cables. The acceleration of protons in a ring accelerator up to particle energies of several TeVs or the magnetic confinement of fusion plasmas of sufficient pressure to generate approx 1 GW of fusion power, or even more, are only two examples. To reach beam to beam collision energies of several TeV for hadrons or heavy ions, accelerator magnets have to provide very high magnetic fields which can only be produced by superconducting magnets. In the case of the Large Hadron Collider (LHC), which is planned to be commissioned in the year 2005, the circumference of the beam line is given by the dimensions of the 27 Km Large Electron Positron (LEP) Collider tunnel. Consequently each superconducting arc dipole has to provide a field of 8.36 T to bend 7 TeV protons around the ring. Apart from the total magnitude of the bending field, which necessitates t...

  11. Magnetization and loss measurements on Nb3Sn and NbTi strands for ITER and LHC

    CERN Document Server

    Foitl, M

    2001-01-01

    Recent developments in high energy physics have led to a demand for high magnetic fields which cannot be generated permanently by conventional magnets wound from Cu cables. The acceleration of protons in a ring accelerator up to particle energies of several TeVs or the magnetic confinement of fusion plasmas of sufficient pressure to generate approx 1 GW of fusion power, or even more, are only two examples. To reach beam to beam collision energies of several TeV for hadrons or heavy ions, accelerator magnets have to provide very high magnetic fields which can only be produced by superconducting magnets. In the case of the Large Hadron Collider (LHC), which is planned to be commissioned in the year 2005, the circumference of the beam line is given by the dimensions of the 27 Km Large Electron Positron (LEP) Collider tunnel. Consequently each superconducting arc dipole has to provide a field of 8.36 T to bend 7 TeV protons around the ring. Apart from the total magnitude of the bending field, which necessitates t...

  12. Fine filament NbTi superconductive composite

    International Nuclear Information System (INIS)

    Hong, S.; Grabinsky, G.; Marancik, W.; Pattanayak, D.

    1986-01-01

    The large superconducting magnet for the high energy physics accelerator requires fine filament composite to minimize the field error due to the persistent current in the filaments. New concepts toward the fine filament composite and its cable fabrication are discussed. Two-stage cables of fine wire with intermediate number of filaments were introduced. The first stage was six wires cables around one and in the second stage this was used to produce a Rutherford cable. The advantage of this process is in the ease of billet fabrication since the number of filaments in a single wire is within the range of easy billet fabrication. The disadvantage is in the cable fabrication. One of the major concerns in the fabrication of fine NbTi filaments composite in a copper matrix is the intermetallic compound formation during the extrusion and heat treatment steps. The hard intermetallic particles degrade the uniformity of the filaments and reduce the critical current density. The process of using Nb barrier between the filaments and copper matrix in order to prevent this CuTi intermetallic particle formation is described

  13. Thermo-magnetic instabilities in Nb3Sn Superconducting Accelerator Magnets

    International Nuclear Information System (INIS)

    Bordini, Bernardo; Pisa U.

    2006-01-01

    The advance of High Energy Physics research using circulating accelerators strongly depends on increasing the magnetic bending field which accelerator magnets provide. To achieve high fields, the most powerful present-day accelerator magnets employ NbTi superconducting technology; however, with the start up of Large Hadron Collider (LHC) in 2007, NbTi magnets will have reached the maximum field allowed by the intrinsic properties of this superconductor. A further increase of the field strength necessarily requires a change in superconductor material; the best candidate is Nb 3 Sn. Several laboratories in the US and Europe are currently working on developing Nb 3 Sn accelerator magnets, and although these magnets have great potential, it is suspected that their performance may be fundamentally limited by conductor thermo-magnetic instabilities: an idea first proposed by the Fermilab High Field Magnet group early in 2003. This thesis presents a study of thermo-magnetic instability in high field Nb 3 Sn accelerator magnets. In this chapter the following topics are described: the role of superconducting magnets in High Energy Physics; the main characteristics of superconductors for accelerator magnets; typical measurements of current capability in superconducting strands; the properties of Nb 3 Sn; a description of the manufacturing process of Nb 3 Sn strands; superconducting cables; a typical layout of superconducting accelerator magnets; the current state of the art of Nb 3 Sn accelerator magnets; the High Field Magnet program at Fermilab; and the scope of the thesis

  14. Nb3Sn accelerator magnet development around the world

    Energy Technology Data Exchange (ETDEWEB)

    Michael J. Lamm

    2003-06-23

    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.

  15. Upper critical fields in multifilamentary NbTi alloy superconducting wires

    International Nuclear Information System (INIS)

    Watanabe, Kazuo; Muto, Yoshio; Noto, Koshichi.

    1991-01-01

    In order to improve the high field performance of superconducting magnets, the upper critical field B c2 for practical multifilamentary alloy wires of NbTi, NbTiTa and NbTiHf were examined in respect with the usage of a pressurized superfluid cooling technique. The addition of Ta or Hf to NbTi enhanced by 0.5 T for B c2 at 1.8 K. Although the addition of a heavy element such as Ta or Hf has been regarded as suppressing Pauli-paramagnetism so far, it was found that the mechanism for B c2 enhancement by Hf addition is different from that by Ta addition. (author)

  16. Argonne lectures on particles accelerator magnets

    International Nuclear Information System (INIS)

    Devred, A.

    1999-09-01

    The quest for elementary particles has promoted the development of particle accelerators producing beams of increasingly higher energies. In a synchrotron, the particle energy is directly proportional to the product of the machine's radius times the bending magnets' field strength. Present proton experiments at the TeV scale require facilities with circumferences ranging from a few to tens of kilometers and relying on a large number (several hundred to several thousand) high field dipole magnets and high field gradient quadrupole magnets. These electro-magnets use high-current-density, low-critical-temperature superconducting cables and are cooled down at liquid helium temperature. They are among the most costly and the most challenging components of the machine. After explaining what are the various types of accelerator magnets and why they are needed (lecture 1), we briefly recall the origins of superconductivity and we review the parameters of existing superconducting particle accelerators (lecture 2). Then, we review the superconducting materials that are available at industrial scale (chiefly, NbTi and Nb 3 Sn) and we explain in details the manufacturing of NbTi wires and cables (lecture 3). We also present the difficulties of processing and insulating Nb 3 Sn conductors, which so far have limited the use of this material in spite of its superior performances. We continue by discussing the two dimensional current distributions which are the most appropriate for generating pure dipole and quadrupole fields and we explain how these ideal distributions can be approximated by so called cosθ and cos 2θ coil designs (lecture 4). We also present a few alternative designs which are being investigated and we describe the difficulties of realizing coil ends. Next, we present the mechanical design concepts that are used in existing accelerator magnets (lecture 5) and we describe how the magnets are assembled (lecture 6). Some of the toughest requirements on the

  17. Argonne lectures on particles accelerator magnets

    Energy Technology Data Exchange (ETDEWEB)

    Devred, A

    1999-09-01

    The quest for elementary particles has promoted the development of particle accelerators producing beams of increasingly higher energies. In a synchrotron, the particle energy is directly proportional to the product of the machine's radius times the bending magnets' field strength. Present proton experiments at the TeV scale require facilities with circumferences ranging from a few to tens of kilometers and relying on a large number (several hundred to several thousand) high field dipole magnets and high field gradient quadrupole magnets. These electro-magnets use high-current-density, low-critical-temperature superconducting cables and are cooled down at liquid helium temperature. They are among the most costly and the most challenging components of the machine. After explaining what are the various types of accelerator magnets and why they are needed (lecture 1), we briefly recall the origins of superconductivity and we review the parameters of existing superconducting particle accelerators (lecture 2). Then, we review the superconducting materials that are available at industrial scale (chiefly, NbTi and Nb{sub 3}Sn) and we explain in details the manufacturing of NbTi wires and cables (lecture 3). We also present the difficulties of processing and insulating Nb{sub 3}Sn conductors, which so far have limited the use of this material in spite of its superior performances. We continue by discussing the two dimensional current distributions which are the most appropriate for generating pure dipole and quadrupole fields and we explain how these ideal distributions can be approximated by so called cos{theta} and cos 2{theta} coil designs (lecture 4). We also present a few alternative designs which are being investigated and we describe the difficulties of realizing coil ends. Next, we present the mechanical design concepts that are used in existing accelerator magnets (lecture 5) and we describe how the magnets are assembled (lecture 6). Some of the toughest

  18. Temperature Induced Degradation of Nb Ti/Cu Composite Superconductors

    CERN Document Server

    Scheuerlein, C; Senatore, C; Di Michiel, M; Thilly, L; Gerardin, A; Reluner, B; Oberli, L; Willering, G; Bottura, L

    2009-01-01

    The degradation mechanisms of state-of-the-art Nb-Ti/Cu superconductors are described, based on in-situ synchrotron X-ray diffraction measurements during heat treatment. A quantitative description of the Nb-Ti/Cu degradation in terms of critical current density, Cu stabiliser resistivity and mechanical composite strength is presented. In an applied magnetic field a significant critical current degradation is already observed after a 5-minute 400 °C heat treatment, due to variations of a-Ti precipitate size and distribution within the Nb-Ti alloy filaments. A strong degradation of the strand mechanical properties is observed after several minutes heating above 550 °C, which is also the temperature at which the formation of Cu Ti intermetallic phases is detected. Several minutes heating at 250 °C are sufficient to increase the RRR of the strongly cold work strands inside a Rutherford type cable from about 80 to about 240. Heating for several minutes at 400 °C does not cause a significant conductor degradati...

  19. Workshop on Accelerator Magnet Superconductors, Design and Optimization

    CERN Document Server

    WAMSDO Workshop

    2009-01-01

    This report contains the proceedings of the CARE-HHH-AMT Workshop on Accelerator Magnet Superconductors, Design and Optimization (WAMSDO) held at CERN from 19 to 23 May 2008. The needs in terms of superconducting magnets for the accelerator projects were discussed, mainly for the LHC interaction regions and injector upgrades, and for the GSI FAIR complex. The first part of the workshop focused on the development of superconductor and cables, i.e., low-loss Nb-Ti cables, Nb$_{3}$Sn and high-temperature superconductors. An industry session summarized the actual plans and status of the activities in the main European industries. Then, a worldwide status of the high field magnets programme was presented. A special session was devoted to fast cycled magnets, including FAIR facilities and LHC injector upgrades. A final session focused on the optimization methods and numerical tools for magnet design.

  20. Comparing the thermal stability of NbTi and Nb3Sn wires

    International Nuclear Information System (INIS)

    Breschi, M; Trevisani, L; Bottura, L; Devred, A; Trillaud, F

    2009-01-01

    The investigation of quenching in low temperature superconducting wires is of great relevance for a proper design of superconductive cables and magnets. This paper reports the experimental results of a vast measurement campaign of quench induced by laser pulses on NbTi and Nb 3 Sn wires in pool boiling helium I. A comparison of the quench behavior of two typical NbTi and Nb 3 Sn wires is shown from different standpoints. Different qualitative behaviors of the voltage traces recorded during quenches and recoveries on NbTi and Nb 3 Sn wires are reported and analyzed. It is shown that the Nb 3 Sn wire exhibits a quench or no-quench behavior, whereas quenches and recoveries are exhibited by the NbTi wire. The two wires are also compared by considering the behaviors of the two main parameters describing quench, i.e. quench energies and quench velocities, with respect to operating current, pulse duration, and magnetic field. It is shown that the Nb 3 Sn wire exhibits a 'kink' of the quench energy versus current curve that makes the quench energy of Nb 3 Sn lower than that of NbTi at some intermediate current levels. Both the qualitative differences of the voltage traces and the different behaviors of quench energies and velocities are interpreted through a coupled electromagnetic-thermal model, with special emphasis on the detailed description of heat exchange with liquid helium.

  1. Residual Resistivity Ratio (RRR) Measurements of LHC Superconducting NbTi Cable Strands

    CERN Document Server

    Charifoulline, Z

    2006-01-01

    The Rutherford-type superconducting NbTi cables of the LHC accelerator are currently manufactured by six industrial companies. As a part of the acceptance tests, the Residual Resistivity Ratio (RRR) of superconducting strands is systematically measured on virgin strands to qualify the strands before cabling and on extracted strands to qualify the cables and to check the final heat treatment (controlled oxidation to control interstrand resistance). More than 12000 samples of virgin and extracted strands have been measured during last five years. Results show good correlation with the measurements done by the companies and reflect well the technological process of cable production (strand annealing, cabling, cable heat treatment). This paper presents a description of the RRR-test station and the measurement procedure, the summary of the results over all suppliers and finally the correlation between RRR-values of the cables and the magnets.

  2. New technology for fabrication of multifilament NbTi composite

    International Nuclear Information System (INIS)

    Yang, Y.K.; Ma, W.M.; Peng, W.N.

    1988-01-01

    Explosive bonding-rolling-drawing process has been developed to produce NbTi multifilamentary superconductors. Multifilamentary wires of 0.5mm in diameter and 2.5km in length with 199 filaments of 25μm in dia. have been produced using this process. The critical current density (Jc) is 1.94x10 5 A/cm 2 at 4.2K and 5T for short samples and 4.9x10 4 A/cm 2 and 4.2/K and 8.5T for the magnet have been reached

  3. State-of-the-art superconducting accelerator magnets

    CERN Document Server

    Rossi, L

    2002-01-01

    With the LHC the technology of NbTi-based accelerator magnets has been pushed to the limit. By operating in superfluid helium, magnetic fields in excess of 10 T have been reached in various one meter-long model magnets while full scale magnets, 15 meter-long dipoles, have demonstrated possibility of safe operation in the 8.3-9 tesla range, with the necessary, very tight, field accuracy. The paper reviews the key points of the technology that has permitted the construction of the largest existing superconducting installations (Fermilab, Desy and Brookhaven), highlighting the novelties of the design of the LHC dipoles, quadrupoles and other superconducting magnets. All together the LHC project will need more than 5000 km of fine filament superconducting cables capable of 14 kA @ 10 T, 1.9 K. (13 refs).

  4. Characterization of the critical current and physical properties of superconducting epitaxial NbTiN sub-micron structures

    Energy Technology Data Exchange (ETDEWEB)

    Klimov, A., E-mail: aklimov@ite.waw.pl [Institute of Electron Technology, Al. Lotników 32/46, 02-668 Warsaw (Poland); Słysz, W.; Guziewicz, M. [Institute of Electron Technology, Al. Lotników 32/46, 02-668 Warsaw (Poland); Kolkovsky, V.; Zaytseva, I.; Malinowski, A. [Institute of Physics Polish Academy of Science, Al. Lotników 32/46, 02-668 Warsaw (Poland)

    2017-05-15

    Highlights: • This manuscript presents investigation of the critical current dependence of Nb(Ti)N nanostructured superconducting single photon detectors (SNSPD) in function of temperature and applied magnetic field. • Presented results are complimentary and compared with the same data received for submicron-wide single bridge Nb(Ti)N structures. • Our data demonstrate significant influence of local constrictions on physical properties of our SNSPD detectors. - Abstract: Measurements of critical current in NbTiN as a function of applied magnetic field and temperature are reported for two samples: 700-nm-wide bridge and 100-nm-wide meander. In 700-nm-wide NbTiN bridge we pinpointed the limiting factors for the critical current density to be current-driven vortex de-pinning at low temperatures and thermally activated flux flow closer to the transition temperature. In 100-nm-wide NbTiN meander we found phase slips activation, accompanied by hotspots formation at all measured temperatures. These two types of structures demonstrate different dependence of the critical current on the applied magnetic field. Although our NbTiN meander structures has high de-pairing critical current densities ∼10{sup 7} A/cm{sup 2} at low temperatures, the real critical currents are smaller due to the presence of the local constrictions.

  5. Recent development of the Cu/Nb-Ti superconducting cables for SSC in Hitachi Cable, Ltd

    International Nuclear Information System (INIS)

    Sakai, S.; Iwaki, G.; Sawada, Y.; Moriai, H.; Ishigami, Y.

    1989-01-01

    In these few years, Cu/Nb-Ti superconducting cables for the dipole magnets of SSC projects have been developed in the industrial scale in Hitachi Cable, Ltd. The features of these developed conductors are as follows. (1) The diameter of Nb-Ti filaments is very small, 4-6 μm. (2) The critical current density (J c ) is very high, 2,850-3,050 A/mm 2 at 5 T on wires, 2750-2950 A/mm 2 at 5 T on cables in industrial scale. The champion J c of wires is 3,460 A/mm 2 at 5 T in the laboratory scale. (3) The RRR Residual Resistivity Ratio values of developed cables is very high, approximately 200, due to the newly developed high purity Oxygen Free Copper (OFC). (4) The conductors have been wound to the 1 m length dipole magnet in Hitachi Ltd., and it has generated 6.7 T in the central magnetic field at 6,595 A. The Cu/Cu-Mn/Nb-Ti composite wires which avoid the possibility of electrical coupling of the filaments have been produced in laboratory scale. The RRR of the copper stabilizer and J c properties have not degraded because of no metallurgical reactions between Cu and Mn, Nb-Ti and Mn. 7 refs., 9 figs., 4 tabs

  6. High field accelerator magnet R&D in Europe

    CERN Document Server

    Devred, Arnaud; Bottura, L; Chorowski, M; Fabbricatore, P; Leroy, D; den Ouden, A; Rifflet, J M; Rossi, L; Vincent-Viry, O; Volpini, G

    2004-01-01

    The LHC magnet R&D program has shown that the limit of NbTi technology at 1.9 K was in the 10-to-10.5-T range. Hence, to go beyond the 10-T threshold, it is necessary to change the superconducting material. Given the state of the art in HTS, the only serious candidate is Nb$_{3}$Sn. A series of dipole magnet models built at Twente University and LBNL as well as a vigorous program carried out at Fermilab have demonstrated the feasibility of Nb$_{3}$Sn magnet technology. The next step is to bring this technology to maturity, which require further conductor and conductor insulation development and a simplification of manufacturing processes. After a brief history, we review ongoing R&D programs in Europe and we present the Next European Dipole (NED) initiative promoted by the European Steering Group on Accelerator R&D (ESGARD).

  7. Carbide precipitation kinetics in austenite of a Nb-Ti-V microalloyed steel

    International Nuclear Information System (INIS)

    Jung, Jae-Gil; Park, June-Soo; Kim, Jiyoung; Lee, Young-Kook

    2011-01-01

    Highlights: → Carbide precipitation kinetic was fastest at 950 deg. C and accelerated by strain. → Nucleation sites for (Nb,Ti)C above 950 deg. C were mainly undissolved (Ti,Nb)(C,N). → Strain enabled (Nb,Ti)C to nucleate on all sides of (Ti,Nb)(C,N) above 950 deg. C. → Strain changed nucleation sites from (Ti,Nb)(C,N) to dislocations below 900 deg. C. → Strain also accelerated the change in particle composition to equilibrium one. - Abstract: The isothermal precipitation kinetics of carbides in both strain-free and strained austenite (γ) of a microalloyed steel were quantitatively investigated through the electrical resistivity and transmission electron microscopy. The (Nb,Ti)C carbides at the interfaces of the undissolved (Ti,Nb)(C,N) carbonitrides were observed at all temperatures in strain-free γ. However, for strain-induced precipitation, above 950 deg. C, the precipitation of (Nb,Ti)C carbides near the undissolved (Ti,Nb)(C,N) carbonitrides was predominant due to the recrystallization of strained γ. Meanwhile, the fine (Nb,Ti,V)C carbides were homogeneously precipitated in non-recrystallized γ at 850 deg. C and 900 deg. C, as well as near the undissolved (Ti,Nb)(C,N) particles. The electrical resistivity method was successfully used to quantitatively measure the isothermal precipitation kinetics of carbides in both strain-free and strained γ. The precipitation-time-temperature diagrams of the carbide in strain-free and strained γ, with nose temperatures of 950 deg. C, were generated and the precipitation kinetics were greatly accelerated by the applied strain.

  8. Comparing Thermal Stability of NbTi and Nb$_3$Sn Wires

    CERN Document Server

    Breschi, M; Bottura, L; Devred, A; Trillaud, F

    2009-01-01

    The investigation of quenching in low temperature superconducting wires is of great relevance for a proper design of superconductive cables and magnets. This paper reports the experimental results of a vast measurement campaign of quench induced by laser pulses on NbTi and Nb$_{3}$Sn wires in pool boiling Helium I. A comparison of the quench behavior of two typical NbTi and Nb$_{3}$Sn wires is shown from different standpoints. Different qualitative behaviors of the voltage traces recorded during quenches and recoveries on NbTi and Nb$_{3}$Sn wires are reported and analyzed. It is shown that the Nb$_{3}$Sn wire exhibits a quench or no-quench behavior, whereas quenches and recoveries are exhibited by the NbTi wire. The two wires are also compared considering the behaviors of the two main parameters describing quench, i.e. quench energies and quench velocities, with respect to operation current and pulse duration and magnetic field. It is shown that the Nb$_{3}$Sn wire exhibits a ‘kink’ of the quench energy ...

  9. Superconducting magnets for future particle accelerators

    International Nuclear Information System (INIS)

    Devred, A.

    2000-05-01

    LHC magnet R and D programs shows that the limit for NbTi at 1.9 K could be between 9 and 10 T. Encouraging results have been obtained on a few Nb 3 Sn magnet models, opening the 10 and 15 T range. Given that LHC will have taken nearly 25 years to builds, it is already time to think of the future. (author)

  10. Joining NbTi superconductors by ultrasonic welding

    International Nuclear Information System (INIS)

    Hafstrom, J.W.; Killpatrick, D.H.; Niemann, R.C.; Purcell, J.R.; Thresh, H.R.

    1976-01-01

    An important consideration in the design and construction of large, high-field, superconducting magnets is the capability to fabricate reliable, high-strength, low-resistance joints. A process for joining NbTi, copper stabilized, superconducting composites by ultrasonic welding is described. This process yields a joint strength comparable to that of the superconducting composite and a resistivity significantly lower than achieved by conventional soft soldering. The superconducting properties of the composite are not affected by the joining process. Scarfing the joint to maintain a constant conductor cross section does not degrade its electrical or mechanical properties. The application of the ultrasonic joining process, including process control, scarfing, and NDT procedures, in the construction of the superconducting magnet (U.S. SCMS) for the joint U. S. -- Soviet MHD program is described

  11. Mirror Fusion Test Facility-B (MFTF-B) axicell configuration: NbTi magnet system. Design and analysis summary. Volume 1

    International Nuclear Information System (INIS)

    Heathman, J.H.; Wohlwend, J.W.

    1985-05-01

    This report summarizes the designs and analyses produced by General Dynamics Convair for the four Axicell magnets (A1 and A20, east and west), the four Transition magnets (T1 and T2, east and west), and the twelve Solenoid magnets (S1 through S6, east and west). Over four million drawings and specifications, in addition to detailed stress analysis, thermal analysis, electrical, instrumentation, and verification test reports were produced as part of the MFTF-B design effort. Significant aspects of the designs, as well as key analysis results, are summarized in this report. In addition, drawing trees and lists off detailed analysis and test reports included in this report define the locations of the detailed design and analysis data

  12. Mirror Fusion Test Facility-B (MFTF-B) axicell configuration: NbTi magnet system. Design and analysis summary. Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    Heathman, J.H.; Wohlwend, J.W.

    1985-05-01

    This report summarizes the designs and analyses produced by General Dynamics Convair for the four Axicell magnets (A1 and A20, east and west), the four Transition magnets (T1 and T2, east and west), and the twelve Solenoid magnets (S1 through S6, east and west). Over four million drawings and specifications, in addition to detailed stress analysis, thermal analysis, electrical, instrumentation, and verification test reports were produced as part of the MFTF-B design effort. Significant aspects of the designs, as well as key analysis results, are summarized in this report. In addition, drawing trees and lists off detailed analysis and test reports included in this report define the locations of the detailed design and analysis data.

  13. Validation of Finite-Element Models of Persistent-Current Effects in Nb3Sn Accelerator Magnets

    International Nuclear Information System (INIS)

    Wang, X.; Ambrosio, G.; Chlachidze, G.; Collings, E. W.; Dietderich, D. R.; DiMarco, J.; Felice, H.; Ghosh, A. K.; Godeke, A.; Gourlay, S. A.; Marchevsky, M.; Prestemon, S. O.; Sabbi, G.; Sumption, M. D.; Velev, G. V.; Xu, X.; Zlobin, A. V.

    2015-01-01

    Persistent magnetization currents are induced in superconducting filaments during the current ramping in magnets. The resulting perturbation to the design magnetic field leads to field quality degradation, in particular at low field where the effect is stronger relative to the main field. The effects observed in NbTi accelerator magnets were reproduced well with the critical-state model. However, this approach becomes less accurate for the calculation of the persistent-current effects observed in Nb 3 Sn accelerator magnets. Here a finite-element method based on the measured strand magnetization is validated against three state-of-art Nb3Sn accelerator magnets featuring different subelement diameters, critical currents, magnet designs and measurement temperatures. The temperature dependence of the persistent-current effects is reproduced. Based on the validated model, the impact of conductor design on the persistent current effects is discussed. The performance, limitations and possible improvements of the approach are also discussed

  14. Stability in a long length NbTi CICC

    CERN Document Server

    Bottura, L; Gislon, P; Spadoni, M; Bellucci, P; Muzzi, L; Turtu, S; Catitti, A; Chiarelli, S; Della Corte, A; Di Ferdinando, E

    2001-01-01

    A crucial issue for a superconducting coil in order to be safely used in the magnetic system of a fusion reactor is stability against all foreseen disturbances. To simulate the fusion machine conditions, including off-normal events, e.g. plasma disruptions, the energy deposition has to be spread over a "long length" cable in conduit conductor (CICC) and a background magnetic field is needed. We have therefore designed and built an experiment consisting of an instrumented NbTi test module inserted in a pair of co-axial pulsed copper coils. A 0.6 m diameter superconducting coil provides a background magnetic field up to 3 T. Calibration of the energy inductively coupled between the pulsed coils and the module has been obtained measuring the system temperature increase just after the pulse by means of thermometers positioned along the conductor. Stability vs. operating current I/sub op/ has been examined for different helium temperatures and different background magnetic fields. The finite element code Gandalf f...

  15. Emergence of Nb-Ti as supermagnet material

    Energy Technology Data Exchange (ETDEWEB)

    Berlincourt, T G

    1987-06-01

    The discovery and emergence of Nb-Ti as a high field superconductor are reviewed. The prehistory and setting for its discovery are described, and an anecdotal history follows its development up to the first successful large scale applications.

  16. Emergence of Nb-Ti as supermagnet material

    International Nuclear Information System (INIS)

    Berlincourt, T.G.

    1987-01-01

    The discovery and emergence of Nb-Ti as a high field superconductor are reviewed. The prehistory and setting for its discovery are described, and an anecdotal history follows its development up to the first successful large scale applications. (author)

  17. Comparative study of heat transfer from Nb-Ti and Nb_{3}Sn coils to He II

    Directory of Open Access Journals (Sweden)

    Marco La China

    2008-08-01

    Full Text Available In superconducting magnets, the energy deposited or generated in the coil must be evacuated to prevent temperature rise and consequent transition of the superconductor to the resistive state. The main barrier to heat extraction is represented by the electric insulation wrapped around superconducting cables. In the LHC, insulation improvement is a key point in the development of interaction region magnets and injector chain fast-pulsed magnets for luminosity upgrade; the high heat load of these magnets, in fact, is not compatible with the use of current insulation schemes. We review the standard insulation schemes for Nb-Ti and Nb_{3}Sn technology from the thermal point of view. We implement, in an analytical model, the strongly nonlinear thermal resistances of the different coil components including the permeability to superfluid helium of Nb-Ti insulations, measured during the LHC main dipole development. We use such a model to compare Nb-Ti and Nb_{3}Sn technologies by taking into account their specific operating margin in different working conditions. Finally, we propose an insulation scheme to enhance the heat transfer capability of Nb-Ti coils.

  18. Characterization of NbTi multifilamentary superconducting wires

    International Nuclear Information System (INIS)

    Vellego, G.

    1988-01-01

    Pirelli is developing superconducting mulfilamentary NbTi wires, with current carrying capacities of up to 500 A, for use in magnetic resonance imaging (MRI) systems and in small research magnets. Pirelli and IFUSP have developed a system for assessing wire performance, whose quality is comparable to the equivalent systems at the Brookhaven National Laboratory (BNL) and at the National Bureau of Standards (NBS). In particular, a high sensitivity is required for critical current measurements, so that the modern criteria for definition of critical current can be used. These involve conductor resistivities of the order of 10 -12 ohm-cm. The methods of measurements of critical current in applied magnetic fields, of residual resistance ratio and of copper to superconductor ratio are described. The results of the first tests performed in Pirelli wires and in wires of other manufacturers are described. These include tests on a NBS standard reference material. These results are of the same quality as results obtained at BNL or NBS on the same wires. So this system can be very useful throughout the Pirelli program. (author) [pt

  19. High Temperature Mechanical Constitutive Modeling of a High-Nb TiAl Alloy

    Directory of Open Access Journals (Sweden)

    DONG Chengli

    2018-02-01

    Full Text Available Uniaxial tensile, low cycle fatigue, fatigue-creep interaction and creep experiments of a novel high-Nb TiAl alloy (i.e. Ti-45Al-8Nb-0.2W-0.2B-0.02Y (atom fraction/% were conducted at 750℃ to obtain its tested data and curves. Based on Chaboche visco-plasticity unified constitutive model, Ohno-Wang modified non-linear kinematic hardening was introduced in Chaboche constitutive model to describe the cyclic hardening/softening, and Kachanov damage was coupled in Chaboche constitutive model to characterize the accelerated creep stage. The differential equations of the constitutive model discretized by explicit Euler method were compiled in to ABAQUS/UMAT to simulate the mechanical behavior of high-Nb TiAl alloy at different test conditions. The results show that Chaboche visco-plasticity unified constitutive model considering both Ohno-Wang modified non-linear kinematic hardening and Kachanov damage is able to simulate the uniaxial tensile, low cycle fatigue, fatigue-creep interaction and creep behavior of high-Nb TiAl alloy and has high accuracy.

  20. AC loss time constant measurements on Nb3Al and NbTi multifilamentary superconductors

    International Nuclear Information System (INIS)

    Painter, T.A.

    1988-03-01

    The AC loss time constant is a previously univestigated property of Nb 3 Al, a superconductor which, with recent technological developments, shows some advantages over the more commonly used superconductors, NbTi and Nb 3 Sn. Four Nb 3 Al samples with varying twist pitches and one NbTi sample are inductively measured for their AC loss time constants. The measured time constants are compared to the theoretical time constant limits imposed by the limits of the transverse resistivity found by Carr [5] and to the theoretical time constants found using the Bean Model as well as to each other. The measured time constants of the Nb 3 Al samples fall approximately halfway between the theoretical time constant limits, and the measured time constants of the NbTi sample is close to the theoretical lower time constant limit. The Bean Model adequately accounts for the variance of the permeability of the Nb 3 Al superconductor in a background magnetic field. Finally, the measured time constant values of the Nb 3 Al samples vary approximately according to the square of their twist pitch. (author)

  1. Cu-Ti Formation in Nb-Ti/Cu Superconducting Strand Monitored by in situ Techniques

    CERN Document Server

    Pong, I; Pong, Ian; Gerardin, Alexandre; Scheuerlein, Christian; Bottura, Luca

    2010-01-01

    In order to investigate the high temperature exposure effect on Nb-Ti/Cu superconducting strands, as might be encountered in joining by soldering and in cabling annealing, X-ray diffraction and resistometry measurements were performed in situ during heat treatment, and complemented by conventional metallography, mechanical tests and superconducting properties measurements. Changes of the Nb-Ti nanostructure at temperatures above 300 degrees C are manifested in the degradation of critical current in an applied external magnetic field, although degradation at self field was insignificant up to 400 degrees C for several minutes. Above 500 degrees C, the formation of various Cu-Ti intermetallic compounds, due to Ti diffusion from Nb-Ti into Cu, is detected by in situ XRD albeit not resolvable by SEM-EDS. There is a ductile to brittle transition near 600 degrees C, and liquid formation is observed below 900 degrees C. The formation of Cu-Ti causes a delayed reduction of the residual resistivity ratio (RRR) and adv...

  2. Short sample training behavior of Nb-Ti fibers at 4. 2 K

    Energy Technology Data Exchange (ETDEWEB)

    Wright, L.S.; Judd, B.A.; Ocampo, G.; Hutchison, T.S.

    1987-05-01

    Experimental results are presented for the stress required to cause quenching during successive runs when bare fibers of Nb-Ti are carrying subcritical currents with no cross field. The data fall into two distinct regimes attributed to regions of magnetic flux stability and instability. Microplastic deformation is believed to supply the energy to initiate the flux jump process in the magnetic instability regime, and is the only source of heat available for triggering a quench when the fiber is magnetically stable. In both cases, quenching is observed at stresses well below the mechanically observed elastic limit. Simple techniques for one-step training and detraining are also described.

  3. Fermilab's SC Accelerator Magnet Program for Future U.S. HEP Facilities

    International Nuclear Information System (INIS)

    Lamm, Michael; Zlobin, Alexander

    2010-01-01

    The invention of SC accelerator magnets in the 1970s opened wide the possibilities for advancing the energy frontier of particle accelerators, while limiting the machine circumference and reducing their energy consumption. The successful development of SC accelerator magnets based on NbTi superconductor have made possible a proton-antiproton collider (Tevatron) at Fermilab, an electron-proton collider (HERA) at DESY, a relativistic heavy ion collider (RHIC) at BNL and recently a proton-proton collider (LHC) at CERN. Further technological innovations and inventions are required as the US HEP looks forward towards the post-LHC energy or/and intensity frontiers. A strong, goal oriented national SC accelerator magnet program must take on this challenge to provide a strong base for the future of HEP in the U.S. The results and experience obtained by Fermilab during the past 30 years will allow us to play a leadership role in the SC accelerator magnet development in the U.S., in particular, focusing on magnets for a Muon Collider/Neutrino Factory (1)-(2). In this paper, we summarize the required Muon Collider magnet needs and challenges, summarize the technology advances in the Fermilab accelerator magnet development over the past few years, and present and discuss our vision and long-term plans for these Fermilab-supported accelerator initiatives.

  4. Superconducting accelerator magnet design

    International Nuclear Information System (INIS)

    Wolff, S.

    1994-01-01

    Superconducting dipoles, quadrupoles and correction magnets are necessary to achieve the high magnetic fields required for big accelerators presently in construction or in the design phase. Different designs of superconducting accelerator magnets are described and the designs chosen at the big accelerator laboratories are presented. The most frequently used cosθ coil configuration is discussed in detail. Approaches for calculating the magnetic field quality including coil end fields are presented. Design details of the cables, coils, mechanical structures, yokes, helium vessels and cryostats including thermal radiation shields and support structures used in superconducting magnets are given. Necessary material properties are mentioned. Finally, the main results of magnetic field measurements and quench statistics are presented. (orig.)

  5. Enhanced flux creep in Nb-Ti superconductors after an increase in temperature

    International Nuclear Information System (INIS)

    Cross, R.W.; Goldfarb, R.B.

    1991-01-01

    The magnetic fields of Superconducting Super Collider (SSC) dipole magnets change with time when the magnets are operated at constant current. The decay of the field is thought to be a consequence of flux creep in the Nb-Ti filaments in the superconducting cables. However, measured magnetic relaxation of small samples of SSC cable as a function of time is unlike the large decays that are observed in the fields of the actual magnets. We have made relaxation measurements on sample SSC conductors at 3.5 and 4.0 K after field cycling. The decay at both temperatures was 2.8% in 50 min. However, the relaxation measured after a temperature increase from 3.5 to 4.0 K was 4.8% in 50 min. A likely reason for the greater magnetization decay is that, after an increase in temperature, the Nb-Ti is in a supercritical state, with shielding currents flowing at a density greater than the new critical current density. This causes enhanced flux creep. We suggest that a small temperature rise during the operation of SSC magnets may contribute to the unexpectedly large magnetic field decay

  6. In situ NiTi/Nb(Ti) composite

    International Nuclear Information System (INIS)

    Jiang, Daqiang; Cui, Lishan; Jiang, Jiang; Zheng, Yanjun

    2013-01-01

    Graphical abstract: - Highlights: • In situ NiTi/Nb(Ti) composites were fabricated. • The transformation temperature was affected by the mixing Ti:Ni atomic ratios. • The NiTi component became micron-scale lamella after forging and rolling. • The composite exhibited high strength and high damping capacity. - Abstract: This paper reports on the creation of a series of in situ NiTi/Nb(Ti) composites with controllable transformation temperatures based on the pseudo-binary hypereutectic transformation of NiTi–Nb system. The composite constituent morphology was controlled by forging and rolling. It is found that the thickness of the NiTi lamella in the composite reached micron level after the hot-forging and cold-rolling. The NiTi/Nb(Ti) composite exhibited high damping capacity as well as high yield strength

  7. Superconducting Accelerator Magnets

    CERN Document Server

    Mess, K H; Wolff, S

    1996-01-01

    The main topic of the book are the superconducting dipole and quadrupole magnets needed in high-energy accelerators and storage rings for protons, antiprotons or heavy ions. The basic principles of low-temperature superconductivity are outlined with special emphasis on the effects which are relevant for accelerator magnets. Properties and fabrication methods of practical superconductors are described. Analytical methods for field calculation and multipole expansion are presented for coils without and with iron yoke. The effect of yoke saturation and geometric distortions on field quality is studied. Persistent magnetization currents in the superconductor and eddy currents the copper part of the cable are analyzed in detail and their influence on field quality and magnet performance is investigated. Superconductor stability, quench origins and propagation and magnet protection are addressed. Some important concepts of accelerator physics are introduced which are needed to appreciate the demanding requirements ...

  8. Recent advances in the technology of superconducting accelerator magnets

    International Nuclear Information System (INIS)

    Taylor, C.E.

    1985-05-01

    Recent progress in technology of high-current-density cables for SSC model magnets is summarized. NbTi cable with J/sub c/ up to 50% higher than Tevatron cable can be expected. Magnetization effects can be predicted and corrected with several new techniques. Development of Superconductor with 2 to 3 μm filament diameter and high J/sub c/ is expected. 15 refs., 3 figs

  9. Mass production system and technology of NbTi superconductors

    International Nuclear Information System (INIS)

    Fukutsuka, Toshiro; Monju, Yoshiyuki; Tatara, Isamu; Noguchi, Masataka; Yokochi, Katsuhiro; Matsubara, Mitsuharu.

    1984-01-01

    A mass production system for NbTi superconductors is described, involving vacuum arc melting of the alloys, hot hydrostatic extrusion of the composite billets and special drawing and stranding techniques for the rods and wires. The qualities required for superconducting wires are assured by a variety of instrument measurement and inspection techniques drawn from accumulated cryogenic experiences. (author)

  10. Numerical simulation of mold shape’s influence on NbTi cold-pressing superconducting joint

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Feng, E-mail: zhoufeng@mail.iee.ac.cn; Cheng, Junsheng; Dai, Yinming; Wang, Qiuliang; Yan, Luguang

    2014-03-15

    Highlights: • Four different shape molds’ influence on NbTi cold-pressing joint are analyzed. • Deformation of filaments is the most uniform in the case of radial compression. • The square mold is the optimum one for decreasing joint resistance in practice. - Abstract: The cold-pressing welding methods are employed to fabricate joints between NbTi multi-filamentary conductors, and a series of joints are made with the molds of different shapes for nuclear magnetic resonance (NMR) magnet applications. The Abaqus–Explicit method was used to do a quasi-static analysis of the cold-pressing welding process. In the simulation, we analyzed four molds with different shapes: plate mold, cap mold, square mold, and radial compression. The simulation shows that the deformation of filaments is the most uniform in the case of radial compression and the square mold is the optimum one for decreasing joint resistance.

  11. Comparative Study of Heat Transfer from Nb-Ti and Nb$_3$Sn coils to He II

    CERN Document Server

    La China, M

    2008-01-01

    In superconducting magnets, the energy deposited or generated in the coil must be evacuated to prevent temperature rise and consequent transition of the superconductor to the resistive state. The main barrier to heat extraction is represented by the electric insulation wrapped around superconducting cables. In the LHC, insulation improvement is a key point in the development of interaction region magnets and injector chain fast-pulsed magnets for luminosity upgrade; the high heat load of these magnets, in fact, is not compatible with the use of current insulation schemes. We review the standard insulation schemes for Nb-Ti and Nb$_{3}$Sn technology from the thermal point of view. We implement, in an analytical model, the strongly nonlinear thermal resistances of the different coil components including the permeability to superfluid helium of Nb-Ti insulations, measured during the LHC main dipole development. We use such a model to compare Nb-Ti and Nb$_{3}$Sn technologies by taking into account their specific...

  12. Superconducting magnets for accelerators

    International Nuclear Information System (INIS)

    Denisov, Yu.N.

    1979-01-01

    Expediency of usage and possibilities arising in application of superconducting devices in magnetic systems of accelerators and experimental nuclear-physical devices are studied. Parameters of specific devices are given. It is emphasized that at the existing level of technological possibilities, construction and usage of superconducting magnetic systems in experimental nuclear physics should be thought of as possible, from the engineering, and expedient, from the economical viewpoints [ru

  13. High field accelerator magnet R&D in Europe

    NARCIS (Netherlands)

    Devred, A.; Baynham, D.E.; Bottura, L.; Chorowski, M; Fabbricatore, P.; Leroy, D.; den Ouden, A.; Rifflet, J.M.; Rossi, L.; Vincent-Viry, O.; Volpini, G.

    2004-01-01

    The LHC magnet R&D Program has shown that the limit of NbTi technology at 1.8 K was in the range 10 to 10.5 T. Hence, to go beyond the 10-T threshold, it is necessary to change of superconducting material. Given the state of the art in HTS, the only serious candidate is Nb/sub 3/Sn. A series of

  14. 1999 Review of superconducting dipole and quadrupole magnets for particle accelerators

    International Nuclear Information System (INIS)

    Devred, A.

    1999-12-01

    The quest for elementary particles has promoted the development of particle accelerators producing beams of increasingly higher energies. In a synchrotron-type accelerator, the particle energy is directly proportional to the product of the machine's radius times the bending magnets' field strength. Present proton experiments at the TeV scale require facilities with circumferences ranging from a few to tens of kilometers and relying on a large number (several hundreds to several thousands) of high field dipole magnets and high field gradient quadrupole magnets. These electro-magnets use high current density, low critical temperature superconducting cables and are cooled down at liquid helium temperature. They are among the most costly and the most challenging components of the machine. After explaining what are the various types of accelerator magnets and why they are needed (section 1), we present a brief history of large superconducting particle accelerators, and we detail ongoing superconducting accelerator magnet R and D programs around the world (Section 2). Then, we review the superconducting materials that are available at industrial scale (chiefly, NbTi and Nb3Sn), and we describe the manufacturing of NbTi wires and cables (section 3). We also present the difficulties of processing and insulating Nb3Sn conductors which, so far, have limited the use of this material in spite of its superior performances. We continue by presenting the complex formalism used to represent two-dimensional fields (section 4), and we discuss the two-dimensional current distributions that are the most appropriate for generating pure dipole and pure quadrupole fields (section 5). We explain how these ideal distributions can be approximated by so-called cosθ and cos 2 θ coil designs and we describe the difficulties of realizing coil ends. Next, we present the mechanical design concepts that have been developed to restrain magnet coils and to ensure proper conductor positioning

  15. 1999 Review of superconducting dipole and quadrupole magnets for particle accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Devred, A. [CEA/Saclay, Dept. d' Astrophysique, de la Physique des Particules, de la Physique Nucleaire et de l' Instrumentation Associee (DAPNIA), 91 - Gif-sur-Yvette (France); CERN, Conseil Europeen pour la recherche nucleaire, Laboratoire europeen pour la physique des particules Geneve (Switzerland)

    1999-12-01

    The quest for elementary particles has promoted the development of particle accelerators producing beams of increasingly higher energies. In a synchrotron-type accelerator, the particle energy is directly proportional to the product of the machine's radius times the bending magnets' field strength. Present proton experiments at the TeV scale require facilities with circumferences ranging from a few to tens of kilometers and relying on a large number (several hundreds to several thousands) of high field dipole magnets and high field gradient quadrupole magnets. These electro-magnets use high current density, low critical temperature superconducting cables and are cooled down at liquid helium temperature. They are among the most costly and the most challenging components of the machine. After explaining what are the various types of accelerator magnets and why they are needed (section 1), we present a brief history of large superconducting particle accelerators, and we detail ongoing superconducting accelerator magnet R and D programs around the world (Section 2). Then, we review the superconducting materials that are available at industrial scale (chiefly, NbTi and Nb3Sn), and we describe the manufacturing of NbTi wires and cables (section 3). We also present the difficulties of processing and insulating Nb3Sn conductors which, so far, have limited the use of this material in spite of its superior performances. We continue by presenting the complex formalism used to represent two-dimensional fields (section 4), and we discuss the two-dimensional current distributions that are the most appropriate for generating pure dipole and pure quadrupole fields (section 5). We explain how these ideal distributions can be approximated by so-called cos{theta} and cos{sup 2}{theta} coil designs and we describe the difficulties of realizing coil ends. Next, we present the mechanical design concepts that have been developed to restrain magnet coils and to ensure proper

  16. Normal state resistance and low temperature magnetoresistance of superconducting cables for accelerator magnets

    International Nuclear Information System (INIS)

    Sampson, W.B.; Garber, M.; Ghosh, A.K.

    1988-01-01

    The normal state resistivity of the superconducting NbTi cable used in accelerator magnets is usually specified by the resistance per unit length at room temperature (295 K) and the residual resistance ratio (RRR). Using these resistance parameters, the amount of copper in the multifilamentary wire can be calculated. This method is consistent with the traditional etch and weigh technique, and as such is a alternative and convenient way of specifying the copper to superconductor ratio. In principle the magnetoresistance can be calculated from the RRR and the ''Kohler Plot'', for copper. In practice however, measurements of magnetoresistance for a wide variety of SSC inner cables show considerable disagreement with calculation. In this paper the magnetoresistance data on cables with RRR ranging from 50 to 175 are analyzed taking into account the conductor geometry and the effect of the small interfilamentary spacing on the resistivity of copper. 8 refs., 5 figs., 1 tab

  17. Moderation of flux jumps dynamics by eddy-currents in a disk shape NbTi superconductor

    International Nuclear Information System (INIS)

    Vasiliev, S.; Nabialek, A.; Piechota, S.; Szymczak, H.; Chabanenko, V.V.; Rusakov, V.

    2004-01-01

    We studied the moderation of the flux jumps dynamics in a disc shape NbTi-50% superconductor caused by eddy-currents induced in two copper cylinders attached to both surfaces of the investigated sample. We investigated experimentally the time of the flux jump duration, amount of the magnetic flux entering the sample during the jump as well as the sine structure of the jumps as a function of temperature and the external magnetic field. A simple theoretical model, which describes the magnetic field dependence of the amount of the magnetic flux entering the superconducting sample during the flux jump, was developed. (author)

  18. Superconducting accelerator magnet technology in the 21st century: A new paradigm on the horizon?

    Science.gov (United States)

    Gourlay, S. A.

    2018-06-01

    Superconducting magnets for accelerators were first suggested in the mid-60's and have since become one of the major components of modern particle colliders. Technological progress has been slow but steady for the last half-century, based primarily on Nb-Ti superconductor. That technology has reached its peak with the Large Hadron Collider (LHC). Despite the superior electromagnetic properties of Nb3Sn and adoption by early magnet pioneers, it is just now coming into use in accelerators though it has not yet reliably achieved fields close to the theoretical limit. The discovery of the High Temperature Superconductors (HTS) in the late '80's created tremendous excitement, but these materials, with tantalizing performance at high fields and temperatures, have not yet been successfully developed into accelerator magnet configurations. Thanks to relatively recent developments in both Bi-2212 and REBCO, and a more focused international effort on magnet development, the situation has changed dramatically. Early optimism has been replaced with a reality that could create a new paradigm in superconducting magnet technology. Using selected examples of magnet technology from the previous century to define the context, this paper will describe the possible innovations using HTS materials as the basis for a new paradigm.

  19. Voltage spikes in Nb3Sn and NbTi strands

    International Nuclear Information System (INIS)

    Bordini, B.; Ambrosio, G.; Barzi, E.; Carcagno, R.; Feher, S.; Kashikhin, V.V.; Lamm, M.J.; Orris, D.; Tartaglia, M.; Tompkins, J.C.; Turrioni, D.; Yamada, R.; Zlobin, A.V.; Fermilab

    2005-01-01

    As part of the High Field Magnet program at Fermilab several NbTi and Nb 3 Sn strands were tested with particular emphasis on the study of voltage spikes and their relationship to superconductor instabilities. The voltage spikes were detected under various experimental conditions using voltage-current (V-I) and voltage-field (V-H) methods. Two types of spikes, designated ''magnetization'' and ''transport current'' spikes, have been identified. Their origin is most likely related to magnetization flux jump and transport current redistribution, respectively. Many of the signals observed appear to be a combination of these two types of spikes; the combination of these two instability mechanisms should play a dominant role in determining the minimum quench current

  20. Voltage spikes in Nb3Sn and NbTi strands

    Energy Technology Data Exchange (ETDEWEB)

    Bordini, B.; Ambrosio, G.; Barzi, E.; Carcagno, R.; Feher, S.; Kashikhin, V.V.; Lamm, M.J.; Orris, D.; Tartaglia, M.; Tompkins, J.C.; Turrioni, D.; Yamada, R.; Zlobin,; /Fermilab

    2005-09-01

    As part of the High Field Magnet program at Fermilab several NbTi and Nb{sub 3}Sn strands were tested with particular emphasis on the study of voltage spikes and their relationship to superconductor instabilities. The voltage spikes were detected under various experimental conditions using voltage-current (V-I) and voltage-field (V-H) methods. Two types of spikes, designated ''magnetization'' and ''transport current'' spikes, have been identified. Their origin is most likely related to magnetization flux jump and transport current redistribution, respectively. Many of the signals observed appear to be a combination of these two types of spikes; the combination of these two instability mechanisms should play a dominant role in determining the minimum quench current.

  1. Minimum Quench Energy and Early Quench Development in NbTi Superconducting Strands

    CERN Document Server

    Breschi, M; Boselli, M; Bottura, Luca; Devred, Arnaud; Ribani, P L; Trillaud, F

    2007-01-01

    The stability of superconducting wires is a crucial task in the design of safe and reliable superconducting magnets. These magnets are prone to premature quenches due to local releases of energy. In order to simulate these energy disturbances, various heater technologies have been developed, such as coated tips, graphite pastes, and inductive coils. The experiments studied in the present work have been performed using a single-mode diode laser with an optical fiber to illuminate the superconducting strand surface. Minimum quench energies and voltage traces at different magnetic flux densities and transport currents have been measured on an LHC-type, Cu/NbTi wire bathed in pool boiling helium I. This paper deals with the numerical analysis of the experimental data. In particular, a coupled electromagnetic and thermal model has been developed to study quench development and propagation, focusing on the influence of heat exchange with liquid helium.

  2. Charge Berezinskii-Kosterlitz-Thouless transition in superconducting NbTiN films

    Energy Technology Data Exchange (ETDEWEB)

    Mironov, Alexey Yu.; Silevitch, Daniel M.; Proslier, Thomas; Postolova, Svetlana V.; Burdastyh, Maria V.; Gutakovskii, Anton K.; Rosenbaum, Thomas F.; Vinokur, Valerii V.; Baturina, Tatyana I.

    2018-03-06

    Three decades after the prediction of charge-vortex duality in the critical vicinity of the two-dimensional superconductor-insulator transition (SIT), one of the fundamental implications of this duality-the charge Berezinskii-Kosterlitz-Thouless (BKT) transition that should occur on the insulating side of the SIT-has remained unobserved. The dual picture of the process points to the existence of a superinsulating state endowed with zero conductance at finite temperature. Here, we report the observation of the charge BKT transition on the insulating side of the SIT in 10 nm thick NbTiN films, identified by the BKT critical behavior of the temperature and magnetic field dependent resistance, and map out the magnetic-field dependence of the critical temperature of the charge BKT transition. Finally, we ascertain the effects of the finite electrostatic screening length and its divergence at the magnetic field-tuned approach to the superconductor-insulator transition.

  3. Radiation-induced changes of critical fields in NbTi superconductors

    International Nuclear Information System (INIS)

    Weber, H.W.; Khier, W.; Wacenovsky, M.; Hoch, H.

    1988-01-01

    Neutron irradiation experiments on a variety of metallurgically different NbTi superconductors for use in fusion magnets were performed. Results on the change in critical current densities with neutron fluence were significantly different in low and in high magnetic fields. Based on the suggestion of a prevailing influence of the upper critical field on critical currents at high fields a systematic study of upper critical fields was made on irradiated and unirradiated samples. The upper critical field decreased upon irradiation by about 2 to 6%. Companion experiments on the change of the transition temperature in the same materials showed excellent correlations between the degradation of these superconductive properties. Implications for the observed critical current density degradation at high fields are discussed

  4. Reduction of coupling in fine filamentary Cu-NbTi composites by the addition of manganese to the matrix

    International Nuclear Information System (INIS)

    Kreilick, T.S.; Gregory, E.; Wong, J.; Scanlan, R.M.; Ghosh, A.K.; Sampson, W.B.; Collings, E.W.

    1988-01-01

    Proximity coupling has been observed in materials containing 4164 filaments in a pure copper matrix designed and fabricated by Supercon Inc. for SSC dipoles. The effect of manganese additions to the copper matrix in reducing this coupling was assessed in this paper. Two multifilamentary NbTi billets were fabricated for SSC inner cable applications. Each composite contains roughly 11,000 filaments embedded in pure copper and copper manganese matrices. Critical current, magnetization, stability, susceptibility and mechanical analyses of these materials indicated no adverse effects from 0.5 wt.% manganese additions to the copper. Results on coupling reduction are evaluated

  5. Effect of stress on the critical current of NbTi multifilamentary composite wire

    International Nuclear Information System (INIS)

    Ekin, J.W.; Fickett, F.R.; Clark, A.F.

    1977-01-01

    Superconducting composites within large-scale magnets can be subjected to high stresses. These stresses arise from several sources, chief among them being the winding tension and prestressing during construction of the magnet, the thermomechanical forces incurred during thermal cycling to cryogenic temperatures, and especially in large-scale systems, the magnetomechanical forces generated when the magnet is energized. Typically, data on the critical-current characteristics of superconducting composites are obtained on wires that are in an unstressed state. Very little is known, however, about how the critical current behaves in wires experiencing stresses of the type described above. To measure these effects, short sample critical current tests were made under conditions simultaneously simulating the mechanical and magnetic environments of high-field superconducting magnets. The program was initiated both to form a basis for the fundamental understanding of stress effects on superconductor stability and to provide engineering data for optimizing design and construction of high-field magnets. The preliminary results indicate that NbTi multifilamentary superconducting composite wires are not characterized by a single critical current vs. field curve, but rather by a family of curves, each corresponding to a different operating stress level

  6. High temperature oxidation of β-NbTi alloys

    International Nuclear Information System (INIS)

    Parida, S.C.; Gupta, N.K.; Rama Rao, G.A.; Sen, B.K.; Krishnan, K.

    2008-01-01

    The isothermal oxidation kinetics of pure Ti metal and two different β-NbTi alloys with compositions of 85 and 75 at.% Ti were studied using thermogravimetric technique in the temperature range of 1073-1323 K at an interval of 50 K. The value of the power exponent n of the rate equation was found to be close to one suggesting that each reaction follows first order kinetic rate law. X-ray diffraction analysis of oxidation products at each temperature revealed the simultaneous formation of TiO 2 and TiNb 2 O 7 . The rate constants and the activation energies of oxidation reactions for each alloy compositions were evaluated. (author)

  7. High temperature superconductor accelerator magnets

    NARCIS (Netherlands)

    van Nugteren, J.

    2016-01-01

    For future particle accelerators bending dipoles are considered with magnetic fields exceeding 20T. This can only be achieved using high temperature superconductors (HTS). These exhibit different properties from classical low temperature superconductors and still require significant research and

  8. Superconducting Magnets for Particle Accelerators

    CERN Document Server

    Bottura, Luca; Yamamoto, Akira; Zlobin, Alexander V

    2016-01-01

    In this paper we summarize the evolution and contributions of superconducting magnets to particle accelerators as chronicled over the last 50 years of Particle Accelerator Conferences (PAC, NA-PAC and IPAC). We begin with an historical overview based primarily on PAC Proceedings augmented with references to key milestones in the development of superconducting magnets for particle accelerators. We then provide some illustrative examples of applications that have occurred over the past 50 years, focusing on those that have either been realized in practice or provided technical development for other projects, with discussion of possible future applications.

  9. Post-LHC accelerator magnets

    International Nuclear Information System (INIS)

    Gourlay, Stephen A.

    2001-01-01

    The design and practicality of future accelerators, such as hadron colliders and neutrino factories being considered to supercede the LHC, will depend greatly on the choice of superconducting magnets. Various possibilities will be reviewed and discussed, taking into account recent progress and projected improvements in magnet design and conductor development along with the recommendations from the 2001 Snowmass workshop

  10. High-field superconductivity in the Nb-Ti-Zr ternary system

    International Nuclear Information System (INIS)

    Ralls, K.M.; Rose, R.M.; Wulff, J.

    1980-01-01

    Resistive critical current densities, critical fields, and normal-state electrical resistivities were obtained at 4.2 0 K for 55 alloys in the Nb-Ti-Zr ternary alloy system, excepting Ti-Zr binary compositions. The resistive critical field as a function of ternary composition has a saddle point between the Nb-Ti and Nb-Zr binaries, so that ternary alloying in this system is not expected to result in higher critical fields than the binary alloys

  11. High-field superconductivity in the Nb-Ti-Zr ternary system

    Science.gov (United States)

    Ralls, K. M.; Rose, R. M.; Wulff, J.

    1980-06-01

    Resistive critical current densities, critical fields, and normal-state electrical resistivities were obtained at 4.2 °K for 55 alloys in the Nb-Ti-Zr ternary alloy system, excepting Ti-Zr binary compositions. The resistive critical field as a function of ternary composition has a saddle point between the Nb-Ti and Nb-Zr binaries, so that ternary alloying in this system is not expected to result in higher critical fields than the binary alloys.

  12. Materials, Strands, and Cables for Superconducting Accelerator Magnets. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Sumption, Mike D. [Ohio State University, Columbia, OH (United States); Collings, Edward W. [Ohio State University, Columbia, OH (United States)

    2014-09-19

    This report focuses on Materials, Strands and Cables for High Energy Physics Particle accelerators. In the materials area, work has included studies of basic reactions, diffusion, transformations, and phase assemblage of Nb3Sn. These materials science aspects have been married to results, in the form of flux pinning, Bc2, Birr, and transport Jc, with an emphasis on obtaining the needed Jc for HEP needs. Attention has also been paid to the “intermediate-temperature superconductor”, magnesium diboride emphasis being placed on (i) irreversibility field enhancement, (ii) critical current density and flux pinning, and (iii) connectivity. We also report on studies of Bi-2212. The second area of the program has been in the area of “Strands” in which, aside from the materials aspect of the conductor, its physical properties and their influence on performance have been studied. Much of this work has been in the area of magnetization estimation and flux jump calculation and control. One of the areas of this work was strand instabilities in high-performance Nb3Sn conductors due to combined fields and currents. Additionally, we investigated quench and thermal propagation in YBCO coated conductors at low temperatures and high fields. The last section, “Cables”, focussed on interstrand contact resistance, ICR, it origins, control, and implications. Following on from earlier work in NbTi, the present work in Nb3Sn has aimed to make ICR intermediate between the two extremes of too little contact (no current sharing) and too much (large and unacceptable magnetization and associated beam de-focussing). Interstrand contact and current sharing measurements are being made on YBCO based Roebel cables using transport current methods. Finally, quench was investigated for YBCO cables and the magnets wound from them, presently with a focus on 50 T solenoids for muon collider applications.

  13. Technology of magnetically driven accelerators

    International Nuclear Information System (INIS)

    Brix, D.L.; Hawkins, S.A.; Poor, S.E.; Reginato, L.L.; Smith, M.W.

    1985-01-01

    The marriage of Induction Linac technology with Nonlinear Magnetic Modulators has produced some unique capabilities. It appears possible to produce electron beams with average currents measured in amperes, at gradients exceeding 1 MeV/meter, and with power efficiencies approaching 50%. A 2 MeV, 5 kA electron accelerator has been constructed at the Lawrence Livermore National Laboratory (LLNL) to demonstrate these concepts and to provide a test facility for high brightness sources. The pulse drive for the accelerator is based on state-of-the-art magnetic pulse compressors with very high peak power capability, repetition rates exceeding a kilohertz and excellent reliability

  14. Technology of magnetically driven accelerators

    International Nuclear Information System (INIS)

    Birx, D.L.; Hawkins, S.A.; Poor, S.E.; Reginato, L.L.; Smith, M.W.

    1985-01-01

    The marriage of Induction Linac technology with Nonlinear Magnetic Modulators has produced some unique capabilities. It appears possible to produce electron beams with average currents measured in amperes, at gradients exceeding 1 MeV/meter, and with power efficiencies approach 50%. A 2 MeV, 5 kA electron accelerator has been constructed at the Lawrence Livermore National Laboratory (LLNL) to demonstrate these concepts and to provide a test facility for high brightness sources. The pulse drive for the accelerator is based on state-of-the-art magnetic pulse compressors with very high peak power capability, repetition rates exceeding a kilohertz and excellent reliability

  15. Processing and properties of Nb-Ti-based alloys

    International Nuclear Information System (INIS)

    Sikka, V.K.; Viswanathan, S.

    1992-01-01

    The processing characteristics, tensile properties, and oxidation response of two Nb-Ti-Al-Cr alloys were investigated. One creep test at 650 C and 172 MPa was conducted on the base alloy which contained 40Nb-40Ti-10Al-10Cr. A second alloy was modified with 0.11 at. % carbon and 0.07 at. % yttrium. Alloys were arc melted in a chamber backfilled with argon, drop cast into a water-cooled copper mold, and cold rolled to obtain a 0.8-mm sheet. The sheet was annealed at 1,100 C for 0.5 h. Longitudinal tensile specimens and oxidation specimens were obtained for both the base alloy and the modified alloy. Tensile properties were obtained for the base alloy at room temperature, 400, 600, 700, 800, 900, and 1,000 C, and for the modified alloy at room temperature, 400, 600, 700, and 800 C. Oxidation tests on the base alloy and modified alloy, as measured by weight change, were carried out at 600, 700, 800, and 900 C. Both the base alloy and the modified alloy were extremely ductile and were cold rolled to the final sheet thickness of 0.8 mm without an intermediate anneal. The modified alloy exhibited some edge cracking during cold during cold rolling. Both alloys recrystallized at the end of a 0.5-h annealing treatment. The alloys exhibited moderate strength and oxidation resistance below 600 C, similar to the results of alloys reported in the literature

  16. High-Field Accelerator Magnets

    International Nuclear Information System (INIS)

    Rijk, G de

    2014-01-01

    In this lecture an overview is given of the present technology for high field accelerator magnets. We indicate how to get high fields and what are the most important parameters. The available conductors and their limitations are presented followed by the most relevant types of coils and support structures. We conclude by showing a number of recent examples of development magnets which are either pure R&D objects or models for the LHC luminosity upgrade

  17. Is magnetic pinning a dominant mechanism in Nb-Ti

    International Nuclear Information System (INIS)

    Cooley, L.D.; Lee, P.J.; Larbalestier, D.C.

    1991-01-01

    In this paper, the authors compare the pinning behavior of an artificial pinning center (APC) composite and a nanometer-filament Nb 46.5 wt% Ti composite to that of a conventional Nb 48 wt% Ti composite. The microstructure of the APC composite resembles the conventional composite, where ribbons of normal metal form the pinning centers, whereas the nanometer-filament composite has no internal normal metal but pins instead at the filament surface. The APC composite exhibits much stronger pinning relative to B c 2 than the conventional composite (21.4 GN/m 3 , 7 T vs. 18.9 GN/m 3 , 11 T), which is possibly due to the increased amount of pinning center (50 vol.% vs. 25 vol.%), however the proximity effect reduces the B c 2 unfavorably

  18. Experimental investigation of copper matrix longitudinal resistance in a composite Nb-Ti wire

    International Nuclear Information System (INIS)

    Gubkin, I.N.; Kozlenkova, N.I.; Nikulin, A.D.; Polikarpova, M.V.; Filkin, V.Ya.

    1994-01-01

    The longitudinal resistance of multifilamentary superconducting wires is among the major parameters used in design and optimization of superconducting magnetic systems. To enhance the conductivity of the copper matrix, it is made of pipes and rods of enhanced quality copper produced by electron beam melting (resistance ratio between two temperatures, 295 K and 4.2 K, R 295 /R 4.2 > 200). Yet for readily obtainable conductors this parameter is much lower. The reduction of the copper-matrix electrical conductivity may be attributed to wire-production technology involving processes such as extrusion, drawing and intermediate thermal processing, as well as to the size effect. Copper-matrix longitudinal resistance was studied as a function of wire diameter on specimens of multifilamentary Nb-Ti wire with filaments coated by a Nb layer. Experimental results are compared with the Sondheimer calculations for a monofilament conductor as well as with the Gavalloni calculations for an ideal wire with hexagonally located filaments. It has been shown that the best fit with the experiment is provided by the Sondheimer approximation. Comparison of the results of this work with other authors' data obtained for the specimens with no niobium barrier, allows the authors to single out the influence of a pure size effect and diffusion of Ti on the resistivity

  19. Characterization of nitride formation in NbTi-50% weight alloy by x-ray diffraction

    International Nuclear Information System (INIS)

    Teixeira, S.R.

    1990-01-01

    Titanium and niobium are so main metals for technology as structural materials, refractories and resistance alloys for corrosion. This interest is based in application of this metals and alloys in aerospacial industry, nuclear reactors, construction of superconductor magnets and in the production of superconductors wires. The NbTi (50% wt. Ti) alloy nitretation under nitrogen atmosphere (p + 760 mm) at 800 - 1000 C was studied by x-ray diffractometry. TEM and optical metallography. During the reaction the two phases (Ti sub(2) N - ε and TiN - δ) growed continuously, the (Ti sub(2) N, N sub(2)) reaction front growed faster than the (TiN,N sub(2)). A method for study the scale growing was proposed using x-ray diffractometry data. By using this method, the growth of TiN scale was analysed and the activation energy of 19 Kcal/mole was determinated using a linear timming law indicating a mechanism not controlled by diffusion through TiN layer. The present results suggest that the diffusion through the tight tunnels, rich in Nb, allow a fast transport of nitrogen through the TiN layer. (author)

  20. Development of multifilamentary NbTi and Nb3Sn composite conductors with very fine filaments

    International Nuclear Information System (INIS)

    Ogasawara, T.; Hubota, T.; Makiura, T.; Oda, Y.; Okon, H.; Yasohama, K.

    1986-01-01

    A NbTi multifilamentary composite conductor with about 10,000 filaments has been manufactured in long lengths. A filament diameter of 0.52 μm, a twist pitch of 1.13 mm, a strand diameter of 0.1 mm and a Cu/CuNi mixed matrix result in strongly reduced a.c. losses. The hysteresis loss and the coupling loss are 73 kW/m 3 and 56 kW/m 3 for a 50 Hz magnetic field with an amplitude of 1.5 T. From three strands a conductor was formed with a twist pitch of 2.4 mm. Several small coils were wound and operated at 50 Hz. One of the coils generated a maximum field of 1.52 T(center) at an operating current of the same size as the static critical current. Similarily the construction of a Nb 3 Sn multifilamentary composite conductor with about 280,000 sub-micron filaments for a.c. use was tried

  1. Characterizations of a CERN NbTi Reference Wire at LBNL

    International Nuclear Information System (INIS)

    Godeke, A.; Dietderich, D.R.; Higley, H.C.; Liggins, N.L.

    2007-01-01

    We report on the measurement of two NbTi reference samples, obtained from CERN through BNL, wire number 02R00056A01UX.265. The purpose of these characterizations is two-fold: (1) To establish an inter-laboratory comparison of short sample tests and analysis between LBNL, BNL and Fermilab within the LARP collaboration. Due to differences in reaction and mounting procedures and their resulting strain differences, Nb3Sn is not suited for this purpose. (2) To determine the accuracy of LBNL's system with regard to magnetic field, temperature and current after a major system overhaul. The results show that at mu0H = 8T, the critical current result falls within the standard deviation of the CERN database, whereas at mu0H = 5 T, it falls outside the CERN standard deviation, but within the range of critical current values that are reported by CERN for this wire. It is concluded that the LBNL results fall within the characterization variance as reported in the CERN database

  2. Decay and snapback in superconducting accelerator magnets

    OpenAIRE

    Haverkamp, M.

    2003-01-01

    This thesis deals with the explanation and compensation of the effects ‘decay’ and ‘snapback’ in superconducting accelerator magnets, in particular in those used in the new Large Hardron Collider at CERN. During periods of constant magnet excitation, as for example during the injection of particles in the storage ring, the magnetic field in superconducting accelerator magnets shows a decay behavior. As soon as the particles are accelerated, the magnets are ramped, and the magnetic field ‘snap...

  3. High Temperature Superconductor Accelerator Magnets

    CERN Document Server

    AUTHOR|(CDS)2079328; de Rijk, Gijs; Dhalle, Marc

    2016-11-10

    For future particle accelerators bending dipoles are considered with magnetic fields exceeding $20T$. This can only be achieved using high temperature superconductors (HTS). These exhibit different properties from classical low temperature superconductors and still require significant research and development before they can be applied in a practical accelerator magnet. In order to study HTS in detail, a five tesla demonstrator magnet named Feather-M2 is designed and constructed. The magnet is based on ReBCO coated conductor, which is assembled into a $10kA$ class Roebel cable. A new and optimized Aligned Block layout is used, which takes advantage of the anisotropy of the conductor. This is achieved by providing local alignment of the Roebel cable in the coil windings with the magnetic field lines. A new Network Model capable of analyzing transient electro-magnetic and thermal phenomena in coated conductor cables and coils is developed. This model is necessary to solve critical issues in coated conductor ac...

  4. High Field Magnet R and D in the USA

    International Nuclear Information System (INIS)

    Gourlay, Stephen A.

    2003-01-01

    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 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

  5. High Field Magnet R and D in the USA

    International Nuclear Information System (INIS)

    Gourlay, S.A.

    2003-01-01

    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 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.

  6. Eddy currents in accelerator magnets

    CERN Document Server

    Moritz, G

    2010-01-01

    This paper covers the main eddy current effects in accelerator magnets - field modification (time delay and field quality) and resistive power losses. In the first part, starting from the Maxwell equations, a basic understanding of the processes is given and explained with examples of simple geometry and time behaviour. Useful formulas are derived for an analytic estimate of the size of the effects. In the second part the effects in real magnets are analysed and described in comparison with numerical and measured results. Finally, based on the previous parts, design recommendations are given regarding how to minimize eddy current effects.

  7. Superconducting magnets technologies for large accelerator

    International Nuclear Information System (INIS)

    Ogitsu, Toru

    2017-01-01

    The first hadron collider with superconducting magnet technologies was built at Fermi National Accelerator Laboratory as TEVATRON. Since then, the superconducting magnet technologies are widely used in large accelerator applications. The paper summarizes the superconducting magnet technologies used for large accelerators. (author)

  8. Development and manufacture of ultra-fine NbTi filament wires at ALSTHOM

    International Nuclear Information System (INIS)

    Hoang, G.K.; Laumond, Y.; Sabrie, J.L.; Dubots, P.

    1986-01-01

    Ultra-fine NbTi filament wires have been developed and manufactured by ALSTHOM. It is now possible to produce industrial copper -copper-nickel matrix wires with 0.6 mu m NbTi filaments for use in 50 / 60 Hz machines. Smaller filaments with diameters down to 0.08 mu m have been obtained with 254 100 filament wire samples. Studies are now being carried out on copper matrix conductors to reduce the filament diameter. The first results show that it is possible to obtain submicron filaments even in copper matrix wires

  9. Elastic stiffnesses of an Nb-Ti/Cu-composite superconductive wire

    Science.gov (United States)

    Kim, Sudook; Ledbetter, Hassel; Ogi, Hirotsugu

    2000-09-01

    Elastic-stiffness coefficients were determined on a 1.4-mm-diameter wire consisting of superconducting Nb-Ti fibers in a copper matrix, with a polyvinyl-resin coating. The matrix contained 324 Nb-Ti fibers. An electromagnetic-acoustic-resonance method was used to obtain five independent elastic-stiffness coefficients assuming transverse-isotropic symmetry. From these we calculated Young moduli, bulk modulus, and principal Poisson ratios. As a check, we used a mechanical-impulse-excitation method to directly measure the Young modulus in the fiber direction. The three-phase composite wire showed a 10% anisotropy in the Young modulus.

  10. Production and fabrication of 2500-lb Nb--Ti ingots to rod

    International Nuclear Information System (INIS)

    Cordier, T.E.; McDonald, W.K.

    1975-01-01

    Interest in Nb--Ti superconducting devices is exploding. This paper outlines the critical production criteria for this material. Areas discussed include ingot blending, melting, forging, extrusion, and rod reducing with emphasis on the metallurgical considerations affecting mechanical properties. Data are included relating process parameters to TEM finding as well as R.T. ductility and optical microscopy

  11. Technology development of fabrication NbTi and Nb3 Sn superconducting wires

    International Nuclear Information System (INIS)

    Rodrigues Junior, D.; Bormio, C.; Baldan, C.A.; Ramos, M.J.; Pinatti, D.G.

    1988-01-01

    The technology development of NbTi and Nb 3 Sn superconducting wires are studied, mentioning the use of fluxes capture theory in the sizing of wires fabrication. The fabrication process, the thermal treatment and the experimental datas of critical temperature and current of Nb 3 Sn wires are described. (C.G.C.) [pt

  12. Magnetically levitated space elevator to low-earth orbit.

    Energy Technology Data Exchange (ETDEWEB)

    Hull, J. R.; Mulcahy, T. M.

    2001-07-02

    The properties of currently available NbTi superconductor and carbon-fiber structural materials enable the possibility of constructing a magnetically levitated space elevator from the earth's surface up to an altitude of {approx} 200 km. The magnetic part of the elevator consists of a long loop of current-carrying NbTi, composed of one length that is attached to the earth's surface in an east-west direction and a levitated-arch portion. The critical current density of NbTi is sufficiently high that these conductors will stably levitate in the earth's magnetic field. The magnetic self-field from the loop increases the levitational force and for some geometries assists levitational stability. The 200-km maximum height of the levitated arch is limited by the allowable stresses of the structural material. The loop is cryogenically cooled with helium, and the system utilizes intermediate pumping and cooling stations along both the ground and the levitated portion of the loop, similar to other large terrestrial cryogenic systems. Mechanically suspended from the basic loop is an elevator structure, upon which mass can be moved between the earth's surface and the top of the loop by a linear electric motor or other mechanical or electrical means. At the top of the loop, vehicles may be accelerated to orbital velocity or higher by rocket motors, electromagnetic propulsion, or hybrid methods.

  13. Magnetically levitated space elevator to low-earth orbit

    International Nuclear Information System (INIS)

    Hull, J. R.; Mulcahy, T. M.

    2001-01-01

    The properties of currently available NbTi superconductor and carbon-fiber structural materials enable the possibility of constructing a magnetically levitated space elevator from the earth's surface up to an altitude of(approx) 200 km. The magnetic part of the elevator consists of a long loop of current-carrying NbTi, composed of one length that is attached to the earth's surface in an east-west direction and a levitated-arch portion. The critical current density of NbTi is sufficiently high that these conductors will stably levitate in the earth's magnetic field. The magnetic self-field from the loop increases the levitational force and for some geometries assists levitational stability. The 200-km maximum height of the levitated arch is limited by the allowable stresses of the structural material. The loop is cryogenically cooled with helium, and the system utilizes intermediate pumping and cooling stations along both the ground and the levitated portion of the loop, similar to other large terrestrial cryogenic systems. Mechanically suspended from the basic loop is an elevator structure, upon which mass can be moved between the earth's surface and the top of the loop by a linear electric motor or other mechanical or electrical means. At the top of the loop, vehicles may be accelerated to orbital velocity or higher by rocket motors, electromagnetic propulsion, or hybrid methods

  14. LHC IR Upgrade Nb-Ti, 120mm Aperture Model Quadrupole Test Results at 1.8K

    CERN Document Server

    Kirby, G A; Bajko, M; Datskov, V I; Durante, M; Fessia, P; Feuvrier, J; Guinchard, M; Giloux, C; Granieri, P P; Manil, P; Perez, J C; Ravaioli, E; Rifflet, J M; Russenschuck, S; Sahner, T; Segreti, M; Todesco, E; Willering, G

    2014-01-01

    Over the last five years, the model MQXC quadruple, a 120 mm aperture, 120 T/m, 1.8 m long, Nb-Ti version of the LHC insertion upgrade (due in 2021), has been developed at CERN. The magnet incorporates several novel concepts to extract high levels of heat flux and provide high quality field harmonics throughout the full operating current range. Existing LHC-dipole cable with new, open cable and ground insulation was used. Two, nominally identical 1.8 m long magnets were built and tested at 1.8 K at the CERN SM18 test facility. This paper compares in detail the two magnet tests and presents: quench performance, internal stresses, heat extraction simulating radiation loading in the superconducting coils, and quench protection measurements. The first set of tests highlighted the conflict between high magnet cooling capability and quench protection. The second magnet had additional instrumentation to investigate further this phenomenon. Finally we present test results from a new type of superconducting magnet pro...

  15. Design of an electrostatic magnetic quadrupole accelerator

    International Nuclear Information System (INIS)

    Mizuno, M.; Ohara, Y.

    1993-01-01

    A new type of electrostatic acceleration system, electrostatic magnetic quadrupole (ESMQ) acceleration system, is proposed for efficient acceleration of negative ion beams. In this system, permanent magnets are buried in the acceleration electrodes so as to produce a quadrupole magnetic field in the electrode aperture region. Envelope simulation indicates that the quadrupole field can deflect electrons stripped from the negative ions. Beam envelope simulations for deuterium ions and electrons have been carried out using the beam envelope code TRACE. Electrons are largely divergent and most appear likely to hit downstream electrodes. Furthermore, maximum beam divergence of the deuterium ions is reduced to the focusing effect of the quadrupole magnetic field

  16. Decay and Snapback in Superconducting Accelerator Magnets

    CERN Document Server

    Haverkamp, M

    2003-01-01

    This thesis deals with the explanation and compensation of the effects 'decay' and 'snapback' in superconducting accelerator magnets, in particular in those used in the new Large Hardron Collider at CERN. During periods of constant magnet excitation, as for example during the injection of particles in the storage ring, the magnetic field in superconducting accelerator magnets shows a decay behavior. As soon as the particles are accelerated, the magnets are ramped, and the magnetic field 'snaps back' to the original hysteresis curve. Decay and snapback affect the beam in the machine and have tobe compensated precisely in order to avoid losses of particles. The research presented in this thesis is a step towards a better understanding of 'decay' and 'snapback' in superconducting particle accelerators. The thesis provides tools for the prediction and compensation of both effects in the magnets, and for the analysis of correlations between different magnet parameters.

  17. Superconducting magnets for particle large accelerators

    International Nuclear Information System (INIS)

    Kircher, F.

    1994-01-01

    The different accelerator types (linear, circular) and the advantages of using superconductivity in particle accelerator are first reviewed. Characteristics of some large superconducting accelerators (Tevatron, HERA, RHIC, LHC CERN) are presented. The design features related to accelerator magnets are reviewed: magnet reproducibility, stability, field homogeneity, etc. and the selected design characteristics are discussed: manufacturing method, winding, shielding, cryostat. CEA involvement in this domain mainly addressing quadrupoles, is presented together with the Large Hadron Collider (LHC) project at CERN. Characteristics and design of detector magnets are also described. 5 figs., 2 tabs

  18. Acceleration of magnetized plasma rings

    International Nuclear Information System (INIS)

    Hartman, D.; Eddleman, J.; Hammer, J.H.

    1982-01-01

    One scheme is considered, acceleration of a ring between coaxial electrodes by a B/sub theta/ field as in a coaxial rail-gun. If the electrodes are conical, a ring accelerated towards the apex of the cone undergoes self-similar compression (focussing) during acceleration. Because the allowable acceleration force F/sub a/ = kappa U/sub m//R (kappa - 2 , the accelerating distance for conical electrodes is considerably shortened over that required for coaxial electrodes. In either case however, since the accelerating flux can expand as the ring moves, most of the accelerating field energy can be converted into kinetic energy of the ring leading to high efficiency

  19. Highly Stable and Active Pt/Nb-TiO2 Carbon-Free Electrocatalyst for Proton Exchange Membrane Fuel Cells

    Directory of Open Access Journals (Sweden)

    Shuhui Sun

    2012-01-01

    Full Text Available The current materials used in proton exchange membrane fuel cells (PEMFCs are not sufficiently durable for commercial deployment. One of the major challenges lies in the development of an inexpensive, efficient, and highly durable and active electrocatalyst. Here a new type of carbon-free Pt/Nb-TiO2 electrocatalyst has been reported. Mesoporous Nb-TiO2 hollow spheres were synthesized by the sol-gel method using polystyrene (PS sphere templates. Pt nanoparticles (NPs were then deposited onto mesoporous Nb-TiO2 hollow spheres via a simple wet-chemical route in aqueous solution, without the need for surfactants or potentiostats. The growth densities of Pt NPs on Nb-TiO2 supports could be easily modulated by simply adjusting the experimental parameters. Electrochemical studies of Pt/Nb-TiO2 show much enhanced activity and stability than commercial E-TEK Pt/C catalyst. PtNP/Nb-TiO2 is a promising new cathode catalyst for PEMFC applications.

  20. Critical current and electric transport properties of superconducting epitaxial Nb(Ti)N submicron structures

    Science.gov (United States)

    Klimov, A.; Słysz, W.; Guziewicz, M.; Kolkovsky, V.; Wegrzecki, M.; Bar, J.; Marchewka, M.; Seredyński, B.

    2016-12-01

    Critical current and current-voltage characteristics of epitaxial Nb(Ti)N submicron ultrathin structures were measured as function of temperature. For 700-nm-wide bridge we found current-driven vortex de-pinning at low temperatures and thermally activated flux flow closer to the transition temperature, as the limiting factors for the critical current density. For 100-nm-wide meander we observed combination of phase-slip activation and vortex-anti-vortex pair (VAP) thermal excitation. Our Nb(Ti)N meander structure demonstrates high de-pairing critical current densities 107 A/cm2 at low temperatures, but the critical currents are much smaller due to presence of the local constrictions.

  1. Effect of Controlled Cooling on Microstructure and Tensile Properties of Low C Nb-Ti-Containing HSLA Steel for Construction

    Directory of Open Access Journals (Sweden)

    Yi Fan

    2017-01-01

    Full Text Available The thermo-mechanical control processing (TMCP of low carbon (C Nb-Ti-containing HSLA steel with different cooling rates from 5 to 20 °C/s was simulated using a Gleeble 3500 system. The samples’ microstructure was characterized and the tensile properties measured. The results show that a microstructure mainly consisting of quasi-polygonal ferrite (QPF, granular bainitic ferrite (GBF, and martensite/austenite (M/A constituent formed in each sample. Furthermore, the accelerated cooling led to a significant grain refinement of the QPF and GBF, and an increase in the density of dislocations, as well as suppressed the precipitation of nanoscale particles; however, the overall yield strength (YS still increased obviously. The accelerated cooling also brought about a decrease in amount of M/A constituent acting as a mixed hard phase, which weakened the overall strain-hardening capacity of the QPF + GBF + M/A multiphase steel and simultaneously elevated yield-to-tensile strength ratio (YR. In addition, the mechanisms in dominating the influence of controlled cooling on the final microstructure and tensile properties were discussed.

  2. Porous Nb-Ti based alloy produced from plasma spheroidized powder

    OpenAIRE

    Li, Qijun; Zhang, Lin; Wei, Dongbin; Ren, Shubin; Qu, Xuanhui

    2017-01-01

    Spherical Nb-Ti based alloy powder was prepared by the combination of plasma spheroidization and mechanical alloying. Phase constituents, microstructure and surface state of the powder, and pore characteristics of the resulting porous alloy were investigated. The results show that the undissolved W and V in the mechanically alloyed powder is fully alloyed after spheroidization, and single β phase is achieved. Particle size of the spheroidized powder is in the range of 20–110 μm. With the decr...

  3. Limitation of critical current density by intermetallic formation in fine filament Nb-Ti superconductors

    International Nuclear Information System (INIS)

    Larbalestier, D.C.; Chengren, L.; Starch, W.; Lee, P.J.

    1985-01-01

    Two experiments have been performed to investigate the role that the intermetallic reaction between the copper matrix and the Nb-Ti filaments plays in limiting the critical current density (J/sub c/) of Nb 45.6 wt% Ti composites. The first experiment involved composites which were industrially extruded. It was found that as the number of heat treatments increased, the J/sub c/ declined, the resistive transition broadened and the filaments sausaged. The filament sausaging was initiated by intermetallic particles at the filament matrix interface. A series of many heat treatment procedures were then applied to composites fabricated in the authors own laboratories without extrusion. Very high J/sub c/ values were obtained at filament sizes of 20 μm. When the same heat treatment procedures were applied to 4 - 5 μm conductors, extensive sausaging and degraded J/sub c/ values resulted. This degradation was also found to be due to the formation of Cu-Nb-Ti intermetallic compounds. It is concluded that a reliable filament diffusion barrier technology is necessary to permit full flexibility in the heat treatment of 2 - 5 μ filament Nb-Ti composites

  4. Limitation of critical current density by intermetallic formation in fine filament Nb-Ti superconductors

    International Nuclear Information System (INIS)

    Larbalestier, D.C.; Chengren, Li; Lee, P.J.; Starch, W.

    1985-01-01

    Two experiments have been performed to investigate the role that the intermetallic reaction between the copper matrix and the Nb-Ti filaments plays in limiting the critical current density (J /SUB c/ ) of Nb 46.5 wt% Ti composites. The first experiment involved composites which were industrially extruded. It was found that as the number of heat treatments increased, the J /SUB c/ declined, the resistive transition broadened and the filaments sausaged. The filament sausaging was initiated by intermetallic particles at the filament matrix interface. A series of many heat treatment procedures were then applied to composites fabricated in our own laboratories without extrusion. Very high J /SUB c/ values were obtained at filament sizes of 20 μm. When the same heat treatment procedures were applied to 4 - 5 μm conductors, extensive sausaging and degraded J /SUB c/ values resulted. This degradation was also found to be due to the formation of Cu-Nb-Ti intermetallic compounds. It is concluded that a reliable filament diffusion barrier technology is necessary to permit full flexibility in the heat treatment of 2 - 5 μm filament Nb-Ti composites

  5. Prototype superconducting magnet for the FFAG accelerator

    International Nuclear Information System (INIS)

    Obana, T.; Ogitsu, T.; Yamamoto, A.; Yoshimoto, M.; Mori, Y.; Fujii, T.; Iwasa, M.; Orikasa, T.

    2006-01-01

    A study of a superconducting magnet for the Fixed Field Alternating Gradient (FFAG) accelerator has been performed. The FFAG accelerator requires static magnetic field, and it is suitable for superconducting magnet applications, because problems associated with time varying magnetic field such as eddy current loss can be eliminated. The superconducting magnet, which can generate high magnetic field, is possible to realize a higher beam energy with a given accelerator size or the size to be smaller for a given beam energy. The FFAG accelerator magnet is demanded to have a complicated nonlinear magnetic field with high accuracy. As a first prototype superconducting coil, the coil configuration which consists of left-right asymmetric cross-section and large aperture has been designed. The prototype coil has been successfully developed by using a 6-axis Computer Numerical Control (CNC) winding machine. The magnetic field of the prototype coil has been demonstrated in warm measurement. As a consequence, the technical feasibility has been verified with the prototype coil development and the performance test. In addition, the technology components developed in the prototype coil have a possibility to transfer to a fusion magnet

  6. Virtual reality visualization of accelerator magnets

    International Nuclear Information System (INIS)

    Huang, M.; Papka, M.; DeFanti, T.; Kettunen, L.

    1995-01-01

    The authors describe the use of the CAVE virtual reality visualization environment as an aid to the design of accelerator magnets. They have modeled an elliptical multipole wiggler magnet being designed for use at the Advanced Photon Source at Argonne National Laboratory. The CAVE environment allows the authors to explore and interact with the 3-D visualization of the magnet. Capabilities include changing the number of periods the magnet displayed, changing the icons used for displaying the magnetic field, and changing the current in the electromagnet and observing the effect on the magnetic field and particle beam trajectory through the field

  7. Manufacturing and Testing of Accelerator Superconducting Magnets

    International Nuclear Information System (INIS)

    Rossi, L

    2014-01-01

    Manufacturing of superconducting magnet for accelerators is a quite complex process that is not yet fully industrialized. In this paper, after a short history of the evolution of the magnet design and construction, we review the main characteristics of the accelerator magnets having an impact on the construction technology. We put in evidence how the design and component quality impact on construction and why the final product calls for a total-quality approach. LHC experience is widely discussed and main lessons are spelled out. Then the new Nb3Sn technology, under development for the next generation magnet construction, is outlined. Finally, we briefly review the testing procedure of accelerator superconducting magnets, underlining the close connection with the design validation and with the manufacturing process

  8. Manufacturing and Testing of Accelerator Superconducting Magnets

    CERN Document Server

    Rossi, L

    2014-01-01

    Manufacturing of superconducting magnet for accelerators is a quite complex process that is not yet fully industrialized. In this paper, after a short history of the evolution of the magnet design and construction, we review the main characteristics of the accelerator magnets having an impact on the construction technology. We put in evidence how the design and component quality impact on construction and why the final product calls for a total-quality approach. LHC experience is widely discussed and main lessons are spelled out. Then the new Nb$_{3}$Sn technology, under development for the next generation magnet construction, is outlined. Finally, we briefly review the testing procedure of accelerator superconducting magnets, underlining the close connection with the design validation and with the manufacturing process.

  9. Manufacturing and Testing of Accelerator Superconducting Magnets

    Energy Technology Data Exchange (ETDEWEB)

    Rossi, L [European Organization for Nuclear Research, Geneva (Switzerland)

    2014-07-01

    Manufacturing of superconducting magnet for accelerators is a quite complex process that is not yet fully industrialized. In this paper, after a short history of the evolution of the magnet design and construction, we review the main characteristics of the accelerator magnets having an impact on the construction technology. We put in evidence how the design and component quality impact on construction and why the final product calls for a total-quality approach. LHC experience is widely discussed and main lessons are spelled out. Then the new Nb3Sn technology, under development for the next generation magnet construction, is outlined. Finally, we briefly review the testing procedure of accelerator superconducting magnets, underlining the close connection with the design validation and with the manufacturing process.

  10. Decay and snapback in superconducting accelerator magnets

    NARCIS (Netherlands)

    Haverkamp, M.

    2003-01-01

    This thesis deals with the explanation and compensation of the effects ‘decay’ and ‘snapback’ in superconducting accelerator magnets, in particular in those used in the new Large Hardron Collider at CERN. During periods of constant magnet excitation, as for example during the injection of particles

  11. Stripline magnetic modulators for lasers and accelerators

    International Nuclear Information System (INIS)

    Nunnally, W.C.

    1981-01-01

    The basics of magnetic modulators including magnetic element and circuit considerations as applied to accelerators and lasers requiring repetitive (1 to 10 kHz), high voltage (50 to 500 kV), short pulse (50 to 100 ns) are discussed. The scaling of energy losses and switching parameters with material are included

  12. Effect of plastic deformation on the supercooled austenite transformations of the Cr-Mo steel with Nb, Ti and B microadditions

    International Nuclear Information System (INIS)

    Adamczyk, J.; Opiela, M.

    1998-01-01

    Effect of plastic deformation at austenizing temperature was investigated on phase transformations, structure and hardness of the supercooled austenite transformation products of the Cr-Mo constructional steel with Nb, Ti and B microadditions. Basing on the analysis of the phase transformation plots of the supercooled undeformed austenite and of the supercooled and plastically deformed one, it was found out that direct cooling of specimens after completing their plastic deformation in the above mentioned conditions, results in significant acceleration of the α→β, and ferritic and pearlitic transformations, and in the decrease of transformation products hardness. These phenomena are of great importance for working out of the thermo-mechanical treatment of products made from the heat-treated microalloyed steel. (author)

  13. Investigation of structural transformations in the Nb-Ti-Al alloy system

    International Nuclear Information System (INIS)

    Vergasova, L.L.; Volin, Eh.M.; Chizhov, I.N.; Lokshina, A.E.

    1975-01-01

    There are given the results of investigating the effect of thermal treatment conditions upon the structure, the phase composition and the mechanical characteristic of VN7 alloy from Nb-Ti-Al system. VN7 alloy was investigated in cast, forged, pressed and rolled state to study the β-α-conversion processes at slow cooling from high temperature. It was found out that slow cooling lowers considerably the plastic characteristic and the impact ductility without changing practically the tensile strength values. Higher plastic characteristic of VN7 alloy can be obtained through hastening the cooling process of the intermediate products after annealing at 950-1050 0 C

  14. Proximity Effect Transfer from NbTi into a Semiconductor Heterostructure via Epitaxial Aluminum

    DEFF Research Database (Denmark)

    Drachmann, A C C; Suominen, H J; Kjærgaard, Morten

    2017-01-01

    We demonstrate the transfer of the superconducting properties of NbTi, a large-gap high-critical-field superconductor, into an InAs heterostructure via a thin intermediate layer of epitaxial Al. Two device geometries, a Josephson junction and a gate-defined quantum point contact, are used...... to characterize interface transparency and the two-step proximity effect. In the Josephson junction, multiple Andreev reflections reveal near-unity transparency with an induced gap Δ* = 0.50 meV and a critical temperature of 7.8 K. Tunneling spectroscopy yields a hard induced gap in the InAs adjacent...

  15. Effects of cold-working on pinning behaviour and critical current densities in NbTi-based superconductors

    International Nuclear Information System (INIS)

    Yamada, Y.; Murase, S.; Wada, H.; Tachikawa, K.

    1985-01-01

    The effects of cold-working on high-field pinning behaviour at 1.8 K and 4.2 K have been studied for multifilamentary NbTi, NbTiHf and NbTiTa superconductors, which were subjected to cold-working, heat treatment and cold-working, in sequence. It is found that the cold-working, either before or after heat treatment, shifts the peak in pinning force density to a higher field, while the maximum pinning force value is first increased with increasing amount of cold-working, and then decreased. This result can not be predicted by existing pinning theories, and we conclude that for pinning behaviour induced by cold-working, not only the introduction of pinning centres but also their size and spacing must be taken into account. (author)

  16. Stability analysis of NbTi-Ta-based high field conductor cooled by pool boiling below 4 K

    International Nuclear Information System (INIS)

    Chen, W.Y.; Alcorn, J.S.; Hsu, Y.H.; Purcell, J.R.

    1980-09-01

    Stability analysis has been performed for cabled NbTi-Ta-based superconductors intended for the high field (12 T) toroidal field coils for a large scale tokamak device such as ETF. Ternary NbTi-Ta was selected as the superconductor because of its superior critical current density at high field as compared to the binary alloy NbTi. The operating temperature was chosen to be 2.5 K or below to optimize the performance of the superconductor. A cabled conductor was selected to minimize the pulsed field losses. The conductor is cooled by pool boiling in a subcooled (approx. 2.5 K, 0.25 atm) bath, or in a superfluid helium (He-II) bath (approx. 1.8 K, 0.02 atm). The analysis was based on numerically simulating the evolution of a normal zone in the conductor. Appropriate superconductor properties and heat transfer characteristics were utilized in the simulation

  17. Further investigations of the upper critical field and the high field critical current density in Nb-Ti and its alloys

    International Nuclear Information System (INIS)

    Hawksworth, D.G.; Larbalestier, D.C.

    1980-09-01

    This paper reports further measurements of Hc 2 in the Nb-Ti-Ta and Nb-Ti-Hf systems. Whilst we find only small enhancements of approx. 0.3 Tesla in μ 0 Hc 2 (4.2 0 K) compared to binary Nb-Ti, at 2 0 K there is a wide composition range in the Nb-Ti-Ta system where μ 0 Hc 2 (2 0 K) exceeds 15 Tesla, reaching a maximum of 15.5 Tesla. This represents an enhancement of 1.3 Tesla over unalloyed Nb-Ti. By comparison alloys in the Nb-Ti-Hf system show a maximum enhancement in μ 0 Hc 2 (2 0 K) of only 0.3 Tesla. The reasons both for the enhancements in Hc 2 and for the differences in behavior shown by alloys containing Ta and Hf are briefly discussed. This paper also discusses common features in the behavior of the high field critical current density, J/sub c/, of four commercial Nb-Ti composites and upon the basis of this behavior predict the enhancements in high field J/sub c/ to be expected from using Nb-Ti-Ta and its alloys

  18. AC-loss considerations of a pulse SMES for an accelerator

    International Nuclear Information System (INIS)

    Lyly, M; Hiltunen, I; Jaervelae, J; Korpela, A; Lehti, L; Stenvall, A; Mikkonen, R

    2010-01-01

    In particle accelerators quasi-DC superconducting magnets are used to keep particles in desired tracks. The needed rapid field variations of these high energy magnets require large energy bursts. If these bursts are taken from and fed back to the utility grid, its voltage is distorted and the quality of the electricity degrades. In addition, these bursts may decrease operation life time of generators and extra arrangements may be required by the electricity producers. Thus, an energy storage is an essential component for a cost-effective particle accelerator. Flywheels, capacitors and superconducting magnetic energy storage (SMES) are possible options for these relatively large and high power energy storages. Here we concentrate on AC-loss of a pulse SMES aiming to demonstrate the feasibility of NbTi SMES in a particle accelerator. The designing of a SMES requires highly reliable AC-loss simulations. In this paper, calorimetric AC-loss measurements of a NbTi magnet have been carried out to consider conductor's suitability in a pulse SMES. In addition, the measured results are compared with AC-loss simulations.

  19. Workshop on accelerator magnet superconductors. Proceedings

    International Nuclear Information System (INIS)

    2004-01-01

    The workshop on accelerator magnet superconductors has gathered 102 registered participants from research laboratories, universities and industry. 8 European companies, active in superconducting materials and cables were present. This workshop has been organized to deal with the status of the world research and development on superconducting materials and cables for high field magnets (B > 10 T). The workshop has also reviewed the status of high temperature superconductors and transmission line cables for potential use in low field superconducting magnets for injectors and beam transfer lines, as well as cables for pulsed magnets that might be used in future hadron colliders or injectors

  20. Workshop on accelerator magnet superconductors. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    The workshop on accelerator magnet superconductors has gathered 102 registered participants from research laboratories, universities and industry. 8 European companies, active in superconducting materials and cables were present. This workshop has been organized to deal with the status of the world research and development on superconducting materials and cables for high field magnets (B > 10 T). The workshop has also reviewed the status of high temperature superconductors and transmission line cables for potential use in low field superconducting magnets for injectors and beam transfer lines, as well as cables for pulsed magnets that might be used in future hadron colliders or injectors.

  1. Fatigue and strain effects in NbTi, Nb3Sn, and V2(Hf, Zr) multifilamentary superconductors

    International Nuclear Information System (INIS)

    Kuroda, T.; Wada, H.; Tachikawa, K.

    1988-01-01

    The effects of cyclic strain on critical current were studied in NbTi, bronze processed Nb 3 Sn, and composite diffusion processed V 2 (Hf,Zr) multifilamentary wires. No appreciable changes in critical current were found in NbTi wires until just prior to fatigue-induced fracture. Critical current degradation was also not observed in Nb 3 Sn or V 2 (Hf,Zr) as long as the wires were strained below the reversible limit strain. For strains beyond this limit strain the critical current was first degraded by an increasing number of cycles and then remained constant after a certain cycle number was passed

  2. Particle acceleration at a reconnecting magnetic separator

    Science.gov (United States)

    Threlfall, J.; Neukirch, T.; Parnell, C. E.; Eradat Oskoui, S.

    2015-02-01

    Context. While the exact acceleration mechanism of energetic particles during solar flares is (as yet) unknown, magnetic reconnection plays a key role both in the release of stored magnetic energy of the solar corona and the magnetic restructuring during a flare. Recent work has shown that special field lines, called separators, are common sites of reconnection in 3D numerical experiments. To date, 3D separator reconnection sites have received little attention as particle accelerators. Aims: We investigate the effectiveness of separator reconnection as a particle acceleration mechanism for electrons and protons. Methods: We study the particle acceleration using a relativistic guiding-centre particle code in a time-dependent kinematic model of magnetic reconnection at a separator. Results: The effect upon particle behaviour of initial position, pitch angle, and initial kinetic energy are examined in detail, both for specific (single) particle examples and for large distributions of initial conditions. The separator reconnection model contains several free parameters, and we study the effect of changing these parameters upon particle acceleration, in particular in view of the final particle energy ranges that agree with observed energy spectra.

  3. Mechanical Design of Superconducting Accelerator Magnets

    International Nuclear Information System (INIS)

    Toral, F

    2014-01-01

    This paper is about the mechanical design of superconducting accelerator magnets. First, we give a brief review of the basic concepts and terms. In the following sections, we describe the particularities of the mechanical design of different types of superconducting accelerator magnets: solenoids, costheta, superferric, and toroids. Special attention is given to the pre-stress principle, which aims to avoid the appearance of tensile stresses in the superconducting coils. A case study on a compact superconducting cyclotron summarizes the main steps and the guidelines that should be followed for a proper mechanical design. Finally, we present some remarks on the measurement techniques

  4. Mechanical Design of Superconducting Accelerator Magnets

    CERN Document Server

    Toral, Fernando

    2014-07-17

    This paper is about the mechanical design of superconducting accelerator magnets. First, we give a brief review of the basic concepts and terms. In the following sections, we describe the particularities of the mechanical design of different types of superconducting accelerator magnets: solenoids, costheta, superferric, and toroids. Special attention is given to the pre-stress principle, which aims to avoid the appearance of tensile stresses in the superconducting coils. A case study on a compact superconducting cyclotron summarizes the main steps and the guidelines that should be followed for a proper mechanical design. Finally, we present some remarks on the measurement techniques.

  5. Mechanical Design of Superconducting Accelerator Magnets

    Energy Technology Data Exchange (ETDEWEB)

    Toral, F [Madrid, CIEMAT (Spain)

    2014-07-01

    This paper is about the mechanical design of superconducting accelerator magnets. First, we give a brief review of the basic concepts and terms. In the following sections, we describe the particularities of the mechanical design of different types of superconducting accelerator magnets: solenoids, costheta, superferric, and toroids. Special attention is given to the pre-stress principle, which aims to avoid the appearance of tensile stresses in the superconducting coils. A case study on a compact superconducting cyclotron summarizes the main steps and the guidelines that should be followed for a proper mechanical design. Finally, we present some remarks on the measurement techniques.

  6. Porous Nb-Ti based alloy produced from plasma spheroidized powder

    Directory of Open Access Journals (Sweden)

    Qijun Li

    Full Text Available Spherical Nb-Ti based alloy powder was prepared by the combination of plasma spheroidization and mechanical alloying. Phase constituents, microstructure and surface state of the powder, and pore characteristics of the resulting porous alloy were investigated. The results show that the undissolved W and V in the mechanically alloyed powder is fully alloyed after spheroidization, and single β phase is achieved. Particle size of the spheroidized powder is in the range of 20–110 μm. With the decrease of particle size, a transformation from typical dendrite solidification structure to fine cell microstructure occurs. The surface of the spheroidized powder is coated by a layer of oxides consisting mainly of TiO2 and Nb2O5. Probabilities of sinter-neck formation and particle coalescence increases with increasing sintering temperature. Porous skeleton with relatively homogeneous pore distribution and open pore channel is formed after vacuum sintering at 1700 °C, and the porosity is 32%. The sintering kinetic analysis indicates that grain boundary diffusion is the primary mass transport mechanism during sintering process. Keywords: Powder metallurgy, Nb-Ti based alloy, Porous material, Mechanical alloying, Plasma spheroidizing, Solidification microstructure

  7. Current sharing temperature of NbTi SULTAN samples compared to prediction using a single pinning mechanism parametrization for NbTi strand

    International Nuclear Information System (INIS)

    Pong, Ian; Vostner, Alexander; Devred, Arnaud; Bessette, Denis; Mitchell, Neil; Bordini, Bernardo; Bottura, Luca; Jewell, Matthew; Long Feng; Wu Yu

    2012-01-01

    NbTi strands to be used in four of the six ITER poloidal field (PF) coils, all the correction coils (CC) and all the superconducting feeder busbars are being produced in China. Short full-size qualification conductor (cabled and jacketed) samples have been developed at ASIPP and tested at CRPP. Single pinning mechanism parametrization for this Chinese strand (type S2) has been obtained using the Bottura scaling law. The determination of the scaling parameters using a Kramer-type regression method will be described. A comparison between the critical temperature at the operating current and field of a single strand as determined by the parametrization and the current sharing temperature (T CS ) of a few conductor samples tested at the SULTAN facility will be made. The validity and limitation of the estimation will be discussed. The estimated T CS dependence on various (superconducting critical as well as geometric and volumetric) parameters will be assessed using the modelled critical surface. Errors propagated from critical current (I c ) measurements of the strands and parameter fitting, and other uncertainties, will be quantified. (paper)

  8. Feedback between Accelerator Physicists and magnet builders

    International Nuclear Information System (INIS)

    Peggs, S.

    1995-01-01

    Our task is not to record history but to change it. (K. Marx (paraphrased)) How should Accelerator Physicists set magnet error specifications? In a crude social model, they place tolerance limits on undesirable nonlinearities and errors (higher order harmonics, component alignments, etc.). The Magnet Division then goes away for a suitably lengthy period of time, and comes back with a working magnet prototype that is reproduced in industry. A better solution is to set no specifications. Accelerator Physicists begin by evaluating expected values of harmonics, generated by the Magnet Division, before and during prototype construction. Damaging harmonics are traded off against innocuous harmonics as the prototype design evolves, lagging one generation behind the evolution of expected harmonics. Finally, the real harmonics are quickly evaluated during early industrial production, allowing a final round of performance trade-offs, using contingency scenarios prepared earlier. This solution assumes a close relationship and rapid feedback between the Accelerator Physicists and the magnet builders. What follows is one perspective of the way that rapid feedback was used to 'change history' (improve linear and dynamic aperture) at RHIC, to great benefit

  9. Behavior of A NbTi very fine filament composite with current feed in the technical range

    International Nuclear Information System (INIS)

    Asdente, M.; Ottoboni, V.; Ripamonti, G.; Zannella, S.

    1985-01-01

    Self-field losses have been measured on a NbTi multifilamentary wire with very fine filaments suitable for use in ac superconducting equipment working at industrial frequency. The loss trends as functions of current intensity and frequency as well as the comparison of the losses in a coil show that they are essentially of hysteretic nature

  10. Dipole-sheet multipole magnets for accelerators

    International Nuclear Information System (INIS)

    Walstrom, P.L.

    1993-01-01

    The dipole-sheet formalism can be used to describe both cylindrical current-sheet multipole magnets and cylindrical-bore magnets made up of permanent magnet blocks. For current sheets, the formalism provides a natural way of finding a finite set of turns that approximate a continuous distribution. The formalism is especially useful In accelerator applications where large-bore, short, high-field-quality magnets that are dominated by fringe fields are needed. A further advantage of the approach is that in systems with either open or cylindrically symmetric magnetic boundaries, analytical expressions for the three-dimensional fields that are suitable for rapid numerical evaluation can be derived. This development is described in some detail. Also, recent developments in higher-order particle-beam optics codes based on the formalism are described briefly

  11. Acceleration of superparamagnetic particles with magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Stange, R., E-mail: Robert.stange@tu-dresden.de; Lenk, F.; Bley, T.; Boschke, E.

    2017-04-01

    High magnetic capture efficiency in the context of Biomagnetic Separation (BMS) using superparamagnetic particles (SMPs) requires efficient mixing and high relative velocities between cellular and other targets and SMPs. For this purpose, batch processes or microfluidic systems are commonly used. Here, we analyze the characteristics of an in-house developed batch process experimental setup, the Electromagnetic Sample Mixer (ESM) described earlier. This device uses three electromagnets to increase the relative velocity between SMPs and targets. We carry out simulations of the magnetic field in the ESM and in a simpler paradigmatic setup, and thus were able to calculate the force field acting on the SMPs and to simulate their relative velocities and fluid dynamics due to SMP movement. In this way we were able to show that alternate charging of the magnets induces a double circular stream of SMPs in the ESM, resulting in high relative velocities of SMPs to the targets. Consequently, due to the conservation of momentum, the fluid experiences an acceleration induced by the SMPs. We validated our simulations by microscopic observation of the SMPs in the magnetic field, using a homemade apparatus designed to accommodate a long working-distance lens. By comparing the results of modeling this paradigmatic setup with the experimental observations, we determined that the velocities of the SMPs corresponded to the results of our simulations. - Highlights: • Investigation of a batch process setup for complex forming at Biomagnetic Separation. • Simulation of fluid flow characteristics in this Electro Magnetic Samplemixer. • Simulation of relative velocities between magnetic particles and fluid in the setup. • Simulation of fluid flow induced by the acceleration of magnet particles. • Validation of magnetic fields and flow characteristics in paradigmatic setups. • Reached relative velocity is higher than the sedimentation velocity of the particles • Alternating

  12. CERN-LHC accelerator superconducting magnet. Development and international cooperation

    International Nuclear Information System (INIS)

    Yamamoto, Akira; Nakamoto, Tatsushi; Sasaki, Ken-ichi

    2009-01-01

    CERN-LHC accelerator superconducting magnets and a cooperative work for interaction region quadrupole magnets are introduced. The accelerator commissioning and the incident happened during the commissioning in 2008 is also briefly discussed. (author)

  13. Prospects for 10T accelerator dipole magnets

    International Nuclear Information System (INIS)

    Taylor, C.E.; Meuser, R.B.

    1981-03-01

    A next-generation major accelerator will require the highest possible field to minimize the circumference; however, there have been no proven designs for suitable magnets with fields substantially higher than 5T. A number of successful 4 to 5T dipole magnets have been built in recent years; these have involved long and difficult development projects. The 3'' bore 4.25T magnets for the Doubler are being produced by the hundreds at Fermilab, and a number of prototypes of the 5.2'' bore 5T ISABELLE magnets have been built. Successful short, approx. 5T models have been made at SACLAY, KEK, and Serpukhov, and a number of model magnets with lower fields have been built at many laboratories. Field uniformity achieved in these magnets is about ΔB/B approx. = 10 -3 . 10T magnets with higher field uniformity will be a challenging development task. The general problems of high-field (10T) magnets are discussed in terms of superconductor performance and mechanical limitations

  14. Effect of niobium clustering and precipitation on strength of an NbTi-microalloyed ferritic steel

    International Nuclear Information System (INIS)

    Kostryzhev, A.G.; Al Shahrani, A.; Zhu, C.; Cairney, J.M.; Ringer, S.P.; Killmore, C.R.; Pereloma, E.V.

    2014-01-01

    The microstructure–property relationship of an NbTi-microalloyed ferritic steel was studied as a function of thermo-mechanical schedule using a Gleeble 3500 simulator, optical and scanning electron microscope, and atom probe tomography. Contributions to the yield stress from grain size, solid solution, work hardening, particle and cluster strengthening were calculated using the established equations and the measured microstructural parameters. With a decrease in the austenite deformation temperature the yield stress decreased, following a decrease in the number density of >20 nm Nb-rich particles and ≈5 nm Nb-C clusters, although the grain refinement contribution increased. To achieve the maximum cluster/precipitation strengthening in ferrite, the austenite deformation should be carried out in the recrystallisation temperature region where there is a limited tendency for strain-induced precipitation. Based on the analysis of cluster strengthening increment, it could be suggested that the mechanism of dislocation–cluster interaction is closer to shearing than looping

  15. TEXTURE AND MECHANICAL BEHAVIOUR OF Ti AND Nb-Ti STABILIZED IF STEELS

    Directory of Open Access Journals (Sweden)

    Fabio Moreira da Silva Dias

    2013-12-01

    Full Text Available An analysis of the crystallographic texture and mechanical behavior of two types of IF steels is presented. Two steels, Ti and Nb-Ti, were submitted to different thermal annealing cycles in a continuous hot-dip galvanizing line, heat treated at temperatures of 860°C and 760°C. The more relevant characteristics of mechanical properties are evaluated. The crystallographic texture of the samples is determined by electron diffraction technique of back-scattering (SEM-EBSD. The intensity of orientation //ND is evaluated and compared. Metallographic characterization is done, and the ferritic grain size is measured with optical microscopy. The mechanical behavior of materials is characterized in the tensile test with 80 mm gauge length.

  16. Further developments in NbTi superconductors with artificial pinning centers

    International Nuclear Information System (INIS)

    Kanithi, H.C.; Valaris, P.; Motowidlo, L.R.; Zeitlin, B.A.; Scanlan, R.M.

    1992-01-01

    Artificial pinning centers (APC) have been successfully incorporated in multifilamentary NbTi based superconductors. using pure niobium as the pinning material and applying state-of-the-art processing technology, we have developed conductors which exhibit record low-field current densities. Two volume fractions of Nb have been investigated. One of the objectives of the present development effort is the feasibility study of billet scale-up from earlier work. A J 3 (3T) of ∼7500 A/mm 2 , which is twice that of the present MRI conductors, and a J c (5T) of ∼3400 A/mm 2 , have been achieved in samples. The results of this ongoing effort, in terms of conductor configuration, microstructure, critical current density, and pinning force, are presented in this paper. Appropriate comparisons with past performances are made

  17. Effect of niobium clustering and precipitation on strength of an NbTi-microalloyed ferritic steel

    Energy Technology Data Exchange (ETDEWEB)

    Kostryzhev, A.G., E-mail: kostryzhev@yahoo.com [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, NSW 2500 (Australia); Al Shahrani, A. [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, NSW 2500 (Australia); Zhu, C.; Cairney, J.M.; Ringer, S.P. [Australian Centre for Microscopy and Microanalysis, The University of Sydney, NSW 2006 (Australia); School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, NSW 2006 (Australia); Killmore, C.R. [BlueScope Steel Limited, Five Islands Road, Port Kembla, NSW 2505 (Australia); Pereloma, E.V. [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, NSW 2500 (Australia); UOW Electron Microscopy Centre, University of Wollongong, NSW 2519 (Australia)

    2014-06-01

    The microstructure–property relationship of an NbTi-microalloyed ferritic steel was studied as a function of thermo-mechanical schedule using a Gleeble 3500 simulator, optical and scanning electron microscope, and atom probe tomography. Contributions to the yield stress from grain size, solid solution, work hardening, particle and cluster strengthening were calculated using the established equations and the measured microstructural parameters. With a decrease in the austenite deformation temperature the yield stress decreased, following a decrease in the number density of >20 nm Nb-rich particles and ≈5 nm Nb-C clusters, although the grain refinement contribution increased. To achieve the maximum cluster/precipitation strengthening in ferrite, the austenite deformation should be carried out in the recrystallisation temperature region where there is a limited tendency for strain-induced precipitation. Based on the analysis of cluster strengthening increment, it could be suggested that the mechanism of dislocation–cluster interaction is closer to shearing than looping.

  18. Innovative Digitally Controlled Particle Accelerator Magnet Power Supply

    DEFF Research Database (Denmark)

    Nielsen, Rasmus Ørndrup; Bidoggia, Benoit; Maheshwari, Ram Krishan

    2013-01-01

    Particle accelerator magnet power supplies needs to be extremely precise. A new and innovative power supply for particle accelerator magnets is proposed. The topologies for the input and the output converter are shown and the control architecture is described.......Particle accelerator magnet power supplies needs to be extremely precise. A new and innovative power supply for particle accelerator magnets is proposed. The topologies for the input and the output converter are shown and the control architecture is described....

  19. The effect of aging on the critical current density in superconducting Nb-Ti-Zr alloys

    International Nuclear Information System (INIS)

    Ishida, Fumihiko; Doi, Toshio

    1979-01-01

    The effect of aging temperature, cold-reduction prior to aging, O 2 content and composition on the variation in the critical current density, J sub(c), by isothermal aging was investigated in heavily cold-worked Nb-Ti-Zr alloys on the Nb-Ti side. The results are summarized as follows: (1) When these alloys are aged isothermally at temperatures from 350 to 500 0 C, J sub(c) increases initially, reaches a maximum value and then decreases. Increase in J sub(c) of three orders of magnitude is possible as a result of aging. (2) The maximum value of J sub(c) on the isothermal aging curve becomes higher at a lower aging temperature, at a less cold-reduction prior to aging or with a higher O 2 content. (3) The J sub(c) of aged alloy becomes a maximum in composition containing 35 at%Nb, 60 to 65 at%Ti and less than 5 at%Zr. (4) The maximum value of J sub(c) was obtained for Nb-60.0 at%Ti-5.0 at%Zr alloy containing 1200 wt ppm O 2 , aged at 350 0 C for 330 h after 98.44% cold-reduction. The values of J sub(c) at 4.2 K were 2.4 x 10 9 A/m 2 at 5.0 T, 1.1 x 10 9 A/m 2 at 7.0 T and 3.0 x 10 8 A/m 2 at 9.0 T, respectively. The upper critical field of this specimen was 11.3 T at 4.2 K and its critical temperature was 8.6 K. (author)

  20. Correcting coils in end magnets of accelerators

    Directory of Open Access Journals (Sweden)

    L. R. P. Kassab

    1998-05-01

    Full Text Available We present an empirical investigation of the correcting coils behavior used to homogenize the field distribution of the race-track microtron accelerator end magnets. These end magnets belong to the second stage of the 30.0 MeV cw electron accelerator under construction at IFUSP, the race-track microtron booster, in which the beam energy is raised from 1.97 to 5.1 MeV. The correcting coils are attached to the pole faces and are based on the inhomogeneities of the magnetic field measured. The performance of these coils, when operating the end magnets with currents that differ by ±10% from the one used in the mappings that originated the coils copper leads, is presented. For one of the magnets, adjusting conveniently the current of the correcting coils makes it possible to homogenize field distributions of different intensities, once their shapes are practically identical to those that originated the coils. For the other one, the shapes are changed and the coils are less efficient. This is related to intrinsic factors that determine the inhomogeneities. However, we obtained uniformity of 0.001% in both cases.

  1. Electron Surfing Acceleration in Magnetic Reconnection

    OpenAIRE

    Hoshino, Masahiro

    2005-01-01

    We discuss that energetic electrons are generated near the X-type magnetic reconnection region due to a surfing acceleration mechanism. In a thin plasma sheet, the polarization electric fields pointing towards the neutral sheet are induced around the boundary between the lobe and plasma sheet in association with the Hall electric current. By using a particle-in-cell simulation, we demonstrate that the polarization electric fields are strongly enhanced in an externally driven reconnection syst...

  2. Application of permanent magnets in accelerators and electron storage rings

    International Nuclear Information System (INIS)

    Halbach, K.

    1984-09-01

    After an explanation of the general circumstances in which the use of permanent magnets in accelerators is desirable, a number of specific magnets will be discussed. That discussion includes magnets needed for the operation of accelerators as well as magnets that are employed for the utilization of charged particle beams, such as the production of synchrotron radiation. 15 references, 8 figures

  3. Accelerator magnet power supply using storage generator

    International Nuclear Information System (INIS)

    Karady, G.; Thiessen, H.A.

    1987-01-01

    Recently, a study investigated the feasibility of a large, 60 GeV accelerator. This paper presents the conceptual design of the magnet power supply (PS() and energy storage system. The main ring magnets are supplied by six, high-voltage and two, low-voltage power supplies. These power supplies drive a trapezoidal shaped current wave through the magnets. The peak current is 10 kA and the repetition frequency is 3.3 Hz. During the acceleration period the current is increased from 1040 A to 10,000 A within 50 msec which requires a loop voltage of 120 kV and a peak power of 1250 MW. During the reset period, the PS operates as an inverter with a peak power of -1250 MW. The large energy fluctuation necessitates the use of a storage generator. Because of the relatively high operation frequency, this generator operates in a transient mode which significantly increases the rotor current and losses. The storage generator is directly driven by a variable speed drive, which draws a practically constant power of 17 MW from the ac supply network and eliminates the pulse loading. For the reduction of dc ripple, the power supplies operate in a 24 pulse mode

  4. A Novel Permanent Magnetic Angular Acceleration Sensor

    Directory of Open Access Journals (Sweden)

    Hao Zhao

    2015-07-01

    Full Text Available Angular acceleration is an important parameter for status monitoring and fault diagnosis of rotary machinery. Therefore, we developed a novel permanent magnetic angular acceleration sensor, which is without rotation angle limitations and could directly measure the instantaneous angular acceleration of the rotating system. The sensor rotor only needs to be coaxially connected with the rotating system, which enables convenient sensor installation. For the cup structure of the sensor rotor, it has a relatively small rotational inertia. Due to the unique mechanical structure of the sensor, the output signal of the sensor can be directed without a slip ring, which avoids signal weakening effect. In this paper, the operating principle of the sensor is described, and simulated using finite element method. The sensitivity of the sensor is calibrated by torsional pendulum and angle sensor, yielding an experimental result of about 0.88 mV/(rad·s−2. Finally, the angular acceleration of the actual rotating system has been tested, using both a single-phase asynchronous motor and a step motor. Experimental result confirms the operating principle of the sensor and indicates that the sensor has good practicability.

  5. Chemical state and phase structure of (TaNbTiW)N films prepared by combined magnetron sputtering and PBII

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Xingguo [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Tang, Guangze [National Key Laboratory of Materials Behavior and Evaluation in Space Environment, Harbin Institute of Technology, Harbin 150001 (China); Sun, Mingren [National Key Laboratory of Science and Technology on Precision Hot Processing of Metals Harbin Institute of Technology, Harbin Institute of Technology, Harbin 150001 (China); Ma, Xinxin, E-mail: maxin@hit.edu.cn [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Wang, Liqin [School of Mechatronics Engineering, Harbin Institute of Technology, Harbin, 150001 (China)

    2013-09-01

    (TaNbTiW)N films with thickness of ∼1000 nm are prepared on titanium alloy substrate by combined magnetron sputtering deposition and nitrogen plasma based ion implantation (N-PBII). Chemical state of the elements and phase structure of the films are investigated using X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD), respectively. The bonds of Ta-N, Nb-N, Ti-N-O and Ta-O are detected in the (TaNbTiW)N films, however both W-N and W-O are not found. The initial alloy film has a BCC structure, while the films with N-PBII treatment are composed of BCC and FCC structures. The hardness and elastic modulus of the films can be improved by increasing nitrogen implantation dose and reach maximum values of 9.0 GPa and 154.1 GPa, respectively.

  6. In situ observation of fatigue crack initiation and propagation behavior of a high-Nb TiAl alloy at 750 °C

    International Nuclear Information System (INIS)

    Min, Zhang; Xi-ping, Song; Long, Yu; Hong-liang, Li; Ze-hui, Jiao; Hui-chen, Yu

    2015-01-01

    In this paper, the fatigue crack initiation and propagation behavior of a high-Nb TiAl alloy with nearly lamellar microstructure was studied by in situ scanning electron microscope observation at 750 °C. Dog-bone shaped specimens with a single-edge notch were used in the test. The results showed that the fatigue crack initiated first at the central portion of the notch, and then shifted to the edge portion. As the cycle numbers went on increasing, these cracks joined together and formed a main fatigue crack, which could propagate along the surface of the specimen. During the fatigue crack propagation two or three propagation stages were found depending on the microstructure of the crack tip. When the fatigue crack was parallel to the lamellar laths, it exhibited the rapid, steady and accelerated propagation stages successively, while when the fatigue crack was perpendicular to the lamellar laths, it exhibited only the steady and accelerated propagation stages, with no rapid propagation stage being found. In these different propagation stages the fatigue crack propagation rates were different and depended intensively on the lamellar laths orientation, lamellar colony size, equiaxed gamma grains and peak stress intensity factor K max . Based on the experimental data it was concluded that the fatigue crack initiation lifetime was much longer than the propagation lifetime for the single-edge notched specimens at 750 °C

  7. In situ observation of fatigue crack initiation and propagation behavior of a high-Nb TiAl alloy at 750 °C

    Energy Technology Data Exchange (ETDEWEB)

    Min, Zhang [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Xi-ping, Song, E-mail: xpsong@skl.ustb.edu.cn [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Long, Yu; Hong-liang, Li [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Ze-hui, Jiao; Hui-chen, Yu [National Key Laboratory of Science and Technology on Advanced High Temperature Structural Materials, Beijing Institute of Aeronautical Materials, Beijing 100095 (China)

    2015-01-12

    In this paper, the fatigue crack initiation and propagation behavior of a high-Nb TiAl alloy with nearly lamellar microstructure was studied by in situ scanning electron microscope observation at 750 °C. Dog-bone shaped specimens with a single-edge notch were used in the test. The results showed that the fatigue crack initiated first at the central portion of the notch, and then shifted to the edge portion. As the cycle numbers went on increasing, these cracks joined together and formed a main fatigue crack, which could propagate along the surface of the specimen. During the fatigue crack propagation two or three propagation stages were found depending on the microstructure of the crack tip. When the fatigue crack was parallel to the lamellar laths, it exhibited the rapid, steady and accelerated propagation stages successively, while when the fatigue crack was perpendicular to the lamellar laths, it exhibited only the steady and accelerated propagation stages, with no rapid propagation stage being found. In these different propagation stages the fatigue crack propagation rates were different and depended intensively on the lamellar laths orientation, lamellar colony size, equiaxed gamma grains and peak stress intensity factor K{sub max}. Based on the experimental data it was concluded that the fatigue crack initiation lifetime was much longer than the propagation lifetime for the single-edge notched specimens at 750 °C.

  8. Design and study of new cables for superconducting accelerator magnets: Synchrotron SIS 100 at GSI and NICA collider at JINR*

    International Nuclear Information System (INIS)

    Khodzhibagiyan, H G; Drobin, V M; Kovalenko, A D; Vladimirova, N M; Fischer, E; Pantsyrny, V I; Potanina, L V; Shikov, A K

    2010-01-01

    Recent data from the design of new optimized options of NbTi composite wires and hollow cables for fast cycling synchrotron SIS100 at GSI and NICA collider at JINR are presented. The SIS100 new cable is proposed to be used for manufacturing of single-layer coil for dipole magnet with maximal amplitude of pulsed magnetic field up to 2 T. The cable should provide continues pulsed operation at the current amplitude of I = 13 kA and magnetic field ramp rate of dB/dt = 4 T/s. The results of experimental study of energy losses in the new wire and cable samples for SIS100 magnets are presented. The design cable parameters for the NICA 4 T dipole magnet are fixed at the level of I = 17 kA and dB/dt = 1 T/s. The status of the work is presented and discussed.

  9. Test results of the first 50 kA NbTi full size sample for ITER

    International Nuclear Information System (INIS)

    Ciazynski, D.; Zani, L.; Huber, S.; Stepanov, B.; Karlemo, B.

    2003-01-01

    Within the framework of the research studies for the International Thermonuclear Experimental Reactor (ITER) project, the first full size NbTi conductor sample was fabricated in industry and tested in the SULTAN facility (Villigen, Switzerland). This sample (PF-FSJS), which is relevant to the Poloidal Field coils of ITER, is composed of two parallel straight bars of conductor, connected at bottom through a joint designed according to the Cea twin-box concept. The two conductor legs are identical except for the use of different strands: a nickel plated NbTi strand with a pure copper matrix in one leg, and a bare NbTi strand with copper matrix and internal CuNi barrier in the other leg. The two conductors and the joint were extensively tested regarding DC (direct current) and AC (alternative current) properties. This paper reports on the tests results and analysis, stressing the differences between the two conductor legs and discussing the impact of the test results on the ITER design criteria for conductor and joint. While joint DC resistance, conductors and joint AC losses, fulfilled the ITER requirements, neither conductor could reach its current sharing temperature at relevant ITER currents, due to instabilities. Although the drop in temperature is slight for the CuNi strand cable, it is more significant for the Ni plated strand cable. (authors)

  10. Quench behavior of a superconducting accelerator magnet

    International Nuclear Information System (INIS)

    McInturff, A.D.; Sampson, W.B.; Garber, M.; Dahl, P.F.

    1980-01-01

    Data are presented on the minimum energy required to cause quenches to propagate in an accelerator dipole magnet. The amount of stored energy dissipated into the magnet was measured as a function of dipole excitation current. This in turn determines the maximum coil temperature reached in a given magnet. Quench velocities in the longitudinal direction of the conductor were as high as 11m/sec. The azimuthal velocities or turn to turn velocities were found to be a function of the number of fiberglass layers of insulation that the quench had to cross and were on the order of a few tens of centimeters/sec. The field shape of a given magnet was found to be unchanged for more than 100 quenches. The coil to coil connection and inter-coil splice resistances were found to be less than a namo-ohm and therefore of litle consequence in the cryogenic load considerations. No definitive answers were found on how to decrease the rate of training (130 Gauss/Quench average) required from 4.OT to 5.1T

  11. Measurement of the magnetic field coefficients of particle accelerator magnets

    International Nuclear Information System (INIS)

    Herrera, J.; Ganetis, G.; Hogue, R.; Rogers, E.; Wanderer, P.; Willen, E.

    1989-01-01

    An important aspect in the development of magnets to be used in particle accelerators is the measurement of the magnetic field in the beam aperture. In general it is necessary to measure the harmonic multipoles in the dipole, quadrupole, and sextupole magnets for a series of stationary currents (plateaus). This is the case for the Superconducting Super Collider (SSC) which will be ramped to high field over a long period (/approximately/1000 sec.) and then remain on the flat top for the duration of the particle collision phase. In contrast to this mode of operation, the Booster ring being constructed for the Brookhaven AGS, will have a fast ramp rate of approximately 10 Hz. The multipole fields for these Booster magnets must therefore be determined ''on the ramp.'' In this way the effect of eddy currents will be taken into account. The measurement system which we will describe in this paper is an outgrowth of that used for the SSC dipoles. It has the capability of measuring the field multipoles on both a plateau or during a fast ramp. In addition, the same basic coil assembly is used to obtain the magnetic multipoles in dipole, quadrupole, and sextupole magnets. 2 refs., 3 figs., 1 tab

  12. Analysis of Flow Behavior of an Nb-Ti Microalloyed Steel During Hot Deformation

    Science.gov (United States)

    Mohebbi, Mohammad Sadegh; Parsa, Mohammad Habibi; Rezayat, Mohammad; Orovčík, L'ubomír

    2018-03-01

    The hot flow behavior of an Nb-Ti microalloyed steel is investigated through hot compression test at various strain rates and temperatures. By the combination of dynamic recovery (DRV) and dynamic recrystallization (DRX) models, a phenomenological constitutive model is developed to derive the flow stress. The predefined activation energy of Q = 270 kJ/mol and the exponent of n = 5 are successfully set to derive critical stress at the onset of DRX and saturation stress of DRV as functions of the Zener-Hollomon parameter by the classical hyperbolic sine equation. The remaining parameters of the constitutive model are determined by fitting them to the experiments. Through substitution of a normalized strain in the DRV model and considering the interconnections between dependent parameters, a new model is developed. It is shown that, despite its fewer parameters, this model is in good agreement with the experiments. Accurate analyses of flow data along with microstructural analyses indicate that the dissolution of NbC precipitates and its consequent solid solution strengthening and retardation of DRX are responsible for the distinguished behaviors in the two temperature ranges between T employed for the present steel in the whole tested temperature ranges.

  13. Perovskite-related Ca(Nb,Ti)O3.33

    International Nuclear Information System (INIS)

    Guevarra, J.; Smaalen, S. van; Daniels, P.; Rotiroti, N.; Lichtenberg, F.

    2005-01-01

    Crystals of nominal composition Ca(Nb 0.8 Ti 0.2 )O 3.4 , an n = 5 member of the homologous series A n B n O 3n+2 , have been synthesized by floating-zone melting. The material was found to be multiphase consisting also of the n = 6 type. A good single crystal of this n = 6 type was found and the crystal structure at room temperature was determined by X-ray diffraction using synchrotron radiation. Structure refinements indicate a composition of Ca(Nb 0.76 Ti 0.24 )O 3.33 . The crystal structure is monoclinic P2 1 and consists of slabs of corner-sharing (Nb,Ti)O 6 octahedra interrupted by layers of oxygen atoms. Ca atoms within the slabs are 12-fold coordinated whereas those at the borders show irregular coordination geometries. The octahedral distortion is greatest near the borders of the slabs and least near the middle of the slabs. Ti 4+ preferentially occupy octahedral sites in the middle of slabs. The non-stoichiometry in the refined composition and the insulating character of the material may be explained in terms of extra oxygen, vacancies on the cation sites, or by localization of the electrons in the 4d orbitals of Nb at the borders of slabs. (orig.)

  14. Microstructure of Fe-Cr-C hardfacing alloys with additions of Nb, Ti and, B

    International Nuclear Information System (INIS)

    Berns, H.; Fischer, A.

    1987-01-01

    The abrasive wear of machine parts and tools used in the mining, earth moving, and transporting of mineral materials can be lowered by filler wire welding of hardfacing alloys. In this paper, the microstructures of Fe-Cr-C and Fe-Cr-C-Nb/Ti hardfacing alloys and deposits and those of newly developed Fe-Cr-C-B and Fe-Ti-Cr-C-B ones are described. They show up to 85 vol.% of primarily solidified coarse hard phases; i.e., Carbides of MC-, M/sub 7/C/sub 3/-, M/sub 3/C-type and Borides of MB/sub 2/-, M/sub 3/B/sub 2/-, M/sub 2/B-, M/sub 3/B-, M/sub 23/B/sub 6/-type, which are embedded in a hard eutectic. This itself consists of eutectic hard phases and a martensitic or austenitic metal matrix. The newly developed Fe-Cr-C-B alloys reach hardness values of up to 1200 HV and are harder than all purchased ones. The primary solidification of the MB/sub 2/-type phase of titanium requires such high amounts of titanium and boron that these alloys are not practical for manufacture as commercial filler wires

  15. Porous Nb-Ti based alloy produced from plasma spheroidized powder

    Science.gov (United States)

    Li, Qijun; Zhang, Lin; Wei, Dongbin; Ren, Shubin; Qu, Xuanhui

    Spherical Nb-Ti based alloy powder was prepared by the combination of plasma spheroidization and mechanical alloying. Phase constituents, microstructure and surface state of the powder, and pore characteristics of the resulting porous alloy were investigated. The results show that the undissolved W and V in the mechanically alloyed powder is fully alloyed after spheroidization, and single β phase is achieved. Particle size of the spheroidized powder is in the range of 20-110 μm. With the decrease of particle size, a transformation from typical dendrite solidification structure to fine cell microstructure occurs. The surface of the spheroidized powder is coated by a layer of oxides consisting mainly of TiO2 and Nb2O5. Probabilities of sinter-neck formation and particle coalescence increases with increasing sintering temperature. Porous skeleton with relatively homogeneous pore distribution and open pore channel is formed after vacuum sintering at 1700 °C, and the porosity is 32%. The sintering kinetic analysis indicates that grain boundary diffusion is the primary mass transport mechanism during sintering process.

  16. NbTi Strands Verification for ITER PF CICC Process Qualification of CNDA

    Science.gov (United States)

    Liu, F.; Liu, H.; Liu, S.; Liu, B.; Lei, L.; Wu, Y.

    2014-05-01

    China is in charge of most of Poloidal Field (PF) conductors production for the International Thermonuclear Experimental Reactor (ITER). The execution for PF conductors shall be in three main phases. According to ITER Procurement Arrangement (PA), the Domestic Agency (DA) shall be required to verify the room and low temperature acceptance tests carried out by the strand suppliers. As the reference laboratory of Chinese DA (CNDA), the superconducting strands test laboratory of Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP) was undertaking the task of strands verification for ITER conductors. The verification test includes: diameter, Nickel plating thickness, copper-to-non-copper volume ratio, twist pitch direction and length, standard critical current (IC) and resistive transition index (n), residual resistance ration (RRR), and hysteresis loss. 48 NbTi strands with 7 billets were supplied for the PF Cable-In-Conduit Conductor (CICC) process qualification. In total, 54 samples were measured. The verification level for PF CICC process qualification was 100%. The test method, facility and results of each item are described in detail in this publication.

  17. Pulse measurement of the hot spot current in a NbTiN superconducting filament

    Science.gov (United States)

    Harrabi, K.; Mekki, A.; Kunwar, S.; Maneval, J. P.

    2018-02-01

    We have studied the voltage response of superconducting NbTiN filaments to a step-pulse of over-critical current I > Ic. The current induces the destruction of the Cooper pairs and initiates different mechanisms of dissipation depending on the bath temperature T. For the sample investigated, and for T above a certain T*, not far from Tc, the resistance manifests itself in the form of a phase-slip center, which turns into a normal hot spot (HS) as the step-pulse is given larger amplitudes. However, at all temperatures below T*, the destruction of superconductivity still occurs at Ic(T), but leads directly to an ever-growing HS. By lowering the current amplitude during the pulse, one can produce a steady HS and thus define a threshold HS current Ih(T). That is achieved by combining two levels of current, the first and larger one to initiate an HS, the second one to search for constant voltage response. The double diagram of the functions Ic(T) and Ih(T) was plotted in the T-range Tc/2 < T < Tc, and their crossing found at T* = (8.07 ± 0.07) K.

  18. Proximity effect depression of the critical temperature in two-phase Nb-Ti superconductors

    International Nuclear Information System (INIS)

    Meingast, C.; Daeumling, M.; Lee, P.J.; Larbalestier, D.C.

    1987-01-01

    The superconducting critical temperature of high critical current density Nb-Ti composites has been measured at various stages in the critical current optimization process. This process involves heat treatment steps which cause precipitation of normal α-Ti and make the matrix more Nb rich. T/sub c/ rises from 9.1 to 9.5 K during this stage. The final optimization stage involves extensive wire drawing during which the α-Ti precipitates are reduced to less than a coherence length in thickness. This does not result in a reduction in J/sub c/ but T/sub c/ is found to fall from 9.44 to 8.7 K during this step. The depression of T/sub c/ is found to be in fair agreement with the predicted proximity effect suppression of T/sub c/. Wires of optimum transport critical current density are seen to have T/sub c/ of around 9 K

  19. Hysteresis effects in the cores of particle accelerator magnets

    CERN Document Server

    AUTHOR|(CDS)2086181; Schoerling, Daniel

    A study of the hysteresis effects in the cores of particle accelerator magnets has been performed in the framework of the work presented in this thesis. This study has been focused on normal conducting particle accelerator magnets whose cores are manufactured using ferromagnetic materials. The magnetic circuits have been modelled using the developed models: one model for the magnetic circuit and one for the magnetization of the material in the core. The parameters of the magnetic circuit model have been identified with the help of simulations which rely on the finite element method (Opera 3D), while the parameters of the magnetic hysteresis model have been identified through experimental measurements performed using a method developed in the framework of this work. The modelling results have been validated by means of experimental measurements performed on two magnets: one small size magnet which has been specifically designed and manufactured, and one magnet which is currently used in a particle accelerator ...

  20. New particle accelerations by magnetized plasma shock waves

    International Nuclear Information System (INIS)

    Takeuchi, Satoshi

    2005-01-01

    Three mechanisms concerning particle accelerations are proposed to account for the high energy of cosmic rays. A model of magnetized plasma clouds is used to simulate a shock-type wave. The attainable energies of test particles colliding with the moving magnetic clouds are investigated by analytical and numerical methods for the three mechanisms. The magnetic trapping acceleration is a new type of particle trapping and acceleration in which, in principle, the test particle is accelerated indefinitely; hence, this mechanism surpasses the Fermi-type acceleration. In the single-step acceleration, the test particle obtains a significant energy gain even though it only experiences a single collision. Lastly, there is the bouncing acceleration by which the test particle is substantially accelerated due to repeated collisions

  1. Design and fabrication of the MFTF-B magnet system

    International Nuclear Information System (INIS)

    Tatro, R.E.; Kozman, T.A.

    1985-09-01

    The MFTF-B superconducting magnet system consists of 40 NbTi magnets and two Nb 3 Sn magnets. General Dynamics (GD) designed all magnets except for the small trim coils. GD then fabricated 20 NbTi magnets, while LLNL fabricated 20 NbTi magnets and two Nb 3 Sn magnets. The design phase was completed in February 1984 and included the competitive procurement of magnet structural fabrication, superconductor, G-10CR insulation, support struts and bearings, vapor-cooled leads, and thermal shields for all magnets. Fabrication of all magnets was completed in March 1985. At GD, dual assembly lines were necessary during fabrication in order to meet the aggressive LLNL schedule. The entire magnet system has been installed and aligned at LLNL, and Tech Demo tests will be performed during September-November 1985

  2. Analysis of ITER NbTi and Nb3Sn CICCs experimental minimum quench energy with JackPot, MCM and THEA models

    Science.gov (United States)

    Bagni, T.; Duchateau, J. L.; Breschi, M.; Devred, A.; Nijhuis, A.

    2017-09-01

    Cable-in-conduit conductors (CICCs) for ITER magnets are subjected to fast changing magnetic fields during the plasma-operating scenario. In order to anticipate the limitations of conductors under the foreseen operating conditions, it is essential to have a better understanding of the stability margin of magnets. In the last decade ITER has launched a campaign for characterization of several types of NbTi and Nb3Sn CICCs comprising quench tests with a singular sine wave fast magnetic field pulse and relatively small amplitude. The stability tests, performed in the SULTAN facility, were reproduced and analyzed using two codes: JackPot-AC/DC, an electromagnetic-thermal numerical model for CICCs, developed at the University of Twente (van Lanen and Nijhuis 2010 Cryogenics 50 139-148) and multi-constant-model (MCM) (Turck and Zani 2010 Cryogenics 50 443-9), an analytical model for CICCs coupling losses. The outputs of both codes were combined with thermal, hydraulic and electric analysis of superconducting cables to predict the minimum quench energy (MQE) (Bottura et al 2000 Cryogenics 40 617-26). The experimental AC loss results were used to calibrate the JackPot and MCM models and to reproduce the energy deposited in the cable during an MQE test. The agreement between experiments and models confirm a good comprehension of the various CICCs thermal and electromagnetic phenomena. The differences between the analytical MCM and numerical JackPot approaches are discussed. The results provide a good basis for further investigation of CICC stability under plasma scenario conditions using magnetic field pulses with lower ramp rate and higher amplitude.

  3. Permanent-magnet material applications in particle accelerators

    International Nuclear Information System (INIS)

    Kraus, R.H. Jr.

    1992-01-01

    The modern charged particle accelerator has found application in a wide range of scientific research, industrial, medical, and defense fields. Researchers began to use permanent-magnet materials in particle accelerators soon after the invention of the alternating gradient principle, which showed that magnetic field could be used to control the transverse envelope of charged particle beams. The history of permanent-magnet use in accelerator physics and technology is outlined, current design methods and material properties of concern for particle accelerator applications are reviewed

  4. Ablation acceleration of macroparticle in spiral magnetic fields

    International Nuclear Information System (INIS)

    Ikuta, Kazunari.

    1981-05-01

    The rocket motion of macroparticles heated by energetic pulses in a spiral magnetic field was studied. The purpose of the present work is to study the ablation acceleration of a macroparticle in a spiral magnetic field with the help of the law of conservation of angular momentum. The basic equation of motion of ablatively accelerated projectile in a spiral magnetic field was derived. Any rocket which is ejecting fully ionized plasma in an intense magnetic field with rotational transform is able to have spin by the law of conservation of momentum. The effect of spiral magnetic field on macroparticle acceleration is discussed. The necessary mass ratio increase exponentially with respect to the field parameter. The spiral field should be employed with care to have only to stabilize the position of macroparticles. As conclusion, it can be said that the ablation acceleration of the projectile in a spiral field can give the accelerated body spin quite easily. (Kato, T.)

  5. submitter Simulation of a quench event in the upgraded High-Luminosity LHC Main dipole circuit including the 11 T Nb$_{3}$Sn dipole magnets

    CERN Document Server

    Fernandez Navarro, Alejandro Manuel; Verweij, Arjan P; Bortot, Lorenzo; Mentink, Matthias; Prioli, Marco; Auchmann, Bernhard; Izquierdo Bermudez, Susana; Ravaioli, Emmanuele; Yammine, Samer

    2018-01-01

    To achieve the goal of increased luminosity, two out of eight main dipole circuits of the accelerator will be reconfigured in the coming LHC upgrade by replacing one standard 14.3-m long, Nb-Ti-based, 8.3 T dipole magnet by two 5.3-m long, Nb$_{3}$Sn-based, 11.2 T magnets (MBH). The modified dipole circuits will contain 153 Nb-Ti magnets and two MBH magnets. The latter will be connected to an additional trim power converter to compensate for the differences in the magnetic transfer functions. These modifications imply a number of challenges from the point of view of the circuit integrity, operation, and quench protection. In order to assess the circuit performance under different scenarios and to validate the circuit quench protection strategy, reliable and accurate numerical transient simulations have to be performed. We present the field/circuit coupling simulation of the reconfigured main dipole magnet chain following the introduction of the MBH magnets. 2-D distributed LEDET models of the MBH's have been ...

  6. Plasma cluster acceleration by means of external magnetic fields

    International Nuclear Information System (INIS)

    Kracik, J.; Maloch, J.; Sobra, K.

    1975-01-01

    The electromagnetic shock tubes are used not only for shock wave creation and study but also for pulse plasma acceleration. By applying the rail acceleration the external magnetic field perpendicular to the plasma cluster velocity can be increased. In the present work is theoretically and experimentally confirmed the external magnetic field influence on the plasma cluster acceleration when the 'snow plough' model is used. (Auth.)

  7. Optical and semiconductive properties of binary and ternary thin films from the Nb-Ti-O system

    Science.gov (United States)

    Aperador, W.; Yate, L.; Pinzón, M. J.; Caicedo, J. C.

    2018-06-01

    A study has been conducted based on the Mott-Schottky model acquisition by potentiodynamic electrochemical impedance spectroscopy, to determine the physical-chemical properties of binary TiO2, Nb2O5 and ternary Nb-Ti-O thin films (semiconductor type) based on Nb,Ti, O elements. The technique used for the study of optical properties was that of spectral transmittance, measurements were performed using a spectrophotometer. The consistency of the impedance data has been studied by calculating the Kramers-Kronig relations. The structural properties were analyzed by XRD patterns; the chemical composition measurements for all thin films were made by using XPS technique. So, in this research the transmittance values change from 72.74% for Nb2O5 to 59.68% for Ti-Nb-O with wavelength around 355 nm. The absorption coefficients for all films were analyzed from 31823.87 cm-1 for Nb2O5 to 91240.90 cm-1 for Nb-Ti-O with wavelength around 355 nm evidencing thus a 65% reduction. The direct band gap it was found that the photon energy (band gap Eg) changes in all films from 3.56 eV for Nb2O5 to 3.96 eV for Ti-Nb-O evidencing a 10% reduction. The extinction coefficient values change in all films from 0.038 cm-1 for Nb2O5 to 0.277 cm-1 for Ti-Nb-O films with wavelength around 355 nm, exhibiting an 86% increasing. Finally, it was observed by the Mott-Schottky analysis that the reference potential (Ag/AgCl) changes for all films from -2.09 V for Nb2O5 to -0.80 V for Ti-Nb-O material showing a 62% reduction.

  8. Experiment to measure the effects of biaxial strain on the critical current of NbTi superconductor

    International Nuclear Information System (INIS)

    Froelich, K.J.

    1975-01-01

    Twisted multifilament, copper-clad NbTi superconductors have been axially and biaxially strained at 4.2K with a 7.5T background field. A simply-constructed cryogenic loading frame was built and used to strain the conductor. Results on 1.27 mm x 3.13 mm conductor have shown that degradation of less than .3 percent of critical current occurred when the wire was biaxially strained to +3260 μepsilon in the axial direction and -1875 μepsilon in the transverse direction. Degradation approaches 3 percent of critical current at approximately 6000 μepsilon in the axial direction only

  9. Study of the implementation of high temperature superconductors to accelerator magnets

    International Nuclear Information System (INIS)

    Fleiter, Jerome

    2013-01-01

    Particle colliders are the main tool for investigating and understanding the fundamental laws of physics. The CERN Large Hadron Collider (LHC), is a circular accelerator which steers and collides two counter-rotating protons beams. It has four collision points where detectors are placed to analyze the products emerging from the collisions. In a synchrotron machine a magnetic flux density is used to guide and focus particles around the orbit. The maximum energy that a circular machine with a given geometry can achieve is limited by the maximum strength of the dipole magnetic flux density. There is therefore an interest in the particle physics community in searching for dipole magnets with higher strength. The LHC has a beam trajectory radius of 4.3 km and a collision center-of-mass energy of 14 TeV. The accelerator employs 1232 large superconducting Nb-Ti dipole magnets operated at a flux density of up to 8.3 T in a bath of superfluid helium at 1.9 K. Energies higher than that achieved with the LHC require magnets made from superconductors with higher upper critical flux density. Nb 3 Sn is an option for magnets operated up to about 14 T. The level of energies of the type being discussed for a potential energy upgrade of the LHC machine - 33 TeV- would require the use of high temperature superconductors (HTS). Three technical HTS are available today: YBCO, Bi-2212 and Bi-2223. At low temperature YBCO conductors present both irreversible flux density and current density in excess of those measured in Bi-2212 and Bi-2223 conductors. In addition, YBCO can be used as reacted conductor, which makes its use for applications simpler than Bi-2212, which requires heat treatment at high temperature and in oxygen atmosphere after cabling and winding. The level of currents required for application to accelerator magnets, which is above 10 kA at the nominal operating temperature and flux density, excludes the use of single strands. The high current and high current density

  10. Accelerated plan to develop magnetic fusion energy

    International Nuclear Information System (INIS)

    Fowler, T.K.

    1986-01-01

    We have shown that, despite funding delays since the passage of the Magnetic Fusion Engineering Act of 1980, fusion development could still be carried to the point of a demonstration plant by the year 2000 as called for in the Act if funding, now about $365 million per year, were increased to the $1 billion range over the next few years (see Table I). We have also suggested that there may be an economic incentive for the private sector to become in accelerating fusion development on account of the greater stability of energy production costs from fusion. Namely, whereas fossil fuel prices will surely escalate in the course of time, fusion fuel will always be abundantly available at low cost; and fusion technology poses less future risk to the public and the investor compared to conventional nuclear power. In short, once a fusion plant is built, the cost of generating electricity mainly the amortization of the plant capital cost - would be relatively fixed for the life of the plant. In Sec. V, we found that the projected capital cost of fusion plants ($2000 to $4000 per KW/sub e/) would probably be acceptable if fusion plants were available today

  11. Superconducting magnet technology for particle accelerators and detectors seminar

    CERN Multimedia

    CERN. Geneva

    2006-01-01

    This lecture is an introduction to superconducting magnets for particle accelerators and detectors, the aim being to explain the vocabulary and describe the basic technology of modern superconducting magnets, and to explore the limits of the technology. It will include the following: - Why we need superconducting magnets - Properties of superconductors, critical field, critical temperature - Why accelerators need fine filaments and cables; conductor manufacture - Temperature rise and temperature margin: the quench process, training - Quench protection schemes. Protection in the case of the LHC. - Magnets for detectors - The challenges of state-of-the-art magnets for High Energy Physics

  12. Specifications, quality control, manufacturing, and testing of accelerator magnets

    CERN Document Server

    Einfeld, D

    2010-01-01

    The performance of the magnets plays an important role in the functioning of an accelerator. Most of the magnets are designed at the accelerator laboratory and built by industry. The link between the laboratory and the manufacturer is the contract containing the Technical Specifications of the magnets. For an overview of the contents of the Technical Specifications, the specifications for the magnets of ALBA (bending, quadrupole, and sextupole) are described in this paper. The basic rules of magnet design are reviewed in Appendix A.

  13. Systems and methods for the magnetic insulation of accelerator electrodes in electrostatic accelerators

    Science.gov (United States)

    Grisham, Larry R

    2013-12-17

    The present invention provides systems and methods for the magnetic insulation of accelerator electrodes in electrostatic accelerators. Advantageously, the systems and methods of the present invention improve the practically obtainable performance of these electrostatic accelerators by addressing, among other things, voltage holding problems and conditioning issues. The problems and issues are addressed by flowing electric currents along these accelerator electrodes to produce magnetic fields that envelope the accelerator electrodes and their support structures, so as to prevent very low energy electrons from leaving the surfaces of the accelerator electrodes and subsequently picking up energy from the surrounding electric field. In various applications, this magnetic insulation must only produce modest gains in voltage holding capability to represent a significant achievement.

  14. Design of digital logic control for accelerator magnet power supply

    International Nuclear Information System (INIS)

    Long Fengli; Hu Wei; Cheng Jian

    2008-01-01

    For the accelerator magnet power supply, usually the Programmable Logic Controller (PLC) is used to server as the controller for logic protection and control. Along with the development of modern accelerator technology, it is a trend to use fully-digital control to the magnet power supply. It is possible to integrate the logic control part into the digital control component of the power supply, for example, the Field Programmable Gate Array (FPGA). The paper introduces to different methods which are designed for the logic protection and control for accelerator magnet power supplies with the FPGA as the control component. (authors)

  15. Irradiation and annealing effects of deuteron irradiated NbTi and V3Ga multifilamentary composite wires at low temperature

    International Nuclear Information System (INIS)

    Seibt, E.

    1975-01-01

    To study the effects of low-temperature irradiation on technological type II-superconductors, NbTi and V 3 Ga multifilamentary composite wires, the critical current I/sub c/ and transition temperature T/sub c/ were measured before and after irradiation with 50-MeV deuterons at 10 and 15 0 K, respectively. While the irradiation effects on I/sub c/ and T/sub c/ of NbTi are substantially unaffected, the V 3 Ga wires undergo a reduction in I/sub c/ of about 50 percent and T/sub c/ decreases from 14.7 +- 0.1 0 K to 12.3 +- 0.1 0 K at a total deuteron flux of 2.6 x 10 17 cm -2 . Annealing experiments at room temperature and 100 0 C show only a small recovery of the superconducting properties up to 15 percent. The field dependence of the volume pinning force densities P/sub V/ was determined and the results are shown to be consistent with a qualitative dynamic pinning model

  16. Porous Nb-Ti-Ta alloy scaffolds for bone tissue engineering: Fabrication, mechanical properties and in vitro/vivo biocompatibility.

    Science.gov (United States)

    Liu, Jue; Ruan, Jianming; Chang, Lin; Yang, Hailin; Ruan, Wei

    2017-09-01

    Porous Nb-Ti-Ta (at.%) alloys with the pore size of 100-600μm and the porosity of 50%-80% were fabricated by the combination of the sponge impregnation technique and sintering method. The results revealed that the pores were well connected with three-dimensional (3D) network structure, which showed morphological similarity to the anisotropic porous structure of human bones. The results also showed that the alloys could provide the compressive Young's modulus of 0.11±0.01GPa to 2.08±0.09GPa and the strength of 17.45±2.76MPa to 121.67±1.76MPa at different level of porosity, indicating that the mechanical properties of the alloys are similar to those of human bones. Pore structure on the compressive properties was also discussed on the basis of the deformation mode. The relationship between compressive properties and porosity was well consistent with the Gibson-Ashby model. The mechanical properties could be tailored to match different requirements of the human bones. Moreover, the alloys had good biocompatibility due to the porous structure with higher surface, which were suitable for apatite formation and cell adhesion. In conclusion, the porous Nb-Ti-Ta alloy is potentially useful in the hard tissue implants for the appropriate mechanical properties as well as the good biocompatible properties. Copyright © 2017. Published by Elsevier B.V.

  17. Novel Approach to Linear Accelerator Superconducting Magnet System

    International Nuclear Information System (INIS)

    Kashikhin, Vladimir

    2011-01-01

    Superconducting Linear Accelerators include a superconducting magnet system for particle beam transportation that provides the beam focusing and steering. This system consists of a large number of quadrupole magnets and dipole correctors mounted inside or between cryomodules with SCRF cavities. Each magnet has current leads and powered from its own power supply. The paper proposes a novel approach to magnet powering based on using superconducting persistent current switches. A group of magnets is powered from the same power supply through the common, for the group of cryomodules, electrical bus and pair of current leads. Superconducting switches direct the current to the chosen magnet and close the circuit providing the magnet operation in a persistent current mode. Two persistent current switches were fabricated and tested. In the paper also presented the results of magnetic field simulations, decay time constants analysis, and a way of improving quadrupole magnetic center stability. Such approach substantially reduces the magnet system cost and increases the reliability.

  18. 2-D and 3-D computations of curved accelerator magnets

    International Nuclear Information System (INIS)

    Turner, L.R.

    1991-01-01

    In order to save computer memory, a long accelerator magnet may be computed by treating the long central region and the end regions separately. The dipole magnets for the injector synchrotron of the Advanced Photon Source (APS), now under construction at Argonne National Laboratory (ANL), employ magnet iron consisting of parallel laminations, stacked with a uniform radius of curvature of 33.379 m. Laplace's equation for the magnetic scalar potential has a different form for a straight magnet (x-y coordinates), a magnet with surfaces curved about a common center (r-θ coordinates), and a magnet with parallel laminations like the APS injector dipole. Yet pseudo 2-D computations for the three geometries give basically identical results, even for a much more strongly curved magnet. Hence 2-D (x-y) computations of the central region and 3-D computations of the end regions can be combined to determine the overall magnetic behavior of the magnets. 1 ref., 6 figs

  19. Generation of magnetic fields for accelerators with permanent magnets

    International Nuclear Information System (INIS)

    Meinander, T.

    1994-01-01

    Commercially available permanent magnet materials and their properties are reviewed. Advantages and disadvantages of using permanent magnets as compared to electromagnets for the generation of specific magnetic fields are discussed. Basic permanent magnet configurations in multipole magnets and insertion devices are presented. (orig.)

  20. Direct measurements of inter-filament resistance in various multi-filamentary superconducting NbTi and Nb3Sn strands

    NARCIS (Netherlands)

    Zhou, Chao; Miyoshi, Y.; van Lanen, E.P.A.; Dhalle, Marc M.J.; Nijhuis, Arend

    2012-01-01

    For a proper characterization of multi-filamentary NbTi and Nb3Sn strands and a better understanding of their performance in short sample tests, as well as for increased understanding of inter-strand current redistribution in cabled conductors, a quantitative knowledge of the inter-filament

  1. Inter-filament resistance, effective transverse resistivity and coupling loss in superconducting multifilamentary NbTi and Nb3Sn strands

    NARCIS (Netherlands)

    Zhou, Chao; Dhalle, Marc M.J.; Nijhuis, Arend

    2012-01-01

    The effective transverse resistivity of a range of multi-filamentary Nb3Sn and NbTi strands is measured with a direct four-probe method and the data are compared to the transverse resistivity values obtained from AC coupling loss experiments. Correspondence between both is satisfactory provided that

  2. Using permanent magnets to boost the dipole field for the High-Energy LHC

    CERN Document Server

    Zimmermann, Frank

    2012-01-01

    The High-Energy LHC (HE-LHC) will be a new accelerator in the LHC tunnel based on novel dipole magnets, with a field up to 20 T, which are proposed to be realized by a hybrid-coil design, comprising blocks made from Nb- Ti, Nb$_{3}$Sn and HTS, respectively. Without the HTS the field would be only 15 T. In this note we propose and study the possibility of replacing the inner HTS layer by (weaker) permanent magnets that might contribute a field of 1-2 T, so that the final field would reach 16-17 T. Advantages would be the lower price of permanent magnets compared with HTS magnets and their availability in principle.

  3. Conduction cooled high temperature superconducting dipole magnet for accelerator applications

    DEFF Research Database (Denmark)

    Zangenberg, N.; Nielsen, G.; Hauge, N.

    2012-01-01

    A 3T proof-of-principle dipole magnet for accelerator applications, based on 2nd generation high temperature superconducting tape was designed, built, and tested by a consortium under the lead of Danfysik. The magnet was designed to have a straight, circular bore with a good field region of radius...

  4. Development of the kicker magnet system for the IHEP accelerator

    International Nuclear Information System (INIS)

    Andreev, V.N.; Kurnaev, O.V.; Sychev, V.A.; Trofimov, Yu.D.

    1982-01-01

    The KM-14 kicker magnet intended for joint operation with the KM-16 kicker magnet in the U-70 accelerator fast beam extraction system is described. The main characteristics and specific features of the magnet, pulse generators and power supplies are considered. The total aperture type KM-14 magnet (aperture height is equal to 100 mm, its width amounts 150 mm) consists of four modules which are supplied in pair-parallel by two pulse generators. The length of each module is 0.56 m, the field in a gap amounts 0.045 Tl. Joint use of the KM-14 and KM-16 magnets provides beam shooting into bending septum magnet when operating with the booster and beam extraction in the direction of the storage-accelerator complex

  5. Mesostructured niobium-doped titanium oxide-carbon (Nb-TiO2-C) composite as an anode for high-performance lithium-ion batteries

    Science.gov (United States)

    Hwang, Keebum; Sohn, Hiesang; Yoon, Songhun

    2018-02-01

    Mesostructured niobium (Nb)-doped TiO2-carbon (Nb-TiO2-C) composites are synthesized by a hydrothermal process for application as anode materials in Li-ion batteries. The composites have a hierarchical porous structure with the Nb-TiO2 nanoparticles homogenously distributed throughout the porous carbon matrix. The Nb content is controlled (0-10 wt%) to investigate its effect on the physico-chemical properties and electrochemical performance of the composite. While the crystalline/surface structure varied with the addition of Nb (d-spacing of TiO2: 0.34-0.36 nm), the morphology of the composite remained unaffected. The electrochemical performance (cycle stability and rate capability) of the Nb-TiO2-C composite anode with 1 wt% Nb doping improved significantly. First, a full cut-off potential (0-2.5 V vs. Li/Li+) of Nb-doped composite anode (1 wt%) provides a higher energy utilization than that of the un-doped TiO2-C anode. Second, Nb-TiO2-C composite anode (1 wt%) exhibits an excellent long-term cycle stability (100% capacity retention, 297 mAh/g at 0.5 C after 100 cycles and 221 mAh/g at 2 C after 500 cycles) and improved rate-capability (192 mAh/g at 5 C), respectively (1 C: 150 mA/g). The superior electrochemical performance of Nb-TiO2-C (1 wt%) could be attributed to the synergistic effect of improved electronic conductivity induced by optimal Nb doping (1 wt%) and lithium-ion penetration (high diffusion kinetics) through unique pore structures.

  6. Concepts and limitations of macroparticle accelerators using travelling magnetic waves

    International Nuclear Information System (INIS)

    Wipf, S.L.

    1980-01-01

    The concept of an accelerator using a travelling magnetic wave acting on magnetized projectiles is discussed. Although superconductors have a high potential as projectile material, their low critical temperature makes them unsuitable. Among ferromagnetic materials dysprosium seems to be superior. For stable suspension and guidance a high conductivity, preferably superconducting, guide sheet is necessary. Magnetic field gradients of 10 9 A/m 2 travelling at 10 6 m/s should be achievable using present state-of-the-art components; resulting accelerations are greater than or equal to 500 km/s 2 . A linear accelerator for final speeds of 50 km/s needs a length of 2.5 km. Guidance forces sufficient to produce acceleration of 2 x 10 6 m/s 2 allow circular accelerators of reasonable size to achieve hypervelocities for small (50 to 100 mg) projectiles. An accelerator of 170 m diameter would surpass the best results from light gas guns. Travelling waves suitable for accelerations of the order of 10 4 m/s 2 can be produced without switching, by means of flux displacing rotors, easily adapted to circular accelerators

  7. Particle Acceleration, Magnetic Field Generation, and Emission in Relativistic Shocks

    Science.gov (United States)

    Nishikawa, Ken-IchiI.; Hededal, C.; Hardee, P.; Richardson, G.; Preece, R.; Sol, H.; Fishman, G.

    2004-01-01

    Shock acceleration is an ubiquitous phenomenon in astrophysical plasmas. Plasma waves and their associated instabilities (e.g., the Buneman instability, two-streaming instability, and the Weibel instability) created in the shocks are responsible for particle (electron, positron, and ion) acceleration. Using a 3-D relativistic electromagnetic particle (m) code, we have investigated particle acceleration associated with a relativistic jet front propagating through an ambient plasma with and without initial magnetic fields. We find only small differences in the results between no ambient and weak ambient parallel magnetic fields. Simulations show that the Weibel instability created in the collisionless shock front accelerates particles perpendicular and parallel to the jet propagation direction. New simulations with an ambient perpendicular magnetic field show the strong interaction between the relativistic jet and the magnetic fields. The magnetic fields are piled up by the jet and the jet electrons are bent, which creates currents and displacement currents. At the nonlinear stage, the magnetic fields are reversed by the current and the reconnection may take place. Due to these dynamics the jet and ambient electron are strongly accelerated in both parallel and perpendicular directions.

  8. Particle Acceleration, Magnetic Field Generation in Relativistic Shocks

    Science.gov (United States)

    Nishikawa, Ken-Ichi; Hardee, P.; Hededal, C. B.; Richardson, G.; Sol, H.; Preece, R.; Fishman, G. J.

    2005-01-01

    Shock acceleration is an ubiquitous phenomenon in astrophysical plasmas. Plasma waves and their associated instabilities (e.g., the Buneman instability, two-streaming instability, and the Weibel instability) created in the shocks are responsible for particle (electron, positron, and ion) acceleration. Using a 3-D relativistic electromagnetic particle (REMP) code, we have investigated particle acceleration associated with a relativistic jet front propagating through an ambient plasma with and without initial magnetic fields. We find only small differences in the results between no ambient and weak ambient parallel magnetic fields. Simulations show that the Weibel instability created in the collisionless shock front accelerates particles perpendicular and parallel to the jet propagation direction. New simulations with an ambient perpendicular magnetic field show the strong interaction between the relativistic jet and the magnetic fields. The magnetic fields are piled up by the jet and the jet electrons are bent, which creates currents and displacement currents. At the nonlinear stage, the magnetic fields are reversed by the current and the reconnection may take place. Due to these dynamics the jet and ambient electron are strongly accelerated in both parallel and perpendicular directions.

  9. Properties and practical performance of SC magnets in accelerators

    International Nuclear Information System (INIS)

    Schmueser, P.

    1992-01-01

    A report is given on the properties and performance of superconducting accelerator magnets in the 5-6 Tesla regime. Most of the information stems from the industrially produced HERA magnets which were thoroughly tested both at industry and at DESY; data from prototype magnets for RHIC and SSC are also included. Persistent current effects were studied in detail. During the commissioning of the proton-electron collider HERA the superconducting magnets worked with high reliability and their properties were exactly as predicted from the magnetic measurements. (author) 11 refs.; 8 figs

  10. High-current power supply for accelerator magnets

    International Nuclear Information System (INIS)

    Bourkland, K.R.; Winje, R.A.

    1978-01-01

    A power supply for controlling the current to accelerator magnets produces a high current at a precisely controlled time rate of change by varying the resonant frequency of an RLC circuit that includes the magnet and applying the current to the magnet during a predetermined portion of the waveform of an oscillation. The current is kept from going negative despite the reverse-current characteristics of thyristors by a quenching circuit

  11. Compact and energy saving magnet technology for particle accelerators

    International Nuclear Information System (INIS)

    Baurichter, A.

    2013-01-01

    Despite the fact that funding agencies and industrial users of particle accelerators get more and more alerted about costs of civil engineering, installation and operation, only little effort has been put into development of sustainable, energy and cost saving accelerator technology. In order to reduce the total-cost-of ownership of accelerator magnets, operating at high electrical power for twenty years or more, permanent magnet based Green Magnet technology has been developed at a consortium around Danfysik's R and D team. Together with our partners from ISA, Aarhus University, the Aarhus School of Engineering, the company Sintex and Aalborg University all obstacles in applying permanent magnet technology as e.g. thermal drift and inhomogeneities of magnetic fields have been overcome. The first Green Magnet has now been operated for more than half a year in an Accelerator Mass Spectrometry facility at the ETH in Zurich. The performance of this B=0.43T 90 deg. H-type bending magnet and the most recently builtB=1T, 30 deg. C-type Green Magnet for the synchrotron light source ASTRID2 at ISA in Aarhus will be presented. Danfysik also is designing, manufacturing and testing 60 compact magnet systems, developed at MAX-Lab for the new MAXIV 3.0 GeV synchrotron light source. In addition, 12 for the 1.5 GeV light source and another 12 for the new SOLARIS light source in Krakow, Poland are buying built. Up to a dozen or more magnet functions have been integrated into one yoke of these compact magnet systems, which makes the new MAXIV light sources compact, energy saving and at the same time very bright. Test results and design concepts of the new MAXIV and SOLARIS magnets will be presented. (author)

  12. Particle acceleration in relativistic magnetic flux-merging events

    Science.gov (United States)

    Lyutikov, Maxim; Sironi, Lorenzo; Komissarov, Serguei S.; Porth, Oliver

    2017-12-01

    Using analytical and numerical methods (fluid and particle-in-cell simulations) we study a number of model problems involving merger of magnetic flux tubes in relativistic magnetically dominated plasma. Mergers of current-carrying flux tubes (exemplified by the two-dimensional `ABC' structures) and zero-total-current magnetic flux tubes are considered. In all cases regimes of spontaneous and driven evolution are investigated. We identify two stages of particle acceleration during flux mergers: (i) fast explosive prompt X-point collapse and (ii) ensuing island merger. The fastest acceleration occurs during the initial catastrophic X-point collapse, with the reconnection electric field of the order of the magnetic field. During the X-point collapse, particles are accelerated by charge-starved electric fields, which can reach (and even exceed) values of the local magnetic field. The explosive stage of reconnection produces non-thermal power-law tails with slopes that depend on the average magnetization . For plasma magnetization 2$ the spectrum power-law index is 2$ ; in this case the maximal energy depends linearly on the size of the reconnecting islands. For higher magnetization, 2$ , the spectra are hard, , yet the maximal energy \\text{max}$ can still exceed the average magnetic energy per particle, , by orders of magnitude (if is not too close to unity). The X-point collapse stage is followed by magnetic island merger that dissipates a large fraction of the initial magnetic energy in a regime of forced magnetic reconnection, further accelerating the particles, but proceeds at a slower reconnection rate.

  13. CAS CERN Accelerator School. Measurement and alignment of accelerator and detector magnets. Proceedings

    International Nuclear Information System (INIS)

    Turner, S.

    1998-01-01

    These proceedings present the lectures given at the eleventh specialised course organised by the CERN Accelerator School (CAS), the topic this time being 'Measurement and Alignment of Accelerator and Detector Magnets'. A similar course was already presented at Montreux, Switzerland in 1992 and its proceedings published as CERN 92-05. However recent progress in the field, especially in the use of superconducting magnets, has been so rapid that a revised course had become imperative. The lectures start with basic magnet theory and the motivation for magnet measurements followed by a review of superconducting magnets and their field dynamics. After a review of measurement methods, the details of search and harmonic coils, magnetic resonance techniques and Hall generators are given followed by methods to minimise errors in mechanical equipment, series production and detector magnet measurements. Turning to magnet metrology and alignment, first data quality control is explained followed by the setting of reference targets, and the alignment methods for accelerators and experiments including alignment by feedback. Finally seminars are presented on the biological effects of magnetic fields and on superconducting magnet fabrication and quality control. (orig.)

  14. Nb-TiO{sub 2}/polymer hybrid solar cells with photovoltaic response under inert atmosphere conditions

    Energy Technology Data Exchange (ETDEWEB)

    Lira-Cantu, Monica; Khoda Siddiki, Mahbube; Munoz-Rojas, David; Amade, Roger [Centre d' Investigacio en Nanociencia i Nanotecnologia (CIN2, CSIC), Laboratory of Nanostructured Materials for Photovoltaic Energy, Campus UAB, Barcelona (Spain); Gonzalez-Pech, Natalia I. [Centre d' Investigacio en Nanociencia i Nanotecnologia (CIN2, CSIC), Laboratory of Nanostructured Materials for Photovoltaic Energy, Campus UAB, Barcelona (Spain); Instituto Tecnologico y de Estudios Superiores de Monterrey (ITESM), Ave. Eugenio Garza Sada, 64640 Monterrey, N.L. (Mexico)

    2010-07-15

    Hybrid Solar Cells (HSC) applying Nb-TiO{sub 2} in direct contact with a conducting organic polymer, MEH-PPV, show higher stability than the bare TiO{sub 2}-based HSC when analyzed under inert atmosphere conditions. IPCE analyses revealed that inert atmospheres affect directly the semiconductor oxide in the first stages of the analyses but photovoltaic performance stabilizes after several hours. A 20 wt% Nb-doped TiO{sub 2} presented the highest stability and photovoltaic properties. The behavior has been attributed to the solubility limit of Nb within the TiO{sub 2} beyond 20 wt% doping level where the co-existence of NbO{sub 2} is observed. The HSCs were analyzed under controlled N{sub 2} atmosphere and 1000 W/m{sup 2} (AM 1.5) irradiation. (author)

  15. Production of superconducting Nb3Sn wire using Nb or Nb(Ti) and Sn(Ga) solid solution powders

    International Nuclear Information System (INIS)

    Thieme, C.L.H.; Foner, S.

    1991-01-01

    This paper reports on superconducting Nb 3 Sn wire produced by the powder metallurgy method using Nb or Nb-2.9 at% Ti powder in combination with Sn-x at% Ga powders (x = 3, 4.2, 6.2 and 9.0). Ga additions to the Sn caused considerable solid solution hardening which improved its workability. It made the Nb-Sn(Ga) powder combinations convenient for swaging and extensive wire drawing. Anneals at 950 degrees C produced wires with an overall J c of 10 4 A/cm 2 at 21.9 T for wires with both Ti in the Nb and 6.2 at% Ga in the Sn. Comparison of this wire with the best Nb(Ti)-Cu-internal Sn(Ti) shows a higher J c per A15 areas, especially in fields of 22T and above

  16. Numerical simulation of superconducting accelerator magnets

    CERN Document Server

    Kurz, Stefan

    2002-01-01

    Modeling and simulation are key elements in assuring the fast and successful design of superconducting magnets. After a general introduction the paper focuses on electromagnetic field computations, which are an indipensable tool in the design process. A technique which is especially well suited for the accurate computation of magnetic fields in superconducting magnets is presented. This method couples Boundary Elements (BEM) which discretize the surface of the iron yoke and Finite Elements (FEM) for the modeling of the non linear interior of the yoke. The formulation is based on a total magnetic scalar potential throughout the whole problem domain. The results for a short dipole model are presented and compared to previous results, which have been obtained from a similar BEM-FEM coupled vector potential formulation. 10 Refs. --- 25 --- AN

  17. Quench antenna for superconducting particle accelerator magnets

    International Nuclear Information System (INIS)

    Ogitsu, T.; Devred, A.; Kim, K.

    1993-10-01

    We report on the design, fabrication, and test of an assembly of stationary pickup coils which can be used to localize quench origins. After describing the pickup coils configuration, we develop a simple model of current redistribution which allows interpretation of the measured voltages and determination of the turn of the magnet coil in which the quench started. The technique is illustrated by analyzing the data from a quench of a 5-cm-aperture, 15-m-long SSC dipole magnet prototype

  18. Turbulence, Magnetic Reconnection in Turbulent Fluids and Energetic Particle Acceleration

    Science.gov (United States)

    Lazarian, A.; Vlahos, L.; Kowal, G.; Yan, H.; Beresnyak, A.; de Gouveia Dal Pino, E. M.

    2012-11-01

    Turbulence is ubiquitous in astrophysics. It radically changes many astrophysical phenomena, in particular, the propagation and acceleration of cosmic rays. We present the modern understanding of compressible magnetohydrodynamic (MHD) turbulence, in particular its decomposition into Alfvén, slow and fast modes, discuss the density structure of turbulent subsonic and supersonic media, as well as other relevant regimes of astrophysical turbulence. All this information is essential for understanding the energetic particle acceleration that we discuss further in the review. For instance, we show how fast and slow modes accelerate energetic particles through the second order Fermi acceleration, while density fluctuations generate magnetic fields in pre-shock regions enabling the first order Fermi acceleration of high energy cosmic rays. Very importantly, however, the first order Fermi cosmic ray acceleration is also possible in sites of magnetic reconnection. In the presence of turbulence this reconnection gets fast and we present numerical evidence supporting the predictions of the Lazarian and Vishniac (Astrophys. J. 517:700-718, 1999) model of fast reconnection. The efficiency of this process suggests that magnetic reconnection can release substantial amounts of energy in short periods of time. As the particle tracing numerical simulations show that the particles can be efficiently accelerated during the reconnection, we argue that the process of magnetic reconnection may be much more important for particle acceleration than it is currently accepted. In particular, we discuss the acceleration arising from reconnection as a possible origin of the anomalous cosmic rays measured by Voyagers as well as the origin cosmic ray excess in the direction of Heliotail.

  19. CAS - CERN Accelerator School: Specialised course on Magnets

    CERN Document Server

    CAS 2009

    2010-01-01

    These proceedings present the lectures given at the twenty-third specialized course organized by the CERN Accelerator School (CAS), the topic being 'Magnets'. The course was held in Bruges, Belgium, from 16 to 25 June 2009. This is the first time this topic has been selected for a specialized course. Taking into account the number of related applications currently in use in accelerators around the world, but, even more important, the worrying decrease in the corresponding expertise in the different laboratories, it was recognized that such a topic should definitively be incorporated into the CAS series of specialized courses. The specific aim of the course was to introduce the participants to the basics of resistive magnet design and its underlying theoretical concepts. The first part of the school dealt with basic introductory courses such as Maxwell's equations for magnets, beam optics, physics and measurement of magnetic materials, the different types of resistive magnets and their respective performance, ...

  20. An example of utilization of the superconductivity for the generation of high magnetic fields: the LHC at CERN

    International Nuclear Information System (INIS)

    Savary, F.; Vlogaert, J.

    2006-01-01

    The Large Hadron Collider, LHC, under construction at CERN (European Organization for Nuclear Research) in Geneva makes use of the low temperature superconductivity of the Nb-Ti alloy to generate high magnetic fields in order to guide and to focus high energy proton beams in a double ring of 27-km circumference; aiming at studying the matter in the sub-nuclear field. In this paper, we will present the main parameters of the collider and the constraints which led to the choice of the low temperature superconductor technology for two of the main components of the LHC: the bending magnet and the focussing quadrupole. Then, the conceptual principles and the main parameters of the bending magnets will be described. To conclude, the results obtained at half of the fabrication of the 1232 superconducting magnets necessary to guide the protons in the accelerator ring will be shown. (authors)

  1. Particle Acceleration, Magnetic Field Generation and Emission from Relativistic Jets

    Science.gov (United States)

    Nishikawa, K.-I.; Hardee, P.; Hededal, C.; Mizuno, Yosuke; Fishman, G. Jerry; Hartmann, D. H.

    2006-01-01

    Nonthermal radiation observed from astrophysical systems containing relativistic jets and shocks, e.g., active galactic nuclei (AGNs), gamma-ray bursts (GRBs), supernova remnants, and Galactic microquasar systems usually have power-law emission spectra. Fermi acceleration is the mechanism usually assumed for the acceleration of particles in astrophysical environments. Recent PIC simulations using injected relativistic electron-ion (electro-positron) jets show that particle acceleration occurs within the downstream jet, rather than by the scattering of particles back and forth across the shock as in Fermi acceleration. Shock acceleration' is a ubiquitous phenomenon in astrophysical plasmas. Plasma waves and their associated instabilities (e.g., the Buneman instability, other two-streaming instability, and the Weibel instability) created in the shocks are responsible for particle (electron, positron, and ion) acceleration. The simulation results show that the Weibel instability is responsible for generating and amplifying highly nonuniform, small-scale magnetic fields. These magnetic fields contribute to the electron's transverse deflection behind the jet head. The "jitter" radiation from deflected electrons has different spectral properties than synchrotron radiation which is calculated in a uniform magnetic field. This jitter radiation may be important to understanding the complex time evolution and/or spectral structure in gamma-ray bursts, relativistic jets, and supernova remnants. We will review recent PIC simulations of relativistic jets and try to make a connection with observations.

  2. Advanced multipoles for accelerator magnets theoretical analysis and their measurement

    CERN Document Server

    Schnizer, Pierre

    2017-01-01

    This monograph presents research on the transversal beam dynamics of accelerators and evaluates and describes the respective magnetic field homogeneity.  The widely used cylindrical circular multipoles have disadvantages for elliptical apertures or curved trajectories, and the book also introduces new types of advanced multipole magnets, detailing their application, as well as the numerical data and measurements obtained. The research presented here provides more precise descriptions of the field and better estimates of the beam dynamics. Moreover, the effects of field inhomogeneity can be estimated with higher precision than before. These findings are further elaborated to demonstrate their usefulness for real magnets and accelerator set ups, showing their advantages over cylindrical circular multipoles. The research findings are complemented with data obtained from the new superconducting beam guiding magnet models (SIS100) for the FAIR (Facility for Antiproton and Ion Research) project.  Lastly, the book...

  3. Superconductor Requirements and Characterization for High Field Accelerator Magnets

    Energy Technology Data Exchange (ETDEWEB)

    Barzi, E.; Zlobin, A. V.

    2015-05-01

    The 2014 Particle Physics Project Prioritization Panel (P5) strategic plan for U.S. High Energy Physics (HEP) endorses a continued world leadership role in superconducting magnet technology for future Energy Frontier Programs. This includes 10 to 15 T Nb3Sn accelerator magnets for LHC upgrades and a future 100 TeV scale pp collider, and as ultimate goal that of developing magnet technologies above 20 T based on both High Temperature Superconductors (HTS) and Low Temperature Superconductors (LTS) for accelerator magnets. To achieve these objectives, a sound conductor development and characterization program is needed and is herein described. This program is intended to be conducted in close collaboration with U.S. and International labs, Universities and Industry.

  4. Magnetic linear accelerator (MAGLAC) for hypervelocity acceleration in impact fusion (IF)

    International Nuclear Information System (INIS)

    Chen, K.W.

    1980-01-01

    This paper presents considerations on the design of a magnetic linear accelerator suitable as driver for impact fusion. We argue that the proposed approach offers an attractive option to accelerate macroscopic matter to centiluminal velocity suitable for fusion applications. The design goal is to attain a velocity approaching 200 km/sec. Recent results in suitable target design suggest that a velocity in the range of 40-100 km/sec might be sufficient to include fusion. An accelerator in this velocity range can be constructed with current-day technology. We present both design and practical engineering considerations. Future work are outlined and recommended. (orig.)

  5. Properties of the superconductor in accelerator dipole magnets

    Science.gov (United States)

    Teravest, Derk

    Several aspects of the application of superconductors to high field dipole magnets for particle accelerators are discussed. The attention is focused on the 10 tesla (1 m model) magnet that is envisaged for the future Large Hadron Collider (LHC) accelerator. The basic motivation behind the study is the intention of employing superconductors to their utmost performance. An overview of practical supercomputers, their applications and their impact on high field dipole magnets used for particle accelerators, is presented. The LHC reference design for the dipole magnets is outlined. Several models were used to study the influence of a number of factors in the shape and in particular, the deviation from the shape that is due to the flux flow state. For the investigated extrinsic and intrinsic factors, a classification can be made with respect to the effect on the shape of the characteristic of a multifilamentary wire. The optimization of the coil structure for high field dipole magnets, with respect to the field quality is described. An analytical model for solid and hollow filaments, to calculate the effect of filament magnetization in the quality of the dipole field, is presented.

  6. 3D accelerator magnet calculations using MAGNUS-3D

    International Nuclear Information System (INIS)

    Pissanetzky, S.; Miao, Y.

    1989-01-01

    The steady trend towards increased magnetic and geometric complexity in the design of accelerator magnets has caused a need for reliable 3D computer models and a better understanding of the behavior of magnetic system in three dimensions. The capabilities of the MAGNUS-3D family of programs are ideally suited to solve this class of problems and provide insight into 3D effects. MAGNUS-3D can solve any problem of magnetostatics involving permanent magnets, nonlinear ferromagnetic materials and electric conductors. MAGNUS-3D uses the finite element method and the two-scalar-potentials formulation of Maxwell's equations to obtain the solution, which can then be used interactively to obtain tables of field components at specific points or lines, plots of field lines, function graphs representing a field component plotted against a coordinate along any line in space (such as the beam line), and views of the conductors, the mesh and the magnetic bodies. The magnetic quantities that can be calculated include the force or torque on conductors or magnetic parts, the energy, the flux through a specified surface, line integrals of any field component along any line in space, and the average field or potential harmonic coefficients. We describe the programs with emphasis placed on their use for accelerator magnet design, and present an advanced example of actual calculations. (orig.)

  7. Magnetic field, reconnection, and particle acceleration in extragalactic jets

    Science.gov (United States)

    Romanova, M. M.; Lovelace, R. V. E.

    1992-01-01

    Extra-galactic radio jets are investigated theoretically taking into account that the jet magnetic field is dragged out from the central rotating source by the jet flow. Thus, magnetohydrodynamic models of jets are considered with zero net poloidal current and flux, and consequently a predominantly toroidal magnetic field. The magnetic field naturally has a cylindrical neutral layer. Collisionless reconnection of the magnetic field in the vicinity of the neutral layer acts to generate a non-axisymmetric radial magnetic field. In turn, axial shear-stretching of reconnected toroidal field gives rise to a significant axial magnetic field if the flow energy-density is larger than the energy-density of the magnetic field. This can lead to jets with an apparent longitudinal magnetic field as observed in the Fanaroff-Riley class II jets. In the opposite limit, where the field energy-density is large, the field remains mainly toroidal as observed in Fanaroff-Riley class I jets. Driven collisionless reconnection at neutral layers may lead to acceleration of electrons to relativistic energies in the weak electrostatic field of the neutral layer. A simple model is discussed for particle acceleration at neutral layers in electron/positron and electron/proton plasmas.

  8. The Superconductors that Magnets Really Want: What Stands in the Way? (Superconductors for Accelerator Use: What Next and How Close is the Ideal Conductor?)

    International Nuclear Information System (INIS)

    Larbalestier, David

    2009-01-01

    There are over 5000 superconducting materials but only about 5 have ever been useful for applications in magnets, while HEP, which has been so vital for the development of superconducting magnet technology has made virtually every magnet out of just one, the simple bcc alloy Nb-Ti with Tc of 9 K and upper critical field ∼ 14T (at 2K). Significant demonstrations of the capability of the brittle intermetallic Nb3Sn have shown that fields of more than 15 T can be generated in dipole form. But Nb-Ti and Nb3Sn are staid, conventional superconductors, far from the cutting edge of superconducting science research where cuprates like YBa2Cu3O7-x and Bi2Sr2CaCu2Ox remain at the scientific forefront and in 2008 were joined by the recently discovered Fe-As pnictide superconductors. What could it mean to have materials for magnets with 10 times the Tc of Nb-Ti (90-120 K) and 3 or more times the critical field (100-240 T)? One enormous barrier is that higher Tc so far always means more complexity and a more localized superconducting interaction which is sensitive to local loss of superconductivity. The issue that has made the cuprate high temperature superconductors so hard to apply is that grain boundaries which form a 3D network in any practical wire form, easily acquire degraded superconducting properties. But conductors can now be made with extreme texture so that grain boundaries are minimized. Moreover almost practical conductors of Bi2Sr2CaCu2Ox and YBa2Cu3O7-x are now are in production and in late 2008 we were, at the Magnet Lab, able to make small solenoids operating at high current density in fields of 32 and almost 34 T respectively. Within the HEP community, there is enthusiasm to embrace HTS conductors for new very high field machines that could, like the Muon Collider, use fields of 30-50 T. In my talk I would like to explore the underlying science controlling such potential applications.

  9. Superconductors with low critical temperature for electro-magnets

    International Nuclear Information System (INIS)

    Devred, A.

    2002-07-01

    Among the superconductors with low critical temperature that are used to build magnets, NbTi has reached a development state that allows a massive production for big equipment of physics and an industrial production in the domain of medicine imaging. The material that might challenge the supremacy of NbTi is Nb 3 Sn but some technical difficulties have yet to be overcome. This report begins with a review of the different industrial processes used to produce superconducting wires based on the NbTi and Nb 3 Sn materials. The transition from the superconducting state to the resistive normal state is described for both materials, the magnetizing of multi-wire superconducting cables is also presented. The author details the different patterns of wires in cables and proposes a formulary that allows the determination, in some simple cases,of energy losses that are generated in a superconducting cable by a variable magnetic field. (A.C.)

  10. ELECTRON ACCELERATION IN CONTRACTING MAGNETIC ISLANDS DURING SOLAR FLARES

    Energy Technology Data Exchange (ETDEWEB)

    Borovikov, D.; Tenishev, V.; Gombosi, T. I. [University of Michigan, Department of Climate and Space Sciences and Engineering, 2455 Hayward Street, Ann Arbor, MI 48104-2143 (United States); Guidoni, S. E. [The Catholic University of America, 620 Michigan Avenue Northeast, Washington, DC 20064 (United States); DeVore, C. R.; Karpen, J. T.; Antiochos, S. K. [Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2017-01-20

    Electron acceleration in solar flares is well known to be efficient at generating energetic particles that produce the observed bremsstrahlung X-ray spectra. One mechanism proposed to explain the observations is electron acceleration within contracting magnetic islands formed by magnetic reconnection in the flare current sheet. In a previous study, a numerical magnetohydrodynamic simulation of an eruptive solar flare was analyzed to estimate the associated electron acceleration due to island contraction. That analysis used a simple analytical model for the island structure and assumed conservation of the adiabatic invariants of particle motion. In this paper, we perform the first-ever rigorous integration of the guiding-center orbits of electrons in a modeled flare. An initially isotropic distribution of particles is seeded in a contracting island from the simulated eruption, and the subsequent evolution of these particles is followed using guiding-center theory. We find that the distribution function becomes increasingly anisotropic over time as the electrons’ energy increases by up to a factor of five, in general agreement with the previous study. In addition, we show that the energized particles are concentrated on the Sunward side of the island, adjacent to the reconnection X-point in the flare current sheet. Furthermore, our analysis demonstrates that the electron energy gain is dominated by betatron acceleration in the compressed, strengthened magnetic field of the contracting island. Fermi acceleration by the shortened field lines of the island also contributes to the energy gain, but it is less effective than the betatron process.

  11. Recent development of the superconducting magnet in Japan

    International Nuclear Information System (INIS)

    Umeda, M.; Aiyama, Y.

    1980-01-01

    The current R and D works on large-scale superconducting magnets in Japan are reviewed with special emphasis on those for fusion power and electric power storage. The contents include Nb-Ti and Nb 3 Sn magnets and pulsed magnets. (E.G.) [pt

  12. Stability of superconducting Rutherford cables for accelerator magnets

    NARCIS (Netherlands)

    Willering, G.P.

    2009-01-01

    The stability of superconducting magnets has a high priority for particle accelerators, since the operational time and operational collision energy depend strongly on it. Local heat dissipation due to beam loss and conductor movement is inevitable, causing local hot spots in the conductor, possibly

  13. Use of permanent magnets in accelerator technology: Present and future

    International Nuclear Information System (INIS)

    Halbach, K.

    1987-05-01

    This report is a collection of viewgraphs discussing accelerator magnets. Permanent magnet systems have some generic properties that, under some circumstances, make them not only mildly preferable over electromagnets, but make it possible to do things that can not be done with any other technology. After a general discussion of these generic advantages, some specific permanent magnet systems will be described. Special emphasis will be placed on systems that have now, or are likely to have in the future, a significant impact on how some materials research is conducted. 4 refs., 33 figs

  14. AIR-MRF: Accelerated iterative reconstruction for magnetic resonance fingerprinting.

    Science.gov (United States)

    Cline, Christopher C; Chen, Xiao; Mailhe, Boris; Wang, Qiu; Pfeuffer, Josef; Nittka, Mathias; Griswold, Mark A; Speier, Peter; Nadar, Mariappan S

    2017-09-01

    Existing approaches for reconstruction of multiparametric maps with magnetic resonance fingerprinting (MRF) are currently limited by their estimation accuracy and reconstruction time. We aimed to address these issues with a novel combination of iterative reconstruction, fingerprint compression, additional regularization, and accelerated dictionary search methods. The pipeline described here, accelerated iterative reconstruction for magnetic resonance fingerprinting (AIR-MRF), was evaluated with simulations as well as phantom and in vivo scans. We found that the AIR-MRF pipeline provided reduced parameter estimation errors compared to non-iterative and other iterative methods, particularly at shorter sequence lengths. Accelerated dictionary search methods incorporated into the iterative pipeline reduced the reconstruction time at little cost of quality. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. MAGNUS-3D: Accelerator magnet calculations in 3-dimensions

    Science.gov (United States)

    Pissanetzky, S.

    1988-12-01

    MAGNUS-3D is a professional finite element code for nonlinear magnetic engineering. MAGNUS-3D can solve numerically any general problem of linear or nonlinear magnetostatics in three dimensions. The problem is formulated in a domain with Dirichlet, Neumann or periodic boundary conditions, that can contain any combination of conductors of any shape in space, nonlinear magnetic materials with magnetic properties specified by magnetization tables, and nonlinear permanent magnets with any given demagnetization curve. MAGNUS-3D uses the two-scalar-potentials formulation of Magnetostatics and the finite element method, has an automatic 3D mesh generator, and advanced post-processing features that include graphics on a variety of supported devices, tabulation, and calculation of design quantities required in Magnetic Engineering. MAGNUS-3D is a general purpose 3D code, but it has been extensively used for accelerator work and many special features required for accelerator engineering have been incorporated into the code. One of such features is the calculation of field harmonic coefficients averaged in the direction of the beam, so important for the design of magnet ends. Another feature is its ability to calculate line integrals of any field component along the direction of the beam, or plot the field as a function of the z coordinate. MAGNUS-3D has found applications to the design of accelerator magnets and spectrometers, steering magnets, wigglers and undulators for free electron lasers, microtrons and magnets for synchrotron light sources, as well as magnets for NMR and medical applications, recording heads and various magnetic devices. There are three more programs closely associated with MAGNUS-3D. MAGNUS-GKS is the graphical postprocessor for the package; it supports a numer of output devices, including color vector or bit map devices. WIRE is an independent program that can calculate the field produced by any configuration of electric conductors in space, at any

  16. Status of the Next European Dipole (NED) activity of the collaborated accelerator research in Europe

    NARCIS (Netherlands)

    Devred, A.; Baudouy, B.; den Ouden, A.; Baynham, D.E.

    2005-01-01

    Plans for LHC upgrade and for the final focalization of linear colliders call for large aperture and/or high-performance dipole and quadrupole magnets that may be beyond the reach of conventional NbTi magnet technology. The Next European Dipole (NED) activity was launched on January 1st, 2004 to

  17. Plasma acceleration by magnetic nozzles and shock waves

    International Nuclear Information System (INIS)

    Hattori, Kunihiko; Murakami, Fumitake; Miyazaki, Hiroyuki; Imasaki, Atsushi; Yoshinuma, Mikirou; Ando, Akira; Inutake, Masaaki

    2001-01-01

    We have measured axial profiles of ion acoustic Mach number, M i , of a plasma flow blowing off from an MPD (magneto-plasma-dynamic) arc-jet in various magnetic configurations. It is found that the Mach number increases in a divergent nozzle up to 3, while it stays at about unity in a uniform magnetic channel. When a magnetic bump is added in the exit of the divergent magnetic nozzle, the Mach number suddenly decreases below unity, due to an occurrence of shock wave. The subsonic flow after the shock wave is re-accelerated to a supersonic flow through a magnetic Laval nozzle. This behavior is explained well by the one-dimensional isotropic flow model. The shock wave is discussed in relation to the Rankine-Hugoniot relation. (author)

  18. Flux Rope Acceleration and Enhanced Magnetic Reconnection Rate

    International Nuclear Information System (INIS)

    C.Z. Cheng; Y. Ren; G.S. Choe; Y.-J. Moon

    2003-01-01

    A physical mechanism of flares, in particular for the flare rise phase, has emerged from our 2-1/2-dimensional resistive MHD simulations. The dynamical evolution of current-sheet formation and magnetic reconnection and flux-rope acceleration subject to continuous, slow increase of magnetic shear in the arcade are studied by employing a non-uniform anomalous resistivity in the reconnecting current sheet under gravity. The simulation results directly relate the flux rope's accelerated rising motion with an enhanced magnetic reconnection rate and thus an enhanced reconnection electric field in the current sheet during the flare rise phase. The simulation results provide good quantitative agreements with observations of the acceleration of flux rope, which manifests in the form of SXR ejecta or erupting filament or CMEs, in the low corona. Moreover, for the X-class flare events studied in this paper the peak reconnection electric field is about O(10 2 V/m) or larger, enough to accelerate p articles to over 100 keV in a field-aligned distance of 10 km. Nonthermal electrons thus generated can produce hard X-rays, consistent with impulsive HXR emission observed during the flare rise phase

  19. Particle acceleration at the magnetic poles of a neutron star

    International Nuclear Information System (INIS)

    Jones, P.B.

    1977-01-01

    The magnetic conversion of a photon in a neutron star magnetosphere near one of the magnetic poles is followed by acceleration of the electron and positron to ultra-relativistic energies. The positron moves along open magnetic flux lines to the light cylinder. The electron incident on the stellar surface produces an electromagnetic shower. Following a comment by Cheng and Ruderman (Astrophys.J.;214:598 (1977)), an order of magnitude estimate has been made of the spectrum of backward moving photons created in the electron shower. The most important source of photons is shown to be the formation of the giant dipole state in Fe 56 . Under the assumption that the surface magnetic flux density exceeds 10 12 G, the photons have, with high probability, mean free paths for magnetic conversion in the magnetosphere of 1 4 cm. An equation for the maximum acceleratin potential has been obtained in a one-dimensional model of pair creation and electron multiplication based on this photon source. The model has been applied to the phenomenon of subpulse drift in pulsars. The plasma accelerated at the magnetic pole has three components; positrons, protons and light nuclei (Z < approximately 6) formed by spallation, and iron group nuclei. Equations determining their relative fluxes have been found. The light nuclei include those with Z = 3 to 5, usually considered to be present in galactic cosmic rays only as a result of the interaction of heavier nuclei with the interstellar medium. (author)

  20. ''Theta gun,'' a multistage, coaxial, magnetic induction projectile accelerator

    International Nuclear Information System (INIS)

    Burgess, T.J.; Duggin, B.W.; Cowan, M. Jr.

    1985-11-01

    We experimentally and theoretically studied a multistage coaxial magnetic induction projectile accelerator. We call this system a ''theta gun'' to differentiate it from other coaxial accelerator concepts such as the mass driver. We conclude that this system can theoretically attain railgun performance only for large caliber or very high injection velocity and, even then, only for long coil geometry. Our experiments with a three-stage, capactor bank-driven accelerator are described. The experiments are modeled with a 1-1/2 dimensional equivalent circuit-hydrodynamics code which is also described. We derive an expression for the conditions of coaxial accelerator-railgun ''velocity breakeven'' in the absence of ohmic and hydrodynamic effects. This, in conjunction with an expression for the magnetic coupling coefficient, defines a set of geometric relations which the coaxial system must simultaneously satisfy. Conclusions concerning both the existence and configuration of a breakeven coaxial system follow from this requirement. The relative advantages and disadvantages of the coaxial induction projectile accelerator, previously cited in the literature, are critiqued from the viewpoint of our analysis and experimental results. We find that the advantages vis-a-vis the railgun have been overstated. 13 refs., 17 figs

  1. A New Concept of Controller for Accelerators' Magnet Power Supplies

    Science.gov (United States)

    Visintini, Roberto; Cleva, Stefano; Cautero, Marco; Ciesla, Tomasz

    2016-04-01

    The complexity of a particle accelerator implies the remote control of very large numbers of devices, with many different typologies, either distributed along the accelerator or concentrated in locations, often far away from each other. Local and global control systems handle the devices through dedicated communication channels and interfaces. Each controlled device is practically a “smart node” performing a specific task. In addition, very often, those tasks are managed in real-time mode. The performances required to the control interface has an influence on the cost of the distributed nodes as well as on their hardware and software implementation. In large facilities (e.g. CERN) the “smart nodes” derive from specific in-house developments. Alternatively, it is possible to find on the market commercial devices, whose performances (and prices) are spread over a broad range, and spanning from proprietary design (customizable to the user's needs) to open source/design. In this paper, we will describe some applications of smart nodes in the particle accelerators field, with special focus on the power supplies for magnets. In modern accelerators, in fact, magnets and their associated power supplies constitute systems distributed along the accelerator itself, and strongly interfaced with the remote control system as well as with more specific (and often more demanding) orbit/trajectory feedback systems. We will give examples of actual systems, installed and operational on two light sources, Elettra and FERMI, located in the Elettra Research Center in Trieste, Italy.

  2. Generation of high magnetic fields using superconducting magnets

    International Nuclear Information System (INIS)

    Kiyoshi, T.; Otsuka, A.; Kosuge, M.; Yuyama, M.; Nagai, H.; Matsumoto, F.

    2006-01-01

    High-field superconducting magnets have opened new frontiers for several kinds of applications, such as fusion reactors, particle accelerators, and nuclear magnetic resonance (NMR) spectrometers. The present record for the highest field in a fully superconducting state is 23.4 T. It was achieved with a combination of NbTi, Nb 3 Sn, and Bi-2212 conductors in 1999. Since high T c (critical temperature) superconductors (HTS) have sufficiently high critical current density even in excess of 30 T, they are promising for use as high-field superconducting magnets. However, several problems still remain to be resolved for practical applications, and the use of HTS coils will be limited to the inner part of a high-field magnet system in the near future. The required technologies to develop a high-field superconducting magnet with a field of up to 28 T have already been established. Such a magnet is certain to provide information to all leading research areas

  3. The Future of Superconducting Technology for Particle Accelerators

    CERN Document Server

    Yamamoto, Akira

    2015-01-01

    Introduction: - Colliders constructed and operated - Future High Energy Colliders under Study - Superconducting Phases and Applications - Possible Choices among SC Materials Superconducting Magnets and the Future - Advances in SC Magnets for Accelerators - Nb$_{3}$Sn for realizing Higher Field - NbTi to Nb$_{3}$Sn for realizing High Field (> 10 T) - HL-LHC as a critical milestone for the Future of Acc. Magnet Technology - Nb$_{3}$Sn Superconducting Magnets (> 11 T)and MgB2 SC Links for HL-LHC - HL-LHC, 11T Dipole Magnet - Nb$_{3}$Sn Quadrupole (MQXF) at IR - Future Circular Collider Study - Conductor development (1998-2008) - Nb$_{3}$Sn conductor program - 16 T Dipole Options and R&D sharing - Design Study and Develoment for SppC in China - High-Field Superconductor and Magnets - HTS Block Coil R&D for 20 T - Canted Cosine Theta (CCT) Coil suitable with Brittle HTS Conductor - A topic at KEK: S-KEKB IRQs just integrated w/ BELLE-II ! Superconducting RF and the Future - Superconducting Phase...

  4. The Future of Superconducting Technology for Particle Accelerators

    CERN Document Server

    Yamamoto, Akira

    2015-01-01

    Introduction: - Colliders constructed and operated - Future High Energy Colliders under Study - Superconducting Phases and Applications - Possible Choices among SC Materials Superconducting Magnets and the Future - Advances in SC Magnets for Accelerators - Nb3Sn for realizing Higher Field - NbTi to Nb3Sn for realizing High Field (> 10 T) - HL-LHC as a critical milestone for the Future of Acc. Magnet Technology - Nb3Sn Superconducting Magnets (> 11 T)and MgB2 SC Links for HL-LHC - HL-LHC, 11T Dipole Magnet - Nb3Sn Quadrupole (MQXF) at IR - Future Circular Collider Study - Conductor development (1998-2008) - Nb3Sn conductor program - 16 T Dipole Options and R&D sharing - Design Study and Develoment for SppC in China - High-Field Superconductor and Magnets - HTS Block Coil R&D for 20 T - Canted Cosine Theta (CCT) Coil suitable with Brittle HTS Conductor - A topic at KEK: S-KEKB IRQs just integrated w/ BELLE-II ! Superconducting RF and the Future - Superconducting Phases and Applications - Poss...

  5. Effect of temperature on the mechanical properties of the high-field superconductor NbTi 50

    International Nuclear Information System (INIS)

    Albert, H.; Pfeiffer, I.

    1976-01-01

    Below 20 K the plastic deformation of NbTi 50 is exclusively determined by shear processes on [100] slip planes which become evident in stress decrements of the stress-strain curves. Increasing cold work facilitates the initiation of shear processes below 20 K inducing a decrease of the yield stress values. This phenomena is assumed to be due to the strengthening of the deformation texture with increasing cold work. Large α-Ti-precipitates (0.1 - 0.2 μm) produced by a 380 0 C heat treatment may act as notches initiating shear processes. They may also cause portions of brittle fracture in the microstructure of the otherwise ductile fracture at 4.2 K and 28 K. The yield stress is diminished. Finer and more homogeneously distributed precipitates resulting from additional deformation after heat treatment block up slip processes and therefore cause increased values of tensile strength and yield stress. In this case the material is not only electrically but also mechanically optimized. (orig.) [de

  6. Investigation of microstructure and irradiation behavior of W–Nb/Ti composites prepared by spark plasma sintering

    International Nuclear Information System (INIS)

    Chen, Jing-Bo; Luo, Lai-Ma; Zhao, Mei-Ling; Xu, Qiu; Zan, Xiang; Wu, Yu-Cheng

    2016-01-01

    W–Nb/Ti composites were prepared by machine milling and spark plasma sintering. Field–emission scanning electron microscopy, high–resolution transmission electron microscopy, and X-ray diffraction analyses were used to characterize the samples. Thermal desorption spectroscopy (TDS) was used to measure the deuterium retention after only deuterium irradiation. The deuterium retention in W–4wt%Ti–wt1%Nb was lower than that in pure W (D_2"+ flux ∼10"2"2 ions/(m"2 s), ion energy ∼5 keV), Nb and Ti will improve the deuterium irradiation resistance of tungsten composite. In addition, transgranular and intergranular fractures were observed on the surface of the W–4 wt% Ti–1 wt% Nb composite. A Ti_(_X_)W_(_1_−_X_) solid solution was formed during sintering. The maximum tensile strength (410.53 MPa) was detected in the W–4wt%Ti–1wt%Nb composite at 600 °C.

  7. Production and qualification of 40 km of Al-stabilized NbTi cable for the ATLAS experiment at CERN

    CERN Document Server

    Baccaglioni, G; Cartegni, G C; Horváth, I L; Neuenschwander, J; Pedrini, D; Rossi, L; Volpini, G

    2002-01-01

    The production of the conductor for the superconducting toroids of the ATLAS experiment at LHC (CERN) is now in progress. The toroid system, composed of one barrel toroid (BT) and two end cap toroids (ECTs), exploits aluminum-clad Rutherford-type NbTi conductors of large size (57 * 12 mm for BT, 42 * 12 mm for ECTs) and high critical current (Ic) (58 kA for BT and 60 kA for ECTs @ 4.2 K, 5 T). Some 55 km of conductor are required for the BT and 26 km for the ECTs, respectively. An Italian-Swiss (ETH Zurich and INFN) consortium is in charge of the delivery of half of the whole amount. This paper describes the results of this production with particular emphasis to the quality control system developed to monitor the production with both on-line controls and the post-production quality assessment protocols. The main result is the confirmation that the technologies selected and the whole process are reliable and reproducible over large production quantities. The overall degradation due to the cabling and the co-ex...

  8. Effect of non-uniform current distribution on the stability in Nb-Ti cable-in-conduit superconducting conductor

    International Nuclear Information System (INIS)

    Wadayama, Y.; Koizumi, N.; Takahashi, Y.; Matsui, K.; Tsuji, H.; Shimamoto, S.

    1996-01-01

    30kA-NbTi Demo Poloidal Coil (DPC-U) exhibited instability such as the conductor quenches at 40% of the rated current which is still much smaller than the expected conductor critical current. It was found that this instability was caused by the non-uniform current distribution in the DPC-U conductor whose strands were insulated from each other. To investigate the instability of the DPC-U conductor, a stability experiment of a subsize conductor consisting of 27 strands was performed and the effect of the current imbalance on the stability was investigated. The current imbalance was forcibly established in the conductor using two current sources in this experiment. The experimental results indicate that the stability margin decreases as the current imbalance becomes larger and that the stability margin of the conductor is governed by the stability of the strand with the highest current in the conductor. Also, it is confirmed from the experimental results that the instability of DPC-U has to be attributed to the current imbalance in the conductor

  9. Thermo-mechanical treatment of the Cr-Mo constructional steel plates with Nb, Ti and B additions

    International Nuclear Information System (INIS)

    Adamczyk, J.; Opiela, M.

    2002-01-01

    Results of investigations of the influence of parameters of thermomechanical treatment, carried out by rolling with controlled recrystallization, on the microstructure and mechanical properties of Cr-Mo constructional steel with Nb, Ti and B microadditions, destined for the manufacturing of weldable heavy plates, are presented. These plates show a yield point of over 960 MPa after heat treatment. Two variants of thermomechanical treatment were worked out, based on the obtained results of investigations, when rolling a plate 40 mm thick in several passes to a plate 15 mm thick in a temperature range from 1100 to 900 o C. It was found that the lack of complete recrystallization of the austenite in the first rolling variant, leads to localization of plastic deformation in form of shear bands. There exists a segregation of MC-type carbides and alloying elements in these bands, causing a distinctive reduction of the crack resistance of the steel, as also a disadvantageous anisotropy of plastic properties of plate after tempering. For plates rolled under the same conditions, using a retention shield, a nearly three times higher impact energy in - 40 o C was obtained, as also only a slight anisotropy of plastic properties, saving the required mechanical properties. (author)

  10. A 40 kA NbTi cable in conduit conductor for the large poloidal field coils of net

    International Nuclear Information System (INIS)

    Torossian, A.; Bessette, D.; Turck, B.; Kazimierzak, B.

    1990-01-01

    The main feature of this cable in conduit design is to separate the manufacture of the full length of the steel conduit (400 m) and of the cable in order to minimize the industrial risk and consequently the cost. A circular cross section for that cable seems to be the most suitable for that purpose: - axisymmetric cabling with full transposition of strands, - cable behaviour independent of the field orientation, - less deformation of subcables, - cross section remains circular when the cable is under tension and makes the slippage of the cable in the conduit easier, - butt welding of 8 m long tubes forming the conduit becomes simpler. The square external shape allows to minimize the amount of insulating material and consequently improves the overall current density of the coil. This conductor is aimed to large poloidal field coils for NET which do not require high field and in that case NbTi seems to be the best choice with regard to reliability and cost but Nb 3 Sn could be used as well. Stainless steel ribbons are inserted between subcables in order to reduce losses induced by the rapid field changes and also to improve the mechanical behaviour of the cable

  11. Magic-Angle-Spinning NMR Magnet Development: Field Analysis and Prototypes

    Science.gov (United States)

    Voccio, John; Hahn, Seungyong; Park, Dong Keun; Ling, Jiayin; Kim, Youngjae; Bascuñán, Juan; Iwasa, Yukikazu

    2013-01-01

    We are currently working on a program to complete a 1.5 T/75 mm RT bore magic-angle-spinning nuclear magnetic resonance magnet. The magic-angle-spinning magnet comprises a z-axis 0.866-T solenoid and an x-axis 1.225-T dipole, each to be wound with NbTi wire and operated at 4.2 K in persistent mode. A combination of the fields creates a 1.5-T field pointed at 54.74 degrees (magic angle) from the rotation (z) axis. In the first year of this 3-year program, we have completed magnetic analysis and design of both coils. Also, using a winding machine of our own design and fabrication, we have wound several prototype dipole coils with NbTi wire. As part of this development, we have repeatedly made successful persistent NbTi-NbTi joints with this multifilamentary NbTi wire. PMID:24058275

  12. Precision Magnet Measurements for X-Band Accelerator Quadrupole Triplets

    Energy Technology Data Exchange (ETDEWEB)

    Marsh, R A; Anderson, S G; Armstrong, J P

    2012-05-16

    An X-band test station is being developed at LLNL to investigate accelerator optimization for future upgrades to mono-energetic gamma-ray (MEGa-Ray) technology at LLNL. Beamline magnets will include an emittance compensation solenoid, windowpane steering dipoles, and quadrupole magnets. Demanding tolerances have been placed on the alignment of these magnets, which directly affects the electron bunch beam quality. A magnet mapping system has been established at LLNL in order to ensure the delivered magnets match their field specification, and the mountings are aligned and capable of reaching the specified alignment tolerances. The magnet measurement system will be described which uses a 3-axis Lakeshore gauss probe mounted on a 3-axis translation stage. Alignment accuracy and precision will be discussed, as well as centering measurements and analysis. The dependence on data analysis over direct multi-pole measurement allows a significant improvement in useful alignment information. Detailed analysis of measurements on the beamline quadrupoles will be discussed, including multi-pole content both from alignment of the magnets, and the intrinsic level of multi-pole magnetic field.

  13. Injection septum magnets for the Loma Linda medical accelerator

    International Nuclear Information System (INIS)

    Satti, J.A.

    1987-01-01

    The injection beamline runs over the last magnet before a long straight section and is then displaced downward 55.88 cm to the accelerator beamline. The displacement is magnetic and the final deflection onto the synchrotron orbit is by an electric kicker. The first component, the reverse septum magnet, bends the injection beam 25/degree/ downward. This is followed by the injection septum (20/degree/ bend upward) and the final injection kicker (5/degree/ bend upward). The septum magnets produce a peak field of 3.4 K gauss at a current of 28,000 amperes within a 0.1 msec long pulse. The electric kicker produces a field of 7.3 KV/cm with a pulse length of 0.0011 msec. The septum magnets are similar to each other in construction with a bending radium of 72.7 cm. The curvature is required to increase the effective aperture. Each magnet has a single-turn copper coil bonded to a stainless steel plate for reinforcement. This eliminates insulating material, which could be subject to radiation damage, at the septum. The stainless steel plate is welded to the magnet laminations. The current is confined to the septum by the insulation between the laminations, which are a standard core material. The total septum thickness with shield is 1.227 cm. Pulsing the magnet eliminates the need for water cooling. 2 refs., 4 figs

  14. Progress with High-Field Superconducting Magnets for High-Energy Colliders

    Science.gov (United States)

    Apollinari, Giorgio; Prestemon, Soren; Zlobin, Alexander V.

    2015-10-01

    One of the possible next steps for high-energy physics research relies on a high-energy hadron or muon collider. The energy of a circular collider is limited by the strength of bending dipoles, and its maximum luminosity is determined by the strength of final focus quadrupoles. For this reason, the high-energy physics and accelerator communities have shown much interest in higher-field and higher-gradient superconducting accelerator magnets. The maximum field of NbTi magnets used in all present high-energy machines, including the LHC, is limited to ˜10 T at 1.9 K. Fields above 10 T became possible with the use of Nb3Sn superconductors. Nb3Sn accelerator magnets can provide operating fields up to ˜15 T and can significantly increase the coil temperature margin. Accelerator magnets with operating fields above 15 T require high-temperature superconductors. This review discusses the status and main results of Nb3Sn accelerator magnet research and development and work toward 20-T magnets.

  15. Magnetized particle motion and acceleration around a Schwarzschild black hole in a magnetic field

    International Nuclear Information System (INIS)

    Abdujabbarov, Ahmadjon; Bobomurat Ahmedov; Rahimov, Ozodbek; Salikhbaev, Umar

    2014-01-01

    The capture cross section of magnetized particles with nonvanishing magnetic moment by a Schwarzschild black hole immersed in an asymptotically uniform magnetic field has been studied as an extension of the approach developed in Zakharov (1994 Class. Quantum Grav. 11 1027) for neutral unmagnetized particles in the Reissner–Nordström spacetime. The magnetic moment of the particle is chosen as in de Felice and Sorge (2003 Class. Quantum Grav. 20 469). It is shown that the spin of the particle sustains the stability of particles circularly orbiting around the black hole immersed in a magnetic field, i.e., a spinning particle's motion near the Schwarzschild black hole horizon is more stable than that of a particle with zero spin. It is shown that the magnetic parameter essentially changes the value of the critical angular momentum and affects the process of capture of the particles by the central black hole. Furthermore, the interaction between the magnetic moment of the particle and the magnetic field forces stable circular orbits to shift to the central object, and this effect should be taken into account in astrophysical scenarios related to the accretion discs and in measuring the spin of the black holes. The magnetized particle's acceleration mechanism near the black hole in an external magnetic field is studied. It is shown that due to the presence of a magnetic field, magnetized particles can accelerate to unlimited high energies. (paper)

  16. Ambipolar ion acceleration in an expanding magnetic nozzle

    Energy Technology Data Exchange (ETDEWEB)

    Longmier, Benjamin W; Carter, Mark D; Cassady, Leonard D; Chancery, William J; Diaz, Franklin R Chang; Glover, Tim W; Ilin, Andrew V; McCaskill, Greg E; Olsen, Chris S; Squire, Jared P [Ad Astra Rocket Company, 141 W. Bay Area Blvd, Webster, TX (United States); Bering, Edgar A III [Department of Physics and Department of Electrical and Computer Engineering, University of Houston, 617 Science and Research Building 1, Houston, TX (United States); Hershkowitz, Noah [Department of Engineering Physics, University of Wisconsin, 1500 Engineering Dr., Madison, WI (United States)

    2011-02-15

    The helicon plasma stage in the Variable Specific Impulse Magnetoplasma Rocket (VASIMR (registered)) VX-200i device was used to characterize an axial plasma potential profile within an expanding magnetic nozzle region of the laboratory based device. The ion acceleration mechanism is identified as an ambipolar electric field produced by an electron pressure gradient, resulting in a local axial ion speed of Mach 4 downstream of the magnetic nozzle. A 20 eV argon ion kinetic energy was measured in the helicon source, which had a peak magnetic field strength of 0.17 T. The helicon plasma source was operated with 25 mg s{sup -1} argon propellant and 30 kW of RF power. The maximum measured values of plasma density and electron temperature within the exhaust plume were 1 x 10{sup 20} m{sup -3} and 9 eV, respectively. The measured plasma density is nearly an order of magnitude larger than previously reported steady-state helicon plasma sources. The exhaust plume also exhibits a 95% to 100% ionization fraction. The size scale and spatial location of the plasma potential structure in the expanding magnetic nozzle region appear to follow the size scale and spatial location of the expanding magnetic field. The thickness of the potential structure was found to be 10{sup 4} to 10{sup 5} {lambda}{sub De} depending on the local electron temperature in the magnetic nozzle, many orders of magnitude larger than typical laboratory double layer structures. The background plasma density and neutral argon pressure were 10{sup 15} m{sup -3} and 2 x 10{sup -5} Torr, respectively, in a 150 m{sup 3} vacuum chamber during operation of the helicon plasma source. The agreement between the measured plasma potential and plasma potential that was calculated from an ambipolar ion acceleration analysis over the bulk of the axial distance where the potential drop was located is a strong confirmation of the ambipolar acceleration process.

  17. Case Studies on Superconducting Magnets for Particle Accelerators

    International Nuclear Information System (INIS)

    Ferracin, P

    2014-01-01

    During the CERN Accelerator School 'Superconductivity for accelerators', the students were divided into 18 groups, and 6 different exercises (case studies), involving the design and analysis of superconducting magnets and RF cavities, were assigned. The problems covered a broad spectrum of topics, from properties of superconducting materials to operation conditions and general dimensions of components. The work carried out by the students turned out to be an extremely useful opportunity to review the material explained during the lectures, to become familiar with the orders of magnitude of the key parameters, and to understand and compare different design options. We provide in this paper a summary of the activities related to the case studies on superconducting magnets and present the main outcomes

  18. Case Studies on Superconducting Magnets for Particle Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Ferracin, P [European Organization for Nuclear Research, Geneva (Switzerland)

    2014-07-01

    During the CERN Accelerator School 'Superconductivity for accelerators', the students were divided into 18 groups, and 6 different exercises (case studies), involving the design and analysis of superconducting magnets and RF cavities, were assigned. The problems covered a broad spectrum of topics, from properties of superconducting materials to operation conditions and general dimensions of components. The work carried out by the students turned out to be an extremely useful opportunity to review the material explained during the lectures, to become familiar with the orders of magnitude of the key parameters, and to understand and compare different design options. We provide in this paper a summary of the activities related to the case studies on superconducting magnets and present the main outcomes.

  19. Grid Connected Power Supplies for Particle Accelerator Magnets

    DEFF Research Database (Denmark)

    Nielsen, Rasmus Ørndrup

    Power supplies play a large role in particle accelerators, for creating, accelerating, steering and shaping the beam. This thesis covers the power supplies for steering and shaping the beam, namely the magnet power supplies. These power supplies have a special set of requirements regarding output...... on this topology is constructed using a single power module on the grid side of the transformer, consisting of a boost rectifier and a dual half-bridge isolated DC/DC converter. It is shown that it is possible to create a power supply using a single module and that this approach can lead to improved layout...... and smaller converter size. A high efficiency converter based on Silicon Carbide switching devices is also presented exhibiting above 96 % efficiency for the entire power range. Finally reliability issues are considered as the reliability of a particle accelerator supply is of utmost importance. Particle...

  20. Electrodeless plasma acceleration system using rotating magnetic field method

    Directory of Open Access Journals (Sweden)

    T. Furukawa

    2017-11-01

    Full Text Available We have proposed Rotating Magnetic Field (RMF acceleration method as one of electrodeless plasma accelerations. In our experimental scheme, plasma generated by an rf (radio frequency antenna, is accelerated by RMF antennas, which consist of two-pair, opposed, facing coils, and these antennas are outside of a discharge tube. Therefore, there is no wear of electrodes, degrading the propulsion performance. Here, we will introduce our RMF acceleration system developed, including the experimental device, e.g., external antennas, a tapered quartz tube, a vacuum chamber, external magnets, and a pumping system. In addition, we can change RMF operation parameters (RMF applied current IRMF and RMF current phase difference ϕ, focusing on RMF current frequency fRMF by adjusting matching conditions of RMF, and investigate the dependencies on plasma parameters (electron density ne and ion velocity vi; e.g., higher increases of ne and vi (∼360 % and 55 %, respectively than previous experimental results were obtained by decreasing fRMF from 5 MHz to 0.7 MHz, whose RMF penetration condition was better according to Milroy’s expression. Moreover, time-varying component of RMF has been measured directly to survey the penetration condition experimentally.

  1. ESCAR, tests of superconducting bending magnets at the accelerator site

    International Nuclear Information System (INIS)

    Gilbert, W.S.; Lambertson, G.R.; Meuser, R.B.; Rechen, J.B.

    1979-03-01

    ESCAR (Experimental Superconducting Accelerator Ring) was conceived as a project in accelerator technology development which would provide data and experience to insure that planning for larger superconducting synchrotrons would proceed in a knowledgeable and responsible manner. It was to consist of the fabrication and operation of a relatively small proton synchrotron and storage ring with superconducting magnet elements for all of the main ring. The project was funded and design work began in July 1974. During the next two years it became increasingly apparent that the funding rate was directly limiting the rate of completion of ESCAR and that an intermediate goal, a test of the unconventional aspects of the project, was desirable. To that end, twelve dipole bending magnets, one-half of those required for the total ring, were installed at the site along with the 1500 watt helium refrigerator, cryogenic distribution system, electrical power supplies, vacuum systems, and necessary instrumentation. This truncated system was put through an extended series of tests which were completed in June 1978 at which time the ESCAR Project was terminated. ESCAR, and the dipole magnets have been described previously. The results of the systems tests have also been reported. The tests involving the dipole magnets are described

  2. Magnetic Reconnection and Particle Acceleration in the Solar Corona

    Science.gov (United States)

    Neukirch, Thomas

    Reconnection plays a major role for the magnetic activity of the solar atmosphere, for example solar flares. An interesting open problem is how magnetic reconnection acts to redistribute the stored magnetic energy released during an eruption into other energy forms, e.g. gener-ating bulk flows, plasma heating and non-thermal energetic particles. In particular, finding a theoretical explanation for the observed acceleration of a large number of charged particles to high energies during solar flares is presently one of the most challenging problems in solar physics. One difficulty is the vast difference between the microscopic (kinetic) and the macro-scopic (MHD) scales involved. Whereas the phenomena observed to occur on large scales are reasonably well explained by the so-called standard model, this does not seem to be the case for the small-scale (kinetic) aspects of flares. Over the past years, observations, in particular by RHESSI, have provided evidence that a naive interpretation of the data in terms of the standard solar flare/thick target model is problematic. As a consequence, the role played by magnetic reconnection in the particle acceleration process during solar flares may have to be reconsidered.

  3. A Scaling Law for the Snapback in Superconducting Accelerator Magnets

    CERN Document Server

    Bottura, L; Bauer, P; Haverkamp, M; Pieloni, T; Sanfilippo, S; Velev, G

    2005-01-01

    The decay of the sextupole component in the bending dipoles during injection and the subsequent snapback at the start of beam acceleration are issues of common concern for all superconducting colliders built or in construction. Recent studies performed on LHC and Tevatron dipole magnets revealed many similarities in the snapback characteristics. Some are expected, e.g. the effect of operational history. One particular similarity, however, is striking and is the subject of this paper. It appears that there is a simple linear relation between the amount of sextupole drift during the decay and the magnet current (or field) change during the ramp required to resolve the snapback. It is surprising that the linear correlation between snapback amplitude and snapback field holds very well for all magnets of the same family (e.g. Tevatron or LHC dipoles). In this paper we present the data collected to date and discuss a simple theory that explains the scaling found.

  4. A flexible and configurable system to test accelerator magnets

    Energy Technology Data Exchange (ETDEWEB)

    Jerzy M. Nogiec et al.

    2001-07-20

    Fermilab's accelerator magnet R and D programs, including production of superconducting high gradient quadrupoles for the LHC insertion regions, require rigorous yet flexible magnetic measurement systems. Measurement systems must be capable of handling various types of hardware and extensible to all measurement technologies and analysis algorithms. A tailorable software system that satisfies these requirements is discussed. This single system, capable of distributed parallel signal processing, is built on top of a flexible component-based framework that allows for easy reconfiguration and run-time modification. Both core and domain-specific components can be assembled into various magnet test or analysis systems. The system configured to comprise a rotating coil harmonics measurement is presented. Technologies as Java, OODB, XML, JavaBeans, software bus and component-based architectures are used.

  5. Effect of Al content on structure and mechanical properties of the Al{sub x}CrNbTiVZr (x = 0; 0.25; 0.5; 1) high-entropy alloys

    Energy Technology Data Exchange (ETDEWEB)

    Yurchenko, N.Yu. [Laboratory of Bulk Nanostructured Materials, Belgorod State University, Belgorod 308015 (Russian Federation); Stepanov, N.D., E-mail: stepanov@bsu.edu.ru [Laboratory of Bulk Nanostructured Materials, Belgorod State University, Belgorod 308015 (Russian Federation); Shaysultanov, D.G. [Laboratory of Bulk Nanostructured Materials, Belgorod State University, Belgorod 308015 (Russian Federation); Tikhonovsky, M.A. [National Science Center “Kharkov Institute of Physics and Technology”, NAS of Ukraine, Kharkov, 61108 (Ukraine); Salishchev, G.A. [Laboratory of Bulk Nanostructured Materials, Belgorod State University, Belgorod 308015 (Russian Federation)

    2016-11-15

    In present study, structure and mechanical properties of the Al{sub x}CrNbTiVZr (x = 0; 0.25; 0.5; 1) high-entropy alloys after arc melting and annealing at 1200 °C for 24 h are investigated. The CrNbTiVZr alloy is composed of body centered cubic (bcc) and C15 (face centered cubic) Laves phases while the Al{sub x}CrNbTiVZr (x = 0.25; 0.5; 1) alloys consist of bcc and two C14 (hexagonal close packed) Laves phases with different chemical compositions. Thermodynamic modeling predicts existence of two phases – bcc and C15 Laves phase and broadening of single bcc phase field due to Al addition. The density of the alloys decreases with the increase of Al content. The alloys are found to be extremely brittle at room temperature and 600 °C. The alloys have high strength at temperatures of 800–1000 °C. For example, yield strength at 800 °C increases from 440 MPa for the CrNbTiVZr alloy to 1250 MPa for the AlCrNbTiVZr alloy. The experimental phase composition of the Al{sub x}CrNbTiVZr alloys is compared with predicted equilibrium phases and the factors governing the transformation of C15 to C14 Laves phases due to Al addition to the CrNbTiVZr alloy analyzed. Specific properties of the alloys are compared with other high-entropy alloys and commercial Ni-based superalloys. - Highlights: •Al{sub x}CrNbTiVZr (x = 0; 0.25; 0.5; 1) alloys are arc melted and annealed at 1200 °C. •The CrNbTiVZr alloy has bcc and C15 Laves phases. •The Al-containing alloys are composed of bcc and two C14 Laves phases. •The alloys demonstrate high specific strength at temperatures of 800 °C and 1000 °C. •The strength of the alloys increases in proportion with increase of Al content.

  6. Fabrication and characterization of fine filaments of NbTi in a copper matrix

    International Nuclear Information System (INIS)

    Hemachalam, K.; King, C.G.; Scanlan, R.M.; Zeitlin, B.A.

    1986-01-01

    Practical multifilamentary Nb-46.5 Wt. % Ti/Cu composites have been made by a double extrusion process. The composites contain up to 6000 filaments with a diameter of 2 to 6 μm at the final wire size. Through careful attention to the billet design and thermo-mechanical processing, the formation of intermetallics (Cu-Ti-Nb) is virtually halted. The intermetallic precipitates, when allowed to form at the filament surface, interfere with the uniform reduction and give rise to poor filament quality; including filament breaks and reduction in critical current density, Jc. The integrity of the present fine filaments is studied with SEM and compared with that of conventionally processed material. The Jc, as a function of the filament size, is investigated over a transverse magnetic field of up to 8 Tesla. The value of 'n' in /rho/=kI /SUP n/ is measured and the results are compared to those obtained for similar M.F. wires currently under study at other institutions. It is hoped that the fine filamentary wire produced by the double extrusion process will greatly reduce the magnetization which is responsible for field distortions in the High Energy Physics program applications

  7. Experimental study of ion heating and acceleration during magnetic reconnection

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, S.C.

    2000-01-28

    This dissertation reports an experimental study of ion heating and acceleration during magnetic reconnection, which is the annihilation and topological rearrangement of magnetic flux in a conductive plasma. Reconnection is invoked often to explain particle heating and acceleration in both laboratory and naturally occurring plasmas. However, a simultaneous account of reconnection and its associated energy conversion has been elusive due to the extreme inaccessibility of reconnection events, e.g. in the solar corona, the Earth's magnetosphere, or in fusion research plasmas. Experiments for this work were conducted on MRX (Magnetic Reconnection Experiment), which creates a plasma environment allowing the reconnection process to be isolated, reproduced, and diagnosed in detail. Key findings of this work are the identification of local ion heating during magnetic reconnection and the determination that non-classical effects must provide the heating mechanism. Measured ion flows are sub-Alfvenic and can provide only slight viscous heating, and classical ion-electron interactions can be neglected due to the very long energy equipartition time. The plasma resistivity in the reconnection layer is seen to be enhanced over the classical value, and the ion heating is observed to scale with the enhancement factor, suggesting a relationship between the magnetic energy dissipation mechanism and the ion heating mechanism. The observation of non-classical ion heating during reconnection has significant implications for understanding the role played by non-classical dissipation mechanisms in generating fast reconnection. The findings are relevant for many areas of space and laboratory plasma research, a prime example being the currently unsolved problem of solar coronal heating. In the process of performing this work, local measurements of ion temperature and flows in a well-characterized reconnection layer were obtained for the first time in either laboratory or observational

  8. Experimental study of ion heating and acceleration during magnetic reconnection

    International Nuclear Information System (INIS)

    Hsu, S.C.

    2000-01-01

    This dissertation reports an experimental study of ion heating and acceleration during magnetic reconnection, which is the annihilation and topological rearrangement of magnetic flux in a conductive plasma. Reconnection is invoked often to explain particle heating and acceleration in both laboratory and naturally occurring plasmas. However, a simultaneous account of reconnection and its associated energy conversion has been elusive due to the extreme inaccessibility of reconnection events, e.g. in the solar corona, the Earth's magnetosphere, or in fusion research plasmas. Experiments for this work were conducted on MRX (Magnetic Reconnection Experiment), which creates a plasma environment allowing the reconnection process to be isolated, reproduced, and diagnosed in detail. Key findings of this work are the identification of local ion heating during magnetic reconnection and the determination that non-classical effects must provide the heating mechanism. Measured ion flows are sub-Alfvenic and can provide only slight viscous heating, and classical ion-electron interactions can be neglected due to the very long energy equipartition time. The plasma resistivity in the reconnection layer is seen to be enhanced over the classical value, and the ion heating is observed to scale with the enhancement factor, suggesting a relationship between the magnetic energy dissipation mechanism and the ion heating mechanism. The observation of non-classical ion heating during reconnection has significant implications for understanding the role played by non-classical dissipation mechanisms in generating fast reconnection. The findings are relevant for many areas of space and laboratory plasma research, a prime example being the currently unsolved problem of solar coronal heating. In the process of performing this work, local measurements of ion temperature and flows in a well-characterized reconnection layer were obtained for the first time in either laboratory or observational

  9. Electron acceleration by wave turbulence in a magnetized plasma

    Science.gov (United States)

    Rigby, A.; Cruz, F.; Albertazzi, B.; Bamford, R.; Bell, A. R.; Cross, J. E.; Fraschetti, F.; Graham, P.; Hara, Y.; Kozlowski, P. M.; Kuramitsu, Y.; Lamb, D. Q.; Lebedev, S.; Marques, J. R.; Miniati, F.; Morita, T.; Oliver, M.; Reville, B.; Sakawa, Y.; Sarkar, S.; Spindloe, C.; Trines, R.; Tzeferacos, P.; Silva, L. O.; Bingham, R.; Koenig, M.; Gregori, G.

    2018-05-01

    Astrophysical shocks are commonly revealed by the non-thermal emission of energetic electrons accelerated in situ1-3. Strong shocks are expected to accelerate particles to very high energies4-6; however, they require a source of particles with velocities fast enough to permit multiple shock crossings. While the resulting diffusive shock acceleration4 process can account for observations, the kinetic physics regulating the continuous injection of non-thermal particles is not well understood. Indeed, this injection problem is particularly acute for electrons, which rely on high-frequency plasma fluctuations to raise them above the thermal pool7,8. Here we show, using laboratory laser-produced shock experiments, that, in the presence of a strong magnetic field, significant electron pre-heating is achieved. We demonstrate that the key mechanism in producing these energetic electrons is through the generation of lower-hybrid turbulence via shock-reflected ions. Our experimental results are analogous to many astrophysical systems, including the interaction of a comet with the solar wind9, a setting where electron acceleration via lower-hybrid waves is possible.

  10. Spallation and 14-MeV neutron irradiation of stabilized NbTi superconductors

    International Nuclear Information System (INIS)

    Hahn, P.; Brown, B.S.; Weber, H.W.; Guinan, M.W.

    1983-08-01

    The results on 5 K irradiation available so far may be summarized as follows. (1) Increases of j/sub c/ following neutron irradiation occur only in conductors which are far from the optimal metallurgical treatments. (2) The changes of j/sub c/ following neutron irradiation and a thermal cycle to room temperature are small and in most cases comparable to the results obtained after 77 K irradiation. (3) The data available so far indicate that the degradation of j/sub c/ at 8 T is larger by about 5 to 10% than the corresponding changes at 5 T at a neutron fluence of 1.3 x 10 22 m -2 (E > 0.1 MeV). (4) The increase of Cu-resistivity is significant even after a thermal cycle to room temperature and requires design changes for a stable magnet operation

  11. Photoluminescence properties of aeschynite-type LaNbTiO6:RE3+ (RE = Tb, Dy, Ho) down-converting phosphors.

    Science.gov (United States)

    Ma, Qian; Lu, Mengkai; Yang, Ping; Zhang, Aiyu; Cao, Yongqiang

    2014-06-01

    In this study, a series of LaNbTiO6:RE(3+) (RE = Tb, Dy, Ho) down-converting phosphors were synthesized using a modified sol-gel combustion method, and their photoluminescence (PL) properties were investigated as a function of activator concentration and annealing temperature. The resultant particles were characterized using X-ray diffraction, transmission electron microscopy, scanning electron microscopy, UV/Vis diffuse reflectance spectroscopy and PL spectra. The highly crystalline LaNbTiO6:RE(3+) (RE = Tb, Dy, Ho) phosphors with an average size of 200-300 nm obtained at 1100°C have an orthorhombic aeschynite-type structure and exhibit the highest luminescent intensity in our study range. The emission spectra of LaNbTiO6:RE(3+) (RE = Tb, Dy, Ho) phosphors under excitations at UV/blue sources are mainly composed of characteristic peaks arising from the f-f transitions of RE(3+), including 489 nm ((5) D4 → (7) F6) and 545 nm ((5) D4 → (7) F5) for Tb(3+), 476 and 482 nm ((4) F9/2 → (6) H15/2) and 571 nm ((4) F9/2 → (6) H13/2) for Dy(3+), and 545 nm ((5) F4 + (5) S2 → (5) I8) for Ho(3+), respectively. The luminescent mechanisms were further investigated. It can be expected that these phosphors are of intense interest and potential importance for many optical applications. Copyright © 2013 John Wiley & Sons, Ltd.

  12. Protecting a full-scale Nb3Sn magnet with CLIQ, the new coupling-loss-induced quench system

    NARCIS (Netherlands)

    Ravaioli, Emanuele; Bajas, H.; Datskov, V.I.; Desbiolles, V.; Feuvrier, J.; Kirby, G.; Maciejewski, M.; Sabbi, G.; ten Kate, Herman H.J.; Verweij, A.P.

    2015-01-01

    A new protection system for superconducting magnets called coupling-loss induced quench system (CLIQ) has been recently developed at CERN. Recent tests on Nb-Ti coils have shown that CLIQ is a valid, efficient, and promising method for the protection of high-magnetic-field superconducting magnets.

  13. Magnetic and mechanical design of a 130 mm aperture Nb{sub 3}Sn dipole magnet

    Energy Technology Data Exchange (ETDEWEB)

    Felice, H.; Vedrine, P. [CEA Saclay, DAPNIA/SACM/LEAS, F-91191 Gif Sur Yvette, (France); Mailfert, A. [LEM, F-54500 Vandoeuvre Les Nancy, (France)

    2007-07-01

    For the next generation of dipoles for accelerators, two main challenges come into play. In one hand, high dipolar fields in the range of 13 to 15 T are targeted. In the other hand, large apertures (above 80 mm) are required in the interaction regions. These two requirements lead to two issues. First, a new superconductor has to replace the NbTi as its limits have been reached around 10 T with the LHC. The superconducting material liable to be its successor is the Nb{sub 3}Sn. However, it is a very mechanical stress sensitive material. Up to now, a mechanical stress of 150 MPa is supposed to degrade its critical properties. Second, large aperture dipole can not be considered with the well-known cosine theta design. Indeed, above 88 mm, azimuthal Lorentz forces in this magnetic configuration produces mechanical stresses on the coil midplane higher than the acceptable limit. In this paper, an alternative coil arrangement based on intersecting ellipses and limiting the mechanical stresses is proposed for a 130 mm aperture dipole. The first part of this paper is dedicated to the magnetic study of this magnet. We can underline the fact that the field quality required in particle accelerators can be reached with a bore field of about 13 T. The second part deals with the mechanical structure of the magnet which is necessary to withstand the Lorentz forces involved and to apply pre-stress. (authors)

  14. submitter Influence of 3D Effects on Field Quality in the Straight Part of Accelerator Magnets for the High Luminosity Large Hadron Collider

    CERN Document Server

    Nilsson, Emelie; Todesco, Ezio; Enomoto, Shun; Farinon, Stefania; Fabbricatore, Pasquale; Nakamoto, Tatsushi; Sugano, Michinaka; Savary, Frederic

    2017-01-01

    A dedicated D1 beam separation dipole is currently being developed at KEK for the Large Hadron Collider Luminosity upgrade (HL-LHC). Four 150 mm aperture, 5.6 T magnetic field and 6.7 m long Nb-Ti magnets will replace resistive D1 dipoles. The development includes fabrication and testing of 2.2 m model magnets. The dipole has a single layer coil and thin spacers between coil and iron, giving a non-negligible impact of saturation on field quality at nominal field. The magnetic design of the straight section coil cross section is based on 2D optimization and a separate optimization concerns the coil ends. However, magnetic measurements of the short model showed a large difference (tens of units) between the sextupole harmonic in the straight part and the 2D calculation. This difference is correctly modelled only by a 3D analysis: 3D calculations show that the magnetic field quality in the straight part is influenced by the coil ends, even for the 6.7 m long magnets. The effect is even more remarkable in the sho...

  15. submitter Influence of 3D Effects on Field Quality in the Straight Part of Accelerator Magnets for the High Luminosity Large Hadron Collider

    CERN Document Server

    Nilsson, Emelie; Todesco, Ezio; Enomoto, Shun; Farinon, Stefania; Fabbricatore, Pasquale; Nakamoto, Tatsushi; Sugano, Michinaka; Savary, Frederic

    2018-01-01

    A dedicated D1 beam separation dipole is currently being developed at KEK for the Large Hadron Collider Luminosity upgrade (HL-LHC). Four 150 mm aperture, 5.6 T magnetic field and 6.7 m long Nb-Ti magnets will replace resistive D1 dipoles. The development includes fabrication and testing of 2.2 m model magnets. The dipole has a single layer coil and thin spacers between coil and iron, giving a non-negligible impact of saturation on field quality at nominal field. The magnetic design of the straight section coil cross section is based on 2D optimization and a separate optimization concerns the coil ends. However, magnetic measurements of the short model showed a large difference (tens of units) between the sextupole harmonic in the straight part and the 2D calculation. This difference is correctly modelled only by a 3D analysis: 3D calculations show that the magnetic field quality in the straight part is influenced by the coil ends, even for the 6.7 m long magnets. The effect is even more remarkable in the sho...

  16. On the Influence of Nb/Ti Ratio on Environmentally-Assisted Crack Growth in High-Strength Nickel-Based Superalloys

    Science.gov (United States)

    Németh, A. A. N.; Crudden, D. J.; Collins, D. M.; Kuksenko, V.; Liebscher, C. H.; Armstrong, D. E. J.; Wilkinson, A. J.; Reed, R. C.

    2018-05-01

    The effect of Nb/Ti ratio on environmentally-assisted crack growth of three prototype Ni-based superalloys is studied. For these alloys, the yield strength is unaltered with increasing Nb/Ti ratio due to an increase in grain size. This situation has allowed the rationalization of the factors influencing damage tolerance at 700 °C. Primary intergranular cracks have been investigated using energy-dispersive X-ray spectroscopy in a scanning transmission electron microscope and the analysis of electron back-scatter diffraction patterns. Any possible detrimental effect of Nb on the observed crack tip damage due to Nb-rich oxide formation is not observed. Instead, evidence is presented to indicate that the tertiary γ'-precipitates are dissolving ahead of the crack consistent with the formation of oxides such as alumina and rutile. Our results have implications for alloy design efforts; at any given strength level, both more and less damage-tolerant variants of these alloys can be designed.

  17. Spectro-photometric determination of niobium in Nb-Ti alloy using in-situ separation of Ti by masking with H3PO4

    International Nuclear Information System (INIS)

    Ghosh, Prasun; Dutta, M.; Jat, J.R.; Reddy, G.B.; Balaji Rao, Y.; Subba Rao, Y.

    2016-01-01

    The present paper details a simple procedure for the determination of Nb content in Nb-Ti alloy. The method involves dissolution of alloy in mixture of HNO 3 and HF followed by fuming with H 2 SO 4 . Subsequently, solution is taken for UV-Vis Spectro-photometric measurement after addition of Conc. H 3 PO 4 and H 2 O 2 . Hydrogen peroxide is added as coloring agent. Hydrogen peroxide (H 2 O 2 ) is known to form yellow color peroxo complex with both Niobium and Titanium in sulfuric acid medium and thus Ti will interfere with Nb in absorbance measurement. In view of this practical difficulty, in-situ separation of Ti during measurement has been resorted by masking Ti using Conc. H 3 PO 4 . Standard synthetic sample solution of Nb-Ti was prepared having Niobium and titanium in the ratio of 60:40, 50:50 and 40:60. Quantitative measurement of Niobium was carried out by UV-Visible spectrophotometer at 365 nm. The interference of titanium is prominent from the obtained Niobium concentration. Different ratios of H 3 PO 4 and H 2 SO 4 tried to arrive at optimum ratio to eliminate titanium interference and results are as shown. Quantitative measurement of Niobium was carried out at 355 nm as absorption maxima shifted from 365 nm to 355 nm in presence of phosphoric acid. Results show a good agreement with synthetic standard at 80:20 sulfuric to phosphoric acid ratio

  18. Magnetic field measurements of superconducting magnets for the colliding beam accelerator

    International Nuclear Information System (INIS)

    Herrera, J.; Kirk, H.; Prodell, A.; Willen, E.

    1983-01-01

    An important aspect of the development and production of superconducting magnets for the Colliding Beam Accelerator is the measurement of the magnetic field in the aperture of these magnets. The measurements have the three-fold purpose of determining the field quality as compared to the lattice requirements of the CBA, of obtaining the survey data necessary to position the magnets in the CBA tunnel, and lastly, of characterizing the magnetic fields for use in initial and future orbit studies of the CBA proton beams. Since for a superconducting storage accelerator it is necessary to carry out these detailed measurements on many (approx. 1000) magnets and at many current values (approx. 1000), we have chosen, in agreement with previous experience, to develop a system which Fourier analyses the voltages induced in a number of rotating windings and thereby obtains the multipole field components. The important point is that such a measuring system can be fast and precise. It has been used for horizontal measurements of the CBA ring dipoles

  19. Magnetization, critical current, and injection field harmonics in superconducting accelerator magnets

    International Nuclear Information System (INIS)

    Ghosh, A.K.; Sampson, W.B.; Wanderer, P.

    1985-01-01

    The very large energy ratio of machines such as the SSC dictates rather low injection field (for 6T, 20 TeV it is approximately 0.3T). Since the harmonic content at such low fields is largely determined by magnetization currents in the superconductor, the random errors depend on the uniformity of the superconducting wire. In principle the magnitude of the residual fields can be reduced indefinitely by using finer filaments, but in practice there is a lower limit of a few microns. We have compared the injection field harmonics for a number of accelerator dipoles with magnetization measurements made on samples of the conductor used to wind the coils. In addition both the magnetization and harmonics have been compared with short sample critical current measurements made at 5T. The results indicated that an accurate estimate of the variation in injection field harmonics can only be obtained from direct measurements of the magnetization of the cable. It appears feasible to use such measurements to ''shuffle'' magnets for a large accelerator by predicting the low field properties of a magnet before actually winding the coils. 10 refs., 4 figs., 2 tabs

  20. Formation of spectrum of accelerated particles and the hydromagnetic turbulence in the variable magnetic field

    International Nuclear Information System (INIS)

    Savane, Y. Sy; Diaby, I.; Faza Barry, M.; Lomonossov, V.

    2002-11-01

    We study the acceleration of charged particles by the variable magnetic field. The study is based on the determination of spectrum of accelerated particles and the spectrum of hydro magnetic turbulence. We plan the self-consistent system of equation and we also find out the solution of the system for the spectrum of particles and hydro magnetic turbulence with the conditions of effective acceleration in the cosmic space of solar system. (author)

  1. Stochastic acceleration by a single wave in a magnetized plasma

    International Nuclear Information System (INIS)

    Smith, R.

    1977-01-01

    A particularly simple problem exhibiting stochasticity is the motion of a charged particle in a uniform magnetic field and a single wave. Detailed studies of this wave-particle interaction show the following features. An electrostatic wave propagating obliquely to the magnetic field causes stochastic motion if the wave amplitude exceeds a certain threshold. The overlap of cyclotron resonances then destroys a constant of the motion, allowing strong particle acceleration. A wave of large enough amplitude would thus suffer severe damping and lead to rapid heating of a particle distribution. The stochastic motion resembles a diffusion process even though the wave spectrum contains only a single wave. The motion of ions in a nonuniform magnetic field and a single electrostatic wave is treated in our study of a possible saturation mechanism of the dissipative trapped-ion instability in a tokamak. A theory involving the overlap of bounce resonances predicts the main features found in the numerical integration of the equations of motion. Ions in a layer near the trapped-circulating boundary move stochastically. This motion leads to nonlinear stabilization mechanisms which are described qualitatively

  2. Mechanical Effects of the Non-Uniform Current Distribution on HTS Coils for Accelerators Wound with REBCO Roebel Cable

    CERN Document Server

    Murtomaeki, Jaako; Kirby, Glen; Rossi, Lucio; Ruuskanen, Janne; Stenvall, Antti; Murtomaeki, Jaako

    2017-01-01

    Future high-energy accelerators will need very high magnetic fields in the range of 20 T. The EuCARD-2 WP10 Future Magnets collaboration is aiming at testing HTS-based Roebel cables in an accelerator magnet. The demonstrator should produce around 17 T, when inserted into the 100 mm aperture of Feather-M2 13 T outsert magnet. HTS Roebel cables are assembled from meander shaped REBCO coated conductor tapes. In comparison with fair level of uniformity of current distribution in cables made out of round Nb-Ti or Nb$_{3}$Sn strands, current distribution within the coils wound from Roebel cables is highly non-homogeneous. It results in nonuniform electromagnetic force distribution over the cable that could damage the very thin REBCO superconducting layer. This paper focuses on the numerical models to describe the effect of the non-homogenous current distribution on stress distribution in the demonstrator magnet designed for the EuCARD-2 project. Preliminary results indicate that the impregnation bonding betweenthe...

  3. ATLAS : magnet industrial production Conference MT17

    CERN Multimedia

    2001-01-01

    With overall dimensions of 26 meters in length and 20 meters in diameter, the ATLAS magnet system is the largest integrated superconducting magnet ever built. The system is made up of four super-conducting magnets, a power supply, cryogenics, vacuum, control, and safety systems. The coils are built with Aluminum stabilized NbTi/Cu superconductor indirectly cooled at 4.5 K by liquid Helium forced flow.

  4. submitter On Roebel Cable Geometry for Accelerator Magnet

    CERN Document Server

    Fleiter, J; Ballarino, A

    2016-01-01

    Roebel-type cables made of a ReBCO conductor are potential candidates for high-field accelerator magnets. The necessity to promote a large effective transverse section in a Roebel cable to avoid local overstress leading to degradation in electrical performance has been recently addressed. In this paper, a new geometry of meander tapes for a Roebel cable that enhances both the transverse effective section and the current margin at crossing segments is discussed. As Roebel cables are bent at the coil ends, the modulation of the bending radius of strands along the cable pitch leads to a shift of the strands with respect to each other. The shift magnitude is analytically investigated in this paper as a function of both cable features and coil geometry. Finally, the minimum transposition pitch of Roebel cables is determined on the basis of coil characteristics.

  5. Rarefaction acceleration in magnetized gamma-ray burst jets

    Science.gov (United States)

    Sapountzis, Konstantinos; Vlahakis, Nektarios

    2013-09-01

    Relativistic jets associated with long/soft gamma-ray bursts are formed and initially propagate in the interior of the progenitor star. Because of the subsequent loss of their external pressure support after they cross the stellar surface, these flows can be modelled as moving around a corner. A strong steady-state rarefaction wave is formed, and the sideways expansion is accompanied by a rarefaction acceleration. We investigate the efficiency and the general characteristics of this mechanism by integrating the steady-state, special relativistic, magnetohydrodynamic equations, using a special set of partial exact solutions in planar geometry (r self-similar with respect to the `corner'). We also derive analytical approximate scalings in the ultrarelativistic cold/magnetized, and hydrodynamic limits. The mechanism is more effective in magnetized than in purely hydrodynamic flows. It substantially increases the Lorentz factor without much affecting the opening of the jet; the resulting values of their product can be much greater than unity, allowing for possible breaks in the afterglow light curves. These findings are similar to the ones from numerical simulations of axisymmetric jets by Komissarov et al. and Tchekhovskoy et al., although in our approach we describe the rarefaction as a steady-state simple wave and self-consistently calculate the opening of the jet that corresponds to zero external pressure.

  6. Retraining of the 1232 Main Dipole Magnets in the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Verweij, A. [CERN; Auchmann, B.; Bednarek, M.; Bottura, L.; Charifoulline, Z.; Feher, S. [Fermilab; Hagen, P.; Modena, M.; Le Naour, S.; Romera, I.; Siemko, A.; Steckert, J.; Tock, J. Ph; Todesco, E.; Willering, G.; Wollmann, D.

    2016-01-05

    The Large Hadron Collider (LHC) contains eight main dipole circuits, each of them with 154 dipole magnets powered in series. These 15-m-long magnets are wound from Nb-Ti superconducting Rutherford cables, and have active quench detection triggering heaters to quickly force the transition of the coil to the normal conducting state in case of a quench, and hence reduce the hot spot temperature. During the reception tests in 2002-2007, all these magnets have been trained up to at least 12 kA, corresponding to a beam energy of 7.1 TeV. After installation in the accelerator, the circuits have been operated at reduced currents of up to 6.8 kA, from 2010 to 2013, corresponding to a beam energy of 4 TeV. After the first long shutdown of 2013-2014, the LHC runs at 6.5 TeV, requiring a dipole magnet current of 11.0 kA. A significant number of training quenches were needed to bring the 1232 magnets up to this current. In this paper, the circuit behavior in case of a quench is presented, as well as the quench training as compared to the initial training during the reception tests of the individual magnets.

  7. A hybrid data acquisition system for magnetic measurements of accelerator magnets

    International Nuclear Information System (INIS)

    Wang, X.; Hafalia, R.; Joseph, J.; Lizarazo, J.; Martchevsky, M.; Sabbi, G.L.

    2011-01-01

    A hybrid data acquisition system was developed for magnetic measurement of superconducting accelerator magnets at LBNL. It consists of a National Instruments dynamic signal acquisition (DSA) card and two Metrolab fast digital integrator (FDI) cards. The DSA card records the induced voltage signals from the rotating probe while the FDI cards records the flux increment integrated over a certain angular step. This allows the comparison of the measurements performed with two cards. In this note, the setup and test of the system is summarized. With a probe rotating at a speed of 0.5 Hz, the multipole coefficients of two magnets were measured with the hybrid system. The coefficients from the DSA and FDI cards agree with each other, indicating that the numerical integration of the raw voltage acquired by the DSA card is comparable to the performance of the FDI card in the current measurement setup.

  8. The overview and history of permanent magnet devices in accelerator technology

    International Nuclear Information System (INIS)

    Kraus, R.H.

    1994-01-01

    This paper looks at the early history of accelerator development with a particular focus on the important discoveries that opened the door for the application of permanent-magnet materials to this area of science. Researchers began to use permanent-magnet materials in particle accelerators soon after the invention of the alternating gradient principle, that showed magnetic fields could be used to control the transverse envelope of charged-particle beams. Since that time, permanent-magnet materials have found wide application in the modern charged particle accelerator. A brief history of permanent-magnet use in accelerator physics and technology is outlined, some of the general design considerations are presented, and several material properties of concern for particle accelerator applications are discussed

  9. The overview and history of permanent magnet devices in accelerator technology

    International Nuclear Information System (INIS)

    Kraus, R.H. Jr.

    1993-01-01

    This paper reviews the early history of accelerator development with a particular focus on the important discoveries that opened the door for the application of permanent-magnet materials to this area of science. Researchers began to use permanent-magnet materials in particle accelerators soon after the invention of the alternating gradient principle, that showed magnetic fields could be used to control the transverse envelope of charged-particle beams. Since that time, permanent-magnet materials have found wide application in the modern charged particle accelerator. The history of permanent-magnet use in accelerator physics and technology is outlined, general design considerations are presented, and material properties of concern for particle accelerator applications are discussed

  10. Magnetic Parameters Of A NB3SN Superconducting Magnet For A 56 HGz ECR Ion Source

    International Nuclear Information System (INIS)

    Ferracin, P.; Caspi, S.; Felice, H.; Leitner, D.; Lyneis, C.M.; Prestemon, S.; Sabbi, G.L.; Todd, D.S.

    2009-01-01

    Third generation Electron Cyclotron Resonance (ECR) ion sources operate at microwave frequencies between 20 and 30 GHz and employ NbTi superconducting magnets with a conductor peak field of 6-7 T. A significant gain in performance can be achieved by replacing NbTi with Nb 3 Sn, allowing solenoids and sextupole coils to reach a field of 15 T in the windings. In this paper we describe the design of a Nb 3 Sn superconducting magnet for a fourth generation ECR source operating at a microwave frequency of 56 GHz. The magnet design features a configuration with an internal sextupole magnet surrounded by three solenoids. A finite element magnetic model has been used to investigate conductor peak fields and the operational margins. Results of the numerical analysis are presented and discussed.

  11. MAGNETIC PARAMETERS OF A NB3SN SUPERCONDUCTING MAGNET FOR A 56 HGz ECR ION SOURCE

    Energy Technology Data Exchange (ETDEWEB)

    Ferracin, P.; Caspi, S.; Felice, H.; Leitner, D.; Lyneis, C. M.; Prestemon, S.; Sabbi, G. L.; Todd, D. S.

    2009-05-04

    Third generation Electron Cyclotron Resonance (ECR) ion sources operate at microwave frequencies between 20 and 30 GHz and employ NbTi superconducting magnets with a conductor peak field of 6-7 T. A significant gain in performance can be achieved by replacing NbTi with Nb{sub 3}Sn, allowing solenoids and sextupole coils to reach a field of 15 T in the windings. In this paper we describe the design of a Nb{sub 3}Sn superconducting magnet for a fourth generation ECR source operating at a microwave frequency of 56 GHz. The magnet design features a configuration with an internal sextupole magnet surrounded by three solenoids. A finite element magnetic model has been used to investigate conductor peak fields and the operational margins. Results of the numerical analysis are presented and discussed.

  12. Superconducting materials suitable for magnets

    CERN Multimedia

    CERN. Geneva. Audiovisual Unit

    2002-01-01

    The range of materials available for superconducting magnets is steadily expanding, even as the choice of material becomes potentially more complex. When virtually all magnets were cooled by helium at ~2-5 K it was easy to separate the domain of Nb-Ti from those of Nb$_{3}$Sn applications and very little surprise that more than 90% of all magnets are still made from Nb-Ti. But the development of useful conductors of the Bi-Sr-Ca-Cu-O and YBa2Cu3Ox high temperature superconductors, coupled to the recent discovery of the 39 K superconductor MgB2 and the developing availability of cryocoolers suggests that new classes of higher temperature, medium field magnets based on other than Nb-based conductors could become available in the next 5-10 years. My talks will discuss the essential physics and materials science of these 5 classes of material - Nb-Ti, Nb$_{3}$Sn, MgB2, Bi-Sr-Ca-Cu-O and YBa2Cu3Ox - in the context of those aspects of their science, properties and fabrication properties, which circumscribe their ap...

  13. Acceleration mechanisms flares, magnetic reconnection and shock waves

    International Nuclear Information System (INIS)

    Colgate, S.A.

    1979-01-01

    Several mechanisms are briefly discussed for the acceleration of particles in the astrophysical environment. Included are hydrodynamic acceleration, spherically convergent shocks, shock and a density gradient, coherent electromagnetic acceleration, the flux tube origin, symmetries and instabilities, reconnection, galactic flares, intergalactic acceleration, stochastic acceleration, and astrophysical shocks. It is noted that the supernova shock wave models still depend critically on the presupernova star structure and the assumption of highly compact presupernova models for type I supernovae. 37 references

  14. Performance of the Superconducting Corrector Magnet Circuits during the Commissioning of the LHC

    International Nuclear Information System (INIS)

    Venturini Delsolaro, W.; Baggiolini, V.; Ballarino, A.; Bellesia, B.; Bordry, F.; Cantone, A.; Casas Lino, M.P.; CastilloTrello, C.; Catalan-Lasheras, N.; Charifoulline, Zinour; Charrondiere, C.; CERN; Madrid, CIEMAT; Fermilab

    2008-01-01

    The LHC is a complex machine requiring more than 7400 superconducting corrector magnets distributed along a circumference of 26.7 km. These magnets are powered in 1446 different electrical circuits at currents ranging from 60 A up to 600 A. Among the corrector circuits the 600 A corrector magnets form the most diverse and differentiated group. All together, about 60000 high current connections had to be made. A fault in a circuit or one of the superconducting connections would have severe consequences for the accelerator operation. All magnets are wound from various types of Nb-Ti superconducting strands, and many contain parallel protection resistors to by-pass the current still flowing in the other magnets of the same circuit when they quench. In this paper the performance of these magnet circuits is presented, focusing on the quench behavior of the magnets. Quench detection and the performance of the electrical interconnects will be dealt with. The results as measured on the entire circuits are compared to the test results obtained at the reception of the individual magnets

  15. Retraining of the 1232 Main Dipole Magnets in the LHC

    CERN Document Server

    Verweij, A; Bednarek, M; Bottura, L; Charifoulline, Z; Feher, S; Hagen, P; Modena, M; Le Naour, S; Romera, I; Siemko, A; Steckert, J; Tock, J Ph; Todesco, E; Willering, G; Wollmann, D

    2016-01-01

    The Large Hadron Collider (LHC) contains eight main dipole circuits, each of them with 154 dipole magnets powered in series. These 15-m-long magnets are wound from Nb-Ti superconducting Rutherford cables, and have active quench detection triggering heaters to quickly force the transition of the coil to the normal conducting state in case of a quench, and hence reduce the hot spot temperature. During the reception tests in 2002-2007, all these magnets have been trained up to at least 12 kA, corresponding to a beam energy of 7.1 TeV. After installation in the accelerator, the circuits have been operated at reduced currents of up to 6.8 kA, from 2010 to 2013, corresponding to a beam energy of 4 TeV. After the first long shutdown of 2013-2014, the LHC runs at 6.5 TeV, requiring a dipole magnet current of 11.0 kA. A significant number of training quenches were needed to bring the 1232 magnets up to this current. In this paper, the circuit behavior in case of a quench is presented, as well as the quench training as...

  16. Status of the Next European Dipole (NED) Activity of the Collaborated Accelerator Research in Europe (CARE) Project

    CERN Document Server

    Devred, Arnaud; Baynham, D Elwyn; Boutboul, T; Canfer, S; Chorowski, M; den Ouden, A; Fabbricatore, P; Farinon, S; Fessia, P; Fydrych, J; Félice, H; Greco, Michela; Greenhalgh, J; Leroy, D; Loveridge, P W; Michel, F; Oberli, L R; Pedrini, D; Polinski, J; Previtali, V; Quettier, L; Rifflet, J M; Rochford, J; Rondeaux, F; Sanz, S; Sgobba, Stefano; Sorbi, M; Toral-Fernandez, F; Van Weelderen, R; Vincent-Viry, O; Volpini, G; Védrine, P

    2005-01-01

    Plans for LHC upgrade and for the final focalization of linear colliders call for large aperture and/or high-performance dipole and quadrupole magnets that may be beyond the reach of conventional NbTi magnet technology. The Next European Dipole (NED) activity was launched on January 1st, 2004 to promote the development of high-performance, Nb$_{3}$Sn wires in collaboration with European industry (aiming at a non-copper critical current density of 1500 A/mm2 at 4.2 K and 15 T) and to assess the suitability of Nb$_{3}$Sn technology to the next generation of accelerator magnets (aiming at an aperture of 88 mm and a conductor peak field of 15 T). It is integrated within the Collaborated Accelerator Research in Europe (CARE) project, involves seven collaborators, and is partly funded by the European Union. We present here an overview of the NED activity and we report on the status of the various work packages it encompasses.

  17. Pulsed high field magnets. An efficient way of shaping laser accelerated proton beams for application

    Energy Technology Data Exchange (ETDEWEB)

    Kroll, Florian; Schramm, Ulrich [Helmholtz-Zentrum Dresden - Rossendorf, 01328 Dresden (Germany); Technische Universitaet Dresden, 01062 Dresden (Germany); Bagnoud, Vincent; Blazevic, Abel; Busold, Simon [GSI Helmholtzzentrum fuer Schwerionenforschung, 64291 Darmstadt (Germany); Helmholtz Institut Jena, 07734 Jena (Germany); Brabetz, Christian; Schumacher, Dennis [GSI Helmholtzzentrum fuer Schwerionenforschung, 64291 Darmstadt (Germany); Deppert, Oliver; Jahn, Diana; Roth, Markus [Technische Universitaet Darmstadt, 64289 Darmstadt (Germany); Karsch, Leonhard; Masood, Umar [OncoRay-National Center for Radiation Research in Oncology, TU Dresden, 01307 Dresden (Germany); Kraft, Stephan [Helmholtz-Zentrum Dresden - Rossendorf, 01328 Dresden (Germany)

    2015-07-01

    Compact laser-driven proton accelerators are a potential alternative to complex, expensive conventional accelerators, enabling unique beam properties, like ultra-high pulse dose. Nevertheless, they still require substantial development in reliable beam generation and transport. We present experimental studies on capture, shape and transport of laser and conventionally accelerated protons via pulsed high-field magnets. These magnets, common research tools in the fields of solid state physics, have been adapted to meet the demands of laser acceleration experiments.Our work distinctively shows that pulsed magnet technology makes laser acceleration more suitable for application and can facilitate compact and efficient accelerators, e.g. for material research as well as medical and biological purposes.

  18. Characteristics of magnetic switch used as main switch of solid-state accelerator

    International Nuclear Information System (INIS)

    Li Song; Qian Baoliang; Yang Hanwu; Meng Zhipeng; Yang Shi

    2012-01-01

    In order to improve the performance of solid-state accelerator, the characteristics of magnetic switch used as the main switch of the accelerator have been investigated. The volume of magnetic core, the loss, and saturated inductance of the magnetic switch have been derived. The results show that the spacing factor of the magnetic switch reaches the peak when the height of the magnetic materials is 0.05 m for selected magnetic cores. The saturated inductance of the windings changes slowly when the average magnetic path length of the core is greater than 1 m. The physical process of saturation in the cores was analyzed by using saturation-wave theory. The rise-time factor of the output pulse was derived. The thickness, resistivity and magnetic path length difference of the magnetic core are shown to be key parameters affecting the rise-time factor. (authors)

  19. Performance of the Superconducting Corrector Magnet Circuits during the Commissioning of the LHC

    CERN Document Server

    Venturini-Delsolaro, W; Ballarino, A; Bellesia, B; Bordry, Frederick; Cantone, A; Casas Lino, M; Castaneda Serra, A; Castillo Trello, C; Catalan-Lasheras, N; Charifoulline, Z; Charrondiere, C; Dahlerup-Petersen, K; D'Angelo, G; Denz, R; Fehér, S; Flora, R; Gruwé, M; Kain, V; Karppinen, M; Khomenko, B; Kirby, G; MacPherson, A; Marqueta Barbero, A; Mess, K H; Modena, M; Mompo, R; Montabonnet, V; le Naour, S; Nisbet, D; Parma, V; Pojer, M; Ponce, L; Raimondo, A; Redaelli, S; Remondino, V; Reymond, H; de Rijk, G; Rijllart, A; Romera Ramirez, I; Saban, R; Sanfilippo, S; Schirm, K; Schmidt, R; Siemko, A; Solfaroli Camillocci, M; Thurel, Y; Thiesen, H; Vergara Fernandez, A; Verweij, A; Wolf, R; Zerlauth, M

    2008-01-01

    The LHC is a complex machine requiring more than 7400 superconducting corrector magnets distributed along a circumference of 26.7 km. These magnets are powered in 1446 different electrical circuits at currents ranging from 60 A up to 600 A. Among the corrector circuits the 600 A corrector magnets form the most diverse and differentiated group. All together, about 60000 high current connections had to be made. A fault in a circuit or one of the superconducting connections would have severe consequences for the accelerator operation. All magnets are wound from various types of Nb-Ti superconducting strands, and many contain parallel protection resistors to by-pass the current still flowing in the other magnets of the same circuit when they quench. In this paper the performance of these magnet circuits is presented, focussing on the quench behaviour of the magnets. Quench detection and the performance of the electrical interconnects will be dealt with. The results as measured on the entire circuits are compar...

  20. Characteristics of the magnetic wall reflection model on ion acceleration in gas-puff z pinch

    International Nuclear Information System (INIS)

    Nishio, M.; Takasugi, K.

    2013-01-01

    The magnetic wall reflection model was examined with the numerical simulation of the trajectory calculation of particles. This model is for the ions accelerated by some current-independent mechanism. The trajectory calculation showed angle dependency of highest velocities of accelerated particles. This characteristics is of the magnetic wall reflection model, not of the other current-independent acceleration mechanism. Thomson parabola measurements of accelerated ions produced in the gas-puff z-pinch experiments were carried out for the verification of the angle dependency. (author)

  1. Amine functionalized magnetic nanoparticles for removal of oil droplets from produced water and accelerated magnetic separation

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Saebom, E-mail: saebomko@austin.utexas.edu [University of Texas, Department of Petroleum and Geosystems Engineering (United States); Kim, Eun Song [University of Texas, Department of Biomedical Engineering (United States); Park, Siman [University of Texas, Department of Civil, Architectural and Environmental Engineering (United States); Daigle, Hugh [University of Texas, Department of Petroleum and Geosystems Engineering (United States); Milner, Thomas E. [University of Texas, Department of Biomedical Engineering (United States); Huh, Chun [University of Texas, Department of Petroleum and Geosystems Engineering (United States); Bennetzen, Martin V. [Maersk Oil Corporate (Denmark); Geremia, Giuliano A. [Maersk Oil Research and Technology Centre (Qatar)

    2017-04-15

    Magnetic nanoparticles (MNPs) with surface coatings designed for water treatment, in particular for targeted removal of contaminants from produced water in oil fields, have drawn considerable attention due to their environmental merit. The goal of this study was to develop an efficient method of removing very stable, micron-scale oil droplets dispersed in oilfield produced water. We synthesized MNPs in the laboratory with a prescribed surface coating. The MNPs were superparamagnetic magnetite, and the hydrodynamic size of amine functionalized MNPs ranges from 21 to 255 nm with an average size of 66 nm. The initial oil content of 0.25 wt.% was reduced by as much as 99.9% in separated water. The electrostatic attraction between negatively charged oil-in-water emulsions and positively charged MNPs controls, the attachment of MNPs to the droplet surface, and the subsequent aggregation of the electrically neutral oil droplets with attached MNPs (MNPs-oils) play a critical role in accelerated and efficient magnetic separation. The total magnetic separation time was dramatically reduced to as short as 1 s after MNPs, and oil droplets were mixed, in contrast with the case of free, individual MNPs with which separation took about 36∼72 h, depending on the MNP concentrations. Model calculations of magnetic separation velocity, accounting for the MNP magnetization and viscous drag, show that the total magnetic separation time will be approximately 5 min or less, when the size of the MNPs-oils is greater than 360 nm, which can be used as an optimum operating condition.

  2. Permanent magnets in accelerators can save energy, space and cost

    DEFF Research Database (Denmark)

    Bødker, F.; Baandrup, L.O.; Hauge, N.

    2013-01-01

    coils permit fine tuning of the magnetic field. Magnetic field measurements and thermal stability tests show that the Green Magnet fully meets the magnetic requirements of the previously used electromagnet. A permanent 30° bending dipole is currently being development to demonstrate the use of Green...

  3. Dynamics of particles accelerated by head-on collisions of two magnetized plasma shocks

    Science.gov (United States)

    Takeuchi, Satoshi

    2018-02-01

    A kinetic model of the head-on collision of two magnetized plasma shocks is analyzed theoretically and in numerical calculations. When two plasmas with anti-parallel magnetic fields collide, they generate magnetic reconnection and form a motional electric field at the front of the collision region. This field accelerates the particles sandwiched between both shock fronts to extremely high energy. As they accelerate, the particles are bent by the transverse magnetic field crossing the magnetic neutral sheet, and their energy gains are reduced. In the numerical calculations, the dynamics of many test particles were modeled through the relativistic equations of motion. The attainable energy gain was obtained by multiplying three parameters: the propagation speed of the shock, the magnitude of the magnetic field, and the acceleration time of the test particle. This mechanism for generating high-energy particles is applicable over a wide range of spatial scales, from laboratory to interstellar plasmas.

  4. MFTF magnet cryostability

    International Nuclear Information System (INIS)

    VanSant, J.H.

    1979-01-01

    A pair of large superconducting magnets will be installed in the Mirror Fusion Test Facility (MFTF), which is to begin operation in 1981. To ensure a stable superconducting state for the niobium-titanium (Nb-Ti) conductor, special consideration has been given to certain aspects of the magnet system design. These include the conductor, joints, coil assembly, vapor plenums, liquid-helium (LHe) supply system, and current leads. Heat transfer is the main consideration; i.e., the helium quality and temperature are limited so that the superconductor will perform satisfactorily in the magnet environment

  5. Rarefaction acceleration of ultrarelativistic magnetized jets in gamma-ray burst sources

    Science.gov (United States)

    Komissarov, Serguei S.; Vlahakis, Nektarios; Königl, Arieh

    2010-09-01

    When a magnetically dominated superfast-magnetosonic long/soft gamma-ray burst (GRB) jet leaves the progenitor star, the external pressure support will drop and the jet may enter the regime of ballistic expansion, during which additional magnetic acceleration becomes ineffective. However, recent numerical simulations by Tchekhovskoy et al. have suggested that the transition to this regime is accompanied by a spurt of acceleration. We confirm this finding numerically and attribute the acceleration to a sideways expansion of the jet, associated with a strong magnetosonic rarefaction wave that is driven into the jet when it loses pressure support, which induces a conversion of magnetic energy into kinetic energy of bulk motion. This mechanism, which we dub rarefaction acceleration, can only operate in a relativistic outflow because in this case the total energy can still be dominated by the magnetic component even in the superfast-magnetosonic regime. We analyse this process using the equations of relativistic magnetohydrodynamics and demonstrate that it is more efficient at converting internal energy into kinetic energy when the flow is magnetized than in a purely hydrodynamic outflow, as was found numerically by Mizuno et al. We show that, just as in the case of the magnetic acceleration of a collimating jet that is confined by an external pressure distribution - the collimation-acceleration mechanism - the rarefaction-acceleration process in a magnetized jet is a consequence of the fact that the separation between neighbouring magnetic flux surfaces increases faster than their cylindrical radius. However, whereas in the case of effective collimation-acceleration the product of the jet opening angle and its Lorentz factor does not exceed ~1, the addition of the rarefaction-acceleration mechanism makes it possible for this product to become >>1, in agreement with the inference from late-time panchromatic breaks in the afterglow light curves of long/soft GRBs.

  6. Design and test of a superconducting magnet in a linear accelerator for an Accelerator Driven Subcritical System

    International Nuclear Information System (INIS)

    Peng, Quanling; Xu, Fengyu; Wang, Ting; Yang, Xiangchen; Chen, Anbin; Wei, Xiaotao; Gao, Yao; Hou, Zhenhua; Wang, Bing; Chen, Yuan; Chen, Haoshu

    2014-01-01

    A batch superconducting solenoid magnet for the ADS proton linear accelerator has been designed, fabricated, and tested in a vertical dewar in Sept. 2013. A total of ten superconducting magnets will be installed into two separate cryomodules. Each cryomodule contains six superconducting spoke RF cavities for beam acceleration and five solenoid magnets for beam focusing. The multifunction superconducting magnet contains a solenoid for beam focusing and two correctors for orbit correction. The design current for the solenoid magnet is 182 A. A quench performance test shows that the operating current of the solenoid magnet can reach above 300 A after natural quenching on three occasions during current ramping (260 A, 268 A, 308 A). The integrated field strength and leakage field at the nearby superconducting spoke cavities all meet the design requirements. The vertical test checked the reliability of the test dewar and the quench detection system. This paper presents the physical and mechanical design of the batch magnets, the quench detection technique, field measurements, and a discussion of the residual field resulting from persistent current effects

  7. NONTHERMALLY DOMINATED ELECTRON ACCELERATION DURING MAGNETIC RECONNECTION IN A LOW-β PLASMA

    International Nuclear Information System (INIS)

    Li, Xiaocan; Li, Gang; Guo, Fan; Li, Hui

    2015-01-01

    By means of fully kinetic simulations, we investigate electron acceleration during magnetic reconnection in a nonrelativistic proton–electron plasma with conditions similar to solar corona and flares. We demonstrate that reconnection leads to a nonthermally dominated electron acceleration with a power-law energy distribution in the nonrelativistic low-β regime but not in the high-β regime, where β is the ratio of the plasma thermal pressure and the magnetic pressure. The accelerated electrons contain most of the dissipated magnetic energy in the low-β regime. A guiding-center current description is used to reveal the role of electron drift motions during the bulk nonthermal energization. We find that the main acceleration mechanism is a Fermi-type acceleration accomplished by the particle curvature drift motion along the electric field induced by the reconnection outflows. Although the acceleration mechanism is similar for different plasma β, low-β reconnection drives fast acceleration on Alfvénic timescales and develops power laws out of thermal distribution. The nonthermally dominated acceleration resulting from magnetic reconnection in low-β plasma may have strong implications for the  highly efficient electron acceleration in solar flares and other astrophysical systems

  8. 3-D computations and measurements of accelerator magnets for the APS

    International Nuclear Information System (INIS)

    Turner, L.R.; Kim, S.H.; Kim, K.

    1993-01-01

    The Advanced Photon Source (APS), now under construction at Argonne National Laboratory (ANL), requires dipole, quadrupole, sextupole, and corrector magnets for each of its circular accelerator systems. Three-dimensional (3-D) field computations are needed to eliminate unwanted multipole fields from the ends of long quadrupole and dipole magnets and to guarantee that the flux levels in the poles of short magnets will not cause saturation. Measurements of the magnets show good agreement with the computations

  9. Accelerator Quality HTS Dipole Magnet Demonstrator designs for the EuCARD-2, 5 Tesla 40 mm Clear Aperture Magnet

    CERN Document Server

    Kirby, G; Ballarino, A; Bottura, L; Chouika, N; Clement, S; Datskov, V; Fajardo, L; Fleiter, J; Gauthier, R; Lambert, L; Lopes, M; Perez, J; DeRijk, G; Rijllart, A; Rossi, L; Ten Kate, H; Durante, M; Fazilleau, P; Lorin, C; Haro, E; Stenvall, A; Caspi, S; Marchevsky, M; Goldacker, W; Kario, A

    2014-01-01

    Future high-energy accelerators will need very high magnetic fields in the range of 20 T. The EuCARD-2 work-package-10 is a collaborative push to take HTS materials into an accelerator quality demonstrator magnet. The demonstrator will produce 5 T standalone and between 17 T and 20 T, when inserted into the 100 mm aperture of Fresca-2 high field out-sert magnet. The HTS magnet will demonstrate the field strength and field quality that can be achieved. An effective quench detection and protection system will have to be developed to operate with the HTS superconducting materials. This paper presents a ReBCO magnet design using multi strand Roebel cable that develops a stand-alone field of 5 T in a 40 mm clear aperture and discusses the challenges associated with good field quality using this type of material. A selection of magnet designs is presented as result of a first phase of development.

  10. Accelerator Quality HTS Dipole Magnet Demonstrator Designs for the EuCARD-2, 5 Tesla 40 mm Clear Aperture Magnet

    CERN Document Server

    Kirby, G A; Ballarino, A; Bottura, L; Chouika, N; Clement, S; Datskov, V; Fajardo, L; Fleiter, J; Gauthier, R; Gentini, L; Lambert, L; Lopes, M; Perez, J C; de Rijk, G; Rijllart, A; Rossi, L; ten Kate, H; Durante, M; Fazilleau, P; Lorin, C; Härö, E; Stenvall, A; Caspi, S; Marchevsky, M; Goldacker, W; Kario, A

    2015-01-01

    Future high-energy accelerators will need very high magnetic fields in the range of 20 T. The EuCARD-2 work-package-10 is a collaborative push to take HTS materials into an accelerator quality demonstrator magnet. The demonstrator will produce 5 T standalone and between 17 T and 20 T, when inserted into the 100 mm aperture of Fresca-2 high field out-sert magnet. The HTS magnet will demonstrate the field strength and field quality that can be achieved. An effective quench detection and protection system will have to be developed to operate with the HTS superconducting materials. This paper presents a ReBCO magnet design using multi strand Roebel cable that develops a stand-alone field of 5 T in a 40 mm clear aperture and discusses the challenges associated with good field quality using this type of material. A selection of magnet designs is presented as result of a first phase of development.

  11. Qualitative models of magnetic field accelerated propagation in a plasma due to the Hall effect

    International Nuclear Information System (INIS)

    Kukushkin, A.B.; Cherepanov, K.V.

    2000-01-01

    Two qualitatively new models of accelerated magnetic field propagation (relative to normal diffusion) in a plasma due to the Hall effect are developed within the frames of the electron magnetic hydrodynamics. The first model is based on a simple hydrodynamic approach, which, in particular, reproduces the number of known theoretical results. The second one makes it possible to obtain exact analytical description of the basic characteristics of the magnetic field accelerated propagation in a inhomogeneous iso-thermic plasma, namely, the magnetic field front and its effective width [ru

  12. Magnetic field structure of the U-120 cyclotron for heavy ions acceleration

    International Nuclear Information System (INIS)

    Schwabe, J.; Starzewski, J.

    1975-01-01

    The proposed magnetic structure makes possible the acceleration, in quasi-isochronous conditions, of ions having the ratio Z/A=0,665 - 0,1 on the U-120 cyclotron in Cracow. Simultaneously, significant improvement of the accelerated beam emittance, decrease in energy scattering down to a value of about 10 -3 , and an increase in the maximum accelerated beam energy may be obtained. (author)

  13. Electron ring diagnostics with magnetic probes during roll-out and acceleration

    International Nuclear Information System (INIS)

    Schumacher, U.; Ulrich, M.

    1976-03-01

    Different methods using magnetic field probes to determine the properties of electron rings during their compression, roll-out and acceleration are presented. The results of the measurements of the electron number and the axial velocity and acceleration of the rings, as obtained with the various diagnostic devices, are discussed and compared. (orig.) [de

  14. Analysis and design of a slotless tubular permanent magnet actuator for high acceleration applications

    NARCIS (Netherlands)

    Meessen, K.J.; Paulides, J.J.H.; Lomonova, E.A.

    2009-01-01

    This paper presents the design of a linear actuator for high acceleration applications. In the analysis, a slotless tubular permanent magnet actuator is modeled by means of semianalytical field solutions. Several slotless topologies are modeled and compared to achieve the highest acceleration. A

  15. Collection of ions in a plasma by magnetic field acceleration with selective polarization

    International Nuclear Information System (INIS)

    Forsen, H.K.

    1976-01-01

    Method and apparatus are described for generating and accelerating ions in a vapor by use of relatively polarized laser radiation and a magnetic field. As applied to uranium isotope enrichment, a flowing uranium vapor has particles of the 235 U isotope type selectively ionized by laser radiation and the ionized flow is subjected to a transverse gradient in a magnetic field. The magnetic field gradient induces an acceleration on the ionized particles of 235 U which deflects them from their normal flow path toward a collecting structure. High magnetic field and corresponding high ion accelerations are achieved without loss in ionization selectivity by maintaining a polarization between the applied laser radiation and magnetic field which minimizes Zeeman splitting of the uranium energy states

  16. Sudden flux change studies in high field superconducting accelerator magnets

    International Nuclear Information System (INIS)

    Feher, S.; Bordini, B.; Carcagno, R.; Makulski, A.; Orris, D.F.; Pischalnikov, Y.M.; Sylvester, C.; Tartaglia, M.; Tompkins, J.C.; Zlobin, A.V.

    2004-01-01

    As part of the High Field Magnet Program at Fermilab many magnets have been tested which utilize multi strand Rutherford type cable made of state-of-the art Nb 3 Sn strands. During these magnet tests we observed sudden flux changes by monitoring coil voltages and the magnetic field close to the magnets. These flux changes might be linked to magnet instabilities. The voltage spike signals were correlated with quench antenna signals, a strong indication that these are magnet phenomena. With a new high resolution voltage spike detection system, we were able to observe the detailed structure of the spikes. Two fundamentally different signal shapes were distinguished, most likely generated by different mechanisms

  17. Particle Acceleration, Magnetic Field Generation and Emission from Relativistic Jets and Supernova Remnants

    Science.gov (United States)

    Nishikawa, K.-I.; Hartmann, D. H.; Hardee, P.; Hededal, C.; Mizunno, Y.; Fishman, G. J.

    2006-01-01

    We performed numerical simulations of particle acceleration, magnetic field generation, and emission from shocks in order to understand the observed emission from relativistic jets and supernova remnants. The investigation involves the study of collisionless shocks, where the Weibel instability is responsible for particle acceleration as well as magnetic field generation. A 3-D relativistic particle-in-cell (RPIC) code has been used to investigate the shock processes in electron-positron plasmas. The evolution of theWeibe1 instability and its associated magnetic field generation and particle acceleration are studied with two different jet velocities (0 = 2,5 - slow, fast) corresponding to either outflows in supernova remnants or relativistic jets, such as those found in AGNs and microquasars. Slow jets have intrinsically different structures in both the generated magnetic fields and the accelerated particle spectrum. In particular, the jet head has a very weak magnetic field and the ambient electrons are strongly accelerated and dragged by the jet particles. The simulation results exhibit jitter radiation from inhomogeneous magnetic fields, generated by the Weibel instability, which has different spectral properties than standard synchrotron emission in a homogeneous magnetic field.

  18. Numerical and experimental investigations of coupled electromagnetic and thermal fields in superconducting accelerator magnets

    International Nuclear Information System (INIS)

    Mierau, Anna

    2013-01-01

    The new international facility for antiproton and ion research FAIR will be built in Darmstadt (Germany). The existing accelerator facility of GSI Helmholtzzentrum for Heavy Ion Research will serve as a pre-accelerator for the new facility. FAIR will provide high-energy antiproton and ion beams with unprecedented intensity and quality for fundamental research of states of matter and the evolution of the universe. The central component of FAIR's accelerator and storage rings complex is a double-ring accelerator consisting of two heavy ion synchrotrons SIS100 and SIS300. The SIS100 is the primary accelerator of FAIR. The desired beam properties of SIS100 require a design of the machine much more challenging than the conventional design of existing proton and ion synchrotrons. The key technical components of each synchrotron are the special electromagnets, which allow guiding the charged particles on their orbits in the synchrotron during the acceleration processes. For a stable operation of the SIS100's the magnets have to produce extremely homogeneous magnetic fields. Furthermore, the SIS100 high-intensity ion beam modes, for example with U 28+ ions, require an ultra-high vacuum in the beam pipe of the synchrotron, which can be generated effectively only at low temperatures below 15 K. Due to the field quality requirements for the magnets, the properties of the dynamic vacuum in the beam pipe but also in order to minimise future operating costs, fast ramped superconducting magnets will be used to guide the beam in SIS100. These magnets have been developed at GSI within the framework of the FAIR project. Developing a balanced design of a superconducting accelerator magnet requires a sound understanding of the interaction between its thermal and electromagnetic fields. Of special importance in this case are the magnetic field properties such as the homogeneity of the static magnetic field in the aperture of the magnet, and the dynamic heat losses of the whole magnet

  19. Nb3Sn accelerator magnet technology R&D at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Zlobin, A.V.; Ambrosio, G.; Andreev, N.; Barzi, E.; Bossert, R.; Carcagno, R.; Chlachidze, G.; DiMarco, J.; Feher, S.; Kashikhin, V.S.; Kashikhin, V.V.; /Fermilab

    2007-06-01

    Accelerator magnets based on Nb{sub 3}Sn superconductor are being developed at Fermilab. Six nearly identical 1-m long dipole models and several mirror configurations were built and tested demonstrating magnet performance parameters and their reproducibility. The technology scale up program has started by building and testing long dipole coils. The results of this work are reported in the paper.

  20. Nb3Sn accelerator magnet technology R and D at Fermilab

    International Nuclear Information System (INIS)

    Zlobin, A.V.; Ambrosio, G.; Andreev, N.; Barzi, E.; Bossert, R.; Carcagno, R.; Chlachidze, G.; DiMarco, J.; Feher, S.; Kashikhin, V.S.; Kashikhin, V.V.; Fermilab

    2007-01-01

    Accelerator magnets based on Nb 3 Sn superconductor are being developed at Fermilab. Six nearly identical 1-m long dipole models and several mirror configurations were built and tested demonstrating magnet performance parameters and their reproducibility. The technology scale up program has started by building and testing long dipole coils. The results of this work are reported in the paper

  1. Magnetic field design for a Penning ion source for a 200 keV electrostatic accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Fathi, A., E-mail: Atefeh.Fathi115@gmail.com [Radiation Applications Department, Shahid Beheshti University, G. C., Tehran (Iran, Islamic Republic of); Feghhi, S.A.H.; Sadati, S.M. [Radiation Applications Department, Shahid Beheshti University, G. C., Tehran (Iran, Islamic Republic of); Ebrahimibasabi, E. [Department of Physics, Shahrood University of Technology, 3619995161, Shahrood (Iran, Islamic Republic of)

    2017-04-01

    In this study, the structure of magnetic field for a Penning ion source has been designed and constructed with the use of permanent magnets. The ion source has been designed and constructed for a 200 keV electrostatic accelerator. With using CST Studio Suite, the magnetic field profile inside the ion source was simulated and an appropriate magnetic system was designed to improve particle confinement. Designed system consists of two ring magnets with 9 mm distance from each other around the anode. The ion source was constructed and the cylindrical magnet and designed magnetic system were tested on the ion source. The results showed that the ignition voltage for ion source with the designed magnetic system is almost 300 V lower than the ion source with the cylindrical magnet. Better particle confinement causes lower voltage discharge to occur.

  2. Analysis of Voltage Signals from Superconducting Accelerator Magnets

    Energy Technology Data Exchange (ETDEWEB)

    Lizarazo, J.; Caspi, S.; Ferracin, P.; Joseph, J.; Lietzke, A. F.; Sabbi, G. L.; Wang, X.

    2009-10-30

    We present two techniques used in the analysis of voltage tap data collected during recent tests of superconducting magnets developed by the Superconducting Magnet Program at Lawrence Berkeley National Laboratory. The first technique was used on a quadrupole to provide information about quench origins that could not be obtained using the time-of-flight method. The second technique illustrates the use of data from transient flux imbalances occurring during magnet ramping to diagnose changes in the current-temperature margin of a superconducting cable. In both cases, the results of this analysis contributed to make improvements on subsequent magnets.

  3. Procedures for measuring the electrical properties of superconductors for accelerator magnets

    International Nuclear Information System (INIS)

    Sampson, W.B.

    1986-01-01

    There are three important electrical properties associated with the superconductor used to fabricate accelerator magnets. The most important is the critical current since this determines the performance potential of the magnet. The normal state resistivity and the volume magnetization are the other principal electrical parameters. In this report methods for measuring these parameters are presented and procedures for including self field effect and magnetoresistance are discussed

  4. Effect of coarse {gamma} grain size on the dynamic and static recrystallisation during hot working in microalloyed Nb and Nb-Ti steels

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, A.I.; Abad, R.; Lopez, B.; Rodriguez-Ibabe, J.M. [Centro de Estudios e Investigaciones Tecnicas de Guipuzcoa (CEIT), San Sebastian (Spain)

    1998-10-01

    The effect of coarse austenite grain size on the dynamic and static recrystallisation kinetics of two microalloyed Nb and Nb-Ti steels has been investigated in the present work. To characterize the dynamic recrystallisation behaviour of the austenite, continuous-torsion tests were carried out after the reheating of the specimen at different temperatures in the range 1000-1420 C. It has been observed that the occurrence of dynamic recrystallisation is dependent on the initial grain size and the deformation conditions (temperature and strain-rate). Decreasing values of the Zener-Hollomon parameter (Z) and grain size promotes dynamic recrystallisation. However for the coarser grain sizes no peaks appear on the flow curves above a determined value of Z. This value seems to decrease with increasing the grain size. An equation to predict the {epsilon}{sub p} peak strain for a wide range of grain sizes has been obtained for both steels. The effect of strain on the static recrystallisation of the austenite, having a large grain size, has been also studied. Interrupted-torsion tests were performed to determined the fractional softening. A quadratic dependence of t{sub 0.5} on strain has been observed, denoting a less dependence of recrystallisation on strain than proposed previously by other authors in the range of lower grain sizes. (orig.) 22 refs.

  5. Influence of Annealing on Microstructure and Mechanical Properties of Refractory CoCrMoNbTi0.4 High-Entropy Alloy

    Science.gov (United States)

    Zhang, Mina; Zhou, Xianglin; Zhu, Wuzhi; Li, Jinghao

    2018-04-01

    A novel refractory CoCrMoNbTi0.4 high-entropy alloy (HEA) was prepared via vacuum arc melting. After annealing treatment at different temperatures, the microstructure evolution, phase stability, and mechanical properties of the alloy were investigated. The alloy was composed of two primary body-centered cubic structures (BCC1 and BCC2) and a small amount of (Co, Cr)2Nb-type Laves phase under different annealing conditions. The microhardness and compressive strength of the heat-treated alloy was significantly enhanced by the solid-solution strengthening of the BCC phase matrix and newborn Laves phase. Especially, the alloy annealed at 1473 K (1200 °C) achieved the maximum hardness and compressive strength values of 959 ± 2 HV0.5 and 1790 MPa, respectively, owing to the enhanced volume fraction of the dispersed Laves phase. In particular, the HEAs exhibited promising high-temperature mechanical performance, when heated to an elevated temperature of 1473 K (1200 °C), with a compressive fracture strength higher than 580 MPa without fracture at a strain of more than 20 pct. This study suggests that the present refractory HEAs have immense potential for engineering applications as a new class of high-temperature structural materials.

  6. Quantitative description of a high Jc Nb-Ti superconductor during its final optimization strain. I. Microstructure, Tc, Hc2, and resistivity

    International Nuclear Information System (INIS)

    Meingast, C.; Lee, P.J.; Larbalestier, D.C.

    1989-01-01

    A most important step in the critical current density (J c ) optimization of Nb-Ti is the large final drawing strain, in which α-Ti precipitates, initially approximately equiaxed and 100--200 nm in diameter, are drawn into ribbons, whose thickness (1--2 nm) is less than the superconducting coherence length [ξ (4.2 K)∼5 nm]. Using transmission electron microscopy, the precipitate thickness, spacing, cross-sectional area, and circumference were measured over the whole final drawing strain range. Each of these parameters was found to have a simple power dependence on the wire diameter. T c , H c2 , and the resistivity (ρ n ) were also change considerably during the refinement of the precipitates. Directly after precipitation, T c increased, and (dH c2 /dT) T c and ρ n were reduced from the single-phase values. Drawing the wire returned these parameters to their single-phase values, as the precipitate thickness was reduced to less than ξ. This observation explains a long-standing peculiarity in this system, namely that the optimum H c2 of high J c conductors occurs for a composition close to Nb 46 wt.% Ti, even when the precipitation of 18 vol % of α-Ti shifts the matrix composition to a Nb-rich composition of theoretically lower H c2

  7. Effect of thermo-mechanical processing on the material properties at low temperature of a large size Al-Ni stabilized Nb-Ti/Cu superconducting cable

    Science.gov (United States)

    Langeslag, S. A. E.; Curé, B.; Sgobba, S.; Dudarev, A.; ten Kate, H. H. J.; Neuenschwander, J.; Jerjen, I.

    2014-01-01

    For future high-resolution particle experiments, a prototype for a 60 kA at 5 T, 4.2 K class conductor is realized by co-extrusion of a large, 40-strand Nb-Ti/Cu superconducting cable with a precipitation type Al-0.1wt.%Ni stabilizer. Microalloying with nickel contributes to the strength of the stabilizer, and avoids significant degradation in residual resistivity ratio, owing to its low solid solubility in aluminum. Sections of the conductor are work hardened to increase the mechanical properties of the as-extruded temper. Mechanical and resistivity characteristics are assessed as function of the amount of work hardening, at room temperature as well as at 4.2 K. Thermal treatments, like resin curing after coil winding, can cause partial annealing of the cold-worked material and reverse the strengthening effect. However, targeted thermal treatments, applied at relatively low temperature can result in precipitation hardening. The depletion of nickel in the aluminum-rich matrix around the precipitates results in an increased strength and a decreased effect of nickel on the thermal and electrical resistivity of the material. The present work aims at identifying an optimal work hardening sequence, and an optimal thermal treatment, possibly coinciding with a suitable coil resin curing cycle, for the Al-Ni stabilized superconductor.

  8. Application of Java Technology to Simulation of Transient Effects in Accelerator Magnets

    CERN Multimedia

    CERN. Geneva

    2017-01-01

    Superconducting magnets are one of the key building blocks of modern high-energy particle accelerators. Operating at extremely low temperatures (1.9 K), superconducting magnets produce high magnetic field needed to control the trajectory of beams travelling at nearly the speed of light. With high performance comes considerable complexity represented by several coupled physical domains characterized by multi-rate and multi-scale behaviour. The full exploitation of the LHC, as well as the design of its upgrades and future accelerators calls for more accurate simulations. With such a long-term vision in mind, the STEAM (Simulation of Transient Effects in Accelerator Magnets) project has been establish and is based on two pillars: (i) models developed with optimised solvers for particular sub-problems, (ii) coupling interfaces allowing to exchange information between the models. In order to tackle these challenges and develop a maintainable and extendable simulation framework, a team of developers implemented a ...

  9. Design of MgB2 superconducting dipole magnet for particle beam transport in accelerators

    DEFF Research Database (Denmark)

    Abrahamsen, A.B.; Zangenberg, N.; Baurichter, A.

    2006-01-01

    for the collaborating company Danfysik A/S, which has a strongtradition in building resistive magnets for particle accelerators[4]. A technology transfer project was formulated at the end of 2005 with the purpose to collect the knowledge about the MgB2 superconductor gained in the STVF program and in the European...... in a dipole magnet for guiding particle beams in a small scale accelerator is examined with the purpose to build lighter and smaller than the present resistive magnets. Here the criticalcurrent density of primarily MgB2 will be compared with current density determined by specifications similar to the Tevatron...... accelerator, B = 4:4 Tesla and coil aperture D = 76 mm [6], which has been identified by Danfysik A/S as interesting. It isconcluded that MgB2 is useful for the dipole application and construction of a small test coil of one half of the magnet is planned in 2007....

  10. A variable-field permanent-magnet dipole for accelerators

    International Nuclear Information System (INIS)

    Kraus, R.H. Jr.; Barlow, D.B.; Meyer, R.

    1992-01-01

    A new concept for a variable-field permanent-magnet dipole has been developed and fabricated at Los Alamos. The application requires an extremely uniform dipole field in the magnet aperture and precision variability over a large operating range. An iron-core permanent- magnet design using a shunt that was specially shaped to vary the field in a precise and reproducible fashion with shunt position. The key to this design is in the shape of the shunt. The field as a function of shunt position is very linear from 90% of the maximum field to 20% of the minimum field. The shaped shunt also results in a small maximum magnetic force attracting the shunt to the yoke allowing a simple mechanical design. Calculated and measured results agree well for the magnet

  11. Magnetic Materials Characterization and Modeling for the Enhanced Design of Magnetic Shielding of Cryomodules in Particle Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Sah, Sanjay [Virginia Commonwealth Univ., Richmond, VA (United States)

    2016-05-31

    Particle accelerators produce beams of high-energy particles, which are used for both fundamental and applied scientific research and are critical to the development of accelerator driven sub-critical reactor systems. An effective magnetic shield is very important to achieve higher quality factor (Qo) of the cryomodule of a particle accelerator. The allowed value of field inside the cavity due to all external fields (particularly the Earth’s magnetic field) is ~15 mG or less. The goal of this PhD dissertation is to comprehensively study the magnetic properties of commonly used magnetic shielding materials at both cryogenic and room temperatures. This knowledge can be used for the enhanced design of magnetic shields of cryomodes (CM) in particle accelerators. To this end, we first studied the temperature dependent magnetization behavior (M-H curves) of Amumetal and A4K under different annealing and deformation conditions. This characterized the effect of stress or deformation induced during the manufacturing processes and subsequent restoration of high permeability with appropriate heat treatment. Next, an energy based stochastic model for temperature dependent anhysteretic magnetization behavior of ferromagnetic materials was proposed and benchmarked against experimental data. We show that this model is able to simulate and explain the magnetic behavior of as rolled, deformed and annealed amumetal and A4K over a large range of temperatures. The experimental results for permeability are then used in a finite element model (FEM) in COMSOL to evaluate the shielding effectiveness of multiple shield designs at room temperature as well as cryogenic temperature. This work could serve as a guideline for future design, development and fabrication of magnetic shields of CMs.

  12. Magnetic Field Generation and Electron Acceleration in Relativistic Laser Channel

    International Nuclear Information System (INIS)

    Kostyukov, I.Yu.; Shvets, G.; Fisch, N.J.; Rax, J.M.

    2001-01-01

    The interaction between energetic electrons and a circularly polarized laser pulse inside an ion channel is studied. Laser radiation can be resonantly absorbed by electrons executing betatron oscillations in the ion channel and absorbing angular momentum from the laser. The absorbed angular momentum manifests itself as a strong axial magnetic field (inverse Faraday effect). The magnitude of this magnetic field is calculated and related to the amount of the absorbed energy. Absorbed energy and generated magnetic field are estimated for the small and large energy gain regimes. Qualitative comparisons with recent experiments are also made

  13. A facility to test short superconducting accelerator magnets at Fermilab

    International Nuclear Information System (INIS)

    Lamm, M.J.; Hess, C.; Lewis, D.; Jaffery, T.; Kinney, W.; Ozelis, J.P.; Strait, J.; Butteris, J.; McInturff, A.D.; Coulter, K.J.

    1992-10-01

    During the past four years the Superconducting Magnet R ampersand D facility at Fermilab (Lab 2) has successfully tested superconducting dipole, quadrupole, and correction coil magnets less than 2 meters in length for the SSC project and the Tevatron D0/B0 Low-β Insertion. During this time several improvements have been made to the facility that have greatly enhanced its magnet testing capabilities. Among the upgrades have been a new rotating coil and data acquisition system for measuring magnetic fields, a controlled flow liquid helium transfer line using an electronically actuated cryo valve, and stand-alone systems for measuring AC loss and training low current Tevatron correction coil packages. A description of the Lab 2 facilities is presented

  14. Estimating and Adjusting Field Quality in Superconducting Accelerator Magnets

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, R. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    1996-02-01

    The experience with estimating and adjusting field quality in RHIC and SSC magnets is discussed. An alternative approach which makes a better estimate for systematic and random values of harmonics is presented.

  15. An in situ Comparison of Electron Acceleration at Collisionless Shocks under Differing Upstream Magnetic Field Orientations

    Energy Technology Data Exchange (ETDEWEB)

    Masters, A.; Dougherty, M. K. [The Blackett Laboratory, Imperial College London, Prince Consort Road, London, SW7 2AZ (United Kingdom); Sulaiman, A. H. [Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 (United States); Stawarz, Ł. [Astronomical Observatory, Jagiellonian University, ul. Orla 171, 30-244 Krakow (Poland); Reville, B. [School of Mathematics and Physics, Queens University Belfast, Belfast BT7 1NN (United Kingdom); Sergis, N. [Office of Space Research and Technology, Academy of Athens, Soranou Efesiou 4, 11527 Athens (Greece); Fujimoto, M. [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan); Burgess, D. [School of Physics and Astronomy, Queen Mary University of London, London E1 4NS (United Kingdom); Coates, A. J., E-mail: a.masters@imperial.ac.uk [Mullard Space Science Laboratory, Department of Space and Climate Physics, University College London, Holmbury St. Mary, Dorking RH5 6NT (United Kingdom)

    2017-07-10

    A leading explanation for the origin of Galactic cosmic rays is acceleration at high-Mach number shock waves in the collisionless plasma surrounding young supernova remnants. Evidence for this is provided by multi-wavelength non-thermal emission thought to be associated with ultrarelativistic electrons at these shocks. However, the dependence of the electron acceleration process on the orientation of the upstream magnetic field with respect to the local normal to the shock front (quasi-parallel/quasi-perpendicular) is debated. Cassini spacecraft observations at Saturn’s bow shock have revealed examples of electron acceleration under quasi-perpendicular conditions, and the first in situ evidence of electron acceleration at a quasi-parallel shock. Here we use Cassini data to make the first comparison between energy spectra of locally accelerated electrons under these differing upstream magnetic field regimes. We present data taken during a quasi-perpendicular shock crossing on 2008 March 8 and during a quasi-parallel shock crossing on 2007 February 3, highlighting that both were associated with electron acceleration to at least MeV energies. The magnetic signature of the quasi-perpendicular crossing has a relatively sharp upstream–downstream transition, and energetic electrons were detected close to the transition and immediately downstream. The magnetic transition at the quasi-parallel crossing is less clear, energetic electrons were encountered upstream and downstream, and the electron energy spectrum is harder above ∼100 keV. We discuss whether the acceleration is consistent with diffusive shock acceleration theory in each case, and suggest that the quasi-parallel spectral break is due to an energy-dependent interaction between the electrons and short, large-amplitude magnetic structures.

  16. Use of permanent magnets in accelerator technology: Present and future

    International Nuclear Information System (INIS)

    Halbach, K.

    1987-01-01

    Permanent magnet systems have some generic properties that, under some circumstances, make them not only mildy preferable over electromagnets, but make it possible to do things that can not be done with any other technology. After a general discussion of these generic advantages, some specific permanent magnet systems will be described. Special emphasis will be placed on systems that have now, or are likely to have in the future, a significant impact on how some materials research is conducted

  17. Magnetic Nozzles for Plasma Thrusters: Acceleration, Thrust, and Detachment Mechanisms

    Science.gov (United States)

    2011-10-01

    neutral double layer. A very detailed study of this surface discontinuity has been culminated [4]. It had been claimed that the presence of this DL could...field assures that electrons are strongly-magnetized whereas ions are partially-magnetized. The use of the method of characteristic surfaces (i.e...z = const disk. (d) Ambipolar electric field and equipotential lines for plasmas with a 0.2 fraction of 9-times hotter electrons at the nozzle

  18. High performance current controller for particle accelerator magnets supply

    DEFF Research Database (Denmark)

    Maheshwari, Ram Krishan; Bidoggia, Benoit; Munk-Nielsen, Stig

    2013-01-01

    The electromagnets in modern particle accelerators require high performance power supply whose output is required to track the current reference with a very high accuracy (down to 50 ppm). This demands very high bandwidth controller design. A converter based on buck converter topology is used...

  19. R and D of Nb(3)Sn accelerator magnets at Fermilab

    International Nuclear Information System (INIS)

    Zlobin, A.V.; Ambrosio, G.; Andreev, N.; Barzi, E; Bordini, B.; Bossert, R.; Carcagno, R.; Chichili, D.R.; DiMarco, J.; Elementi, L.; Feher, S.; Kashikhin, V.S.; Kashikhin, V.V.; Kephart, R.; Lamm, M.; Limon, P.J.; Novitski, I.; Orris, D.; Pischalnikov, Yu.; Schlabach, P.; Stanek, R.

    2004-01-01

    Fermilab is developing and investigating different high-field magnet designs for present and future accelerators. The magnet RandD program was focused on the 10-12 T accelerator magnets based on Nb 3 Sn 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 are being performed. A series of 1-m long single-bore models of cos-theta Nb 3 Sn dipoles based on 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 wide reacted Nb 3 Sn cable, have also been fabricated and tested. Extensive theoretical studies of magnetic instabilities in Nb 3 Sn strands, cable and magnet were performed which led to successful 10 T dipole model. This paper presents the details of the Fermilab's high field accelerator magnet program, reports its status and major results, and formulates the program next steps

  20. R and D of Nb(3)Sn accelerator magnets at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Zlobin, A.V.; Ambrosio, G.; Andreev, N.; Barzi, E; Bordini, B.; Bossert, R.; Carcagno, R.; Chichili, D.R.; DiMarco, J.; Elementi, L.; Feher, S.; Kashikhin, V.S.; Kashikhin, V.V.; Kephart, R.; Lamm, M.; Limon, P.J.; Novitski, I.; Orris, D.; Pischalnikov, Yu.; Schlabach, P.; Stanek, R.; /Fermilab

    2004-11-01

    Fermilab is developing and investigating different high-field magnet designs for present and future accelerators. The magnet R&D program was focused on the 10-12 T accelerator magnets based on Nb{sub 3}Sn 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 are being performed. A series of 1-m long single-bore models of cos-theta Nb{sub 3}Sn dipoles based on 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 wide reacted Nb{sub 3}Sn cable, have also been fabricated and tested. Extensive theoretical studies of magnetic instabilities in Nb{sub 3}Sn strands, cable and magnet were performed which led to successful 10 T dipole model. This paper presents the details of the Fermilab's high field accelerator magnet program, reports its status and major results, and formulates the program next steps.

  1. Quench protection challenges in long nb3sn accelerator magnets

    Science.gov (United States)

    Salmi, Tiina-Mari; Ambrosio, G.; Caspi, S.; Chlachidze, Guram; Dhallé, Marc; Felice, Helene; Ferracin, Paolo; Marchevsky, M.; Sabbi, G. L.; ten Kate, H. H. J.

    2012-06-01

    The quench protection of the several meter long, large aperture high-field Nb3Sn quadrupoles that the LARP collaboration is developing for the LHC interaction region upgrade, requires efficient protection heaters to quickly generate large resistive segments across the windings. To support the protection design, experiments in the recently tested LARP R&D magnets are aimed to characterize the coil response to different protection schemes. In particular, the delay to quench and the final hotspot temperatures are evaluated after firing the heaters at different powering regimes and coverage. Also, the contribution of external energy extraction is investigated. Based on the performed studies and computer simulations, it seems that if the same protection efficiency per unit length that is measured in a 1 m long model magnet can be scaled to a 3.6 m long magnet, and the heater coverage can be improved, about 1 MJ/m of stored energy can be absorbed in the magnet after a quench. However, significant technology developments are needed to scale the protection heater efficiency to longer magnets and to increase the coverage.

  2. Comparison of Achievable Magnetic Fields with Superconducting and Cryogenic Permanent Magnet Undulators – A Comprehensive Study of Computed and Measured Values

    Energy Technology Data Exchange (ETDEWEB)

    Moog, E. R. [Argonne National Lab. (ANL), Argonne, IL (United States); Dejus, R. J. [Argonne National Lab. (ANL), Argonne, IL (United States); Sasaki, S. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2017-01-01

    Magnetic modeling was performed to estimate achievable magnetic field strengths of superconducting undulators (SCUs) and to compare them with those of cryogenically cooled permanent magnet undulators (CPMUs). Starting with vacuum (beam stay-clear) gaps of 4.0 and 6.0 mm, realistic allowances for beam chambers (in the SCU case) and beam liners (in the CPMU case) were added. (A 6.0-mm vacuum gap is planned for the upgraded APS). The CPMU magnetic models consider both CPMUs that use NdFeB magnets at ~150 K and PrFeB magnets at 77 K. Parameters of the magnetic models are presented along with fitted coefficients of a Halbach-type expression for the field dependence on the gap-to-period ratio. Field strengths for SCUs are estimated using a scaling law for planar SCUs; an equation for that is given. The SCUs provide higher magnetic fields than the highest-field CPMUs – those using PrFeB at 77 K – for period lengths longer than ~14 mm for NbTi-based SCUs and ~10 mm for Nb3Sn-based SCUs. To show that the model calculations and scaling law results are realistic, they are compared to CPMUs that have been built and NbTi-based SCUs that have been built. Brightness tuning curves of CPMUs (PrFeB) and SCUs (NbTi) for the upgraded APS lattice are also provided for realistic period lengths.

  3. The periodically pulsed mode of operation of magnet systems in particle accelerators

    International Nuclear Information System (INIS)

    Stange, G.

    1980-01-01

    Since in many applications in particle accelerator technology the beam duty factor, defined by the ratio of beam pulse length to the pulse to pulse period, is very small- typically in the order of 10 - 3 to 10 - 9 - it is interesting to operate the beam optical magnetic system in the periodically pulsed mode as well. Thus, by reducing the average Ohmic losses, it is possible to save energy and material. The pulsed mode of operation of magnet systems is especially adapted to those of linear accelerators and their beam transport systems, since linear accelerators are exclusively operated in this mode. But it is equally suitable for transport systems between cyclic accelerators and large storage rings as they are under development at present. (orig./WL) [de

  4. Method of correcting eddy current magnetic fields in particle accelerator vacuum chambers

    Science.gov (United States)

    Danby, Gordon T.; Jackson, John W.

    1991-01-01

    A method for correcting magnetic field aberrations produced by eddy currents induced in a particle accelerator vacuum chamber housing is provided wherein correction windings are attached to selected positions on the housing and the windings are energized by transformer action from secondary coils, which coils are inductively coupled to the poles of electro-magnets that are powered to confine the charged particle beam within a desired orbit as the charged particles are accelerated through the vacuum chamber by a particle-driving rf field. The power inductively coupled to the secondary coils varies as a function of variations in the power supplied by the particle-accelerating rf field to a beam of particles accelerated through the vacuum chamber, so the current in the energized correction coils is effective to cancel eddy current flux fields that would otherwise be induced in the vacuum chamber by power variations in the particle beam.

  5. Hall MHD Stability and Turbulence in Magnetically Accelerated Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    H. R. Strauss

    2012-11-27

    The object of the research was to develop theory and carry out simulations of the Z pinch and plasma opening switch (POS), and compare with experimental results. In the case of the Z pinch, there was experimental evidence of ion kinetic energy greatly in excess of the ion thermal energy. It was thought that this was perhaps due to fine scale turbulence. The simulations showed that the ion energy was predominantly laminar, not turbulent. Preliminary studies of a new Z pinch experiment with an axial magnetic field were carried out. The axial magnetic is relevant to magneto - inertial fusion. These studies indicate the axial magnetic field makes the Z pinch more turbulent. Results were also obtained on Hall magnetohydrodynamic instability of the POS.

  6. Voltage spike detection in high field superconducting accelerator magnets

    Energy Technology Data Exchange (ETDEWEB)

    Orris, D.F.; Carcagno, R.; Feher, S.; Makulski, A.; Pischalnikov, Y.M.; /Fermilab

    2004-12-01

    A measurement system for the detection of small magnetic flux changes in superconducting magnets, which are due to either mechanical motion of the conductor or flux jump, has been developed at Fermilab. These flux changes are detected as small amplitude, short duration voltage spikes, which are {approx}15mV in magnitude and lasts for {approx}30 {micro}sec. The detection system combines an analog circuit for the signal conditioning of two coil segments and a fast data acquisition system for digitizing the results, performing threshold detection, and storing the resultant data. The design of the spike detection system along with the modeling results and noise analysis will be presented. Data from tests of high field Nb{sub 3}Sn magnets at currents up to {approx}20KA will also be shown.

  7. Voltage spike detection in high field superconducting accelerator magnets

    International Nuclear Information System (INIS)

    Orris, D.F.; Carcagno, R.; Feher, S.; Makulski, A.; Pischalnikov, Y.M.

    2004-01-01

    A measurement system for the detection of small magnetic flux changes in superconducting magnets, which are due to either mechanical motion of the conductor or flux jump, has been developed at Fermilab. These flux changes are detected as small amplitude, short duration voltage spikes, which are ∼15mV in magnitude and lasts for ∼30(micro)sec. The detection system combines an analog circuit for the signal conditioning of two coil segments and a fast data acquisition system for digitizing the results, performing threshold detection, and storing the resultant data. The design of the spike detection system along with the modeling results and noise analysis will be presented. Data from tests of high field Nb3Sn magnets at currents up to ∼20KA will also be shown

  8. High field superconducting magnets for accelerators and particle beams

    International Nuclear Information System (INIS)

    Allinger, J.; Danby, G.; Jackson, J.

    1975-01-01

    Experience in designing precision superconducting magnets for fields up to 60 kG is described. Realizable construction tolerances and their impact on field accuracy are discussed. For dipole fields up to 60 kG or more, rectangular coil window frame type magnets are compared with circular or elliptical coil designs. In all cases, the same superconductor current density versus maximum field performance is assumed. The comparison will include field quality and correction required as a function of aperture size, stored energy, ampere turns required, and overall magnet size. In quadrupole design the impact of the allowed superconductor current density being roughly inversely proportional to peak field is severe. For gradients up to one Tesla/cm or greater, similar comparisons for different types of quadrupole construction are made. (U.S.)

  9. Development of scanning magnet for 750 keV DC accelerator

    International Nuclear Information System (INIS)

    Pramod, R.; Pankaj Kumar; Venkateswaran, S.V.; Bapna, S.C.

    2003-01-01

    In the radiation processing technologies, the surface to be irradiated has to be as large as possible, but keeping a good uniformity of the absorbed dose. To attain such a goal, the beam should be scanned in a plane perpendicular on the displacement of the conveyor belt. Therefore, scanning magnets are necessary. A scanning magnet should ensure the homogeneity of the absorbed dose (and, similarly, of the beam current distribution) on the items to be irradiated. In this paper some simple relations needed in the design of the scanning magnets are deduced, the design and fabrication aspects of the scanning magnet for the 750 keV DC accelerator are discussed

  10. Design, simulation and construction of quadrupole magnets for focusing electron beam in powerful industrial electron accelerator

    Directory of Open Access Journals (Sweden)

    S KH Mousavi

    2015-09-01

    Full Text Available In this paper the design and simulation of quadrupole magnets and electron beam optical of that by CST Studio code has been studied. Based on simulation result the magnetic quadrupole has been done for using in beam line of first Iranian powerful electron accelerator. For making the suitable magnetic field the effects of material and core geometry and coils current variation on quadrupole magnetic field have been studied. For test of quadrupole magnet the 10 MeV beam energy and 0.5 pi mm mrad emittance of input beam has been considered. We see the electron beam through the quadrupole magnet focus in one side and defocus in other side. The optimum of distance between two quadrupole magnets for low emittance have been achieved. The simulation results have good agreement with experimental results

  11. Kinetic Simulations of Plasma Energization and Particle Acceleration in Interacting Magnetic Flux Ropes

    Science.gov (United States)

    Du, S.; Guo, F.; Zank, G. P.; Li, X.; Stanier, A.

    2017-12-01

    The interaction between magnetic flux ropes has been suggested as a process that leads to efficient plasma energization and particle acceleration (e.g., Drake et al. 2013; Zank et al. 2014). However, the underlying plasma dynamics and acceleration mechanisms are subject to examination of numerical simulations. As a first step of this effort, we carry out 2D fully kinetic simulations using the VPIC code to study the plasma energization and particle acceleration during coalescence of two magnetic flux ropes. Our analysis shows that the reconnection electric field and compression effect are important in plasma energization. The results may help understand the energization process associated with magnetic flux ropes frequently observed in the solar wind near the heliospheric current sheet.

  12. Modeling of electron cyclotron resonance acceleration in a stationary inhomogeneous magnetic field

    Directory of Open Access Journals (Sweden)

    Valeri D. Dougar-Jabon

    2008-04-01

    Full Text Available In this paper, the cyclotron autoresonance acceleration of electrons in a stationary inhomogeneous magnetic field is studied. The trajectory and energy of electrons are found through a numerical solution of the relativistic Newton-Lorentz equation by a finite difference method. The electrons move along a TE_{112} cylinder cavity in a steady-state magnetic field whose axis coincides with the cavity axis. The magnetic field profile is such that it keeps the phase difference between the electric microwave field and the electron velocity vector within the acceleration phase band. The microwaves amplitude of 6  kV/cm is used for numerical calculations. It is shown that an electron with an initial longitudinal energy of 8 keV can be accelerated up to 260 keV by 2.45 GHz microwaves at a distance of 17 cm.

  13. Programmable Power Supply for AC Switching Magnet of Proton Accelerator

    CERN Document Server

    Jeong, Seong-Hun; Kang Heung Sik; Lee, Chi-Hwan; Lee, Hong-Gi; Park, Ki-Hyeon; Ryu, Chun-Kil; Sik Han, Hong; Suck Suh, Hyung

    2005-01-01

    The 100-MeV PEFP proton linac has two proton beam extraction lines for user' experiment. Each extraction line has 5 beamlines and has 5 Hz operating frequency. An AC switching magnet is used to distribute the proton beam to the 5 beamlines, An AC switching magnet is powered by PWM-controlled bipolar switching-mode converters. This converter is designed to operate at ±350A, 5 Hz programmable step output. The power supply is employed IGBT module and has controlled by a DSP (Digital Signal Process). This paper describes the design and test results of the power supply.

  14. Development and manufacturing of a Nb$_{3}$Sn quadrupole magnet Model at CEA/Saclay for TESLA Interaction Region

    CERN Document Server

    Durante, Maria; Fratini, M; Leboeuf, D; Segreti, M; Védrine, Pierre; 10.1109/TASC.2004.829129

    2004-01-01

    One possible application of Nb/sub 3/Sn, whose superconducting properties far exceed those of NbTi, is the fabrication of short and powerful quadrupole magnets for the interaction regions of large particle accelerators. In some projects, as in the future linear collider TESLA, the quadrupole magnets are inside the detector solenoid and must operate in its background field. This situation gives singular Lorentz force distribution in the ends of the magnet. To learn about Nb/sub 3/Sn technology, evaluate fabrication techniques and test the interaction with a solenoidal field, DAPNIA /SACM at CEA/Saclay has started the manufacturing of a 1-m-long, 56- mm-single-aperture quadrupole magnet model. The model relies on the same coil geometry as the LHC arc quadrupole magnets, but has no iron yoke. It will produce a nominal field gradient of 211 T/m at 11,870 A. The coils are wound from Rutherford-type cables insulated with glass fiber tape, before being heat-treated and vacuum-impregnated with epoxy resin. Laminated,...

  15. THE EFFECT OF COOLING ON PARTICLE TRAJECTORIES AND ACCELERATION IN RELATIVISTIC MAGNETIC RECONNECTION

    Energy Technology Data Exchange (ETDEWEB)

    Kagan, Daniel; Nakar, Ehud [Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978 (Israel); Piran, Tsvi, E-mail: daniel.kagan@mail.huji.ac.il [Racah Institute of Physics, The Hebrew University, Jerusalem 91904 (Israel)

    2016-12-20

    The maximum synchrotron burnoff limit of 160 MeV represents a fundamental limit to radiation resulting from electromagnetic particle acceleration in one-zone ideal plasmas. In magnetic reconnection, however, particle acceleration and radiation are decoupled because the electric field is larger than the magnetic field in the diffusion region. We carry out two-dimensional particle-in-cell simulations to determine the extent to which magnetic reconnection can produce synchrotron radiation above the burnoff limit. We use the test particle comparison (TPC) method to isolate the effects of cooling by comparing the trajectories and acceleration efficiencies of test particles incident on such a reconnection region with and without cooling them. We find that the cooled and uncooled particle trajectories are typically similar during acceleration in the reconnection region, and derive an effective limit on particle acceleration that is inversely proportional to the average magnetic field experienced by the particle during acceleration. Using the calculated distribution of this average magnetic field as a function of uncooled final particle energy, we find analytically that cooling does not affect power-law particle energy spectra except at energies far above the synchrotron burnoff limit. Finally, we compare fully cooled and uncooled simulations of reconnection, confirming that the synchrotron burnoff limit does not produce a cutoff in the particle energy spectrum. Our results indicate that the TPC method accurately predicts the effects of cooling on particle acceleration in relativistic reconnection, and that, even far above the burnoff limit, the synchrotron energy of radiation produced in reconnection is not limited by cooling.

  16. THE EFFECT OF COOLING ON PARTICLE TRAJECTORIES AND ACCELERATION IN RELATIVISTIC MAGNETIC RECONNECTION

    International Nuclear Information System (INIS)

    Kagan, Daniel; Nakar, Ehud; Piran, Tsvi

    2016-01-01

    The maximum synchrotron burnoff limit of 160 MeV represents a fundamental limit to radiation resulting from electromagnetic particle acceleration in one-zone ideal plasmas. In magnetic reconnection, however, particle acceleration and radiation are decoupled because the electric field is larger than the magnetic field in the diffusion region. We carry out two-dimensional particle-in-cell simulations to determine the extent to which magnetic reconnection can produce synchrotron radiation above the burnoff limit. We use the test particle comparison (TPC) method to isolate the effects of cooling by comparing the trajectories and acceleration efficiencies of test particles incident on such a reconnection region with and without cooling them. We find that the cooled and uncooled particle trajectories are typically similar during acceleration in the reconnection region, and derive an effective limit on particle acceleration that is inversely proportional to the average magnetic field experienced by the particle during acceleration. Using the calculated distribution of this average magnetic field as a function of uncooled final particle energy, we find analytically that cooling does not affect power-law particle energy spectra except at energies far above the synchrotron burnoff limit. Finally, we compare fully cooled and uncooled simulations of reconnection, confirming that the synchrotron burnoff limit does not produce a cutoff in the particle energy spectrum. Our results indicate that the TPC method accurately predicts the effects of cooling on particle acceleration in relativistic reconnection, and that, even far above the burnoff limit, the synchrotron energy of radiation produced in reconnection is not limited by cooling.

  17. Mechanical engineering and design criteria for the Magnetically Insulated Transmission Experiment Accelerator

    International Nuclear Information System (INIS)

    Staller, G.E.; Hamilton, I.D.; Aker, M.F.; Fifer, H.G.

    1978-02-01

    A single-unit electron beam accelerator was designed, fabricated, and assembled in Sandia's Technical Area V to conduct magnetically insulated transmission experiments. Results of these experiments will be utilized in the future design of larger, more complex accelerators. This design makes optimum use of existing facilities and equipment. When designing new components, possible future applications were considered as well as compatibility with existing facilities and hardware

  18. Particle acceleration through the resonance of high magnetic field and high frequency electromagnetic wave

    International Nuclear Information System (INIS)

    Hong, Liu; He, X.T.; Chen, S.G.; Zhang, W.Y.; He, X.T.; Hong, Liu

    2004-01-01

    We propose a new particle acceleration mechanism. Electrons can be accelerated to relativistic energy within a few electromagnetic wave cycles through the mechanism which is named electromagnetic and magnetic field resonance acceleration (EMRA). We find that the electron acceleration depends not only on the electromagnetic wave intensity, but also on the ratio between electron Larmor frequency and electromagnetic wave frequency. As the ratio approaches to unity, a clear resonance peak is observed, corresponding to the EMRA. Near the resonance regime, the strong magnetic fields still affect the electron acceleration dramatically. We derive an approximate analytical solution of the relativistic electron energy in adiabatic limit, which provides a full understanding of this phenomenon. In typical parameters of pulsar magnetospheres, the mechanism allows particles to increase their energies through the resonance of high magnetic field and high frequency electromagnetic wave in each electromagnetic wave period. The energy spectra of the accelerated particles exhibit the synchrotron radiation behavior. These can help to understand the remaining emission of high energy electron from radio pulsar within supernova remnant. The other potential application of our theory in fast ignition scheme of inertial confinement fusion is also discussed. (authors)

  19. Permanent Magnets In Steerers Of The Beam Extracted From The Electron Accelerator

    CERN Document Server

    Dovbnya, A N; Shendrik, V A; Tolstoj, A E

    2004-01-01

    The results of test bench simulation and magnetic measurements were used to develop and manufacture "dipole magnet"-type units with a constant field of intensity up to 1.8 kOe in the working gap, 3 to 3.5 cm in height. The operating experience at the technological accelerators has shown that these devices are convenient in service, are easy-to-transport and can be used for solving the various problems in electron beam formation and steering at the exit of the accelerator.

  20. Accurate Calculation of Magnetic Fields in the End Regions of Superconducting Accelerator Magnets using the BEM-FEM Coupling Method

    CERN Document Server

    Kurz, S

    1999-01-01

    In this paper a new technique for the accurate calculation of magnetic fields in the end regions of superconducting accelerator magnets is presented. This method couples Boundary Elements (BEM) which discretize the surface of the iron yoke and Finite Elements (FEM) for the modelling of the nonlinear interior of the yoke. The BEM-FEM method is therefore specially suited for the calculation of 3-dimensional effects in the magnets, as the coils and the air regions do not have to be represented in the finite-element mesh and discretization errors only influence the calculation of the magnetization (reduced field) of the yoke. The method has been recently implemented into the CERN-ROXIE program package for the design and optimization of the LHC magnets. The field shape and multipole errors in the two-in-one LHC dipoles with its coil ends sticking out of the common iron yoke is presented.

  1. Nb$_{3}$Sn quadrupole magnets for the LHC IR

    CERN Document Server

    Sabbi, G L; Chiesa, L; Coccoli, M; Dietderich, D R; Ferracin, P; Gourlay, S A; Hafalia, R R; Lietzke, A F; McInturff, A D; Scanlan, R M

    2003-01-01

    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 * 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. (25 refs).

  2. Nb3Sn Quadrupole Magnets for the LHC IR

    International Nuclear Information System (INIS)

    Sabbi, G.; Caspi, S.; Chiesa, L.; Coccoli, M.; Dietderich, D.R.; Ferracin, P.; Gourlay, S.A.; Hafalia, R.R.; Lietzke, A.F.; McInturff, A.D.; Scanlan, R.M.

    2001-01-01

    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 34 cm -2 s -1 at the Large Hadron Collider (LHC). At present, Nb 3 Sn is the only practical conductor which can meet these requirements. Since Nb 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.

  3. A compact permanent magnet cyclotrino for accelerator mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Young, A.T.; Clark, D.J.; Kunkel, W.B.; Leung, K.N.; Li, C.Y. [Lawrence Berkeley Lab., CA (United States)

    1995-02-01

    The authors describe the development of a new instrument for the detection of trace amounts of rare isotopes, a Cyclotron Mass Spectrometer (CMS). A compact low energy cyclotron optimized for high mass resolution has been designed and has been fabricated. The instrument has high sensitivity and is designed to measure carbon-14 at abundances of < 10{sup {minus}12}. A novel feature of the instrument is the use of permanent magnets to energize the iron poles of the cyclotron. The instrument uses axial injection, employing a spiral inflector. The instrument has been assembled and preliminary measurements of the magnetic field show that it has a uniformity on the order of 2 parts in 10{sup 4}.

  4. A Conduction-Cooled Superconducting Magnet System-Design, Fabrication and Thermal Tests

    DEFF Research Database (Denmark)

    Song, Xiaowei (Andy); Holbøll, Joachim; Wang, Qiuliang

    2015-01-01

    A conduction-cooled superconducting magnet system with an operating current of 105.5 A was designed, fabricated and tested for material processing applications. The magnet consists of two coaxial NbTi solenoid coils with an identical vertical height of 300 mm and is installed in a high-vacuumed c......A conduction-cooled superconducting magnet system with an operating current of 105.5 A was designed, fabricated and tested for material processing applications. The magnet consists of two coaxial NbTi solenoid coils with an identical vertical height of 300 mm and is installed in a high......-vacuumed cryostat. A two-stage GM cryocooler with a cooling power of 1.5 W at 4.2 K in the second stage is used to cool the system from room temperature to 4.2 K. In this paper, the detailed design, fabrication, thermal analysis and tests of the system are presented....

  5. Instrument for the measuring magnetic field characteristics of induction acceleration

    International Nuclear Information System (INIS)

    Novikov, V.M.; Romasheva, P.I.

    1976-01-01

    An instrument for the measuring instantaneous values of variable and pulsed magnetic fields with an amplitide of 0.005-2.0 and duration of 5x10 -6 -2x10 -2 sec is described. Time resolution is not less than 0.5 musec, measuring accuracy is about 1%. Induction coils are used as sensors. A digital voltmeter serves as a secondary recorder

  6. Explosive coalescence of magnetic islands and explosive particle acceleration

    International Nuclear Information System (INIS)

    Tajima, T.; Sakai, J.I.

    1985-07-01

    An explosive reconnection process associated with the nonlinear evolution of the coalescence instability is found through studies of the electromagnetic particle simulation and the magnetohydrodynamic particle simulation. The explosive coalescence is a process of magnetic collapse, in which we find the magnetic and electrostatic field energies and temperatures (ion temperature in the coalescing direction, in particular) explode toward the explosion time t 0 as (t 0 - t)/sup -8/3/, (t 0 - t) -4 , and (t 0 - t)/sup -8/3/, respectively for a canonical case. Single-peak, double-peak, and triple-peak structures of magnetic energy, temperature, and electrostatic energy, respectively, are observed on the simulation as overshoot amplitude oscillations and are theoretically explained. The heuristic model of Brunel and Tajima is extended to this explosive coalescence in order to extract the basic process. Since the explosive coalescence exhibits self-similarity, a temporal universality, we theoretically search for a self-similar solution to the two-fluid plasma equations

  7. Superconducting magnetic quadrupole

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J.W.; Shepard, K.W.; Nolen, J.A.

    1995-08-01

    A design was developed for a 350 T/m, 2.6-cm clear aperture superconducting quadrupole focussing element for use in a very low q/m superconducting linac as discussed below. The quadrupole incorporates holmium pole tips, and a rectangular-section winding using standard commercially-available Nb-Ti wire. The magnet was modeled numerically using both 2D and 3D codes, as a basis for numerical ray tracing using the quadrupole as a linac element. Components for a prototype singlet are being procured during FY 1995.

  8. Advanced materials, strands, and conductors for particle accelerators. Technical report for the year 1994

    International Nuclear Information System (INIS)

    1994-01-01

    The authors research for the Division of High Energy Physics (HEP) began with studies of both the superconducting and matrix components of multifilamentary composites, viz (1) attempts to increase the flux-pinning strength in NbTi, and (2) a method of suppressing proximity effect coupling in fine-filament strands. The latter was fully successful, and stands ready to be invoked as soon as the need arises to: (a) very closely space the filaments in the interests of quality, or (b) re-introduce fine-filament composites for strand-magnetization reduction or AC-loss minimization. But there were also many spin-offs during the life of the program, as indicated in the complete list of publications (copy available on request). For instance, the various other effects and properties that were studied and published over the period of this association with HEP include: (i) reduction in T c due to proximity effect between thin αphase precipitates and the NbTi matrix, (ii) critical field enhancement with reduction of filament diameter in fine-filament composites, (iii) studies and systematics of AC loss in composite strands, (iv) compensation of strand magnetization by means of Ni plating or filament substitution, (v) hysteretic loss due to surface pinning in multifilamentary NbTi, (vi) flux creep in SSC-type strands, (vii) temperature and field dependence of eddy current decay, (vii) influence of Mn doping on the properties of NbTi, (viii) transverse and longitudinal resistivities (including a size-effect contribution) in strands with various filament/matrix configurations

  9. The LACARA Vacuum Laser Accelerator Experiment: Beam Positioning and Alignment in a Strong Magnetic Field

    International Nuclear Information System (INIS)

    Shchelkunov, Sergey V.; Marshall, T. C.; Hirshfield, J. L.; Wang, Changbiao; LaPointe, M. A.

    2006-01-01

    LACARA (laser cyclotron auto-resonance accelerator) is a vacuum laser accelerator of electrons that is under construction at the Accelerator Test Facility (ATF), Brookhaven National Laboratory. It is expected that the experiment will be assembled by September 2006; this paper presents progress towards this goal. According to numerical studies, as an electron bunch moves along the LACARA solenoidal magnetic field (∼5.2 T, length ∼1 m), it will be accelerated from 50 to ∼75 MeV by interacting with a 0.8 TW Gaussian-mode circularly polarized optical pulse provided by the ATF CO2 10.6μm laser system. The LACARA laser transport optics must handle 10 J and be capable of forming a Gaussian beam inside the solenoid with a 1.4 mm waist and a Rayleigh range of 60 cm. The electron optics must transport a bunch having input emittance of 0.015 mm-mrad and 100 μm waist through the magnet. Precision alignment between the electron beam and the solenoid magnetic axis is required, and a method to achieve this is described in detail. Emittance- filtering may be necessary to yield an accelerated bunch having a narrow (∼1%) energy-spread

  10. Acceleration of particles by electron plasma waves in a moderate magnetic field

    International Nuclear Information System (INIS)

    Smith, D.F.

    1976-01-01

    A general scheme is established to examine any magnetohydrodynamic (MHD) configuration for its acceleration potential including the effects of various types of plasma waves. The analysis is restricted to plasma waves in a magnetic field with electron cyclotron frequency less than, but comparable to, the electron plasma frequency (moderate field). The general role of electron plasma waves is examined in this paper independent of a specific MHD configuration or generating mechanism in the weak turbulence limit. The evolution of arbitrary wave spectra in a non-relativistic plasma is examined, and it is shown that the nonlinear process of induced scattering on the polarization clouds of ions leads to the collapse of the waves to an almost one-dimensional spectrum directed along the magnetic field. The subsequent acceleration of non-relativistic and relativistic particles is considered. It is shown for non-relativistic particles that when the wave distribution has a negative slope the acceleration is retarded for lower velocities and enhanced for higher velocities compared to acceleration by an isotropic distribution of electron plasma waves in a magnetic field. This change in behaviour is expected to affect the development of wave spectra and the subsequent acceleration spectrum. (Auth.)

  11. Superconducting magnets and cryogenics for the steady state superconducting tokamak SST-1

    International Nuclear Information System (INIS)

    Saxena, Y.C.

    2000-01-01

    SST-1 is a steady state superconducting tokamak for studying the physics of the plasma processes in tokamak under steady state conditions and to learn technologies related to the steady state operation of the tokamak. SST-1 will have superconducting magnets made from NbTi based conductors operating at 4.5 K temperature. The design of the superconducting magnets and the cryogenic system of SST-1 tokamak are described. (author)

  12. Applied metrology in the production of superconducting model magnets for particle accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Ferradas Troitino, Jose [CERN; Bestmann, Patrick [CERN; Bourcey, Nicolas [CERN; Carlon Zurita, Alejandro [CERN; Cavanna, Eugenio [ASG Supercond., Genova; Ferracin, Paolo [CERN; Ferradas Troitino, Salvador [CERN; Holik, Eddie Frank [Fermilab; Izquierdo Bermudez, Susana [CERN; Lackner, Friedrich [CERN; Löffler, Christian [CERN; Maury, Gregory [CERN; Perez, Juan Carlos [CERN; Savary, Frederic [CERN; Semeraro, Michela [CERN; Vallone, Giorgio [CERN

    2017-12-22

    The production of superconducting magnets for particle accelerators involves high precision assemblies and tight tolerances, in order to achieve the requirements for their appropriate performance. It is therefore essential to have a strict control and traceability over the geometry of each component of the system, and also to be able to compensate possible inherent deviations coming from the production process.

  13. Electron Acceleration by Cascading Reconnection in the Solar Corona. I. Magnetic Gradient and Curvature Drift Effects

    Czech Academy of Sciences Publication Activity Database

    Zhou, X.; Büchner, J.; Bárta, Miroslav; Gan, W.; Liu, S.

    2015-01-01

    Roč. 815, č. 1 (2015), 6/1-6/17 ISSN 0004-637X Institutional support: RVO:67985815 Keywords : acceleration of particles * magnetic reconnection * magnetohydrodynamics Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 5.909, year: 2015

  14. Automated installations for reeling up of superconducting magnet windings of the accelerating-storage complex

    International Nuclear Information System (INIS)

    Dolzhenkov, V.I.; Elistratov, V.V.; Kuznetsov, Yu.V.; Petrov, V.B.; Popov, V.V.; Savel'ev, A.V.; Sokolov, B.V.; Sytnik, V.V.; Tarakanov, N.M.; Ustinov, E.A.

    1992-01-01

    An automated facility for reeling up the windings of model and full-scale superconducting magnets of the accelerating-storage complex is described. The control system monitors superconducting cable tension, transport carriage linear velocity and some other parameters. Maximum length of the winded coils is 6 m. Cable tension stability - 5%

  15. Design of Nb$_{3}$Sn magnetic devices to study the superconductor degradation under variable mechanical load

    CERN Document Server

    Regis, Federico

    2009-01-01

    The Large Hadron Collider (LHC) is a two-ring, superconducting synchrotron accelerator and collider installed in a 27 km long tunnel aiming at the discovery of the Higgs particle and the study of rare events with center mass collision energies of up to 14 TeV. The number of collisions per unit of area and time in a collider are evaluated trough the Luminosity function. Inside the LHC, superconducting magnets aligned with a precision of a few tenths of millimeters are used to bend and focus the particle trajectories. The LHC can be considered as the state of the art for superconducting magnets using the Nb-Ti superconductor technology. Therefore, a higher luminosity and beam energy can be achieved in the LHC only by using a more performing superconductor, such as the Nb$_{3}$Sn. This is considered as the most suitable superconductor to be used in high field magnets, allowing peak field of the order of 15 T. Nevertheless, the critical current jc variations in a Nb$_{3}$Sn has been found as strongly dependent on...

  16. Time variations of fields in superconducting magnets and their effects on accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Herrup, D.A.; Syphers, M.J.; Johnson, D.E.; Johnson, R.P.; Tollestrup, A.V.; Hanft, R.W.; Brown, B.C.; Lamm, M.J.; Kuchnir, M.; McInturff, A.D.

    1988-08-22

    A report on the time dependence of magnetic fields in the superconducting magnets of the Fermilab Tevatron has been published. A field variation of order 1 gauss at the aperture radius is observed. Studies on both full sized Tevatron, dipoles and prototype magnets have been used to elucidate these effects. Explanations based on eddy currents in the coil matrix or on flux creep in the superconducting filaments are explored with these tests. Measurement results and techniques for controlling the effect based on new laboratory tests and the latest accelerator operation are presented. 9 refs., 4 figs.

  17. Time variations of fields in superconducting magnets and their effects on accelerators

    International Nuclear Information System (INIS)

    Herrup, D.A.; Syphers, M.J.; Johnson, D.E.

    1988-01-01

    A report on the time dependence of magnetic fields in the superconducting magnets of the Fermilab Tevatron has been published. A field variation of order 1 gauss at the aperture radius is observed. Studies on both full sized Tevatron, dipoles and prototype magnets have been used to elucidate these effects. Explanations based on eddy currents in the coil matrix or on flux creep in the superconducting filaments are explored with these tests. Measurement results and techniques for controlling the effect based on new laboratory tests and the latest accelerator operation are presented. 9 refs., 4 figs

  18. Magnet R and D for the US LHC Accelerator Research Program (LARP)

    International Nuclear Information System (INIS)

    Gourlay, S.A.; Ambrosio, G.; Andreev, N.; Anerella, M.; Barzi, E.; Bossert, R.; Caspi, S.; Dietderich, D.R.; Ferracin, P.; Gupta, R.; Ghosh, A.; Hafalia, A.R.; Hannaford, C.R.; Harrison, M.; Kashikhin, V.S.; Kashikhin, V.V.; Lietzke, A.F.; Mattafirri, S.; McInturff, A.D.; Nobrega, F.; Novitsky, I.; Sabbi, G.L.; Schmazle, J.; Stanek, R.; Turrioni, D.; Wanderer, P.; Yamada, R.; Zlobin, A.V.

    2006-01-01

    In 2004, the US DOE established the LHC Accelerator Research Program (LARP) with the goal of developing a technology base for future upgrades of the LHC. The focus of the magnet program, which is a collaboration of three US laboratories, BNL, FNAL and LBNL, is on development of high gradient quadrupoles using Nb 3 Sn superconductor. Other program components address issues regarding magnet design, radiation-hard materials, long magnet scale-up, quench protection, fabrication techniques and conductor and cable R and D. This paper presents an overall view of the program with emphasis on the current quadrupole project and outlines the long-term goals of the program

  19. Double-layer ion acceleration triggered by ion magnetization in expanding radiofrequency plasma sources

    International Nuclear Information System (INIS)

    Takahashi, Kazunori; Charles, Christine; Boswell, Rod W.; Fujiwara, Tamiya

    2010-01-01

    Ion energy distribution functions downstream of the source exit in magnetically expanding low-pressure plasmas are experimentally investigated for four source tube diameters ranging from about 5 to 15 cm. The magnetic-field threshold corresponding to a transition from a simple expanding plasma to a double layer-containing plasma is observed to increase with a decrease in the source tube diameter. The results demonstrate that for the four geometries, the double layer and the accelerated ion beam form when the ion Larmour radius in the source becomes smaller than the source tube radius, i.e., when the ions become magnetized in the source tube.

  20. Magnetic field alignment for a 20 MeV linear induction accelerator

    International Nuclear Information System (INIS)

    Zhang Wenwei; Pan Haifeng; Li Hong; Liu Yunlong; Zhang Linwen

    2002-01-01

    'Dragon-1' accelerator now is being constructed in CAEP. It will produce high current pulse electron beams. The main components of the accelerator include 72 induction accelerating cells and 18 connection cells with ports for beam di gnostic hardware and vacuum pump. In order to acquire high quality beams, a lot of problems have to be addressed such as to reduce the emittance, to control the increase of corkscrew and so on. The alignment of the focus magnetic field is the most concerned. A laser track has been used for mechanical alignment, magnetic alignment is performed by using pulsed-wire technique, and the natural tilt errors is corrected by a pair of steering coil, which is located inside the cell

  1. The role of magnetic loops in particle acceleration at nearly perpendicular shocks

    Science.gov (United States)

    Decker, R. B.

    1993-01-01

    The acceleration of superthermal ions is investigated when a planar shock that is on average nearly perpendicular propagates through a plasma in which the magnetic field is the superposition of a constant uniform component plus a random field of transverse hydromagnetic fluctuations. The importance of the broadband nature of the transverse magnetic fluctuations in mediating ion acceleration at nearly perpendicular shocks is pointed out. Specifically, the fluctuations are composed of short-wavelength components which scatter ions in pitch angle and long-wavelength components which are responsible for a spatial meandering of field lines about the mean field. At nearly perpendicular shocks the field line meandering produces a distribution of transient loops along the shock. As an application of this model, the acceleration of a superthermal monoenergetic population of seed protons at a perpendicular shock is investigated by integrating along the exact phase-space orbits.

  2. Magnetization as a critical defining parameter for strand in precision dipole applications implications for field error and F-J stability

    CERN Document Server

    Collings, E W; Lee, E

    2001-01-01

    In hadron accelerators, between low energy particle injection and beam accumulation, the guiding dipoles are ramped at some rate dB/dt. Both at injection and during ramping the static and dynamic magnetizations of the magnet windings introduce multipolar distortions into the beam-line field. Dynamic magnetization, controllable by cable design, is estimated and used to provide a criterion against which to evaluate the allowable magnitude of static (persistent-current) magnetization, M, from a field-quality standpoint. The it is of NbTi and advanced Nb/sub 3/Sn conductors are compared and with regard to the latter the question of flux-jump stability is explored. A magnetization criterion for such stability is presented and compared to experiment. It is noted that since Delta M is proportional to critical current density, J/sub c/, and the strand's effective filament diameter, d/sub eff/, the latter has frequently been specified as a critical parameter, although it will need to be re-specified with every increas...

  3. Particle Acceleration and Magnetic Field Generation in Electron-Positron Relativistic Shocks

    Science.gov (United States)

    Nishikawa, K.-I.; Hardee, P.; Richardson, G.; Preece, R.; Sol, H.; Fishman, G. J.

    2005-01-01

    Shock acceleration is a ubiquitous phenomenon in astrophysical plasmas. Plasma waves and their associated instabilities (e.g., Buneman, Weibel, and other two-stream instabilities) created in collisionless shocks are responsible for particle (electron, positron, and ion) acceleration. Using a three-dimensional relativistic electromagnetic particle (REMP) code, we have investigated particle acceleration associated with a relativistic electron-positron jet front propagating into an ambient electron-positron plasma with and without initial magnetic fields. We find small differences in the results for no ambient and modest ambient magnetic fields. New simulations show that the Weibel instability created in the collisionless shock front accelerates jet and ambient particles both perpendicular and parallel to the jet propagation direction. Furthermore, the nonlinear fluctuation amplitudes of densities, currents, and electric and magnetic fields in the electron-positron shock are larger than those found in the electron-ion shock studied in a previous paper at a comparable simulation time. This comes from the fact that both electrons and positrons contribute to generation of the Weibel instability. In addition, we have performed simulations with different electron skin depths. We find that growth times scale inversely with the plasma frequency, and the sizes of structures created by tine Weibel instability scale proportionally to the electron skin depth. This is the expected result and indicates that the simulations have sufficient grid resolution. While some Fermi acceleration may occur at the jet front, the majority of electron and positron acceleration takes place behind the jet front and cannot be characterized as Fermi acceleration. The simulation results show that the Weibel instability is responsible for generating and amplifying nonuniform, small-scale magnetic fields, which contribute to the electron s (positron s) transverse deflection behind the jet head. This

  4. The role of magnetic-field-aligned electric fields in auroral acceleration

    International Nuclear Information System (INIS)

    Block, L.P.; Faelthammar, C.G.

    1990-01-01

    Electric field measurements on the Swedish satellite Viking have confirmed and extended earlier observations on S3-3 and provided further evidence of the role of dc electric fields in auroral acceleration processes. On auroral magnetic field lines the electric field is strongly fluctuating both transverse and parallel to the magnetic field. The significance of these fluctuations for the auroral acceleration process is discussed. A definition of dc electric fields is given in terms of their effects on charged particles. Fluctuations below several hertz are experienced as dc by typical auroral electrons if the acceleration length is a few thousand kilometers. For ions the same is true below about 0.1 Hz. The magnetic-field-aligned (as well as the transverse) component of the electric field fluctuations has a maximum below 1 Hz, in a frequency range that appears as dc to the electrons but not to the ions. This allows it to cause a selective acceleration, which may be important in explaining some of the observed characteristics of auroral particle distributions. The electric field observations on Viking support the conclusion that magnetic-field-aligned potential drops play an important role in auroral acceleration, in good agreement with particle observations boht on Viking and on the DE satellites. They also show that a large part, or even all, of the accelerating potential drop may be accounted for by numerous weak (about a volt) electric double layers, in agreement with earlier observations on the S3-3 satellite and with an early theoretical suggestion by L. Block

  5. Neutrinos from Cosmic Accelerators including Magnetic Field and Flavor Effects

    Directory of Open Access Journals (Sweden)

    Walter Winter

    2012-01-01

    Full Text Available We review the particle physics ingredients affecting the normalization, shape, and flavor composition of astrophysical neutrinos fluxes, such as different production modes, magnetic field effects on the secondaries (muons, pions, and kaons, and flavor mixing, where we focus on pγ interactions. We also discuss the interplay with neutrino propagation and detection, including the possibility to detect flavor and its application in particle physics, and the use of the Glashow resonance to discriminate pγ from pp interactions in the source. We illustrate the implications on fluxes and flavor composition with two different models: (1 the target photon spectrum is dominated by synchrotron emission of coaccelerated electrons and (2 the target photon spectrum follows the observed photon spectrum of gamma-ray bursts. In the latter case, the multimessenger extrapolation from the gamma-ray fluence to the expected neutrino flux is highlighted.

  6. Electromagnetic nonlinearities in a Roebel-cable-based accelerator magnet prototype: variational approach

    Science.gov (United States)

    Ruuskanen, J.; Stenvall, A.; Lahtinen, V.; Pardo, E.

    2017-02-01

    Superconducting magnets are the most expensive series of components produced in the Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN). When developing such magnets beyond state-of-the-art technology, one possible option is to use high-temperature superconductors (HTS) that are capable of tolerating much higher magnetic fields than low-temperature superconductors (LTS), carrying simultaneously high current densities. Significant cost reductions due to decreased prototype construction needs can be achieved by careful modelling of the magnets. Simulations are used, e.g. for designing magnets fulfilling the field quality requirements of the beampipe, and adequate protection by studying the losses occurring during charging and discharging. We model the hysteresis losses and the magnetic field nonlinearity in the beampipe as a function of the magnet’s current. These simulations rely on the minimum magnetic energy variation principle, with optimization algorithms provided by the open-source optimization library interior point optimizer. We utilize this methodology to investigate a research and development accelerator magnet prototype made of REBCO Roebel cable. The applicability of this approach, when the magnetic field dependence of the superconductor’s critical current density is considered, is discussed. We also scrutinize the influence of the necessary modelling decisions one needs to make with this approach. The results show that different decisions can lead to notably different results, and experiments are required to study the electromagnetic behaviour of such magnets further.

  7. GPU-accelerated denoising of 3D magnetic resonance images

    Energy Technology Data Exchange (ETDEWEB)

    Howison, Mark; Wes Bethel, E.

    2014-05-29

    The raw computational power of GPU accelerators enables fast denoising of 3D MR images using bilateral filtering, anisotropic diffusion, and non-local means. In practice, applying these filtering operations requires setting multiple parameters. This study was designed to provide better guidance to practitioners for choosing the most appropriate parameters by answering two questions: what parameters yield the best denoising results in practice? And what tuning is necessary to achieve optimal performance on a modern GPU? To answer the first question, we use two different metrics, mean squared error (MSE) and mean structural similarity (MSSIM), to compare denoising quality against a reference image. Surprisingly, the best improvement in structural similarity with the bilateral filter is achieved with a small stencil size that lies within the range of real-time execution on an NVIDIA Tesla M2050 GPU. Moreover, inappropriate choices for parameters, especially scaling parameters, can yield very poor denoising performance. To answer the second question, we perform an autotuning study to empirically determine optimal memory tiling on the GPU. The variation in these results suggests that such tuning is an essential step in achieving real-time performance. These results have important implications for the real-time application of denoising to MR images in clinical settings that require fast turn-around times.

  8. Enhancement of electron energy during vacuum laser acceleration in an inhomogeneous magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Saberi, H.; Maraghechi, B., E-mail: behrouz@aut.ac.ir [Department of Physics, Amirkabir University of Technology, 15875-4413 Tehran (Iran, Islamic Republic of)

    2015-03-15

    In this paper, the effect of a stationary inhomogeneous magnetic field on the electron acceleration by a high intensity Gaussian laser pulse is investigated. A focused TEM (0,0) laser mode with linear polarization in the transverse x-direction that propagates along the z-axis is considered. The magnetic field is assumed to be stationary in time, but varies longitudinally in space. A linear spatial profile for the magnetic field is adopted. In other words, the axial magnetic field increases linearly in the z-direction up to an optimum point z{sub m} and then becomes constant with magnitude equal to that at z{sub m}. Three-dimensional single-particle simulations are performed to find the energy and trajectory of the electron. The electron rotates around and stays near the z-axis. It is shown that with a proper choice of the magnetic field parameters, the electron will be trapped at the focus of the laser pulse. Because of the cyclotron resonance, the electron receives enough energy from the laser fields to be accelerated to relativistic energies. Using numerical simulations, the criteria for optimum regime of the acceleration mechanism is found. With the optimized parameters, an electron initially at rest located at the origin achieves final energy of γ=802. The dynamics of a distribution of off-axis electrons are also investigated in which shows that high energy electrons with small energy and spatial spread can be obtained.

  9. The Acceleration of Charged Particles at a Spherical Shock Moving through an Irregular Magnetic Field

    Energy Technology Data Exchange (ETDEWEB)

    Giacalone, J. [Department of Planetary Sciences, University of Arizona, Tucson, AZ (United States)

    2017-10-20

    We investigate the physics of charged-particle acceleration at spherical shocks moving into a uniform plasma containing a turbulent magnetic field with a uniform mean. This has applications to particle acceleration at astrophysical shocks, most notably, to supernovae blast waves. We numerically integrate the equations of motion of a large number of test protons moving under the influence of electric and magnetic fields determined from a kinematically defined plasma flow associated with a radially propagating blast wave. Distribution functions are determined from the positions and velocities of the protons. The unshocked plasma contains a magnetic field with a uniform mean and an irregular component having a Kolmogorov-like power spectrum. The field inside the blast wave is determined from Maxwell’s equations. The angle between the average magnetic field and unit normal to the shock varies with position along its surface. It is quasi-perpendicular to the unit normal near the sphere’s equator, and quasi-parallel to it near the poles. We find that the highest intensities of particles, accelerated by the shock, are at the poles of the blast wave. The particles “collect” at the poles as they approximately adhere to magnetic field lines that move poleward from their initial encounter with the shock at the equator, as the shock expands. The field lines at the poles have been connected to the shock the longest. We also find that the highest-energy protons are initially accelerated near the equator or near the quasi-perpendicular portion of the shock, where the acceleration is more rapid.

  10. Thermal analysis of the cryocooled superconducting magnet for the liquid helium-free hybrid magnet

    International Nuclear Information System (INIS)

    Ishizuka, Masayuki; Hamajima, Takataro; Itou, Tomoyuki; Sakuraba, Junji; Nishijima, Gen; Awaji, Satoshi; Watanabe, Kazuo

    2010-01-01

    The liquid helium-free hybrid magnet, which consists of an outer large bore cryocooled superconducting magnet and an inner water-cooled resistive magnet, was developed for magneto-science in high fields. The characteristic features of the cryogen-free outsert superconducting magnet are described in detail in this paper. The superconducting magnet cooled by Gifford-McMahon cryocoolers, which has a 360 mm room temperature bore in diameter, was designed to generate high magnetic fields up to 10 T. The hybrid magnet has generated the magnetic field of 27.5 T by combining 8.5 T generation of the cryogen-free superconducting magnet with 19 T generation of the water-cooled resistive magnet. The superconducting magnet was composed of inner Nb 3 Sn coils and outer NbTi coils. In particular, inner Nb 3 Sn coils were wound using high-strength CuNi-NbTi/Nb 3 Sn wires in consideration of large hoop stress. Although the cryocooled outsert superconducting magnet achieved 9.5 T, we found that the outsert magnet has a thermal problem to generate the designed maximum field of 10 T in the hybrid magnet operation. This problem is associated with unexpected AC losses in Nb 3 Sn wires.

  11. A fiber optic strain measurement and quench localization for use in superconducting accelerator dipole magnets

    International Nuclear Information System (INIS)

    van Oort, J.M.; Scanlan, R.M.; ten Kate, H.H.J.

    1994-01-01

    A novel fiber-optic measurement system for superconducting accelerator magnets is described. The principal component is an extrinsic Fabry-Perot Interferometer to determine localized strain and stress in coil windings. The system can be used either as a sensitive relative strain measurement system or as an absolute strain detector. Combined, one can monitor the mechanical behaviour of the magnet system over time during construction, long time storage and operation. The sensing mechanism is described, together with various tests in laboratory environments. The test results of a multichannel test matrix to be incorporated first in the dummy coils and then in the final version of a 13T Nb 3 Sn accelerator dipole magnet are presented. Finally, the possible use of this system as a quench localization system is proposed

  12. Concepts for the magnetic design of the MITICA neutral beam test facility ion accelerator.

    Science.gov (United States)

    Chitarin, G; Agostinetti, P; Marconato, N; Marcuzzi, D; Sartori, E; Serianni, G; Sonato, P

    2012-02-01

    The megavolt ITER injector concept advancement neutral injector test facility will be constituted by a RF-driven negative ion source and by an electrostatic Accelerator, designed to produce a negative Ion with a specific energy up to 1 MeV. The beam is then neutralized in order to obtain a focused 17 MW neutral beam. The magnetic configuration inside the accelerator is of crucial importance for the achievement of a good beam efficiency, with the early deflection of the co-extracted and stripped electrons, and also of the required beam optic quality, with the correction of undesired ion beamlet deflections. Several alternative magnetic design concepts have been considered, comparing in detail the magnetic and beam optics simulation results, evidencing the advantages and drawbacks of each solution both from the physics and engineering point of view.

  13. Electron Fermi acceleration in collapsing magnetic traps: Computational and analytical models

    International Nuclear Information System (INIS)

    Gisler, G.; Lemons, D.

    1990-01-01

    The authors consider the heating and acceleration of electrons trapped on magnetic field lines between approaching magnetic mirrors. Such a collapsing magnetic trap and consequent electron energization can occur whenever a curved (or straight) flux tube drifts into a relatively straight (or curved) perpendicular shock. The relativistic, three-dimensional, collisionless test particle simulations show that an initial thermal electron distribution is bulk heated while a few individual electrons are accelerated to many times their original energy before they escape the trap. Upstream field-aligned beams and downstream pancake distributions perpendicular to the field are predicted. In the appropriate limit the simulation results agree well with a nonrelativistic analytic model of the distribution of escaping electrons which is based on the first adiabatic invariant and energy conservation between collisions with the mirrors. Space science and astrophysical applications are discussed

  14. Generation of mesoscale magnetic fields and the dynamics of Cosmic Ray acceleration

    Science.gov (United States)

    Diamond, P. H.; Malkov, M. A.

    The problem of the cosmic ray origin is discussed in connection with their acceleration in supernova remnant shocks. The diffusive shock acceleration mechanism is reviewed and its potential to accelerate particles to the maximum energy of (presumably) galactic cosmic rays (1018eV ) is considered. It is argued that to reach such energies, a strong magnetic field at scales larger than the particle gyroradius must be created as a result of the acceleration process, itself. One specific mechanism suggested here is based on the generation of Alfven wave at the gyroradius scale with a subsequent transfer to longer scales via interaction with strong acoustic turbulence in the shock precursor. The acoustic turbulence in turn, may be generated by Drury instability or by parametric instability of the Alfven waves. The generation mechanism is modulational instability of CR generated Alfven wave packets induced, in turn, by scattering off acoustic fluctuations in the shock precursor which are generated by Drury instability.

  15. Intense laser driven collision-less shock and ion acceleration in magnetized plasmas

    Science.gov (United States)

    Mima, K.; Jia, Q.; Cai, H. B.; Taguchi, T.; Nagatomo, H.; Sanz, J. R.; Honrubia, J.

    2016-05-01

    The generation of strong magnetic field with a laser driven coil has been demonstrated by many experiments. It is applicable to the magnetized fast ignition (MFI), the collision-less shock in the astrophysics and the ion shock acceleration. In this paper, the longitudinal magnetic field effect on the shock wave driven by the radiation pressure of an intense short pulse laser is investigated by theory and simulations. The transition of a laminar shock (electro static shock) to the turbulent shock (electromagnetic shock) occurs, when the external magnetic field is applied in near relativistic cut-off density plasmas. This transition leads to the enhancement of conversion of the laser energy into high energy ions. The enhancement of the conversion efficiency is important for the ion driven fast ignition and the laser driven neutron source. It is found that the total number of ions reflected by the shock increases by six time when the magnetic field is applied.

  16. Experience with the procurement of ferrite and temperature compensator for permanent magnets for accelerators

    International Nuclear Information System (INIS)

    Fowler, W.B.; Brown, B.C.; Volk, J.

    1997-07-01

    The use of permanent magnets for transporting the 8 GeV proton beam from the Fermilab Booster to the new Fermilab Main Injector accelerator has been implemented and the magnets for a new 8 GeV ring to be installed in the Main Injector tunnel for increasing the luminosity of pbar/p collisions in the Tevatron are about to start being produced. Strontium oxide ferrite was selected for the magnets due to it's low cost and satisfactory magnetic properties for the 1.5 kilogauss fields required in the 2-inch gap magnets. Fermilab has received 96,000 pounds of ferrite and by working with the Vendor (HITACHI, Edmore, MI) improved uniformity of Residual Induction (Br) has reached 3905 gauss ± 0.65%. Further details are given in the paper. Overcoming the magnetic field variation when the temperature of the magnets changes is accomplished by incorporation of approximately 30% nickel steel alloy. The ferrite changes approximately -0.2% per degree C, which is compensated for by the 13% by the volume of compensator alloy incorporated in the magnet. Fourteen thousand (14,000) pounds of this material has been received and in order to obtain sufficient uniformity the authors mixed equal amounts from each batch into each magnet. Results of this process are given in the paper

  17. Magnetic-Island Contraction and Particle Acceleration in Simulated Eruptive Solar Flares

    Science.gov (United States)

    Guidoni, S. E.; Devore, C. R.; Karpen, J. T.; Lynch, B. J.

    2016-01-01

    The mechanism that accelerates particles to the energies required to produce the observed high-energy impulsive emission in solar flares is not well understood. Drake et al. proposed a mechanism for accelerating electrons in contracting magnetic islands formed by kinetic reconnection in multi-layered current sheets (CSs). We apply these ideas to sunward-moving flux ropes (2.5D magnetic islands) formed during fast reconnection in a simulated eruptive flare. A simple analytic model is used to calculate the energy gain of particles orbiting the field lines of the contracting magnetic islands in our ultrahigh-resolution 2.5D numerical simulation. We find that the estimated energy gains in a single island range up to a factor of five. This is higher than that found by Drake et al. for islands in the terrestrial magnetosphere and at the heliopause, due to strong plasma compression that occurs at the flare CS. In order to increase their energy by two orders of magnitude and plausibly account for the observed high-energy flare emission, the electrons must visit multiple contracting islands. This mechanism should produce sporadic emission because island formation is intermittent. Moreover, a large number of particles could be accelerated in each magneto hydro dynamic-scale island, which may explain the inferred rates of energetic-electron production in flares. We conclude that island contraction in the flare CS is a promising candidate for electron acceleration in solar eruptions.

  18. Particle Acceleration, Magnetic Field Generation, and Emission in Relativistic Pair Jets

    Science.gov (United States)

    Nishikawa, K.-I.; Ramirez-Ruiz, E.; Hardee, P.; Hededal, C.; Mizuno, Y.

    2005-01-01

    Shock acceleration is a ubiquitous phenomenon in astrophysical plasmas. Plasma waves and their associated instabilities (e.g., the Buneman instability, two-streaming instability, and the Weibel instability) created by relativistic pair jets are responsible for particle (electron, positron, and ion) acceleration. Using a 3-D relativistic electromagnetic particle (REMP) code, we have investigated particle acceleration associated with a relativistic jet propagating through an ambient plasma with and without initial magnetic fields. The growth rates of the Weibel instability depends on the distribution of pair jets. Simulations show that the Weibel instability created in the collisionless shock accelerates particles perpendicular and parallel to the jet propagation direction. The simulation results show that this instability is responsible for generating and amplifying highly nonuniform, small-scale magnetic fields, which contribute to the electron's transverse deflection behind the jet head. The "jitter" radiation from deflected electrons has different properties than synchrotron radiation which is calculated in a uniform magnetic field. This jitter radiation may be important to understanding the complex time evolution and/or spectral structure in gamma-ray bursts, relativistic jets, and supernova remnants.

  19. In situ baking method for degassing of a kicker magnet in accelerator beam line

    International Nuclear Information System (INIS)

    Kamiya, Junichiro; Ogiwara, Norio; Yanagibashi, Toru; Kinsho, Michikazu; Yasuda, Yuichi

    2016-01-01

    In this study, the authors propose a new in situ degassing method by which only kicker magnets in the accelerator beam line are baked out without raising the temperature of the vacuum chamber to prevent unwanted thermal expansion of the chamber. By simply installing the heater and thermal radiation shield plates between the kicker magnet and the chamber wall, most of the heat flux from the heater directs toward the kicker magnet. The result of the verification test showed that each part of the kicker magnet was heated to above the target temperature with a small rise in the vacuum chamber temperature. A graphite heater was selected in this application to bake-out the kicker magnet in the beam line to ensure reliability and easy maintainability of the heater. The vacuum characteristics of graphite were suitable for heater operation in the beam line. A preliminary heat-up test conducted in the accelerator beam line also showed that each part of the kicker magnet was successfully heated and that thermal expansion of the chamber was negligibly small

  20. In situ baking method for degassing of a kicker magnet in accelerator beam line

    Energy Technology Data Exchange (ETDEWEB)

    Kamiya, Junichiro, E-mail: kamiya.junichiro@jaea.go.jp; Ogiwara, Norio; Yanagibashi, Toru; Kinsho, Michikazu [Japan Atomic Energy Agency, J-PARC Center, Ooaza Shirakata 2-4, Tokai, Naka, Ibaraki 319-1195 (Japan); Yasuda, Yuichi [SAKAGUCHI E.H VOC CORP., Sakura Dai-san Kogyodanchi 1-8-6, Osaku, Sakura, Chiba 285-0802 (Japan)

    2016-03-15

    In this study, the authors propose a new in situ degassing method by which only kicker magnets in the accelerator beam line are baked out without raising the temperature of the vacuum chamber to prevent unwanted thermal expansion of the chamber. By simply installing the heater and thermal radiation shield plates between the kicker magnet and the chamber wall, most of the heat flux from the heater directs toward the kicker magnet. The result of the verification test showed that each part of the kicker magnet was heated to above the target temperature with a small rise in the vacuum chamber temperature. A graphite heater was selected in this application to bake-out the kicker magnet in the beam line to ensure reliability and easy maintainability of the heater. The vacuum characteristics of graphite were suitable for heater operation in the beam line. A preliminary heat-up test conducted in the accelerator beam line also showed that each part of the kicker magnet was successfully heated and that thermal expansion of the chamber was negligibly small.

  1. Ajuste de las curvas tensión-deformación a alta temperatura de un acero microaleado Nb-Ti

    Directory of Open Access Journals (Sweden)

    Pol, L. A.

    1997-02-01

    Full Text Available A series of hot plane strain compression tests have been conducted on a Nb-Ti microalloyed steel in a Servotest machine on samples of approx. 10 mm in thickness. Two sets of tests at strain rates of 5 s-1 and 15 s-1 were used and monitored the stress-strain behavior at deformation temperatures varying from 850 to 1,025 °C. The experimental data were corrected for friction, deviation from plane strain compression (PSC conditions and adiabatic rise of temperature, to give the isothermal equivalent tensile stress-strain curves. Thereafter these curves have been modeled by two types of equations depending on the softening mechanism operating during the deformation process and calculated the value of the coefficients in the equation by the application of a Taylor series around an initial point close to the solution. Finally, by the application of the least squared method, the previous values are compared to the experimental ones in order to determine an optimized value of the coefficients in the equations which model the stress-strain behaviour of the steel.

    Se ha realizado una serie de ensayos de compresión plana en caliente en muestras de un acero microaleado con niobio y titanio en una máquina Servotest, en probetas trapezoidales de aproximadamente 10 mm de espesor. Se efectuaron dos series de ensayos con dos velocidades de deformación, 5 y 15 s-1, y temperaturas de deformación entre 850 y 1.025 °C. Los datos experimentales fueron corregidos por rozamiento probeta-herramientas, ausencia de condiciones de deformación plana y aumento de la temperatura en la muestra debido a que la deformación no es estrictamente adiabática, para obtener las curvas isotermas equivalentes en tracción. Dichas curvas han sido modelizadas según dos tipos de ecuaciones constitutivas que caracterizan el proceso de ablandamiento que tiene lugar concurrente a la deformación. Se calculan los coeficientes de las mismas por

  2. Accelerators

    CERN Multimedia

    CERN. Geneva

    2001-01-01

    The talk summarizes the principles of particle acceleration and addresses problems related to storage rings like LEP and LHC. Special emphasis will be given to orbit stability, long term stability of the particle motion, collective effects and synchrotron radiation.

  3. Energy dissipation of composite multifilamentary superconductors for high-current ramp-field magnet applications

    International Nuclear Information System (INIS)

    Gung, C.Y.

    1993-01-01

    Energy dissipation, which is also called AC loss, of a composite multifilamentary superconducting wire is one of the most fundamental concerns in building a stable superconducting magnet. Characterization and reduction of AC losses are especially important in designing a superconducting magnet for generating transient magnetic fields. The goal of this thesis is to improve the understanding of AC-loss properties of superconducting wires developed for high-current ramp-field magnet applications. The major tasks include: (1) building an advanced AC-loss measurement system, (2) measuring AC losses of superconducting wires under simulated pulse magnet operations, (3) developing an analytical model for explaining the new AC-loss properties found in the experiment, and (4) developing a computational methodology for comparing AC losses of a superconducting wire with those of a cable for a superconducting pulse magnet. A new experimental system using an isothermal calorimetric method was designed and constructed to measure the absolute AC losses in a composite superconductor. This unique experimental setup is capable of measuring AC losses of a brittle Nb 3 Sn wire carrying high AC current in-phase with a large-amplitude pulse magnetic field. Improvements of the accuracy and the efficiency of this method are discussed. Three different types of composite wire have been measured: a Nb 3 Sn modified jelly-roll (MJR) internal-tin wire used in a prototype ohmic heating coil, a Nb 3 Sn internal-tin wire developed for a fusion reactor ohmic heating coil, and a NbTi wire developed for the magnets in a particle accelerator. The cross sectional constructions of these wires represent typical commercial wires manufactured for pulse magnet applications

  4. Measurement of internal forces in superconducting accelerator magnets with strain gauge transducers

    International Nuclear Information System (INIS)

    Goodzeit, C.L.; Anerella, M.D.; Ganetis, G.L.

    1988-01-01

    An improved method has been developed for the measurement of internal forces in superconducting accelerator magnets, in particular the compressive stresses in coils and the end restraint forces on the coils. The transducers have been designed to provide improved sensitivity to purely mechanical strain by using bending mode deflections for sensing the applied loads. Strain gauge resistance measurements are made with a new system that eliminates sources of errors due to spurious resistance changes in interconnecting wiring and solder joints. The design of the transducers and their measurement system is presented along with a discussion of the method of compensation for thermal and magnetic effects, methods of calibration with typical calibration data, and measured effect in actual magnets of the thermal stress changes from cooldown and the Lorentz forces during magnet excitation. 13 figs., 1 tab

  5. An FPGA-based quench detection and protection system for superconducting accelerator magnets

    International Nuclear Information System (INIS)

    Carcagno, R.H.; Feher, S.; Lamm, M.; Makulski, A.; Nehring, R.; Orris, D.F.; Pischalnikov, Y.; Tartaglia, M.; Fermilab

    2005-01-01

    A new quench detection and protection system for superconducting accelerator magnets was developed for the Fermilab's Magnet Test Facility (MTF). This system is based on a Field-Programmable Gate Array (FPGA) module, and it is made of mostly commercially available, integrated hardware and software components. It provides all the functions of our existing VME-based quench detection and protection system, but in addition the new system is easily scalable to protect multiple magnets powered independently and a more powerful user interface and analysis tools. The new system has been used successfully for testing LHC Interaction Region Quadrupoles correctors and High Field Magnet HFDM04. In this paper we describe the system and present results

  6. Magnetic field simulation of wiggler on LUCX accelerator facility using Radia

    Science.gov (United States)

    Sutygina, Y. N.; Harisova, A. E.; Shkitov, D. A.

    2016-11-01

    A flat wiggler consisting of NdFeB permanent magnets was installed on a compact linear electron accelerator LUCX (KEK) in Japan. After installing the wiggler on LUCX, the experiments on the generation of undulator radiation (UR) in the terahertz wavelength range is planned. To perform the detailed calculations and optimization of UR characteristics, it is necessary to know the parameters of the magnetic field generated in the wiggler. In this paper extended simulation results of wiggler magnetic field over the entire volume between the poles are presented. The obtained in the Radia simulation magnetic field is compared with the field calculated by another code, which is based on the finite element method.

  7. An FPGA-based quench detection and protection system for superconducting accelerator magnets

    Energy Technology Data Exchange (ETDEWEB)

    Carcagno, R.H.; Feher, S.; Lamm, M.; Makulski, A.; Nehring, R.; Orris, D.F.; Pischalnikov, Y.; Tartaglia, M.; /Fermilab

    2005-05-01

    A new quench detection and protection system for superconducting accelerator magnets was developed for the Fermilab's Magnet Test Facility (MTF). This system is based on a Field-Programmable Gate Array (FPGA) module, and it is made of mostly commercially available, integrated hardware and software components. It provides all the functions of our existing VME-based quench detection and protection system, but in addition the new system is easily scalable to protect multiple magnets powered independently and a more powerful user interface and analysis tools. The new system has been used successfully for testing LHC Interaction Region Quadrupoles correctors and High Field Magnet HFDM04. In this paper we describe the system and present results.

  8. Experimental studies on the thermal properties of fast pulsed superconducting accelerator magnets

    International Nuclear Information System (INIS)

    Bleile, Alexander

    2016-01-01

    The new Facility for Antiproton and Ion Research FAIR is being constructed at the GSI research center in Darmstadt (Germany). This wordwide unique accelerator facility will provide beams of ions and antiprotons at high intensities and high energies for the fundamental research in nuclear, atomic and plasma physics as well as for applied science. The superconducting synchrotron SIS100 with a magnetic rigidity of 100 T/m, the core component of the FAIR facility will provide primary ion beams of all types from hydrogen up to uranium. One of the key technical systems of a new synchrotron are fast ramped electromagnets for the generation of fast ramped magnetic fields for deflecting and focusing of the ion beams. To reduce the energy consumption and to keep the operating costs of the synchrotron as low as possible superconducting magnet technology is applied in the SIS100. Superconducting magnets have been developed at GSI within the scope of the FAIR project. Although the superconducting magnet technology promises high cost saving, the power consumption of the fast ramped superconducting magnets can't be completely neglected. The pulsed operation generates dynamic losses in the iron yokes as well as in the superconducting coils of the magnets. A forced two-phase helium flow provides effective cooling for supercounducting magnets exposed to a continous relative high heat flow. The subject of this PhD thesis is experimental investigations and analysis of the dynamic power losses in fast ramped superconducting magnets and their dependencies on the operation cycles of the synchrotron. This research was conducted on the the first series SIS100 dipole magnet. Based on the experimentally defined dynamic heat loads and helium mass flow rates in the dipole magnet the heat loads and helium consumption for all other types of superconducting magnet modules of the SIS100 have been estimated. These results are essential for the development of the cooling system for the the

  9. A procedure for combining rotating-coil measurements of large-aperture accelerator magnets

    Energy Technology Data Exchange (ETDEWEB)

    Köster, Oliver, E-mail: oliver.koester@cern.ch; Fiscarelli, Lucio, E-mail: lucio.fiscarelli@cern.ch; Russenschuck, Stephan, E-mail: stephan.russenschuck@cern.ch

    2016-05-11

    The rotating search coil is a precise and widely used tool for measuring the magnetic field harmonics of accelerator magnets. This paper deals with combining several such multipole measurements, in order to cover magnet apertures largely exceeding the diameter of the available search coil. The method relies on the scaling laws for multipole coefficients and on the method of analytic continuation along zero-homotopic paths. By acquiring several measurements of the integrated magnetic flux density at different transverse positions within the bore of the accelerator magnet, the uncertainty on the field harmonics can be reduced at the expense of tight tolerances on the positioning. These positioning tolerances can be kept under control by mounting the rotating coil and its motor-drive unit on precision alignment stages. Therefore, the proposed technique is able to yield even more precise results for the higher-order field components than a dedicated rotating search coil of larger diameter. Moreover, the versatility of the measurement bench is enhanced by avoiding the construction of rotating search coils of different measurement radii.

  10. Measurement of asymmetric optical pumping of ions accelerating in a magnetic-field gradient

    International Nuclear Information System (INIS)

    Sun Xuan; Scime, Earl; Miah, Mahmood; Cohen, Samuel; Skiff, Frederick

    2004-01-01

    We report observations of asymmetric optical pumping of argon ions accelerating in a magnetic-field gradient. The signature is a difference in the laser-induced-fluorescence emission amplitude from a pair of Zeeman-split states. A model that reproduces the dependence of the asymmetry on magnetic-field and ion-velocity gradients is described. With the model, the fluorescence intensity ratio provides a new method of measuring ion collisionality. This phenomenon has implications for interpreting stellar plasma spectroscopy data which often exhibit unequal Zeeman state intensities

  11. Measurement of Asymmetric Optical Pumping of Ions Accelerating in a Magnetic-field Gradient

    Energy Technology Data Exchange (ETDEWEB)

    Xuan Sun; Earl Scime; Mahmood Miah; Samuel Cohen; Frederick Skiff

    2004-10-28

    We report observations of asymmetric optical pumping of argon ions accelerating in a magnetic field gradient. The signature is a difference in the laser-induced-fluorescence (LIF) emission amplitude from a pair of Zeeman-split states. A model that reproduces the dependence of the asymmetry on magnetic-field and ion-velocity gradients is described. With the model, the fluorescence intensity ratio provides a new method of measuring ion collisionality. This phenomenon has implications for interpreting stellar plasma spectroscopy data which often exhibit unequal Zeeman state intensities.

  12. Measurement of Asymmetric Optical Pumping of Ions Accelerating in a Magnetic-field Gradient

    International Nuclear Information System (INIS)

    Xuan Sun; Earl Scime; Mahmood Miah; Samuel Cohen; Frederick Skiff

    2004-01-01

    We report observations of asymmetric optical pumping of argon ions accelerating in a magnetic field gradient. The signature is a difference in the laser-induced-fluorescence (LIF) emission amplitude from a pair of Zeeman-split states. A model that reproduces the dependence of the asymmetry on magnetic-field and ion-velocity gradients is described. With the model, the fluorescence intensity ratio provides a new method of measuring ion collisionality. This phenomenon has implications for interpreting stellar plasma spectroscopy data which often exhibit unequal Zeeman state intensities

  13. The acceleration of a gaseous plasma by intense microwave fields in a constant inhomogeneous magnetic field

    International Nuclear Information System (INIS)

    Mourier, Georges

    1971-01-01

    A gaseous plasma excited by a powerful microwave source (up to 300 kW) was studied theoretically and experimentally. The large amplitude electric field excites, in a constant inhomogeneous magnetic field, a plasma near to the electron cyclotron resonance. These particles are accelerated to energies of between 100 and 10000 eV and subsequently drift to the regions of lower magnetic field. The ions are accelerated by the resulting electrostatic forces. Ion and electron currents of some tens of milli-amperes to a few amperes are obtained. The energy of the electrons is limited by their relativistic mass; a three-dimensional of space charge model is set up to describe the particle flow. (author) [fr

  14. Bulk ion acceleration and particle heating during magnetic reconnection in a laboratory plasma

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Jongsoo; Yamada, Masaaki; Ji, Hantao; Jara-Almonte, Jonathan; Myers, Clayton E. [Center for Magnetic Self-Organization, Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

    2014-05-15

    Bulk ion acceleration and particle heating during magnetic reconnection are studied in the collisionless plasma of the Magnetic Reconnection Experiment (MRX). The plasma is in the two-fluid regime, where the motion of the ions is decoupled from that of the electrons within the ion diffusion region. The reconnection process studied here is quasi-symmetric since plasma parameters such as the magnitude of the reconnecting magnetic field, the plasma density, and temperature are compatible on each side of the current sheet. Our experimental data show that the in-plane (Hall) electric field plays a key role in ion heating and acceleration. The electrostatic potential that produces the in-plane electric field is established by electrons that are accelerated near the electron diffusion region. The in-plane profile of this electrostatic potential shows a “well” structure along the direction normal to the reconnection current sheet. This well becomes deeper and wider downstream as its boundary expands along the separatrices where the in-plane electric field is strongest. Since the in-plane electric field is 3–4 times larger than the out-of-plane reconnection electric field, it is the primary source of energy for the unmagnetized ions. With regard to ion acceleration, the Hall electric field causes ions near separatrices to be ballistically accelerated toward the outflow direction. Ion heating occurs as the accelerated ions travel into the high pressure downstream region. This downstream ion heating cannot be explained by classical, unmagnetized transport theory; instead, we conclude that ions are heated by re-magnetization of ions in the reconnection exhaust and collisions. Two-dimensional (2-D) simulations with the global geometry similar to MRX demonstrate downstream ion thermalization by the above mechanisms. Electrons are also significantly heated during reconnection. The electron temperature sharply increases across the separatrices and peaks just outside of the

  15. Neutron irradiation effects on superconducting and stabilizing materials for fusion magnets

    International Nuclear Information System (INIS)

    Maurer, W.

    1984-05-01

    Available low-temperature neutron irradiation data for the superconductors NbTi and Nb 3 Sn and the stabilization materials Cu and Al are collected and maximum tolerable doses for these materials are defined. A neutron flux in a reactor of about 10 9 n/cm 2 s at the magnet position is expected. However, in fusion experiments the flux can be higher by an order of magnitude or more. The energy spectrum is similar to a fission reactor. A fluence of about 10 18 n/cm 2 results during the lifetime of a fusion magnet (about 20 full power years). At this fluence and energy spectrum no severe degradation of the superconducting properties of NbTi and Nb 3 Sn will occur. But the radiation-induced resistivity is for Cu about a twentieth of the room temperature resistivity and a tenth for Al. (orig.) [de

  16. The use of induction linacs with nonlinear magnetic drive as high average power accelerators

    International Nuclear Information System (INIS)

    Birx, D.L.; Cook, E.G.; Hawkins, S.A.; Newton, M.A.; Poor, S.E.; Reginato, L.L.; Schmidt, J.A.; Smith, M.W.

    1985-01-01

    The marriage of induction linac technology with Nonlinear Magnetic Modulators has produced some unique capabilities. It appears possible to produce electron beams with average currents measured in amperes, at gradients exceeding 1 MeV/m, and with power efficiences approaching 50%. A 2 MeV, 5 kA electron accelerator is under construction at Lawrence Livermore National Laboratory (LLNL) to allow us to demonstrate some of these concepts. Progress on this project is reported here. (orig.)

  17. Physics of the saturation of particle acceleration in relativistic magnetic reconnection

    Science.gov (United States)

    Kagan, Daniel; Nakar, Ehud; Piran, Tsvi

    2018-05-01

    We investigate the saturation of particle acceleration in relativistic reconnection using two-dimensional particle-in-cell simulations at various magnetizations σ. We find that the particle energy spectrum produced in reconnection quickly saturates as a hard power law that cuts off at γ ≈ 4σ, confirming previous work. Using particle tracing, we find that particle acceleration by the reconnection electric field in X-points determines the shape of the particle energy spectrum. By analysing the current sheet structure, we show that physical cause of saturation is the spontaneous formation of secondary magnetic islands that can disrupt particle acceleration. By comparing the size of acceleration regions to the typical distance between disruptive islands, we show that the maximum Lorentz factor produced in reconnection is γ ≈ 5σ, which is very close to what we find in our particle energy spectra. We also show that the dynamic range in Lorentz factor of the power-law spectrum in reconnection is ≤40. The hardness of the power law combined with its narrow dynamic range implies that relativistic reconnection is capable of producing the hard narrow-band flares observed in the Crab nebula but has difficulty producing the softer broad-band prompt gamma-ray burst emission.

  18. Nonlinear Monte Carlo model of superdiffusive shock acceleration with magnetic field amplification

    Science.gov (United States)

    Bykov, Andrei M.; Ellison, Donald C.; Osipov, Sergei M.

    2017-03-01

    Fast collisionless shocks in cosmic plasmas convert their kinetic energy flow into the hot downstream thermal plasma with a substantial fraction of energy going into a broad spectrum of superthermal charged particles and magnetic fluctuations. The superthermal particles can penetrate into the shock upstream region producing an extended shock precursor. The cold upstream plasma flow is decelerated by the force provided by the superthermal particle pressure gradient. In high Mach number collisionless shocks, efficient particle acceleration is likely coupled with turbulent magnetic field amplification (MFA) generated by the anisotropic distribution of accelerated particles. This anisotropy is determined by fast particle transport, making the problem strongly nonlinear and multiscale. Here, we present a nonlinear Monte Carlo model of collisionless shock structure with superdiffusive propagation of high-energy Fermi accelerated particles coupled to particle acceleration and MFA, which affords a consistent description of strong shocks. A distinctive feature of the Monte Carlo technique is that it includes the full angular anisotropy of the particle distribution at all precursor positions. The model reveals that the superdiffusive transport of energetic particles (i.e., Lévy-walk propagation) generates a strong quadruple anisotropy in the precursor particle distribution. The resultant pressure anisotropy of the high-energy particles produces a nonresonant mirror-type instability that amplifies compressible wave modes with wavelengths longer than the gyroradii of the highest-energy protons produced by the shock.

  19. Final Report: MATERIALS, STRANDS, AND CABLES FOR SUPERCONDUCTING ACCELERATOR MAGNETS [Grant Number DE-SC0010312

    Energy Technology Data Exchange (ETDEWEB)

    Sumption, Mike D. [The Ohio State Univ., Columbus, OH (United States). Center for Superconducting and Magnetic Materials (CSMM); Collings, Edward W. [The Ohio State Univ., Columbus, OH (United States). Center for Superconducting and Magnetic Materials (CSMM)

    2014-10-29

    Our program consisted of the two components: Strand Research and Cable Research, with a focus on Nb3Sn, Bi2212, and YBCO for accelerator magnet applications. We demonstrated a method to refine the grains in Nb3Sn by a factor of two, reaching 45 nm grain sizes, and layer Jcs of 6 kA/mm2 at 12 T. W also measured conductor magnetization for field quality. This has been done both with Nb3Sn conductor, as well as Bi:2212 strand. Work in support of quench studies of YBCO coils was also performed. Cable loss studies in Nb3Sn focused on connecting and comparing persistent magnetization and coupling magnetization for considering their relative impact on HEP machines. In the area of HTS cables, we have investigated both the quench in multistrand YBCO CORC cables, as well as the magnetization of these cables for use in high field magnets. In addition, we examined the magnetic and thermal properties of large (50 T) solenoids.

  20. Particle Acceleration, Magnetic Field Generation and Associated Emission in Collisionless Relativistic Jets

    Science.gov (United States)

    Nishikawa, K. I.; Ramirez-Ruiz, E.; Hardee, P.; Mizuno, Y.; Fishman. G. J.

    2007-01-01

    Nonthermal radiation observed from astrophysical systems containing relativistic jets and shocks, e.g., active galactic nuclei (AGNs), gamma-ray bursts (GRBs), and Galactic microquasar systems usually have power-law emission spectra. Recent PIC simulations using injected relativistic electron-ion (electro-positron) jets show that acceleration occurs within the downstream jet. Shock acceleration is a ubiquitous phenomenon in astrophysical plasmas. Plasma waves and their associated instabilities (e.g., the Buneman instability, other two-streaming instability, and the Weibel instability) created in the shocks are responsible for particle (electron, positron, and ion) acceleration. The simulation results show that the Weibel instability is responsible for generating and amplifying highly nonuniform, small-scale magnetic fields. These magnetic fields contribute to the electron's transverse deflection behind the jet head. The "jitter" radiation from deflected electrons has different properties than synchrotron radiation which is calculated in a uniform magnetic field. This jitter radiation may be important to understanding the complex time evolution and/or spectral structure in gamma-ray bursts, relativistic jets, and supernova remnants.

  1. Tests of high gradient superconducting quadrupole magnets for the Tevatron

    International Nuclear Information System (INIS)

    Lamm, M.J.; Carson, J.; Gourlay, S.; Hanft, R.; Koepke, K.; Mantsch, P.; McInturff, A.D.; Riddiford, A.; Strait, J.

    1989-09-01

    Tests have been completed on three prototype magnets and two production magnets to be used for the Tevatron Dφ/Bφ low- β insertion. These cold iron, two shell quadrupoles are made of 36 strand Rutherford type NbTi superconducting cable. Magnet field gradients well in excess of the design 1.41 T/cm have been achieved at a transfer function of 0.291 T/cm/kA. Quench performance at 4.2 K and 3.7 K and magnetic multipole measurement data are presented and discussed. 9 refs., 4 figs., 4 tabs

  2. SMALL-SCALE MAGNETIC ISLANDS IN THE SOLAR WIND AND THEIR ROLE IN PARTICLE ACCELERATION. I. DYNAMICS OF MAGNETIC ISLANDS NEAR THE HELIOSPHERIC CURRENT SHEET

    Energy Technology Data Exchange (ETDEWEB)

    Khabarova, O. [Heliophysical Laboratory, Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radiowave Propagation RAS (IZMIRAN), Troitsk, Moscow 142190 (Russian Federation); Zank, G. P.; Li, G.; Roux, J. A. le; Webb, G. M.; Dosch, A. [Center for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville, Huntsville, AL 35805 (United States); Malandraki, O. E. [IAASARS, National Observatory of Athens, GR-15236 Penteli (Greece)

    2015-08-01

    Increases of ion fluxes in the keV–MeV range are sometimes observed near the heliospheric current sheet (HCS) during periods when other sources are absent. These resemble solar energetic particle events, but the events are weaker and apparently local. Conventional explanations based on either shock acceleration of charged particles or particle acceleration due to magnetic reconnection at interplanetary current sheets (CSs) are not persuasive. We suggest instead that recurrent magnetic reconnection occurs at the HCS and smaller CSs in the solar wind, a consequence of which is particle energization by the dynamically evolving secondary CSs and magnetic islands. The effectiveness of the trapping and acceleration process associated with magnetic islands depends in part on the topology of the HCS. We show that the HCS possesses ripples superimposed on the large-scale flat or wavy structure. We conjecture that the ripples can efficiently confine plasma and provide tokamak-like conditions that are favorable for the appearance of small-scale magnetic islands that merge and/or contract. Particles trapped in the vicinity of merging islands and experiencing multiple small-scale reconnection events are accelerated by the induced electric field and experience first-order Fermi acceleration in contracting magnetic islands according to the transport theory of Zank et al. We present multi-spacecraft observations of magnetic island merging and particle energization in the absence of other sources, providing support for theory and simulations that show particle energization by reconnection related processes of magnetic island merging and contraction.

  3. Laboratory studies of magnetized collisionless flows and shocks using accelerated plasmoids

    Science.gov (United States)

    Weber, T. E.; Smith, R. J.; Hsu, S. C.

    2015-11-01

    Magnetized collisionless shocks are thought to play a dominant role in the overall partition of energy throughout the universe, but have historically proven difficult to create in the laboratory. The Magnetized Shock Experiment (MSX) at LANL creates conditions similar to those found in both space and astrophysical shocks by accelerating hot (100s of eV during translation) dense (1022 - 1023 m-3) Field Reversed Configuration (FRC) plasmoids to high velocities (100s of km/s); resulting in β ~ 1, collisionless plasma flows with sonic and Alfvén Mach numbers of ~10. The FRC subsequently impacts a static target such as a strong parallel or anti-parallel (reconnection-wise) magnetic mirror, a solid obstacle, or neutral gas cloud to create shocks with characteristic length and time scales that are both large enough to observe yet small enough to fit within the experiment. This enables study of the complex interplay of kinetic and fluid processes that mediate cosmic shocks and can generate non-thermal distributions, produce density and magnetic field enhancements much greater than predicted by fluid theory, and accelerate particles. An overview of the experimental capabilities of MSX will be presented, including diagnostics, selected recent results, and future directions. Supported by the DOE Office of Fusion Energy Sciences under contract DE-AC52-06NA25369.

  4. Study of heat transfer in superconducting cable electrical insulation of accelerator magnet cooled by superfluid helium; Etude des transferts de chaleur dans les isolations electriques de cables supraconducteurs d'aimant d'accelerateur refroidi par helium superfluide

    Energy Technology Data Exchange (ETDEWEB)

    Baudouy, B

    1996-10-04

    Heat transfer studies of electrical cable insulation in superconducting winding are of major importance for stability studies in superconducting magnets. This work presents an experimental heat transfer study in superconducting cables of Large Hadron Collider dipoles cooled by superfluid helium and submitted to volume heat dissipation due to beam losses. For NbTi magnets cooled by superfluid helium the most severe heat barrier comes from the electrical insulation of the cables. Heat behaviour of a winding is approached through an experimental model in which insulation characteristics can be modified. Different tests on insulation patterns show that heat transfer is influenced by superfluid helium contained in insulation even for small volume of helium (2 % of cable volume). Electrical insulation can be considered as a composite material made of a solid matrix with a helium channels network which cannot be modelled easily. This network is characterised by another experimental apparatus which allows to study transverse and steady-state heat transfer through an elementary insulation pattern. Measurements in Landau regime ({delta}T{approx}10{sup -5} to 10{sup -3} K) and in Gorter-Mellink regime ({delta}T>10{sup -3} K) and using assumptions that helium thermal paths and conduction in the insulation are decoupled allow to determine an equivalent channel area (10{sup -6} m{sup 2}) and an equivalent channel diameter (25 {mu}). (author)

  5. Study of heat transfer in superconducting cable electrical insulation of accelerator magnet cooled by superfluid helium; Etude des transferts de chaleur dans les isolations electriques de cables supraconducteurs d'aimant d'accelerateur refroidi par helium superfluide

    Energy Technology Data Exchange (ETDEWEB)

    Baudouy, B

    1996-10-04

    Heat transfer studies of electrical cable insulation in superconducting winding are of major importance for stability studies in superconducting magnets. This work presents an experimental heat transfer study in superconducting cables of Large Hadron Collider dipoles cooled by superfluid helium and submitted to volume heat dissipation due to beam losses. For NbTi magnets cooled by superfluid helium the most severe heat barrier comes from the electrical insulation of the cables. Heat behaviour of a winding is approached through an experimental model in which insulation characteristics can be modified. Different tests on insulation patterns show that heat transfer is influenced by superfluid helium contained in insulation even for small volume of helium (2 % of cable volume). Electrical insulation can be considered as a composite material made of a solid matrix with a helium channels network which cannot be modelled easily. This network is characterised by another experimental apparatus which allows to study transverse and steady-state heat transfer through an elementary insulation pattern. Measurements in Landau regime ({delta}T{approx}10{sup -5} to 10{sup -3} K) and in Gorter-Mellink regime ({delta}T>10{sup -3} K) and using assumptions that helium thermal paths and conduction in the insulation are decoupled allow to determine an equivalent channel area (10{sup -6} m{sup 2}) and an equivalent channel diameter (25 {mu}). (author)

  6. Accounting for the fringe magnetic field from the bending magnet in a Monte Carlo accelerator treatment head simulation.

    Science.gov (United States)

    O'Shea, Tuathan P; Foley, Mark J; Faddegon, Bruce A

    2011-06-01

    Monte Carlo (MC) simulation can be used for accurate electron beam treatment planning and modeling. Measurement of large electron fields, with the applicator removed and secondary collimator wide open, has been shown to provide accurate simulation parameters, including asymmetry in the measured dose, for the full range of clinical field sizes and patient positions. Recently, disassembly of the treatment head of a linear accelerator has been used to refine the simulation of the electron beam, setting tightly measured constraints on source and geometry parameters used in simulation. The simulation did not explicitly include the known deflection of the electron beam by a fringe magnetic field from the bending magnet, which extended into the treatment head. Instead, the secondary scattering foil and monitor chamber were unrealistically laterally offset to account for the beam deflection. This work is focused on accounting for this fringe magnetic field in treatment head simulation. The magnetic field below the exit window of a Siemens Oncor linear accelerator was measured with a Tesla-meter from 0 to 12 cm from the exit window and 1-3 cm off-axis. Treatment head simulation was performed with the EGSnrc/BEAMnrc code, modified to incorporate the effect of the magnetic field on charged particle transport. Simulations were used to analyze the sensitivity of dose profiles to various sources of asymmetry in the treatment head. This included the lateral spot offset and beam angle at the exit window, the fringe magnetic field and independent lateral offsets of the secondary scattering foil and electron monitor chamber. Simulation parameters were selected within the limits imposed by measurement uncertainties. Calculated dose distributions were then compared with those measured in water. The magnetic field was a maximum at the exit window, increasing from 0.006 T at 6 MeV to 0.020 T at 21 MeV and dropping to approximately 5% of the maximum at the secondary scattering foil. It

  7. An FPGA-Based Quench Detection and Protection System for Superconducting Accelerator Magnets

    CERN Document Server

    Carcagno, Ruben H; Lamm, Michael J; Makulski, Andrzej; Nehring, Roger; Orris, Darryl; Pishchalnikov, Yu M; Tartaglia, M

    2005-01-01

    A new quench detection and protection system for superconducting accelerator magnets was developed at the Fermilab's Magnet Test Facility (MTF). This system is based on a Field-Programmable Gate Array (FPGA) module, and it is made of mostly commerically available, integrated hardware and software components. It provides most of the functionality of our existing VME-based quench detection and protection system, but in addition the new system is easily scalable to protect multiple magnets powered independently and has a more powerful user interface and analysis tools. First applications of the new system will be for testing corrector coil packages. In this paper we describe the new system and present results of testing LHC Interaction Region Quadrupole (IRQ) correctors.

  8. Determination of microturbulence enhanced electron collisionality in magnetized coaxial accelerator channels by direct magnetic field measurement

    International Nuclear Information System (INIS)

    Black, D.C.; Mayo, R.M.; Caress, R.W.

    1997-01-01

    A miniature magnetic probe array, consisting of 10 spatially separated coils, has been used to obtain profile information on the time varying magnetic field within the 2.54 cm wide flow channel of the coaxial plasma source experiment (CPS-1) [R. M. Mayo et al., Plasma Sources Sci. Technol. 4, 47 (1995)]. The magnetic field data have been used, together with a resistive, Hall magnetohydrodynamic (MHD) model of applied field distortion by the flowing plasma, to obtain estimates of the microturbulent enhancement to electron collisionality within the CPS-1 flow channel. These measurements provide direct experimental evidence of anomalous electron collisionality, a previously predicted effect in these devices. The anomaly parameter, a=ν an /ν cl , determined both from the distortion of contours of constant magnetic flux, and from local B θ and B z measurements scales with the classical electron magnetization parameter (Ω cl =ω ce /ν e cl ), indicating that collisionality plays a strong role in determining the level of anomalous transport in the plasma. When this anomaly parameter scaling is cast in terms of the ratio ν e cl /ω lh , it is found that the resistivity enhancement scales with ν e cl /ω lh , and becomes significant at ν e cl /ω lh ≤1, suggesting that a lower hybrid drift instability may be the responsible mechanism for enhanced transport. copyright 1997 American Institute of Physics

  9. Large magnetic coils for fusion technology

    International Nuclear Information System (INIS)

    Komarek, P.; Ulbricht, A.

    1989-01-01

    This paper reviews the current status of research in this field and outlines future tasks and experiments for the Next European Torus (NET). Research and development work accomplished so far permits generation and safe operation of magnetic fields up to 9 T by means of NbTi coils. Fields up to 11 T are feasible if the coils are cooled with superfluid helium at 1.8 K. The potential of the Nb 3 Sn coils promise achievement of magnetic fields between 12 and 13 T. (MM) [de

  10. Low-noise pulse-mode current power supply for magnetic field measurements of magnets for accelerators

    International Nuclear Information System (INIS)

    Omel'yanenko, M.M.; Borisov, V.V.; Donyagin, A.M.; Kostromin, S.A.; Makarov, A.A.; Khodzhibagiyan, G.G.; Shemchuk, A.V.

    2017-01-01

    The described pulse-mode current power supply has been designed and fabricated for the magnetic field measurement system of superconducting magnets for accelerators. The power supply is based on a current regulator with pass transistor bank in linear mode. The output current pulses (0-100 A) are produced by using the energy of preliminary charged capacitor bank (5-40 V), which is charged additionally after each pulse. There is no AC-line frequency and harmonics ripple in the output current, the relative noise level is less than -100 dB (or 10 -5 ) of RMS value (it is defined as the ratio of output RMS noise current to the maximal output current 100 A within the operating bandwidth, expressed in dB).

  11. Design of MgB{sub 2} superconducting dipole magnet for particle beam transport in accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Abrahamsen, A.B.; Givel, J.C.; Andersen, N.H. [Risoe National Lab., Materials Research Dept., Roskilde (Denmark); Zangenberg, N.; Baurichter, A. [Danfysik A/S, Jyllinge (Denmark)

    2006-11-15

    A comprehensive analysis of the innovation potential of superconductivity at Risoe was performed in February 2004 by the main author of this report. Several suggestions for new products and new markets were formulated by the superconductivity group and examined by the innovation staff at Risoe. The existing markets of superconducting technology is within highly specialized scientific areas such as magnetic confinement in fusion energy, sample environment in neutron scattering and large scale accelerators such as the Large Hadron Collider(LHC) at Cern, or in the nuclear magnetic resonance (NMR) community using MR-imaging scanners in medicine and phase identification in organic chemistry. Only the NMR applications can be categorized as a highly profitable and commercial market today. The superconductivity group of Risoe formulated and presented the gearless superconducting wind turbine multipole generator as the most promising new concept, but further initiatives were stopped due to unclear patent possibilities. The experience of the innovation review was used in the STVF framework program 'New superconductors: mechanisms, processes and products' to identify potential new product for the collaborating company Danfysik A/S, which has a strong tradition in building resistive magnets for particle accelerators. A technology transfer project was formulated at the end of 2005 with the purpose to collect the knowledge about the MgB2 superconductor gained in the STVF program and in the European Framework Program 6 project HIPERMAG. It was presented at the Risoe innovation seminar January 2006, and recently a collaboration between Risoe and Danfysik A/S was initialized. The present report aims to outline a potential superconducting product within the STVF program. The use of the MgB{sub 2} superconductors in a dipole magnet for guiding particle beams in a small scale accelerator is examined with the purpose to build lighter and smaller than the present resistive

  12. Design of MgB2 superconducting dipole magnet for particle beam transport in accelerators

    International Nuclear Information System (INIS)

    Abrahamsen, A.B.; Givel, J.C.; Andersen, N.H.; Zangenberg, N.; Baurichter, A.

    2006-11-01

    A comprehensive analysis of the innovation potential of superconductivity at Risoe was performed in February 2004 by the main author of this report. Several suggestions for new products and new markets were formulated by the superconductivity group and examined by the innovation staff at Risoe. The existing markets of superconducting technology is within highly specialized scientific areas such as magnetic confinement in fusion energy, sample environment in neutron scattering and large scale accelerators such as the Large Hadron Collider(LHC) at Cern, or in the nuclear magnetic resonance (NMR) community using MR-imaging scanners in medicine and phase identification in organic chemistry. Only the NMR applications can be categorized as a highly profitable and commercial market today. The superconductivity group of Risoe formulated and presented the gearless superconducting wind turbine multipole generator as the most promising new concept, but further initiatives were stopped due to unclear patent possibilities. The experience of the innovation review was used in the STVF framework program 'New superconductors: mechanisms, processes and products' to identify potential new product for the collaborating company Danfysik A/S, which has a strong tradition in building resistive magnets for particle accelerators. A technology transfer project was formulated at the end of 2005 with the purpose to collect the knowledge about the MgB2 superconductor gained in the STVF program and in the European Framework Program 6 project HIPERMAG. It was presented at the Risoe innovation seminar January 2006, and recently a collaboration between Risoe and Danfysik A/S was initialized. The present report aims to outline a potential superconducting product within the STVF program. The use of the MgB 2 superconductors in a dipole magnet for guiding particle beams in a small scale accelerator is examined with the purpose to build lighter and smaller than the present resistive magnets. Here the

  13. Nb3Sn accelerator magnet technology scale up using cos-theta dipole coils

    Energy Technology Data Exchange (ETDEWEB)

    Nobrega, F.; Andreev, N.; Ambrosio, G.; Barzi, E.; Bossert, R.; Carcagno, R.; Chlachidze, G.; Feher, S.; Kashikhin, V.S.; Kashikhin, V.V.; Lamm, M.J.; /Fermilab

    2007-06-01

    Fermilab is working on the development of Nb{sub 3}Sn accelerator magnets using shell-type dipole coils and the wind-and-react 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 T. 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) Nb{sub 3}Sn dipole mirror magnet design and fabrication technology, as well as the magnet test results which are compared with 1 m long models.

  14. Nb3Sn accelerator magnet technology scale up using cos-theta dipole coils

    International Nuclear Information System (INIS)

    Nobrega, F.; Andreev, N.; Ambrosio, G.; Barzi, E.; Bossert, R.; Carcagno, R.; Chlachidze, G.; Feher, S.; Kashikhin, V.S.; Kashikhin, V.V.; Lamm, M.J.; Fermilab

    2007-01-01

    Fermilab is working on the development of Nb 3 Sn accelerator magnets using shell-type dipole coils and the wind-and-react 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 T. 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) Nb 3 Sn dipole mirror magnet design and fabrication technology, as well as the magnet test results which are compared with 1 m long models

  15. Comparison of mechanical concepts for $Nb_3Sn$ high field accelerator magnets

    CERN Document Server

    AUTHOR|(CDS)2084469; Peter, Schmolz

    Several magnets using Nb$_{3}$Sn as conductor are currently developed at CERN; these magnets are either slated for future updates of the LHC or for research purposes relating to future accelerators. The mechanical structure is one of the challenging aspects of superconducting high-field magnets. The main purpose of the mechanical structure is to keep the coils in compression till the emergence of the highest electromagnetic forces that are developed in the ultimate field of the magnet. Any loss of pre-compression during the magnet’s excitation would cause too large deformation of the coil and possibly a quench in the conductor owing to relative movements of strands in contact associated with excessive local heat release. However, too high pre-compression would overstrain the conductor and thereby limit the performance of the magnet. This thesis focuses on the mechanical behaviour of three of these magnets. All of them are based on different mechanical designs, “bladder and key” and “collar-based”, ...

  16. R&D of Nb$_{3}$Sn accelerator magnets at Fermilab

    CERN Document Server

    Zlobin, A V; Andreev, N; Barzi, E; Bordini, B; Bossert, R; Carcagno, R; Chichili, D R; Di Marco, J; Elementi, L; Fehér, S; Kashikhin, V S; Kashikhin, V V; Kephart, R; Lamm, M J; Limon, P J; Novitski, I; Orris, D; Pischalnikov, Y; Schlabach, P; Stanek, R; Strait, J; Sylvester, C D; Tartaglia, M; Tompkins, J C; Turrioni, D; Velev, G; Yamada, R; Yarba, V A; 10.1109/TASC.2005.849507

    2005-01-01

    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 Nb/sub 3/Sn 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 Nb/sub 3/Sn 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.

  17. Performance of magnetically-injected-plasma opening switches on the particle beam fusion accelerator 2

    International Nuclear Information System (INIS)

    Rochau, G.E.; McDaniel, D.H.; Mendel, C.W.; Sweeney, M.A.; Moore, W.B.S.; Mowrer, G.R.; Zagar, D.M.

    1990-01-01

    Plasma opening switch (POS) experiments have been performed on the PBFA II ion beam accelerator to develop a switch which will provide voltage and power gain to an applied-B lithium ion diode. These experiments have successfully coupled power to electron and ion beam diodes using a Magnetically-Injected-Plasma (MIP) POS. Carbon plasma with electron densities of 1 x 10 12 to 2 x 10 13 /cm 3 have been injected from the anode into the 8 cm gap of the 20-ohm Magnetically-Insulated-Transmission Line (MITL) of PBFA II along a B r,z magnetic field. The MIP switch uses the inertia of the plasma to keep the switch closed and the magnetic pressure of B θ from the conduction current to open the switch. The configuration of the injecting magnetic field and the plasma source has a significant effect on the efficiency of coupling power to high impedance loads. Plasma near the center of the injecting magnetic field limits the opening impedance of the switch and subsequently the power delivered to the load. The axial location of the switch with respect to the load has also been identified as a critical parameter in increasing the coupling efficiency. A length of 10 to 20 cm of MITL between the POS and the load has increased the power delivered to the load. Data on switch performance with high impedance loads and factors which improved performance are discussed

  18. Characterisation and dissolution studies on the uranium pyrochlore mineral betafite (Ca,U)_2(Nb,Ti,Ta)_2O_7

    International Nuclear Information System (INIS)

    McMaster, S.; Ram, R.; Tardio, J.; Bhargava, S.

    2014-01-01

    The pyrochlore group mineral, betafite (nominally (Ca,U)_2(Nb,Ti,Ta)_2O_7); is a refractory uranium mineral found in many ore deposits, including the currently mined deposit at Rössing, Namibia and the currently unmined deposit at Saima Massif, China. The decreasing abundance of “easy to leach” uranium minerals (i.e. uraninite), has led to interest in the extraction of uranium from refractory uranium minerals such as betafite. In the current study, three naturally occurring betafite mineral samples (obtained from Ambatofotsky and Miarinarivo, Madagascar (BAM and BMM respectively) and Silver Crater Mine, Canada (BSC)) were characterised using ex-situ high temperature X-Ray Diffraction (XRD), multi acid digestion / ICP-MS analysis (composition) and X-Ray Photoelectron Spectroscopy (XPS). Dissolution of the three samples was also investigated under conditions similar to those used in commercial tank based uranium leaching processes. XRD analysis showed that all three samples were highly metamict. Samples BMM and BSC showed no assignable diffraction lines before heat treating, whereas the XRD pattern obtained for sample BAM contained diffraction lines that confirmed the presence of crystalline anatase (TiO_2). Heat treatment studies on the samples showed that the betafite in the samples was converted into a crystalline form at 700°C in all 3 samples. Gangue minerals, rutile, Nb-rutile, UTiNb_2O_1_0, and studitite were also found to be present in the heat treated samples. Multi acid digestion ICP-MS analysis showed the natural samples contained between 16 and 26% w/w uranium as well as all the major elements present typically in betafite. XPS analysis was conducted on the unheated betafite samples. XPS analysis showed that the uranium in the samples was predominately in U"5"+ oxidation state. Some U"6"+ was also identified though this was most likely restricted to the outer surface of the samples. Dissolution studies (batch mode) were conducted under the following

  19. Gamma radiation and magnetic field mediated delay in effect of accelerated ageing of soybean

    International Nuclear Information System (INIS)

    Mahesh Kumar; Anand, Anjali; Singh, Bhupinder; Ahuja, Sumedha; Dahuja, Anil

    2015-01-01

    Soybean seeds were exposed to gamma radiation (0.5, 1, 3 and 5 kGy), static magnetic field (50, 100 and 200 mT) and a combination of gamma radiation and magnetic energy (0.5 kGy+200 mT and 5 kGy+50 mT) and stored at room temperature for six months. These seeds were later subjected to accelerated ageing treatment at 42°C temperature and 95-100 % relative humidity and were compared for various physical and biochemical characteristics between the untreated and the energized treatments. Energy treatment protected the quality of stored seeds in terms of its protein and oil content. Accelerated aging conditions, however, affected the oil and protein quantity and quality of seed negatively. Antioxidant enzymes exhibited a decline in their activity during aging while the LOX activity, which reflects the rate of lipid peroxidation, in general, increased during the aging. Gamma irradiated (3 and 5 kGy) and magnetic field treated seeds (100 and 200 mT) maintained a higher catalase and ascorbate peroxidase activity which may help in efficient scavenging of deleterious free radical produced during the aging. Aging caused peroxidative changes to lipids, which could be contributed to the loss of oil quality. Among the electromagnetic energy treatments, a dose of 1-5 kGy of gamma and 100 mT, 200 mT magnetic field effectively slowed the rate of biochemical degradation and loss of cellular integrity in seeds stored under conditions of accelerated aging and thus, protected the deterioration of seed quality. Energy combination treatments did not yield any additional protection advantage. (author)

  20. Dynamic stress effects in technical superconductors and the ''training'' problem of superconducting magnets

    International Nuclear Information System (INIS)

    Pasztor, G.; Schmidt, C.

    1978-01-01

    The behavior of NbTi superconductors under dynamic mechanical stress was investigated. A training effect was found in short-sample tests when the conductor was strained in a magnetic field and with a transport current applied. Possible mechanisms are discussed which were proposed to explain training in short samples and in magnets. A stress-induced microplastic as well as an incomplete pseudoelastic behavior of NbTi was detected by monitoring acoustic emission. The experiments support the hypothesis that microplastic or shape memory effects in NbTi involving dislocation processes are responsible for training. The minimum energy needed to induce a normal transition in short-sample tests is calculated with a computer program, which gives the exact solution of the heat equation. A prestrain treatment of the conductor at room temperature is shown to be a simple method of reducing training of short samples and of magnets. This is a direct proof that the same mechanisms are involved in both cases

  1. Superconductors with low critical temperature for electro-magnets; Supraconducteurs a basse temperature critique pour electroaimants

    Energy Technology Data Exchange (ETDEWEB)

    Devred, A

    2002-07-01

    Among the superconductors with low critical temperature that are used to build magnets, NbTi has reached a development state that allows a massive production for big equipment of physics and an industrial production in the domain of medicine imaging. The material that might challenge the supremacy of NbTi is Nb{sub 3}Sn but some technical difficulties have yet to be overcome. This report begins with a review of the different industrial processes used to produce superconducting wires based on the NbTi and Nb{sub 3}Sn materials. The transition from the superconducting state to the resistive normal state is described for both materials, the magnetizing of multi-wire superconducting cables is also presented. The author details the different patterns of wires in cables and proposes a formulary that allows the determination, in some simple cases,of energy losses that are generated in a superconducting cable by a variable magnetic field. (A.C.)

  2. Mirror Fusion Test Facility-B (MFTF-B) axicell configuration: NbTi magnet system. Manufacturing/producibility final report. Volume 2

    International Nuclear Information System (INIS)

    Ritschel, A.J.; White, W.L.

    1985-05-01

    This Final MFTF-B Manufacturing/Producibility Report covers facilities, tooling plan, manufacturing sequence, schedule and performance, producibility, and lessons learned for the solenoid, axicell, and transition coils, as well as a deactivation plan, conclusions, references, and appendices

  3. Impact of compressibility and a guide field on Fermi acceleration during magnetic island coalescence

    Science.gov (United States)

    Montag, Peter; Egedal, Jan; Lichko, Emily; Wetherton, Blake

    2017-10-01

    Previous work has shown that Fermi acceleration can be an effective heating mechanism during magnetic island coalescence, where electrons may undergo repeated reflections as the magnetic field lines contract. This energization has the potential to account for the power-law distributions of particle energy inferred from observations of solar flares. Here, we develop a generalized framework for the analysis of Fermi acceleration that can incorporate the effects of compressibility and non-uniformity along field lines, which have commonly been neglected in previous treatments of the problem. Applying this framework to the simplified case of the uniform flux tube allows us to find both the power-law scaling of the distribution function and the rate at which the power-law behavior develops. We find that a guide magnetic field of order unity effectively suppresses the development of power-law distributions. The work was supported by NASA Grant No. NNX14AC68G, NSF GEM Grant No. 1405166, NSF Award 1404166, and NASA Award NNX15AJ73G.

  4. Collective acceleration of laser plasma in a nonstationary and nonuniform magnetic field

    Science.gov (United States)

    Isaev, A.; Kozlovskiy, K.; Shikanov, A.; Vovchenko, E.

    2017-12-01

    This paper presents the new experimental results concerning acceleration of deuterium ions extracted from laser plasma in the rapid-growing nonuniform magnetic field in order to initiate the nuclear reactions D(d, n)3He and T(d, n)4He. For obtaining of laser plasma a Nd: YAG laser (λ = 1,06 μm) that generates in Q-switched mode the radiation pulses with the energy W ≤ 0,85 J and duration of τ ≈ 10 ns was used. Rapid-growing magnetic field was created with the discharge of Arkadyev-Marx pulsed-voltage generator to conical coil with the inductance of 0,65 μΗ. At characteristic discharge time of 30 ns, the rate of magnetic field growth achieved 2·107 T/s. Ion velocity was determined with the time-of-flight technique. During the experiment on deuterium plasma an ion flux velocity of ∼3 · 108 cm/s was obtained, which corresponds to the deuteron energy of ∼100 keV. Herewith, for target power density of ∼5·1011 W/cm2 obtaining of up to 1015 of accelerated deuterons and up to 108 of neutrons per a pulse is expected.

  5. Application of magnetically insulated transmission lines for high current, high voltage electron beam accelerators

    International Nuclear Information System (INIS)

    Shope, S.L.; Mazarakis, M.G.; Frost, C.A.; Poukey, J.W.; Turman, B.N.

    1993-01-01

    Self Magnetically Insulated Transmission Lines (MITL) adders have been used successfully in a number of Sandia accelerators such as HELIA, HERMES III, and SABRE. Most recently the authors used a MITL adder in the RADLAC/SMILE electron beam accelerator to produce high quality, small radius (r b < 2 cm), 11 to 15 MeV, 50 to 100-kA beams with a small transverse velocity v perpendicular/c = β perpendicular ≤ 0.1. In RADLAC/SMILE, a coaxial MITL passed through the eight, 2 MV vacuum envelopes. The MITL summed the voltages of all eight feeds to a single foilless diode. The experimental results are in good agreement with code simulations. The authors' success with the MITL technology led them to investigate the application to higher energy accelerator designs. They have a conceptual design for a cavity-fed MITL that sums the voltages from 100 identical, inductively-isolated cavities. Each cavity is a toroidal structure that is driven simultaneously by four 8-ohm pulse-forming lines, providing a 1-MV voltage pulse to each of the 100 cavities. The point design accelerator is 100 MV, 500 kA, with a 30-50-ns FWHM output pulse

  6. Application of Magnetically Insulated Transmission Lines for high current, high voltage electron beam accelerators

    International Nuclear Information System (INIS)

    Shope, S.L.; Mazarakis, M.G.; Frost, C.A.; Poukey, J.W.; Turman, B.N.

    1991-01-01

    Self Magnetically Insulated Transmission Lines (MITL) adders have been used successfully in a number of Sandia accelerators such as HELIA, HERMES III, and SABRE. Most recently we used at MITL adder in the RADLAC/SMILE electron beam accelerator to produce high quality, small radius (r ρ < 2 cm), 11 to 15 MeV, 50 to 100-kA beams with a small transverse velocity v perpendicular/c = β perpendicular ≤ 0.1. In RADLAC/SMILE, a coaxial MITL passed through the eight, 2 MV vacuum envelopes. The MITL summed the voltages of all eight feeds to a single foilless diode. The experimental results are in good agreement with code simulations. Our success with the MITL technology led us to investigate the application to higher energy accelerator designs. We have a conceptual design for a cavity-fed MITL that sums the voltages from 100 identical, inductively-isolated cavities. Each cavity is a toroidal structure that is driven simultaneously by four 8-ohm pulse-forming lines, providing a 1-MV voltage pulse to each of the 100 cavities. The point design accelerator is 100 MV, 500 kA, with a 30--50 ns FWHM output pulse. 10 refs

  7. Application of magnetically insulated transmission lines for high current, high voltage electron beam accelerators

    Science.gov (United States)

    Shope, S. L.; Mazarakis, M. G.; Frost, C. A.; Poukey, J. W.; Turman, B. N.

    Self Magnetically Insulated Transmission Lines (MITL) adders were used successfully in a number of Sandia accelerators such as HELIA, HERMES III, and SABRE. Most recently we used at MITL adder in the RADLAC/SMILE electron beam accelerator to produce high quality, small radius (r(sub rho) less than 2 cm), 11 - 15 MeV, 50 - 100-kA beams with a small transverse velocity v(perpendicular)/c = beta(perpendicular) less than or equal to 0.1. In RADLAC/SMILE, a coaxial MITL passed through the eight, 2 MV vacuum envelopes. The MITL summed the voltages of all eight feeds to a single foilless diode. The experimental results are in good agreement with code simulations. Our success with the MITL technology led us to investigate the application to higher energy accelerator designs. We have a conceptual design for a cavity-fed MITL that sums the voltages from 100 identical, inductively-isolated cavities. Each cavity is a toroidal structure that is driven simultaneously by four 8-ohm pulse-forming lines, providing a 1-MV voltage pulse to each of the 100 cavities. The point design accelerator is 100 MV, 500 kA, with a 30 - 50 ns FWHM output pulse.

  8. Cost Based Failure Modes and Effects Analysis (FMEA) for Systems of Accelerator Magnets

    International Nuclear Information System (INIS)

    Spencer, Cherrill M

    2003-01-01

    The proposed Next Linear Collider (NLC) has a proposed 85% overall availability goal, the availability specifications for all its 7200 magnets and their 6167 power supplies are 97.5% each. Thus all of the electromagnets and their power supplies must be highly reliable or quickly repairable. Improved reliability or repairability comes at a higher cost. We have developed a set of analysis procedures for magnet designers to use as they decide how much effort to exert, i.e. how much money to spend, to improve the reliability of a particular style of magnet. We show these procedures being applied to a standard SLAC electromagnet design in order to make it reliable enough to meet the NLC availability specs. First, empirical data from SLAC's accelerator failure database plus design experience are used to calculate MTBF for failure modes identified through a FMEA. Availability for one particular magnet can be calculated. Next, labor and material costs to repair magnet failures are used in a Monte Carlo simulation to calculate the total cost of all failures over a 30-year lifetime. Opportunity costs are included. Engineers choose from amongst various designs by comparing lifecycle costs

  9. Magnetic and Structural Design of a 15 T $Nb_3Sn$ Accelerator Depole Model

    Energy Technology Data Exchange (ETDEWEB)

    Kashikhin, V. V. [Fermilab; Andreev, N. [Fermilab; Barzi, E. [Fermilab; Novitski, I. [Fermilab; Zlobin, A. V. [Fermilab

    2015-01-01

    Hadron Colliders (HC) are the most powerful discovery tools in modern high energy physics. A 100 TeV scale HC with a nominal operation field of at least 15 T is being considered for the post-LHC era. The choice of a 15 T nominal field requires using the Nb3Sn technology. Practical demonstration of this field level in an accelerator-quality magnet and substantial reduction of the magnet costs are the key conditions for realization of such a machine. FNAL has started the development of a 15 T $Nb_{3}Sn$ dipole demonstrator for a 100 TeV scale HC. The magnet design is based on 4-layer shell type coils, graded between the inner and outer layers to maximize the performance. The experience gained during the 11-T dipole R&D campaign is applied to different aspects of the magnet design. This paper describes the magnetic and structural designs and parameters of the 15 T $Nb_3Sn$ dipole and the steps towards the demonstration model.

  10. Combining rotating-coil measurements of large-aperture accelerator magnets

    CERN Document Server

    AUTHOR|(CDS)2089510

    2016-10-05

    The rotating coil is a widely used tool to measure the magnetic field and the field errors in accelerator magnets. The coil has a length that exceeds the entire magnetic field along the longitudinal dimension of the magnet and gives therefore a two-dimensional representation of the integrated field. Having a very good precision, the rotating coil lacks in versatility. The fixed dimensions make it impractical and inapplicable in situations, when the radial coil dimension is much smaller than the aperture or when the aperture is only little covered by the coil. That being the case for rectangular apertures with large aspect ratio, where a basic measurement by the rotating coil describes the field only in a small area of the magnet. A combination of several measurements at different positions is the topic of this work. Very important for a combination is the error distribution on the measured field harmonics. To preserve the good precision of the higher-order harmonics, the combination must not rely on the main ...

  11. Instabilities of bellows: Dependence on internal pressure, end supports, and interactions in accelerator magnet systems

    International Nuclear Information System (INIS)

    Shutt, R.P.; Rehak, M.L.

    1990-01-01

    For superconducting magnets, one needs many bellows for connection of various helium cooling transfer lines in addition to beam tube bellows. There could be approximately 10,000 magnet interconnection bellows in the SSC exposed to an internal pressure. When axially compressed or internally pressurized, bellows can become unstable, leading to gross distortion or complete failure. If several bellows are contained in an assembly, failure modes might interact. If designed properly, large bellows can be a very feasible possibility for connecting the large tubular shells that support the magnet iron yokes and superconducting coils and contain supercritical helium for magnet cooling. We present here (1) a spring-supported bellows model, in order to develop necessary design features for bellows and end supports so that instabilities will not occur in the bellows pressure operating region, including some margin, (2) a model of three superconducting accelerator magnets connected by two large bellows, in order to ascertain that support requirements are satisfied and in order to study interaction effects between the two bellows. Reliability of bellows for our application will be stressed. 3 refs., 4 figs

  12. Properties and parameters of the electron beam injected into the mirror magnetic trap of a plasma accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Andreev, V. V., E-mail: temple18@mail.ru; Novitsky, A. A.; Vinnichenko, L. A.; Umnov, A. M.; Ndong, D. O. [Peoples’ Friendship University of Russia (Russian Federation)

    2016-03-15

    The parameters of the injector of an axial plasma beam injected into a plasma accelerator operating on the basis of gyroresonance acceleration of electrons in the reverse magnetic field are determined. The trapping of the beam electrons into the regime of gyroresonance acceleration is numerically simulated by the particle- in-cell method. The optimal time of axial injection of the beam into a magnetic mirror trap is determined. The beam parameters satisfying the condition of efficient particle trapping into the gyromagnetic autoresonance regime are found.

  13. Influence of the power supply parameters on the projectile energy in the permanent magnet electrodynamic accelerator

    Science.gov (United States)

    Waindok, Andrzej; Piekielny, Paweł

    2017-10-01

    The main objective of the research is to investigate, how the power supply parameters influence the kinetic energy of the movable element, called commonly a projectile or bullet. A calculation and measurement results of transient characteristics for an electrodynamic accelerator with permanent magnet support were presented in the paper. The calculations were made with using field-circuit model, which includes the parameters of the power supply, mass of the bullet and friction phenomenon. Characteristics of energy and muzzle velocity verso supply voltage (50 V to 350 V) and capacitance value (60 mF to 340.5 mF) were determined, as well. A measurement verification of selected points of calculation characteristics were carried out for investigated values of muzzle velocity. A good conformity between calculation and measurement results was obtained. Concluding, presented characteristics of the muzzle velocity and energy of the projectile vs. power supply parameters indicate, that accelerators could be used for fatigue testing of materials.

  14. Radiation Field Forming for Industrial Electron Accelerators Using Rare-Earth Magnetic Materials

    Science.gov (United States)

    Ermakov, A. N.; Khankin, V. V.; Shvedunov, N. V.; Shvedunov, V. I.; Yurov, D. S.

    2016-09-01

    The article describes the radiation field forming system for industrial electron accelerators, which would have uniform distribution of linear charge density at the surface of an item being irradiated perpendicular to the direction of its motion. Its main element is non-linear quadrupole lens made with the use of rare-earth magnetic materials. The proposed system has a number of advantages over traditional beam scanning systems that use electromagnets, including easier product irradiation planning, lower instantaneous local dose rate, smaller size, lower cost. Provided are the calculation results for a 10 MeV industrial electron accelerator, as well as measurement results for current distribution in the prototype build based on calculations.

  15. Design and optimization of superconducting magnet system for energy storage application

    International Nuclear Information System (INIS)

    Bhunia, Uttam

    2015-01-01

    In view of developing superconducting magnetic energy storage system (SMES) technology that will mitigate voltage sag/dip in the utility line, VEC centre has taken up a leading role in the country. In the first phase a solenoid-type 0.6 MJ SMES system using cryo-stable NbTi superconductor has been designed, developed and tested successfully with resistive load to mitigate power line voltage dips. The cryogenic test results of 0.6 MJ SMES coil will be highlighted. Further, effort is underway to develop a 4.5 MJ/1 MW SMES system with toroidal coil configuration. The lecture will also cover the superconducting coil development for SMES application with special emphasis on design aspects and the optimization issue of the toroidal system using NbTi based Rutherford-type cable. (author)

  16. Nonthermal Particle Acceleration in 3D Relativistic Magnetic Reconnection in Pair Plasma

    Energy Technology Data Exchange (ETDEWEB)

    Werner, Gregory R.; Uzdensky, Dmitri A., E-mail: Greg.Werner@colorado.edu [Center for Integrated Plasma Studies, Physics Department, University of Colorado, 390 UCB, Boulder, CO 80309 (United States)

    2017-07-10

    As a fundamental process converting magnetic to plasma energy in high-energy astrophysical plasmas, relativistic magnetic reconnection is a leading explanation for the acceleration of particles to the ultrarelativistic energies that are necessary to power nonthermal emission (especially X-rays and gamma-rays) in pulsar magnetospheres and pulsar wind nebulae, coronae and jets of accreting black holes, and gamma-ray bursts. An important objective of plasma astrophysics is therefore the characterization of nonthermal particle acceleration (NTPA) effected by reconnection. Reconnection-powered NTPA has been demonstrated over a wide range of physical conditions using large 2D kinetic simulations. However, its robustness in realistic 3D reconnection—in particular, whether the 3D relativistic drift-kink instability (RDKI) disrupts NTPA—has not been systematically investigated, although pioneering 3D simulations have observed NTPA in isolated cases. Here, we present the first comprehensive study of NTPA in 3D relativistic reconnection in collisionless electron–positron plasmas, characterizing NTPA as the strength of 3D effects is varied systematically via the length in the third dimension and the strength of the guide magnetic field. We find that, while the RDKI prominently perturbs 3D reconnecting current sheets, it does not suppress particle acceleration, even for zero guide field; fully 3D reconnection robustly and efficiently produces nonthermal power-law particle spectra closely resembling those obtained in 2D. This finding provides strong support for reconnection as the key mechanism powering high-energy flares in various astrophysical systems. We also show that strong guide fields significantly inhibit NTPA, slowing reconnection and limiting the energy available for plasma energization, yielding steeper and shorter power-law spectra.

  17. Fabrication and component testing results for a Nb3Sn dipole magnet

    International Nuclear Information System (INIS)

    Dell'Orco, D.; Scanlan, R.M.; Taylor, C.E.; Lietzke, A.; Caspi, S.; van Oort, J.M.; McInturff, A.D.

    1994-10-01

    At present, the maximum field achieved in accelerator R ampersand D dipoles is slightly over 10T, with NbTi conductor at 1.8 K. Although Nb 3 Sn has the potential to achieve much higher fields, none of the previous dipoles constructed from Nb 3 Sn have broken the 10T barrier. We report here on the construction of a dipole with high current density Nb 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 3 SD in earlier dipole magnets were investigated in a series of supplemental tests. This includes measurement of the degradation of J 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 3 Sn cable. We report here the results of these tests and the construction status of this 50 mm bore dipole

  18. Large Signal Model of a Four-quadrant AC to DC Converter for Accelerator Magnets

    CERN Document Server

    De la Calle, R; Rinaldi, L; Völker, F V

    2001-01-01

    This paper presents the large signal model of a four-quadrant AC to DC converter, which is expected to be used in the area of particle accelerators. The system’s first stage is composed of a three-phase boost PWM (Pulse Width Modulated) rectifier with DSP (Digital Signal Processing) based power factor correction (PFC) and output voltage regulation. The second stage is a full-bridge PWM inverter that allows fast four-quadrant operation. The structure is fully reversible, and an additional resistance (brake chopper) is not needed to dissipate the energy when the beam deflection magnet acts as generator.

  19. On radiation heating of superconducting magnets of the accelerating-storage complex

    International Nuclear Information System (INIS)

    Maslov, M.A.; Mokhov, N.V.

    1981-01-01

    To analyze regularities of energy release formation in a superconducting winding (SCW) of superconducting magnets (SCM) of the IHEP accelerating-storage facility the energy release values in the SCM when 400-3000 GeV proton beam incidence onto the SCM vacuum chamber are calculated. Two SCM modifications (a dipole one and a quadrupole one) and two modes of irradiation (uniform irradiation along the SCM azimuth and length and a thin beam incidence uniform along the SCM length) are considered. It is shown that for the SCM with the 26 cm aperture at the 1 mrad angle of incidence 25% of the initial proton energy is released [ru

  20. PARTICLE ACCELERATION AND MAGNETIC FIELD AMPLIFICATION IN THE JETS OF 4C74.26

    International Nuclear Information System (INIS)

    Araudo, A. T.; Blundell, K. M.; Bell, A. R.

    2015-01-01

    We model the multi-wavelength emission in the southern hotspot of the radio quasar 4C74.26. The synchrotron radio emission is resolved near the shock with the MERLIN radio-interferometer, and the rapid decay of this emission behind the shock is interpreted as the decay of the amplified downstream magnetic field as expected for small scale turbulence. Electrons are accelerated to only 0.3 TeV, consistent with a diffusion coefficient many orders of magnitude greater than in the Bohm regime. If the same diffusion coefficient applies to the protons, their maximum energy is only ∼100 TeV

  1. Magnetic permeability of stainless steel for use in accelerator beam transport systems

    International Nuclear Information System (INIS)

    Wilson, N.G.; Bunch, P.

    1991-01-01

    High-vacuum beam transport tubes are being designed for use in an accelerator under development at Los Alamos. In areas such as weld-heat-affected zones, the tubes will require localized magnetic permeability of less than 1.02. Seven austenitic stainless steel candidates, 304L, 310, 316L, 317LN, 20Cb-3, Nitronic 33, and Nitronic 40, have been evaluated to determine their permeability in cold-worked, annealed, and weld-affected zones. 310 and 20Cb-3 showed permeability after welding of less than 1.01. 1 ref., 1 fig., 1 tab

  2. Standard map in magnetized relativistic systems: fixed points and regular acceleration.

    Science.gov (United States)

    de Sousa, M C; Steffens, F M; Pakter, R; Rizzato, F B

    2010-08-01

    We investigate the concept of a standard map for the interaction of relativistic particles and electrostatic waves of arbitrary amplitudes, under the action of external magnetic fields. The map is adequate for physical settings where waves and particles interact impulsively, and allows for a series of analytical result to be exactly obtained. Unlike the traditional form of the standard map, the present map is nonlinear in the wave amplitude and displays a series of peculiar properties. Among these properties we discuss the relation involving fixed points of the maps and accelerator regimes.

  3. Observation of multipactor suppression in a dielectric-loaded accelerating structure using an applied axial magnetic field

    International Nuclear Information System (INIS)

    Jing, C.; Konecny, R.; Antipov, S.; Chang, C.; Gold, S. H.; Schoessow, P.; Kanareykin, A.; Gai, W.

    2013-01-01

    Efforts by a number of institutions to develop a Dielectric-Loaded Accelerating (DLA) structure capable of supporting high gradient acceleration when driven by an external radio frequency source have been ongoing over the past decade. Single surface resonant multipactor has been previously identified as one of the major limitations on the practical application of DLA structures in electron accelerators. In this paper, we report the results of an experiment that demonstrated suppression of multipactor growth in an X-band DLA structure through the use of an applied axial magnetic field. This represents an advance toward the practical use of DLA structures in many accelerator applications

  4. D.C. side active filter for high stability accelerator magnet power supplies

    International Nuclear Information System (INIS)

    Singh, Yash Pal; Thakurta, A.C.; Kotaiah, S.

    2006-01-01

    Accelerator d.c, magnets have to produce a highly stable magnetic field which in turn needs highly stable d.c. current sources to energise them. Indus-II Q4 and Q5 power supplies are SCR based power supplies wherein the rectified voltage is fed to a passive filter to reduce the ripple voltage. The output of the passive filter still contains some ripple particularly on the low frequency side. The design and the test results of an active filter module have been discussed wherein the low frequency attenuation can be very effectively taken care of by allowing this to be absorbed in a coupling transformer put after the passive filter. Considerable size reduction has been achieved by using switching techniques. Low frequency attenuation has been made quite a simple task. This filter also helps in handling transients from input. (author)

  5. A new 3-D integral code for computation of accelerator magnets

    International Nuclear Information System (INIS)

    Turner, L.R.; Kettunen, L.

    1991-01-01

    For computing accelerator magnets, integral codes have several advantages over finite element codes; far-field boundaries are treated automatically, and computed field in the bore region satisfy Maxwell's equations exactly. A new integral code employing edge elements rather than nodal elements has overcome the difficulties associated with earlier integral codes. By the use of field integrals (potential differences) as solution variables, the number of unknowns is reduced to one less than the number of nodes. Two examples, a hollow iron sphere and the dipole magnet of Advanced Photon Source injector synchrotron, show the capability of the code. The CPU time requirements are comparable to those of three-dimensional (3-D) finite-element codes. Experiments show that in practice it can realize much of the potential CPU time saving that parallel processing makes possible. 8 refs., 4 figs., 1 tab

  6. Development of large bore superconducting magnet for wastewater treatment application

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hui Ming; Xu, Dong; Shen, Fuzhi; Zhang, Hengcheng; Li, Lafeng [State Key Laboratory of Technologies in Space Cryogenic Propellants, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing (China)

    2017-03-15

    Water issue, especially water pollution, is a serious issue of 21st century. Being an significant technique for securing water resources, superconducting magnetic separation wastewater system was indispensable. A large bore conduction-cooled magnet was custom-tailored for wastewater treatment. The superconducting magnet has been designed, fabricated and tested. The superconducting magnet was composed of NbTi solenoid coils with an effective horizontal warm bore of 400 mm and a maximum central field of 2.56T. The superconducting magnet system was cooled by a two-stage 1.5W 4K GM cryocooler. The NbTi solenoid coils were wound around an aluminum former that is thermally connected to the second stage cold head of the cryocooler through a conductive copper link. The temperature distribution along the conductive link was measured during the cool-down process as well as at steady state. The magnet was cooled down to 4.8K in approximately 65 hours. The test of the magnetic field and quench analysis has been performed to verify the safe operation for the magnet system. Experimental results show that the superconducting magnet reached the designed magnetic performance.

  7. Fiber Bragg Grating Sensors Based Monitoring System for Superconducting Accelerator Magnets

    CERN Document Server

    Chiuchiolo, A; Perez, J C; Bajas, H; Consales, M; Giordano, M; Breglio, G; Cusano, A

    2014-01-01

    New generation of accelerator magnets for high energy applications currently designed, manufactured and tested at the European Organization for Nuclear Research (CERN) require the implementation of precise cryogenic sensors with long-term robustness and reliability able to withstand cryogenic temperature and to monitor the mechanical stresses affecting the winding during all the stages of his service life, assembly, cool down and powering. Monitoring the mechanical behavior of the magnet from assembly to operation is a critical task which aims to assure the integrity of the magnet and to safely handle the coils made of new brittle material. This contribution deals with the first successful embedding of Fiber Bragg Grating sensors in a subscale Nb$_{3}$Sn dipole magnet in order to monitor the strain developed in the coil during the cool down to 1.9 K, the powering up to 15.8 kA and the warm up, offering new perspectives for the development of a complementary sensing technology based on fiber optic sensors.

  8. The Effect of Temperature Dependence of AC Losses in a Bi-2223/Ag Insert of an 8-T Superconducting Magnet

    DEFF Research Database (Denmark)

    Wang, Lei; Wang, Qiuliang; Wang, Hui

    2016-01-01

    A conduction-cooled split-gap superconducting magnet system with a center field of 8 T has been designed and fabricated in the Institute of Electrical Engineering, Chinese Academy of Sciences. The system consists of two Bi-2223/Ag coils and six NbTi coils. Due to a large aspect ratio of the high-...... in the second case. Hence, it is a good way to reduce the ac losses by changing the charging sequences of the Bi-2223/Ag and NbTi cols. Afterward, the calculated results are compared with the experimental data, and they show a good agreement.......A conduction-cooled split-gap superconducting magnet system with a center field of 8 T has been designed and fabricated in the Institute of Electrical Engineering, Chinese Academy of Sciences. The system consists of two Bi-2223/Ag coils and six NbTi coils. Due to a large aspect ratio of the high......-temperature superconducting tape, there will be large ac losses when the magnet is ramped up and down. An accurate estimation of the total ac losses in the high-temperature superconducting coils is essential for the cryogenic system design. In the Bi-2223/Ag coils, the total ac losses mainly originate from two parts: One...

  9. Ponderomotive ion acceleration in dense magnetized laser-irradiated thick target plasmas

    Science.gov (United States)

    Sinha, Ujjwal; Kaw, Predhiman

    2012-03-01

    When a circularly polarized laser pulse falls on an overdense plasma, it displaces the electrons via ponderomotive force creating a double layer. The double layer constitutes of an ion and electron sheath with in which the electrostatic field present is responsible for ion acceleration. In this paper, we have analyzed the effect a static longitudinal magnetic field has over the ion acceleration mechanism. The longitudinal magnetic field changes the plasma dielectric constant due to cyclotron effects which in turn enhances or reduces the ponderomotive force exerted by the laser depending on whether the laser is left or right circularly polarized. Also, the analysis of the ion space charge region present behind the ion sheath of the laser piston that undergoes coulomb explosion has been explored for the first time. We have studied the interaction of an incoming ion beam with the laser piston and the ion space charge. It has been found that the exploding ion space charge has the ability to act as an energy amplifier for incoming ion beams.

  10. A permanent magnet electron beam spread system used for a low energy electron irradiation accelerator

    International Nuclear Information System (INIS)

    Huang Jiang; Xiong Yongqian; Chen Dezhi; Liu Kaifeng; Yang Jun; Li Dong; Yu Tiaoqin; Fan Mingwu; Yang Bo

    2014-01-01

    The development of irradiation processing industry brings about various types of irradiation objects and expands the irradiation requirements for better uniformity and larger areas. This paper proposes an innovative design of a permanent magnet electron beam spread system. By clarifying its operation principles, the author verifies the feasibility of its application in irradiation accelerators for industrial use with the examples of its application in electron accelerators with energy ranging from 300 keV to 1 MeV. Based on the finite element analyses of electromagnetic fields and the charged particle dynamics, the author also conducts a simulation of electron dynamics in magnetic field on a computer. The results indicate that compared with the traditional electron beam scanning system, this system boosts the advantages of a larger spread area, non-power supply, simple structure and low cost, etc., which means it is not only suitable for the irradiation of objects with the shape of tubes, strips and panels, but can also achieve a desirable irradiation performance on irregular constructed objects of large size. (authors)

  11. Superconducting magnet

    Science.gov (United States)

    1985-01-01

    Extensive computer based engineering design effort resulted in optimization of a superconducting magnet design with an average bulk current density of approximately 12KA/cm(2). Twisted, stranded 0.0045 inch diameter NbTi superconductor in a copper matrix was selected. Winding the coil from this bundle facilitated uniform winding of the small diameter wire. Test coils were wound using a first lot of the wire. The actual packing density was measured from these. Interwinding voltage break down tests on the test coils indicated the need for adjustment of the wire insulation on the lot of wire subsequently ordered for construction of the delivered superconducting magnet. Using the actual packing densities from the test coils, a final magnet design, with the required enhancement and field profile, was generated. All mechanical and thermal design parameters were then also fixed. The superconducting magnet was then fabricated and tested. The first test was made with the magnet immersed in liquid helium at 4.2K. The second test was conducted at 2K in vacuum. In the latter test, the magnet was conduction cooled from the mounting flange end.

  12. Strong ion accelerating by collisionless magnetosonic shock wave propagating perpendicular to a magnetic field

    International Nuclear Information System (INIS)

    Ohsawa, Yukiharu.

    1984-12-01

    A 2-1/2 dimensional fully relativistic, fully electromagnetic particle code is used to study a time evolution of nonlinear magnetosonic pulse propagating in the direction perpendicular to a magnetic field. The pulse is excited by an instantaneous piston acceleration, and evolves totally self-consistently. Large amplitude pulse traps some ions and accelerates them parallel to the wave front. They are detrapped when their velocities become of the order of the sum of the ExB drift velocity and the wave phase velocity, where E is the electric field in the direction of wave propagation. The pulse develops into a quasi-shock wave in a collisionless plasma by a dissipation due to the resonant ion acceleration. Simple nonlinear wave theory for a cold plasma well describes the shock properties observed in the simulation except for the effects of resonant ions. In particular, magnitude of an electric potential across the shock region is derived analytically and is found to be in good agreement with our simulations. The potential jump is proportional to B 2 , and hence the ExB drift velocity of the trapped ions is proportional to B. (author)

  13. SMALL-SCALE MAGNETIC ISLANDS IN THE SOLAR WIND AND THEIR ROLE IN PARTICLE ACCELERATION. II. PARTICLE ENERGIZATION INSIDE MAGNETICALLY CONFINED CAVITIES

    International Nuclear Information System (INIS)

    Khabarova, Olga V.; Zank, Gary P.; Li, Gang; Le Roux, Jakobus A.; Webb, Gary M.; Malandraki, Olga E.

    2016-01-01

    We explore the role of heliospheric magnetic field configurations and conditions that favor the generation and confinement of small-scale magnetic islands associated with atypical energetic particle events (AEPEs) in the solar wind. Some AEPEs do not align with standard particle acceleration mechanisms, such as flare-related or simple diffusive shock acceleration processes related to interplanetary coronal mass ejections (ICMEs) and corotating interaction regions (CIRs). As we have shown recently, energetic particle flux enhancements may well originate locally and can be explained by particle acceleration in regions filled with small-scale magnetic islands with a typical width of ∼0.01 au or less, which is often observed near the heliospheric current sheet (HCS). The particle energization is a consequence of magnetic reconnection-related processes in islands experiencing either merging or contraction, observed, for example, in HCS ripples. Here we provide more observations that support the idea and the theory of particle energization produced by small-scale-flux-rope dynamics (Zank et al. and Le Roux et al.). If the particles are pre-accelerated to keV energies via classical mechanisms, they may be additionally accelerated up to 1–1.5 MeV inside magnetically confined cavities of various origins. The magnetic cavities, formed by current sheets, may occur at the interface of different streams such as CIRs and ICMEs or ICMEs and coronal hole flows. They may also form during the HCS interaction with interplanetary shocks (ISs) or CIRs/ICMEs. Particle acceleration inside magnetic cavities may explain puzzling AEPEs occurring far beyond ISs, within ICMEs, before approaching CIRs as well as between CIRs.

  14. Influence of a transverse magnetic field on the dose deposited by a 6 MV linear accelerator

    Directory of Open Access Journals (Sweden)

    Richter Sebastian

    2017-09-01

    Full Text Available An integrated system of a linear accelerator and a magnetic resonance imaging (MRI device may provide real-time imaging during radiotherapy treatments. This work investigated changes affecting the dose deposition caused by a magnetic field (B-field transverse to the beam direction by means of Monte Carlo simulations. Two different phantoms were used: A water phantom (Ph1 and a water-air phantom (Ph2 with a 4-2-4 cm water-air-water cross section. Dose depositions were scored for B-field values of 0 T, 0.35 T, 0.5 T, 1.5 T, 3 T and 5 T. Beams were based on a precalculated photon spectrum taken from an earlier simulated Elekta 6 MV FFF accelerator. All lateral profiles in Ph1 showed a Lorentz force driven shift w.r.t. the B-field strength, presenting a steeper penumbra in the shift's direction. Depositions were shifted up to 0.3 cm for 5 T, showing a constant central axis plateau-dose or an increase by 2.3 % for small fields. Depth-dose curves in Ph1 showed a shift of the dose maximum towards the beam entrance direction for increasing B-field of up to 1.1 cm; the maximum dose was increased by 6.9 %. In Ph2, an asymmetric dose increase by up to 36.9 % was observed for 1.5 T at the water-air boundary, resulting from the electron return effect (ERE. In our scenario, B-field dependent dose shifts and local build-ups were observed, which consequently affect the resulting dose distribution and need to be considered in magnetic resonance guided radiotherapy treatment planning.

  15. Development of Experimental Superconducting Magnet for the Collector Ring of FAIR Project

    International Nuclear Information System (INIS)

    Zhu Yinfeng; Wu Weiyue; Wu Songtao; Liu Changle; Xu Houchang

    2010-01-01

    A pool cooled experimental magnet based on the copper stabilized NbTi superconducting wire was designed, fabricated and tested, in order to evaluate the engineering design of the dipole superconducting magnet for the collector ring (CR) of the facility for antiproton and ion research (FAIR) project. In this paper, the experimental setup including quench protection system was presented. Performance of the liquid helium pool cooled test was introduced. All of the results indicate both the performance of conductor and the experimental superconducting magnet under low temperature is stable, which suggests the engineering design are feasible for the formal magnet in CR of the FAIR project.

  16. Does the magnetic expansion factor (fs) play a role in solar wind acceleration?

    Science.gov (United States)

    Wallace, Samantha; Arge, Charles N.; Pihlstrom, Ylva

    2017-08-01

    For the past 25 years, magnetic expansion factor (fs) has been a key parameter used in the calculation of terminal solar wind speed (vsw) in both the Wang-Sheeley-Arge (WSA) model and its predecessor the Wang-Sheeley (WS) model. Since the discovery of an inverse relationship between fs and vsw, the physical role that magnetic expansion factor plays in the acceleration of the solar wind has been explored and debated. In this study, we investigate whether magnetic expansion factor plays a causal role in determining the terminal speed of the solar wind or merely serves as proxy. To do so, we explore how fs, as determined by WSA, relates to vsw for two different scenarios: 1) extended periods where the fast solar wind emerges from the centers of large coronal holes, and 2) periods where the solar wind emerges from pseudostreamers. For these same scenarios, we will also consider an alternative empirical relationship between solar wind speed and the minimum angular distance at the photosphere of a solar wind source to the nearest coronal hole boundary (i.e., DCHB, θb). We then compare these two different prediction techniques directly with heliospheric observations (i.e., ACE, STEREO-A & B, Ulysses) of solar wind speed to determine whether one clearly out performs the other.

  17. Cryogenic test facility instrumentation with fiber optic and fiber optic sensors for testing superconducting accelerator magnets

    Science.gov (United States)

    Chiuchiolo, A.; Bajas, H.; Bajko, M.; Castaldo, B.; Consales, M.; Cusano, A.; Giordano, M.; Giloux, C.; Perez, J. C.; Sansone, L.; Viret, P.

    2017-12-01

    The magnets for the next steps in accelerator physics, such as the High Luminosity upgrade of the LHC (HL- LHC) and the Future Circular Collider (FCC), require the development of new technologies for manufacturing and monitoring. To meet the HL-LHC new requirements, a large upgrade of the CERN SM18 cryogenic test facilities is ongoing with the implementation of new cryostats and cryogenic instrumentation. The paper deals with the advances in the development and the calibration of fiber optic sensors in the range 300 - 4 K using a dedicated closed-cycle refrigerator system composed of a pulse tube and a cryogen-free cryostat. The calibrated fiber optic sensors (FOS) have been installed in three vertical cryostats used for testing superconducting magnets down to 1.9 K or 4.2 K and in the variable temperature test bench (100 - 4.2 K). Some examples of FOS measurements of cryostat temperature evolution are presented as well as measurements of strain performed on a subscale of High Temperature Superconducting magnet during its powering tests.

  18. Electron Acceleration in the Field-reversed Configuration (FRC) by Slowly Rotation Odd-parity Magnetic Fields (RMFo)

    International Nuclear Information System (INIS)

    Glasser, A.H.; Cohen, S.A.

    2001-01-01

    The trajectories of individual electrons are studied numerically in a 3D, prolate, FRC [field-reversed configuration] equilibrium magnetic geometry with added small-amplitude, slowly rotating, odd-parity magnetic fields (RMFos). RMFos cause electron heating by toroidal acceleration near the O-point line and by field-parallel acceleration away from it, both followed by scattering from magnetic-field inhomogeneities. Electrons accelerated along the O-point line move antiparallel to the FRC's current and attain average toroidal angular speeds near that of the RMFo, independent of the sense of RMFo rotation. A conserved transformed Hamiltonian, dependent on electron energy and RMFo sense, controls electron flux-surface coordinate

  19. Purification of condenser water in thermal power station by superconducting magnetic separation

    International Nuclear Information System (INIS)

    Ha, D.W.; Kwon, J.M.; Baik, S.K.; Lee, Y.J.; Han, K.S.; Ko, R.K.; Sohn, M.H.; Seong, K.C.

    2011-01-01

    Magnetic separation using cryo-cooled Nb-Ti superconducting magnet was applied for the purification of condenser water. Iron oxides in condenser water were effectively removed by superconducting magnetic separation. The effect of magnetic field strength and filter size was determined. Thermal power station is made up of a steam turbine and a steam condenser which need a lot of water. The water of steam condenser should be replaced, since scales consisting of iron oxide mainly are accumulated on the surface of condenser pipes as it goes. Superconducting high gradient magnetic separation (HGMS) system has merits to remove paramagnetic substance like iron oxides because it can generate higher magnetic field strength than electromagnet or permanent magnet. In this paper, cryo-cooled Nb-Ti superconducting magnet that can generate up to 6 T was used for HGMS systems. Magnetic filters were designed by the analysis of magnetic field distribution at superconducting magnets. The result of X-ray analysis showed contaminants were mostly α-Fe 2 O 3 (hematite) and γ-Fe 2 O 3 (maghemite). The higher magnetic field was applied up to 6 T, the more iron oxides were removed. As the wire diameter of magnetic filter decreased, the turbidity removal of the sample was enhanced.

  20. THE EFFECT OF LARGE-SCALE MAGNETIC TURBULENCE ON THE ACCELERATION OF ELECTRONS BY PERPENDICULAR COLLISIONLESS SHOCKS

    International Nuclear Information System (INIS)

    Guo Fan; Giacalone, Joe

    2010-01-01

    We study the physics of electron acceleration at collisionless shocks that move through a plasma containing large-scale magnetic fluctuations. We numerically integrate the trajectories of a large number of electrons, which are treated as test particles moving in the time-dependent electric and magnetic fields determined from two-dimensional hybrid simulations (kinetic ions and fluid electron). The large-scale magnetic fluctuations effect the electrons in a number of ways and lead to efficient and rapid energization at the shock front. Since the electrons mainly follow along magnetic lines of force, the large-scale braiding of field lines in space allows the fast-moving electrons to cross the shock front several times, leading to efficient acceleration. Ripples in the shock front occurring at various scales will also contribute to the acceleration by mirroring the electrons. Our calculation shows that this process favors electron acceleration at perpendicular shocks. The current study is also helpful in understanding the injection problem for electron acceleration by collisionless shocks. It is also shown that the spatial distribution of energetic electrons is similar to in situ observations. The process may be important to our understanding of energetic electrons in planetary bow shocks and interplanetary shocks, and explaining herringbone structures seen in some type II solar radio bursts.

  1. Proton beam transport experiments with pulsed high-field magnets at the Dresden laser acceleration source Draco

    Energy Technology Data Exchange (ETDEWEB)

    Kroll, Florian; Schramm, Ulrich [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Technische Universitaet Dresden, Dresden (Germany); Kraft, Stephan; Metzkes, Josefine; Schlenvoigt, Hans-Peter; Zeil, Karl [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany)

    2016-07-01

    Compact laser-driven ion accelerators are a potential alternative to large and expensive conventional accelerators. High-power short-pulse lasers, impinging on e.g. thin metal foils, enable multi-MeV ion acceleration on μm length and fs to ps time scale. The generated ion bunches (typically protons) show unique beam properties, like ultra-high pulse dose. Nevertheless, laser accelerators still require substantial development in reliable beam generation and transport. Recently developed pulsed magnets meet the demands of laser acceleration and open up new research opportunities: We present a pulsed solenoid for effective collection and focusing of laser-accelerated protons that acts as link between fundamental research and application. The solenoid is powered by a capacitor-based pulse generator and can reach a maximum magnetic field of 20 T. It was installed in the target chamber of the Draco laser at HZDR. The transported beam was detected by means of radiochromic film, scintillator and Thomson parabola spectrometer. We present the characterization of the solenoid with regard to future application in radiobiological irradiation studies. Furthermore, a detailed comparison to previous experiments with a similar magnet at the PHELIX laser at GSI, Darmstadt is provided.

  2. Comparison Study of Electromagnet and Permanent Magnet Systems for an Accelerator Using Cost-Based Failure Modes and Effects Analysis

    International Nuclear Information System (INIS)

    Spencer, C

    2004-01-01

    The next generation of particle accelerators will be one-of-a-kind facilities, and to meet their luminosity goals they must have guaranteed availability over their several decade lifetimes. The Next Linear Collider (NLC) is one viable option for a 1 TeV electron-positron linear collider, it has an 85% overall availability goal. We previously showed how a traditional Failure Modes and Effects Analysis (FMEA) of a SLAC electromagnet leads to reliability-enhancing design changes. Traditional FMEA identifies failure modes with high risk but does not consider the consequences in terms of cost, which could lead to unnecessarily expensive components. We have used a new methodology, ''Life Cost-Based FMEA'', which measures risk of failure in terms of cost, in order to evaluate and compare two different technologies that might be used for the 8653 NLC magnets: electromagnets or permanent magnets. The availabilities for the two different types of magnet systems have been estimated using empirical data from SLAC's accelerator failure database plus expert opinion on permanent magnet failure modes and industry standard failure data. Labor and material costs to repair magnet failures are predicted using a Monte Carlo simulation of all possible magnet failures over a 30-year lifetime. Our goal is to maximize up-time of the NLC through magnet design improvements and the optimal combination of electromagnets and permanent magnets, while reducing magnet system lifecycle costs

  3. Analysis of Uncertainties in Protection Heater Delay Time Measurements and Simulations in Nb$_{3}$Sn High-Field Accelerator Magnets

    CERN Document Server

    Salmi, Tiina; Marchevsky, Maxim; Bajas, Hugo; Felice, Helene; Stenvall, Antti

    2015-01-01

    The quench protection of superconducting high-field accelerator magnets is presently based on protection heaters, which are activated upon quench detection to accelerate the quench propagation within the winding. Estimations of the heater delay to initiate a normal zone in the coil are essential for the protection design. During the development of Nb3Sn magnets for the LHC luminosity upgrade, protection heater delays have been measured in several experiments, and a new computational tool CoHDA (Code for Heater Delay Analysis) has been developed for heater design. Several computational quench analyses suggest that the efficiency of the present heater technology is on the borderline of protecting the magnets. Quantifying the inevitable uncertainties related to the measured and simulated delays is therefore of pivotal importance. In this paper, we analyze the uncertainties in the heater delay measurements and simulations using data from five impregnated high-field Nb3Sn magnets with different heater geometries. ...

  4. Analysis of Uncertainties in Protection Heater Delay Time Measurements and Simulations in Nb$_{3}$Sn High-Field Accelerator Magnets

    CERN Document Server

    Salmi, Tiina; Marchevsky, Maxim; Bajas, Hugo; Felice, Helene; Stenvall, Antti

    2015-01-01

    The quench protection of superconducting high-field accelerator magnets is presently based on protection heaters, which are activated upon quench detection to accelerate the quench propagation within the winding. Estimations of the heater delay to initiate a normal zone in the coil are essential for the protection design. During the development of Nb$_{3}$Sn magnets for the LHC luminosity upgrade, protection heater delays have been measured in several experiments, and a new computational tool CoHDA (Code for Heater Delay Analysis) has been developed for heater design. Several computational quench analyses suggest that the efficiency of the present heater technology is on the borderline of protecting the magnets. Quantifying the inevitable uncertainties related to the measured and simulated delays is therefore of pivotal importance. In this paper, we analyze the uncertainties in the heater delay measurements and simulations using data from five impregnated high-field Nb$_{3}$Sn magnets with different heater ge...

  5. A fiber optics sensor for strain and stress management in superconducting accelerator magnets

    International Nuclear Information System (INIS)

    van Oort, J.M.; ten Kate, H.H.J.

    1993-01-01

    A novel cryogenic interferometric fiber optics sensor for the measurement of strain and stress in the coil windings of superconducting accelerator magnets is described. The sensor can operate with two different readout sources, monochromatic laser light and white light respectively. The sensor head is built up as an extrinsic Fabry-Perot interferometer formed with two cleaved fiber surfaces, and can be mounted in several configurations. When read with laser light, the sensor is an extremely sensitive relative strain or temperature detector. When read with white light the absolute strain and pressure can be measured. Results are presented of tests in several configurations at 77 K and 4.2 K, both for the relative and absolute readout method. Finally, the possible use for quench localization using the temperature sensitivity is described

  6. Image acceleration in parallel magnetic resonance imaging by means of metamaterial magnetoinductive lenses

    Directory of Open Access Journals (Sweden)

    Manuel J. Freire

    2012-06-01

    Full Text Available Parallel Magnetic Resonance imaging (pMRI is an image acceleration technique which takes advantage of localized sensitivities of multiple receivers. In this letter, we show that metamaterial lenses based on capacitively-loaded rings can provide higher localization of coil sensitivities compared to conventional loop designs. Several lens designs are systematically analyzed in order to find the structure providing higher signal-to-noise-ratio. The magnetoinductive (MI lens has been found to be the optimum structure and an experiment is developed to show it. The ability of the MI lens for pMRI is investigated by means of the parameter known in the MRI community as g-Factor.

  7. Transverse phase space diagnostics for ionization injection in laser plasma acceleration using permanent magnetic quadrupoles

    Science.gov (United States)

    Li, F.; Nie, Z.; Wu, Y. P.; Guo, B.; Zhang, X. H.; Huang, S.; Zhang, J.; Cheng, Z.; Ma, Y.; Fang, Y.; Zhang, C. J.; Wan, Y.; Xu, X. L.; Hua, J. F.; Pai, C. H.; Lu, W.; Mori, W. B.

    2018-04-01

    We report the transverse phase space diagnostics for electron beams generated through ionization injection in a laser-plasma accelerator. Single-shot measurements of both ultimate emittance and Twiss parameters are achieved by means of permanent magnetic quadrupole. Beams with emittance of μm rad level are obtained in a typical ionization injection scheme, and the dependence on nitrogen concentration and charge density is studied experimentally and confirmed by simulations. A key feature of the transverse phase space, matched beams with Twiss parameter α T ≃ 0, is identified according to the measurement. Numerical simulations that are in qualitative agreement with the experimental results reveal that a sufficient phase mixing induced by an overlong injection length leads to the matched phase space distribution.

  8. Influence of the power supply parameters on the projectile energy in the permanent magnet electrodynamic accelerator

    Directory of Open Access Journals (Sweden)

    Waindok Andrzej

    2017-01-01

    Full Text Available The main objective of the research is to investigate, how the power supply parameters influence the kinetic energy of the movable element, called commonly a projectile or bullet. A calculation and measurement results of transient characteristics for an electrodynamic accelerator with permanent magnet support were presented in the paper. The calculations were made with using field-circuit model, which includes the parameters of the power supply, mass of the bullet and friction phenomenon. Characteristics of energy and muzzle velocity verso supply voltage (50 V to 350 V and capacitance value (60 mF to 340.5 mF were determined, as well. A measurement verification of selected points of calculation characteristics were carried out for investigated values of muzzle velocity. A good conformity between calculation and measurement results was obtained. Concluding, presented characteristics of the muzzle velocity and energy of the projectile vs. power supply parameters indicate, that accelerators could be used for fatigue testing of materials.

  9. Novel technique for injecting and extracting beams in a circular hadron accelerator without using septum magnets

    Directory of Open Access Journals (Sweden)

    Andrea Franchi

    2015-07-01

    Full Text Available With a few exceptions, all on-axis injection and extraction schemes implemented in circular particle accelerators, synchrotrons, and storage rings, make use of magnetic and electrostatic septa with systems of slow-pulsing dipoles acting on tens of thousands of turns and fast-pulsing dipoles on just a few. The dipoles create a closed orbit deformation around the septa, usually referred to as an orbit bump. A new approach is presented which obviates the need for the septum deflectors. Fast-pulsing elements are still required, but their strength can be minimized by choosing appropriate local accelerator optics. This technique should increase the beam clearance and reduce the usually high radiation levels found around the septa and also reduce the machine impedance introduced by the fast-pulsing dipoles. The basis of the technique is the creation of stable islands around stable fixed points in horizontal phase space. The trajectories of these islands may then be adjusted to match the position and angle of the incoming or outgoing beam.

  10. Electron surfing acceleration by the electron two-stream instability in a weak magnetic field

    International Nuclear Information System (INIS)

    Dieckmann, M E; Shukla, P K

    2006-01-01

    The thermalization of relativistically flowing colliding plasmas is not well understood. The transition layer, in which both plasmas interact and thermalize, is wide and highly structured and the instabilities in this layer may yield non-thermal particle distributions and shock-less energy dissipation. The objective in this work is to explore the ability of an electron two-stream instability for thermalizing a plasma beam that moves at the mildly relativistic speed 0.3c through weakly magnetized plasma and to identify the resulting particle distributions. It is demonstrated here with particle-in-cell simulations that the electron two-stream instability leads to waves that propagate within a wide angular range relative to the flow velocity. The waves are thus not planar, as required for efficient electron surfing acceleration (ESA). The short lifetime of the waves implies, however, only weak modifications of the ESA by the oblique modes, since the waves are sufficiently homogeneous. The ion (proton) beams are not modulated, which would be required to extract some of their energy. The instability can thus heat the electrons significantly, but it fails to accelerate them to relativistic energies and it cannot form a shock layer by thermalizing the protons, at least not for the system and the resolved timescales considered here

  11. Electron surfing acceleration by the electron two-stream instability in a weak magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Dieckmann, M E; Shukla, P K [Institut fuer Theoretische Physik IV, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany)

    2006-10-15

    The thermalization of relativistically flowing colliding plasmas is not well understood. The transition layer, in which both plasmas interact and thermalize, is wide and highly structured and the instabilities in this layer may yield non-thermal particle distributions and shock-less energy dissipation. The objective in this work is to explore the ability of an electron two-stream instability for thermalizing a plasma beam that moves at the mildly relativistic speed 0.3c through weakly magnetized plasma and to identify the resulting particle distributions. It is demonstrated here with particle-in-cell simulations that the electron two-stream instability leads to waves that propagate within a wide angular range relative to the flow velocity. The waves are thus not planar, as required for efficient electron surfing acceleration (ESA). The short lifetime of the waves implies, however, only weak modifications of the ESA by the oblique modes, since the waves are sufficiently homogeneous. The ion (proton) beams are not modulated, which would be required to extract some of their energy. The instability can thus heat the electrons significantly, but it fails to accelerate them to relativistic energies and it cannot form a shock layer by thermalizing the protons, at least not for the system and the resolved timescales considered here.

  12. Accelerating two-dimensional nuclear magnetic resonance correlation spectroscopy via selective coherence transfer

    Science.gov (United States)

    Ye, Qimiao; Chen, Lin; Qiu, Wenqi; Lin, Liangjie; Sun, Huijun; Cai, Shuhui; Wei, Zhiliang; Chen, Zhong

    2017-01-01

    Nuclear magnetic resonance (NMR) spectroscopy serves as an important tool for both qualitative and quantitative analyses of various systems in chemistry, biology, and medicine. However, applications of one-dimensional 1H NMR are often restrained by the presence of severe overlap among different resonances. The advent of two-dimensional (2D) 1H NMR constitutes a promising alternative by extending the crowded resonances into a plane and thereby alleviating the spectral congestions. However, the enhanced ability in discriminating resonances is achieved at the cost of extended experimental duration due to necessity of various scans with progressive delays to construct the indirect dimension. Therefore, in this study, we propose a selective coherence transfer (SECOT) method to accelerate acquisitions of 2D correlation spectroscopy by converting chemical shifts into spatial positions within the effective sample length and then performing an echo planar spectroscopic imaging module to record the spatial and spectral information, which generates 2D correlation spectrum after 2D Fourier transformation. The feasibility and effectiveness of SECOT have been verified by a set of experiments under both homogeneous and inhomogeneous magnetic fields. Moreover, evaluations of SECOT for quantitative analyses are carried out on samples with a series of different concentrations. Based on these experimental results, the SECOT may open important perspectives for fast, accurate, and stable investigations of various chemical systems both qualitatively and quantitatively.

  13. Design and test of a short mockup magnet for the superconducting undulator at the SSRF

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Jieping, E-mail: jpxu@sinap.ac.cn; Ding, Yi; Cui, Jian; Zhang, Wei; Wang, Hongfei; Yin, Lixin [Department of Mechanical Engineering, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204 (China)

    2016-07-27

    A superconducting planar undulator is under development at the Shanghai Synchrotron Radiation Facility (SSRF) to provide the SSRF users with higher photon fluxes at higher photon energies. A 5-period magnet was designed and built for feasibility study. The short mockup magnet is composed of NbTi/Cu winding and low carbon steel former and was tested in a vertical cryocooler-cooled cryostat. The nominal current of 387 A was reached after 2 quenches and the maximum current of 433.2 A was achieved. The magnetic field profile was measured and a peak field of 0.93 T was obtained when stably operating at 400 A.

  14. Technologies pioneered by LHC. Superconducting magnet and radiation-tolerant tracking detector

    International Nuclear Information System (INIS)

    Yamamoto, Akira; Unno, Yoshinobu

    2007-01-01

    In the LHC project of proton-proton collisions exploring the energy frontier, superconducting magnets and radiation-tolerant tracking detector play fundamental roles as key technologies. The superconducting magnets contribute to bending and focusing particle beam by using high magnetic field created with the NbTi superconductor cooled to the superfluid temperature of He (1.9 K). In order to overcome the unprecedented radiation damage and to capture the particles emerging with high energy and high density, the large area and highly radiation-tolerant silicon semiconductor tracking detector has been developed for the LHC experiment. (author)

  15. Computer simulations of quench properties of thin, large superconducting solenoid magnets

    International Nuclear Information System (INIS)

    Kishimoto, Takeshi; Mori, Shigeki; Noguchi, Masaharu

    1983-01-01

    Measured quench data of a 1 m diameter x 1 m thin superconducting solenoid magnet with a single layer aluminum-stabilized NbTi/Cu superconductor of 269 turns were fitted by computer simulations using the one-dimensional approximation. Parameters obtained were used to study quench properties of a 3 m diameter x 5 m (1.5 Tesla) thin superconducting solenoid magnet with a stored magnetic energy of 30 x 10 6 J. Conductor dimensions with which the solenoid could be built substantially safe for the full field quench were optimized. (author)

  16. Analysis of ITER NbTi and Nb3Sn CICCs experimental minimum quench energy with JackPot, MCM and THEA models

    NARCIS (Netherlands)

    Bagni, T.; Duchateau, J.L.; Breschi, M.; Devred, A.; Nijhuis, A.

    2017-01-01

    Cable-in-conduit conductors (CICCs) for ITER magnets are subjected to fast changing magnetic fields during the plasma-operating scenario. In order to anticipate the limitations of conductors under the foreseen operating conditions, it is essential to have a better understanding of the stability

  17. The outflows accelerated by the magnetic fields and radiation force of accretion disks

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Xinwu, E-mail: cxw@shao.ac.cn [Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai, 200030 (China)

    2014-03-01

    The inner region of a luminous accretion disk is radiation-pressure-dominated. We estimate the surface temperature of a radiation-pressure-dominated accretion disk, Θ=c{sub s}{sup 2}/r{sup 2}Ω{sub K}{sup 2}≪(H/r){sup 2}, which is significantly lower than that of a gas-pressure-dominated disk, Θ ∼ (H/r){sup 2}. This means that the outflow can be launched magnetically from the photosphere of the radiation-pressure-dominated disk only if the effective potential barrier along the magnetic field line is extremely shallow or no potential barrier is present. For the latter case, the slow sonic point in the outflow will probably be in the disk, which leads to a slow circular dense flow above the disk. This implies that hot gas (probably in the corona) is necessary for launching an outflow from the radiation-pressure-dominated disk, which provides a natural explanation for the observational evidence that the relativistic jets are related to hot plasma in some X-ray binaries and active galactic nuclei. We investigate the outflows accelerated from the hot corona above the disk by the magnetic field and radiation force of the accretion disk. We find that with the help of the radiation force, the mass loss rate in the outflow is high, which leads to a slow outflow. This may be why the jets in radio-loud narrow-line Seyfert galaxies are in general mildly relativistic compared with those in blazars.

  18. A fiber-optic strain measurement and quench localization system for use in superconducting accelerator dipole magnets

    NARCIS (Netherlands)

    van Oort, J.M.; Scanlan, Ronald M.; ten Kate, Herman H.J.

    1995-01-01

    A novel fiber-optic measurement system for superconducting accelerator magnets is described. The principal component is an extrinsic Fabry-Perot interferometer to determine localized strain and stress in coil windings. The system can be used either as a sensitive relative strain measurement system

  19. Magnetic field decay in model SSC dipoles

    International Nuclear Information System (INIS)

    Gilbert, W.S.; Althaus, R.F.; Barale, P.J.; Benjegerdes, R.W.; Green, M.A.; Green, M.I.; Scanlan, R.M.

    1988-08-01

    We have observed that some of our model SSC dipoles have long time constant decays of the magnetic field harmonics with amplitudes large enough to result in significant beam loss, if they are not corrected. The magnets were run at constant current at the SSC injection field level of 0.3 tesla for one to three hours and changes in the magnetic field were observed. One explanation for the observed field decay is time dependent superconductor magnetization. Another explanation involves flux creep or flux flow. Data are presented on how the decay changes with previous flux history. Similar magnets with different Nb-Ti filament spacings and matrix materials have different long time field decay. A theoretical model using proximity coupling and flux creep for the observed field decay is discussed. 10 refs., 5 figs., 2 tabs

  20. High magnetic field uniformity superconducting magnet for a movable polarized target

    International Nuclear Information System (INIS)

    Anishchenko, N.G.; Bartenev, V.D.; Blinov, N.A.

    1998-01-01

    The superconducting polarizing magnet was constructed for movable polarized target (MPT) with working volume 200 mm long and 30 mm in diameter. The magnet provides a polarizing magnetic field up to 6 T with the uniformity of 4.5 x 10 -4 in the working volume of the target. The magnet windings are made of a NbTi wire, impregnated with the epoxy resin and placed in the horizontal cryostat with 'warm' aperture diameter of 96 mm. The design and technology of the magnet winding are described. Results of the magnetic field map measurements using a NMR-magnetometer are given. The MPT set-up is installed in the beam line of polarized neutrons produced by break-up of polarized deuterons extracted from the Synchrophasotron of the Laboratory of High Energies (LHE), JINR, Dubna