Texas A&M University, College Station, Texas, USA
A design is being developed to prototype for a dipole for this purpose: a block-coil dipole with 13 T short- sample field, 11 T working field, and 6 cm aperture. The dipole is a natural application of the high-field dipole strategy developed at Texas A&M, using simple pancake windings, flux-plate suppression of low-field multipoles, and bladder preloading. A short model dipole is planned.
Fermilab, Batavia, USA
Muons, Inc, Batavia, USA
A helical cooling channel (HCC) is a new technique proposed for six-dimensional (6D) cooling of muon beams. To achieve the optimal cooling rate, the high field section of HCC need to be developed, which suggests using High Temperature Superconductors (HTS). This paper updates the parameters of a YBCO based helical solenoid (HS) model, describes the fabrication of HS segments (double-pancake units) and the assembly of six-coil short HS model with two dummy cavity insertions. Three HS segments and the six-coil short model were tested. The results are presented and discussed.
ANL, Argonne, USA
The quench properties of two 42-pole prototype superconducting undulators (SCUs) (one having a steel core the other with an aluminium core) have been tested. Since the SCUs have relatively low stored energy, the quench protection has relied on an over-voltage protection feature of the power supply, and the inherent quench back from the core. Concerns about conductor damage (during a quench) due to heating and high induced voltages were raised. The maximum conductor temperatures and voltages have been deduced from voltage and current measurements during a quench. The deduced maximum hot-spot temperature of the conductor was less than 150 K and the maximum voltage across each SCU coil was less than 300 V.
BNL, Upton, Long Island, New York, USA
FRIB, East Lansing, Michigan, USA
The coils of the first quadrupole in the fragment separator region of the Facility for Rare Isotope Beams (FRIB) must withstand an intense level of radiation and accommodate a very high heat load. Magnets produced with High Temperature Superconductors (HTS) are especially suitable in such an environment. The proposed design employs second generation (2G) HTS, permitting operation at ~50K. The engineering considerations this design are summarized. The goal has been to engineer a compact, readily producible magnet with a warm bore and yoke, made from radiation-resistant materials, capable of operating within the heat load limit, whose four double-layered coils will be adequately restrained under high radial Lorentz forces. Results of ANSYS finite element thermal and structural analyses of the coil clamping system are presented. Coil winding, lead routing and splicing, magnet assembly as well as remote tunnel installation/removal considerations are factored into this design and will also be discussed.
BNL, Upton, Long Island, New York, USA
AES, Medford, NY, USA
An innovative feature of the proposed Energy Recovery Linac (ERL) at Brookhaven National Laboratory (BNL) is the use of a solenoid made with High Temperature Superconductor (HTS) with the Superconducting RF cavity. The use of HTS in the solenoid offers many advantages. The solenoid is located in the transition region (4 K to room temperature) where the temperature is too high for a conventional low temperature superconductor and the heat load on the cryogenic system too high for copper coils. Proximity to the cavity provides early focusing and thus a reduction in the emittance of the electron beam. In addition, taking full advantage of the high critical temperature of HTS, the solenoid has been designed to reach the required field at ~77 K, which can be obtained with liquid nitrogen. This significantly reduces the cost of testing and allows a variety of critical pre‐tests (e.g. measurements of the axial and fringe fields) which would have been very expensive at 4 K in liquid helium because of the additional requirements for a cryostat and associated facilities. This paper will present the design, construction, test results and current status of this HTS solenoid.
BNL, Upton, Long Island, New York, USA
As a part of the proposed electron lens system for RHIC, two 6 T, 200 mm aperture, 2.5 meter long superconducting solenoids are being designed and built at BNL. Because of several demanding requirements this has become a unique and technologically advanced magnet. For example, the field lines on axis must be straight over the length of the solenoid within ±50 microns. Since this is beyond the normal construction techniques, a correction package becomes an integral part of the design for which a new design has been developed. In addition, a minimum of 0.3 T field is required along the electron beam trajectory in the space between magnets. To achieve this fringe field superconducting solenoidal coils have been added at the two ends of the main solenoid. The main solenoid itself is a challenging magnet because of the high Lorentz forces and stored energy associated with the large aperture and high fields. An innovative structure has been developed to deal with the large axial forces at the ends. This paper will summarize the magnetic design and optimization of the entire package consisting of the main solenoid, the fringe field solenoids, and the corrector system.
BNL, Upton, Long Island, New York, USA
This paper will describe design, construction and test results of a cryo-mechanical structure to study coils made with the second generation High Temperature Superconductor (HTS) for the Facility for Rare Isotope Beams (FRIB). A magnet comprised of HTS coils mounted in a vacuum vessel and conduction-cooled with Gifford-McMahon cycle cryocoolers is used to develop and refine design and construction techniques. The study of these techniques and their effect on operations provides a better understanding of the use of cryogen free magnets in future accelerator projects. A cryogen-free, superconducting HTS magnet possesses certain operational advantages over cryogenically cooled, low temperature superconducting magnets.
BNL, Upton, Long Island, New York, USA
BNL, Upton, Long Island, New York, USA
The Bronx High School of Science, Bronx, New York, USA
A spiral wound “pancake” coil made from YBCO coated conductor has been stressed to a pressure of 100MPa in the axial direction at 77K. In this case axial refers to the coil so that the force is applied to the edge of the conductor. The effect on the critical current was small and completely reversible. Repeatedly cycling the pressure had no measureable permanent effect on the coil. The small current change observed exhibited a slight hysteretic behaviour during the loading cycle.
BNL, Upton, Long Island, New York, USA
Fermilab, Batavia, USA
LBNL, Berkeley, California, USA
An alternate structure for the 120mm Nb3Sn quadrupole magnet is presently under development for use in the upgrade for LHC at CERN. The design aims to build on existing technology developed in LARP with the LQ and HQ magnets and to further optimize the features required for operation in the accelerator. The structure includes features for maintaining mechanical alignment of the coils to achieve the required field quality. It also includes a helium containment vessel and provisions for cooling with 1.9k helium. The development effort includes the assembly of a six inch model to verify required coil load is achieved. Status of the R&D effort and an update on the magnet design, including its incorporation into the design of a complete one meter long cold mass is presented.
BNL, Upton, Long Island, New York, USA
In the Facility for Rare Isotope Beams (FRIB), superconducting magnets will be exposed to high levels of ionizing radiation. Quadruples in the fragment separator will be exposed to radiation doses as high as ~20 MGy/yr and heat loads as high as ~10 kW/m. High temperature superconducting (HTS) tapes are good candidates for this magnet because they can be operated in the temperature range ~30-50 K to tolerate higher temperatures than low temperature superconductors. Thus, radiation damage studies of HTS tapes are crucial to ensure that they will perform satisfactorily in such a high radiation environment. Therefore, the effects of proton irradiation on second generation HTS tapes from two vendors were studied. Each sample of HTS tape from SuperPower and American Superconductor was irradiated by a 42μA, 142 MeV proton beam at the Brookhaven Linac Isotope Producer. Two of each were irradiated at 5 dose levels: 2.5, 25, 50, 75 and 100μA•hr. The angular dependence of the critical current was measured in a magnetic field at 77K. Based on these measurements, conductors from both vendors appear to satisfy the FRIB radiation-tolerance requirement of 10 years of operation.
Fermilab, Batavia, USA
The Helical Cooling Channel (HCC) was proposed for 6D cooling of muon beams required for muon collider and some other applications. HCC uses a continuous absorber inside superconducting magnets which produce solenoidal field superimposed with transverse helical dipole and helical gradient fields. HCC is usually divided into several sections each with progressively stronger fields, smaller aperture and shorter helix period to achieve the optimal muon cooling rate. This paper presents the design issues of the high field section of HCC with coil separation. The effect of coil spacing on the longitudinal and transverse field components is presented and its impact on the muon cooling is evaluated and discussed. The paper also describes methods for field corrections and their practical limits.
LBNL, Berkeley, California, USA
The Muon Ionization Cooling Experiment (MICE) is an international effort sited at Rutherford Appleton Laboratory (RAL) in the UK that will demonstrate ionization cooling in a section of realistic cooling channel using a muon beam. The spectrometer solenoids are an identical pair of five-coil superconducting magnets that will provide a 4-tesla uniform field region at each end of the cooling channel. Scintillating fiber trackers within each of the 400-mm diameter magnet bore tubes will measure the emittance of the beam as it enters and exits the cooling channel. Each of the 3-meter long magnets incorporates a three-coil spectrometer magnet section and a two-coil section that matches the solenoid uniform field into the MICE cooling channel. The cold mass, radiation shield and leads are kept cold by means of a series of two-stage cryocoolers and one single-stage cryocooler. Various thermal, electrical and magnetic analyses are being carried out in order to develop design improvements related to magnet cooling and reliability. The key features of the spectrometer solenoid magnets are presented along with some of the details of the analyses.
LBNL, Berkeley, California, USA
Fermilab, Batavia, USA
BNL, Upton, Long Island, New York, USA
Meyer Tool & MFG, Oak Lawn, Illinois, USA
Particle Beam Lasers, Inc., Northridge, California, USA
BNL, Upton, Long Island, New York, USA
UCLA, Los Angeles, California, USA
For a muon collider with copious decay particles in the plane of the storage ring, open-midplane dipoles (OMD) may be preferable to tungsten-shielded cosine-theta dipoles of large aperture. The OMD should have its midplane completely free of material, so as to dodge the radiation from decaying muons. Analysis funded by a Phase I SBIR suggests that a field of 10-20 T should be feasible, with homogeneity of 1x10-4 and energy deposition low enough for conduction cooling to 4.2 K helium. If funded, a Phase II SBIR would refine the analysis and build and test a proof-of-principle magnet.
Texas A&M University, College Station, Texas, USA
TAMU3 is a block-coil short model dipole which embodies for the first time at high field (>12T) strength the techniques of stress management within the superconducting windings. The dipole consists of two planar racetrack coil assemblies, assembled within the rectangular aperture of a flux return core. Each assembly contains an inner and outer winding, and a high-strength support structure which is integrated within the assembly to intercept the Lorentz stress produced from the inner winding so that it does not accumulate to produce high stress in the outer winding. Iso-static preload is applied by pressurizing a set of thin stainless steel bladders with molten Woods metal and then freezing the metal under pressure. Current technology, difficulties, and present status of construction of magnet assembly will be presented.
UCLA, Los Angeles, California, USA
University of Warwick, Coventry, United Kingdom
BNL, Upton, Long Island, New York, USA
PU, Princeton, New Jersey, USA
Particle Beam Lasers, Inc., Northridge, California, USA
A study of energy deposition within superconducting coils of a 4 MW target station for a neutrino factory or muon collider is presented. Using the MARS code, we simulate the energy deposition within the environment surrounding the target. The radiation is produced by interactions of intense proton beams with a free liquid mercury jet. We study the influence of different shielding materials and shielding configurations on the energy deposition in the superconducting coils of the target/capture system. We also examine energy depositions for alternative configurations that allow more space for shielding, thus providing more protection for the superconducting coils.
LBNL, Berkeley, California, USA
Fermilab, Batavia, USA
CERN, Geneva, Switzerland
The LHC collimation upgrade foresees additional collimators installed in dispersion suppressor regions. To obtain the necessary space for the collimators, a solution based on the substitution of LHC main dipoles for stronger dipoles is being considered. CERN and FNAL have started a joint program to demonstrate the feasibility of Nb3Sn technology for this purpose. The goal of the first phase is the design and construction of a 2-m long single-aperture demonstrator magnet with a nominal field of 11 T at 11.85 kA with 20% margin. This paper describes the magnetic and mechanical design of the demonstrator magnet and summarizes its design parameters.
WEOCS3
BNL, Upton, Long Island, New York, USA
UCLA, Los Angeles, California, USA
Particle Beam Lasers, Inc., Northridge, California, USA
High Temperature Superconductors (HTS) are now becoming a crucial part of future medium and high field magnet applications in several areas including accelerators, energy storage, medical and user facilities. A second generation HTS quadrupole is being constructed for the Facilities for Rare Isotope Beams (FRIB). The muon collider requires high field solenoids in the range of 40-50 T - an R&D that is partly supported by SBIRs and partly programs at various laboratories. Superconducting Magnetic Energy Storage (SMES) R&D, recently funded by ARPA-E, requires large aperture HTS solenoid in the range of 25-30 T. A user facility at National High Magnetic Field Laboratory (NHMFL) has been funded to develop a 32 T solenoid. All of these programs require HTS in a quantity never obtained before for magnet applications and would play a key role in developing HTS for magnet applications. High field magnets pose special challenges in terms of quench protection, large stored energy and large stresses, etc. This presentation will review various ongoing activities, and examine the future prospects of HTS magnets in a number of applications, with a particular emphasis on high field applications.