BNL, Upton, Long Island, New York, USA
An electron lens for head-on beam-beam compensation planned for RHIC requires precise overlap of the electron and proton beams which both can have down to 0.3 mm rms transverse radial widths along the 2m long interaction region. Here we describe a new diagnostic tool that is being considered to aid in the tuning and verification of this overlap. Some of ultra relativistic protons (100 or 250 GeV) colliding with low energy electrons (2 to 10 keV) will transfer sufficient transverse momentum to cause the electrons to spiral around the magnetic guiding field in a way that will make them detectable outside of the main solenoid. Time-of-flight of the halo electron signals will provide position-sensitive information along the overlap region. Scattering cross sections are calculated and counting rate estimates are presented as function of electron energy and detector position.
BNL, Upton, Long Island, New York, USA
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
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.
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.
BNL, Upton, Long Island, New York, USA
We are designing two electron lenses (E-lens) to compensate for the large beam-beam tune spread from proton-proton interactions at IP6 and IP8 in the Relativistic Heavy Ion Collider (RHIC). They will be installed in RHIC IR10. First, the layout of these two E-lenses is introduced. Then the effects of e-lenses on proton beam are discussed. For example, the transverse fields of the e-lens bending solenoids and the fringe field of the main solenoids will shift the proton beam. For the effects of the e-lens on proton beam trajectory, we calculate the transverse kicks that the proton beam receives in the electron lens via Opera at first. Then, after incorporating the simplified E-lens lattice in the RHIC lattice, we obtain the closed orbit effect with the Simtrack Code.
BNL, Upton, Long Island, New York, USA
We designed two electron lenses to apply head-on beam-beam compensation for RHIC; they will be installed near IP10. The electron-beam transport system is an important subsystem of the entire electron-lens system. Electrons are transported from the electron gun to the main solenoid and further to the collector. The system must allow for changes of the electron beam size inside the superconducting magnet, and for changes of the electron position by 5 mm in the horizontal- and vertical-planes.
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.
BNL, Upton, Long Island, New York, USA
Two electron lenses are under construction for RHIC to partially compensate the head-on beam-beam effect in order to increase both the peak and average luminosity. The final design of the overall system is reported as well as the status of the component design, acquisition, and manufacturing.
BNL, Upton, Long Island, New York, USA
Two electron lenses for a head-on beam-beam compensation are being planned for RHIC; one for each circulating proton beam. The transverse profile of the electron beam will be Gaussian up to a maximum radius of re=3σ. Simulations and design of the electron gun with Gaussian radial emission current density profile and of the electron collector are presented. Ions of the residual gas generated in the interaction region by electron and proton beams will be removed by an axial gradient of the electric field towards the electron collector. A method of optical observation the transverse profile of the electron beam is described.