The proposed muon collider requires very high field solenoids in the range of 30-50 T. The use of High Temperature Superconductors (HTS) operating at low temperature (~ 4 K) is essential for ...achieving such high fields in a superconducting magnet. As a part of this program, we have built and successfully tested a 25 mm aperture HTS insert generating 16 T peak field (the highest field ever achieved in an all-HTS magnet), a 100 mm aperture HTS midsert generating 9 T peak field, and designed an outsert with a conventional Low Temperature Superconductor (LTS) to provide additional field. In addition to presenting the test results and progress made in support technologies, we will also discuss a number of challenges associated with the high field HTS magnets. Finally, we present a set of strategies to overcome some of those challenges.
A new design principle of a nonscaling fixed field alternating gradient accelerator is proposed. It is based on optics that produce approximate scaling properties. A large field index k is chosen to ...squeeze the orbit shift as much as possible by setting the betatron oscillation frequency in the second stability region of Hill’s equation. Then, the lattice magnets and their alignment are simplified. To simplify the magnets, we expand the field profile of rk into multipoles and keep only a few lower order terms. A rectangular-shaped magnet is assumed with lines of constant field parallel to the magnet axis. The lattice employs a triplet of rectangular magnets for focusing, which are parallel to one another to simplify alignment. These simplifications along with fringe fields introduce finite chromaticity and the fixed field alternating gradient accelerator is no longer a scaling one. However, the tune excursion of the whole ring can be within half an integer and we avoid the crossing of strong resonances.
Presently, the electron-ion collider electron relativistic heavy ion collider (eRHIC) is under design. It aims to provide a facility with a peak luminosity of 10 34 cm -2 sec -1 . In terms of magnet ...design, the IR magnets are particularly challenging due to the close proximity of the electron and hadron beams. This paper outlines the design for the so-called Q1 rear side magnet, which is a double aperture quadrupole magnet, 7.2 m from the interaction region. Due to space restrictions, both magnets are housed in the same iron yoke. The aperture of the hadron quadrupole is relatively small, but requires high gradients. While the required gradient for the electron quadrupole is relatively small, the aperture of this magnet needs to accommodate the beam and allow the synchrotron radiation fan to pass through. To accomplish this, both quadrupole magnets have a tapered aperture. To keep the gradients constant along the length of the magnets, a special winding pattern has been identified, which is described in this paper.
The design of interaction region (IR) magnets for the Electron Ion Collider (EIC), demands tight boundary conditions on the magnet design given by the high field requirements and the proximity of ...electron and hadron beams within a common yoke and resultant crosstalk. This article discusses the electromagnetic design of the superconducting collared magnet B1pF. The magnet will be built as the prototype for several collared magnets (dipoles and quadrupoles) for the hadron beam in the forward direction of the IR. The magnet design is based on a single layer coil with an inner diameter of 300 mm over a slot length of 3 m. The magnet produces an integral field of 10.34 T.m at a current of 11.9 kA to produce a nominal field of about 3.96 T at its center. Given by the common Rutherford cable parameters, the magnet will be used as a baseline for optimization of all the collared magnets. The article further discusses yoke optimizations, quench analysis, coil end design and efforts on fine tuning of field quality.
The Design of B1APF Dipole for the EIC Kumar, Mithlesh; Joshi, Piyush; Witte, Holger ...
IEEE transactions on applied superconductivity,
08/2024, Letnik:
34, Številka:
5
Journal Article
Recenzirano
Brookhaven National Laboratory has been chosen to host the Electron-Ion Collider (EIC). Part of this is to install an additional electron ring to the existing RHIC tunnel. The electron hadron ...Interaction Region (IR) will host nine superconducting magnets on the forward side and six superconducting magnets on the rear side of the Interaction Point (IP). B1APF dipole is the last magnet of the near IR in the outgoing hadron direction. The magnet has a physical aperture of 370 mm diameter and is 1.5 m long. This large aspect ratio makes this magnet particularly challenging. It is a collared magnet and uses a NbTi Rutherford cable with 15.1 mm X 1.9 mm. It is expected to operate at a maximum current of 13400 A at 2 K. The required integrated dipole field is 4.05 Tm. This paper discusses the current design status of the B1ApF dipole and presents the electromagnetic analysis and thermal quench propagation analysis.
Muon ionization cooling is theoretically well understood but has never been fully demonstrated experimentally. Ionization cooling is regarded as an important technology both in terms of cost and ...performance for a Neutrino Factory and is absolutely essential for a Muon Collider. The MICE experiment (Muon Ionization Cooling Experiment), based at the Rutherford Appleton Laboratory, U.K., is currently collecting data to prove the concept. Part of MICE are two spectrometer magnets, each consisting of five superconducting large bore solenoids. The spectrometer solenoid is designed for a peak field of 4T. Both spectrometer magnets required about 15 quenches to reach the design current. However, it was discovered that both spectrometers do not remember their training; after a warm-up the spectrometers have to be retrained, following a very similar training curve. The MICE spectrometer was analyzed using 2-D and 3-D finite element software to understand the quench and training behavior; the analysis revealed a clamping mechanism, leading to a stick-slip situation for one of the coils in its coil pocket. This paper summarizes the results and makes suggestions how to improve the design.
Reduction of the Hot Spot Temperature in HTS Coils Witte, Holger; Sampson, William B.; Weggel, Robert ...
IEEE transactions on applied superconductivity,
06/2014, Letnik:
24, Številka:
3
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
A potential future muon collider requires high field solenoids ( 30 T) for the final cooling stage; the Magnet Division at Brookhaven National Laboratory is undertaking the task of demonstrating ...feasibility using high-temperature superconductors (HTS). The aim is to construct an all-HTS dual-coil system capable of delivering more than 20 T. Recently, a new record for an all-HTS solenoid has been established with a field of 15 T on-axis. In coil tests, it was noticed that during a fast energy extraction, the current in the solenoids decays faster in comparison to the expected exponential decay. This paper describes the effect and shows how it can be simulated using commercial finite element code. The faster current decay helps to lower the integral current density squared with time by about 10% and is therefore beneficial for quench protection.
Integrable non-linear accelerator lattices are regarded as one potential option for the next generation of high-intensity accelerators. In particle tracking studies non-linear integrable lattices ...have shown to be effective in suppressing machine resonances, tune shifts and instabilities. This paper gives an update on the magnet design for a 150 MeV electron test facility. The required magnetic field is difficult to generate with conventional multipole magnets; we outline a potential solution and discuss the implications for a high energy proton driver.
Most of today's particle accelerators are used in industry or for medical applications, for example, in radioisotope production and cancer therapy. One important factor for these applications is the ...size of the accelerator, which ideally should be as small as possible. In this respect, fixed-field alternating-gradient accelerators (FFAGs) can be an attractive alternative, which combine the best features of conventional synchrotrons and cyclotrons: FFAGs deliver better performance than synchrotrons while retaining flexibility. Of particular interest are accelerators for protons of moderate energy (0.25-1 GeV) and light ions such as carbon (up to 400 MeV per nucleon), for example, for proton/carbon-ion charged particle therapy or potential future applications such as accelerator-driven subcritical reactors. Due to high magnetic rigidity, a compact machine can be only achieved by using high field superconducting magnets. A disadvantage of FFAGs is that the magnetic elements can be very challenging. Quite often, complicated multipole fields are required, in combination with stringent geometric constraints. In this paper, we demonstrate the advantages of helical coil technology by means of an accelerator for proton therapy.
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