Canted–Cosine–Theta Magnet (CCT)—A Concept for High Field Accelerator Magnets

IEEE Trans. Appl. Supercond.

et al. 2017

Abstract-Cable and magnet applications require bending REBa2Cu3O 7−δ (REBCO, RE = Rare Earth) tapes around a former to carry high current or generate specific magnetic fields. With a high aspect ratio, REBCO tapes favor the bending along their broad surfaces (easy way) than their thin edges (hard way). The easy-way bending forms can be effectively determined by the constant-perimeter method that was developed in the 1970s to fabricate accelerator magnets with flat thin conductors. The method, however, does not consider the strain distribution in the REBCO layer that can result from bending. Therefore, the REBCO layer can be over-strained and damaged even if it is bent in an easy way as determined by the constant-perimeter method.To address this issue, we developed a numerical approach to determine the strain in the REBCO layer using the local curvatures of the tape neutral plane. Two orthogonal strain components are determined: the axial component along the tape length and the transverse component along the tape width. These two components can be used to determine the conductor critical current after bending. The approach is demonstrated with four examples relevant for applications: a helical form for cables, forms for canted cos θ dipole and quadrupole magnets, and a form for the coil end design. The approach allows to optimize the design of REBCO cables and magnets based on the constantperimeter geometry and to reduce the strain-induced critical current degradation.

“…Originally proposed by Meyer and Flasck in 1969 [32], the concept has recently gained interest for various accelerator magnet applications [33][34][35][36][37][38].…”

Section: B a Canted Cos θ Dipole Windingmentioning

confidence: 99%

Strain Distribution in REBCO-Coated Conductors Bent With the Constant-Perimeter Geometry

Wang

Arbelaez

IEEE Trans. Appl. Supercond.

et al. 2017

“…For typical high field accelerator dipoles this angle is between 15 and 30 degrees. The resulting field is very close to a perfect dipole, as described in [25]. A similar approach of simply canting the windings to produce a dipole, when applied in the curved geometry of a gantry magnet, leads to the generation of a "dipole" plus higher order "harmonics" (quadrupole, sexupole, etc.).…”

Section: A Magneticsmentioning

confidence: 69%

“…These studies have shown the feasibility and advantages of using the canted cosine theta (CCT) design [19][20][21][22][23][24][25] to generate desired field multipoles in a large aperture superconducting gantry magnet. Using the CCT approach, a novel magnet concept has been developed to produce the alternating focusing and defocusing fields needed for the achromatic gantry, which is described in detail in Sec.…”

Section: A Combined-function Efficient Alternating-gradient (Agmentioning

confidence: 99%

Alternating-gradient canted cosine theta superconducting magnets for future compact proton gantries

Wan

Brouwer

Phys. Rev. ST Accel. Beams

et al. 2015

We present a design of superconducting magnets, optimized for application in a gantry for proton therapy. We have introduced a new magnet design concept, called an alternating-gradient canted cosine theta (AG-CCT) concept, which is compatible with an achromatic layout. This layout allows a large momentum acceptance. The 15 cm radius of the bore aperture enables the application of pencil beam scanning in front of the SC-magnet. The optical and dynamic performance of a gantry based on these magnets has been analyzed using the fields derived (via Biot-Savart law) from the actual windings of the AG-CCT combined with the full equations of motion. The results show that with appropriate higher order correction, a large 3D volume can be rapidly scanned with little beam shape distortion. A very big advantage is that all this can be done while keeping the AG-CCT fields fixed. This reduces the need for fast field ramping of the superconducting magnets between the successive beam energies used for the scanning in depth and it is important for medical application since this reduces the technical risk (e.g., a quench) associated with fast field changes in superconducting magnets. For proton gantries the corresponding superconducting magnet system holds promise of dramatic reduction in weight. For heavier ion gantries there may furthermore be a significant reduction in size.

“…This design, first proposed many years ago [2], [3], has more recently been of interest for reducing Lorentz force induced stress in high field Nb 3 Sn magnets [4]- [6]. This reduction is achieved by introducing a mechanical structure internal to the winding pack to intercept and prevent the accumulation of Lorentz forces on the level of individual turns [7].…”

Section: T He Us Magnet Development Program (Us-mdp) Is Pur-mentioning

confidence: 99%

Improved Modeling of Canted–Cosine–Theta Magnets

Brouwer

Arbelaez

IEEE Trans. Appl. Supercond.

et al. 2018

Self Cite

Abstract-The Canted-Cosine-Theta is a design option for the next generation of high field superconducting dipoles being pursued within the US Magnet Development Program. This paper presents new modeling techniques developed for design and analysis of CCT magnets. For mechanical modeling in ANSYS, three approaches with increasing accuracy are compared: 2-D symmetry models; 3-D periodic symmetry models; and full 3-D models. Methods for the static and transient magnetic simulation using ANSYS are presented with a focus on circuit-coupled models for predicting magnet behavior following quench. Where applicable, simulation results are compared to data from CCT magnet tests at Berkeley.