Design of HD2: a 15 tesla Nb/sub 3/Sn dipole with a 35 mm bore

Abstract

Abstract-The Nb 3 Sn dipole HD1, recently fabricated and tested at LBNL, pushes the limits of accelerator magnet technology into the 16 T field range, and opens the way to a new generation of HEP colliders. HD1 is based on a flat racetrack coil configuration and has a 10 mm bore. These features are consistent with the HD1 goals: exploring the Nb 3 Sn conductor performance limits at the maximum fields and under high stress. However, in order to further develop the block-coil geometry for future high-field accelerators, the bore size has to be increased to 30-50 mm. With respect to HD1, the main R&D challenges are: (a) design of the coil ends, to allow a magnetically efficient crosssection without obstructing the beam path; (b) design of the bore, to support the coil against the pre-load force; (c) correction of the geometric field errors. HD2 represents a first step in addressing these issues, with a central dipole field above 15 T, a 35 mm bore, and nominal field harmonics within a fraction of one unit. This paper describes the HD2 magnet design concept and its main features, as well as further steps required to develop a costeffective block-coil design for future high-field, acceleratorquality dipoles.Index Terms-High-field accelerator magnets, Nb 3 Sn.

Electromagnetic Efficiency of Block Design in Superconducting Dipoles

“…2, right). This design has been successfully implemented in the model HD2 [9] which presently has the highest reported magnetic field in a superconducting accelerator magnet. The curvature radius of the cable in the ends is similar to the layout, and therefore in the case of a wind and react technique has to be applied.…”

“…1). In the second case, the cable and the blocks are rectangular, and they are arranged along vertical and horizontal guidelines ([5]- [9], see Fig. 2).…”

“…Moreover, it gave a benchmark to judge the efficiency of any design. Here, we apply these tools to study the designs based on block coils that have been proposed in the literature [5]- [9], or that have been built in short models. In Section II we present the different layouts.…”

CLIQ : a new quench protection technology for superconducting magnets

“…In block-type coils, these regions comprise most coil turns, as will be evident observing the configurations proposed in this section. The selected case is the high-field dipole magnet developed at the Lawrence Berkeley National Laboratory [135][136][137][138][139][140][141][142][143], whose geometry and magnetic-field map are shown in figures 3.13a-b. The three analyzed CLIQ configurations, presented in table 3.6, follow the same concept introduced for the two-layer cos-θ dipole geometry in section 3.3.2.…”

“…Nb 3 Sn magnets are currently selected as the baseline technology, and one of the proposed designs features the block-coil geometry presented in section 3.3.4 [135][136][137][138][139][140][141][142][143][144]173]. This coil generates a dipole magnetic field B d =16 T with a transport current of about 18.6 kA.…”