Design of MgB₂ superconducting dipole magnet for particle beam transport in accelerators

A comprehensive analysis of the innovation potential of superconductivity at Risø was performed in February 2004 by the main author of this report [1]. Several suggestions for new products and new markets were formulated by the superconductivity group and examined by the innovation staff at Risø. The existing markets of superconducting technology is within highly specialized scientific areas such as magnetic confinement in fusion energy, sample environment in neutron scattering and large scale accelerators such as the Large Hadron Collider(LHC) at Cern, or in the nuclear magnetic resonance (NMR) community using MR-imaging scanners in medicine and phase identification in organic chemistry.

Only the NMR applications can be categorized as a highly profitable and commercial market today. The superconductivity group of Risø formulated and presented the gearless superconducting wind turbine multipole generator as the most promising new concept [2], but further initiatives were stopped due to unclear patent possibilities.

The experience of the innovation review was used in the STVF framework program "New superconductors: mechanisms, processes and products"[3] to identify potential new product for the collaborating company Danfysik A/S, which has a strong tradition in building resistive magnets for particle accelerators[4].

A technology transfer project was formulated at the end of 2005 with the purpose to collect the knowledge about the MgB2 superconductor gained in the STVF program and in the European Framework Program 6 project HIPERMAG[5]. It was presented at the Risø innovation seminar January 2006, and recently a collaboration between Risø and Danfysik A/S was initialized.

The present report aims to outline a potential superconducting product within the STVF program. The use of the MgB2 superconductors in a dipole magnet for guiding particle beams in a small scale accelerator is examined with the purpose to build lighter and smaller than the present resistive magnets.

Here the critical current density of primarily MgB2  will be compared with current density determined by specifications similar to the Tevatron accelerator, B = 4:4 Tesla and coil aperture D = 76 mm [6], which has been identified by Danfysik A/S as interesting. It is concluded that MgB2  is useful for the dipole application and construction of a small test coil of one half of the magnet is planned in 2007.