Design for a 30 T resistive insert in a 40+ T hybrid magnet at the Nijmegen HFML

We present our design for a 30 T resistive insert to combine with an 11 T superconducting outsert to a 40+ T hybrid magnet. The insert is matched to a 40 kA, 500 V power supply. The free bore is 32 mm. The design uses five subcoils, of which the inner four are from Cu-Ag alloy. Special care was taken with respect to the end windings, which can become critically stressed. Design tools from NHMFL in Tallahassee FL were used to optimize the magnetic field, staying well within limits of available conductor ultimate tensile strength. Finite element calculations were used to check details of stress, strain and temperature distribution. Fabrication methods include laser cutting of the two inner coils. The insert is mounted semi-rigidly to the outsert to accommodate fault forces by allowing the insert move.

I. Introduction

The new 20 MW Nijmegen High Field Magnet Laboratory in the Netherlands has opened its doors in April 2003, and has since been in operation to provide 33 T resistively to several users. Three 33 T resistive magnets have been installed to meet the demands of having several users simultaneously.