A four layer, two inch bore, superconducting dipole magnet

Abstract

Two superconductors can be considered for a 10 T accelerator. The first is Nb/sub 3/Sn, which can operate at 10 T at about 4.4 K, and the second is NbTi, which must operate in superfluid helium at 1.8 K to achieve 10 T. Several different designs were considered for these magnets and two were selected as the basis for a model testing program. The one described here, the cylindrical layer design, was selected because of the experience with this type of winding in the ESCAR, the Fermilab Doubler/ Saver, the Brookhaven ISABELLE magnets, and the recent results in the development and testing of model magnets at LBL. A somewhat similar design was described by Ishibashi and McInturff. The 50 mm (2'') bore was selected for these models to minimize costs. This program to develop 10 Tesla coils includes perfecting the 4 layer design including fabrication and assembly and developing a suitable conductor. The general conductor type selected is a Rutherford cable of approximately the width of the FNAL cable. To achieve 10 T in 4 layers with NbTi at 1.8 K requires an efficient coil design with graded conductor and a copper to superconductor ratio of about 1. The authorsmore » are now developing suitable graded cable. However, they used the cable with the lowest copper-tosuperconductor ratio available, 1.5, in the model dipoles described here. The current density is the same in all four layers.« less