The NHMFL Hybrid Magnet Projects

Abstract

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> The National High Magnetic Field Laboratory is developing resistive-superconducting hybrid magnets both for internal use and for installation at other facilities. The Tallahassee magnet will have a vertical bore and provide 36 T in a 40-mm bore with 1-ppm homogeneity over a 10-mm diameter spherical volume. The Berlin version will provide a horizontal field of 25 T in a converging-diverging bore configuration suitable for neutron-scattering experiments. A design study is underway for a third magnet for Oak Ridge that will be similar to the Berlin version but provide <formula formulatype="inline"> <tex Notation="TeX">$&gt;$</tex></formula>30 T. The three magnets will use very similar <formula formulatype="inline"><tex Notation="TeX">$\sim$</tex></formula>13 T <formula formulatype="inline"><tex Notation="TeX">${\rm Nb}_{3}{\rm Sn}$</tex> </formula> CICC coils for the superconducting outserts. The resistive insert magnets will be different configurations operating at different power levels. In designing the magnet systems we have developed a new numerical model to predict the critical current of <formula formulatype="inline"><tex Notation="TeX">${\rm Nb}_{3}{\rm Sn}$</tex></formula> CICC's, tested several conductors in-house and abroad, designed cryostats and refrigeration systems, and developed new resistive magnet technology. An overview of the innovations and present status is presented. </para>