Design and Optimization of Niobium-Titanium based Superconductive Magnet for the Magneto Resistive Heat Switch

Abstract

A superconducting magnet is an ordinary electromagnet with no current resistance. To attain the superconducting state, it is necessary to hold the material below its critical temperature. There are three types of superconducting magnets viz., low-temperature, medium-temperature, and high-temperature superconductors with an operating temperature range of 4.2K, 20K, and 100K, respectively. This work addresses the design and optimization of 6T LTS magnets for use in an adiabatic demagnetization refrigerator. LTS utilizes a Niobium-Titanium alloy wire that can generate a magnetic field between 3 T and 10 T. NbTi wires are wrapped around a hollow metal cylinder called a former. The surrounding coils are kept at a cryogenic temperature of 4.2K. A hollow cylindrical base with NbTi wires wrapped around it serves as a solenoid. In this study, the characteristics that affect the design and optimization of the length of the former, the diameter of the coil, the number of turns necessary to generate a 6 T magnetic field, and the required current are examined by developing an analytical model. 304L-grade stainless steel is considered as solenoid/former material in the present investigation. The optimal length and diameter of the former are determined by developing analytical model. Various situations are addressed by adjusting the wire's length, number of turns, and current, which results in a change in magnetic field density. Further, by developing a numerical model, type of superconducting alloy wire preferred below 9 K is also studied in detail.