A New Method to Improve Field Uniformity for Application to a Newly Developed 5 T EMPS Superconducting Magnet System

A 5 T low-temperature superconducting magnet is fabricated and tested for an EMPS (electro-magnetic property measurement system) whose sample space is 40 mm in diameter. Because the sample space is larger than that of conventional property measurement systems, it will be possible to measure the electro-magnetic properties of several samples simultaneously, thus reducing the measurement time. With a genetic algorithm incorporated with linear-programming, the optimal design of the 5 T LTS magnet was accomplished. A multi-coil 5 T EMPS magnet was fabricated according to the optimal design and tested in liquid helium. During current charging tests up to 43.5 A, the magnet voltage, current, and magnetic field were measured to monitor the magnet performance. Due to the manufacturing errors of the magnet, the field uniformity is usually worse than the design result. The concept of a newly proposed field uniformity improvement method was also introduced to compensate for field errors. The 5 T EMPS magnet system will be integrated with an EMPS console for electro-magnetic properties analyses.