Title: Thermal analysis of a 3 T cryogen-free superconducting magnet for electromagnetic property measurement system

Authors: Yojong Choi; Seunghyun Song; Myung Su Kim; Yeon Suk Choi

Addresses: Division of Scientific Instrument, Korea Basic Science Institute, 169-148, Gwahak-ro, Yuseong-gu, Daejeon, South Korea ' Division of Scientific Instrument, Korea Basic Science Institute, 169-148, Gwahak-ro, Yuseong-gu, Daejeon, South Korea ' Division of Scientific Instrument, Korea Basic Science Institute, 169-148, Gwahak-ro, Yuseong-gu, Daejeon, South Korea ' Division of Scientific Instrument, Korea Basic Science Institute, 169-148, Gwahak-ro, Yuseong-gu, Daejeon, South Korea

Abstract: The Korea Basic Science Institute (KBSI) is currently developing a conduction-cooled electromagnetic property measurement system (EMPS) utilising a cryocooler, thereby eliminating the reliance on liquid helium or liquid nitrogen. The primary objective of this system is to achieve a magnetic field strength of 3 T at the centre of the room temperature bore, which serves as the measurement space for the samples. To ensure the stable operation of the NbTi coil, an analysis of the required cooling temperature was conducted to enable the magnet to charge the current and generate the target magnetic field. The analysis revealed that the NbTi coil can operate with a safety margin of 68% at 6 K, and a central magnetic field of 3 T is generated at temperatures below 7 K. Through comprehensive thermal analysis of the entire system, we have confirmed that the system can provide sufficient cooling below 3 K to the superconducting coil prior to operation. Additionally, considering the Joule heating of the metal lead and the heat generated by AC losses in the structure during current application, the temperature rise of NbTi is predicted to be below 5.5 K, thus ensuring the stable generation of the magnetic field. The analysis results demonstrate the feasibility of a cryogen-free, low-temperature superconducting magnet system for conducting electromagnetic property measurement experiments.

Keywords: cryogen-free; EMPS; electromagnetic property measurement system; NbTi coil; superconducting magnet; thermal analysis.

DOI: 10.1504/IJNT.2024.137417

International Journal of Nanotechnology, 2024 Vol.21 No.3, pp.179 - 185

Published online: 18 Mar 2024 *

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