Title :
Analysis of an Abnormal Event in a 3-T MRI Magnet Wound With Bi-2223 Tape Conductors
Author :
Terao, Yutaka ; Ozaki, Osamu ; Kawashima, S. ; Saito, Kazuyuki ; Hase, Tomohiro ; Kitaguchi, Hitoshi ; Sato, Ken-ichi ; Urayama, Shin-ichi ; Fukuyama, Hidenao
Author_Institution :
Kobe Steel Ltd., Kobe, Japan
Abstract :
We have designed and fabricated a 3-T Magnetic Resonance Imaging (MRI) magnet system for the human brain, which was wound with Bi-2223 tape conductors. The magnet was successfully energized to 1.5 T and then up to 3.0 T. The magnet experienced more than 60 ramp-up and down processes to 1.5 T with no trouble. A magnetic field of 3.0 T (184.8 A) could be maintained for longer than 3 h without any problems. However, abnormal voltage behavior was observed during the ramp down for the third trial to 3.0 T, and the temperature rapidly increased with a ramping rate of 1.7 K/min. To investigate the cause, we opened the cryostat and inspected the inside of the magnet. In addition, we have analyzed the details of this event using the recorded current, voltage, and temperature data. The purpose of this paper is to report the investigation of this abnormal event in the magnet.
Keywords :
biomedical MRI; biomedical equipment; bismuth compounds; brain; calcium compounds; cryostats; high-temperature superconductors; medical disorders; neurophysiology; strontium compounds; superconducting magnets; superconducting tapes; 3T MRI magnet wound; 3T magnetic resonance imaging magnet system; Bi-2223 tape conductors; abnormal event; abnormal event analysis; abnormal voltage behavior; cryostat; current data; human brain; magnetic field; magnetic flux density 1.5 T to 3.0 T; temperature data; voltage data; Coils; Magnetic circuits; Magnetic noise; Magnetic resonance imaging; Power supplies; Superconducting magnets; Windings; Abnormal event; Bi-2223; Magnetic Resonance Imaging (MRI); protection;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
DOI :
10.1109/TASC.2013.2285278
