Katsumi Kose1, Tomoyuki Haishi2
1Institute of Applied Physics,
Temperature drift of the magnetic field of a thermally insulated yokeless permanent magnet (field strength = 1.04 T) was measured for about 68 hours. The temperature coefficient of the magnetic field was about -950 ppm/deg. The largest Larmor frequency change was about 50 Hz/min. The performance of the thermal insulation was evaluated with high resolution imaging (20~40 micron square) of several samples. The results have suggested that careful choice of the NMR lock interval and the pixel bandwidth will solve the temperature drift problem of the high field yokeless magnet.