Magnetic shielding characteristics were investigated at 4.2°K in transverse magnetic field up to 17.5KOe for the solution treated sample and for the samples aged at 700°C for 3, 10 and 100hr after solution treated in the hollow cylinder of Nb-40Zr-10Ti alloy. It was found that there are three regions between the two critical rates of increase of the applied field, C1 and C2 (0<C1<C2), and that the magnetic shielding behavior is different corresponding to each region. The magnetic shielding field was over 17.5KOe for the sample aged at 700°C for 100hr in this alloy. Assuming that the flux front in the Bean critical state penentrates isothermally and adiabatically from outer to inner surface of the hollow cylinder, possible models were proposed to estimate the maximum and minimum values of the magnetic shielding capacity. The calculated values based on these models agreed well with the measured values.
An 100kG Superconducting magnet wound by Nb3Sn tape is described. The magnet has an inner diameter of 25mm, an outer diameter of 130mm and a length of 110mm. It produces a field strength of about 100kG over the space of 20mm sphere around the center of the bore with the field uniformity of within 1%. Measured field strength differs from that of calculated by about few percentage on account of the diamagnetic characteristics of the superconducting wire. And therefore, the magnet has different profiles of field distribution in accordance with the field strength which is generated in the magnet. The appearence of the coil terminal voltage and decay of the coil current occured when the magnet goes to normal state from superconductive state are described. It is shown that persistent current operation is tested successfully by using heater switch together with mechanical switch.