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Examines the field performance of a high-resolution nuclear magnetic resonance superconducting magnet. Persistent-mode operation of the magnet; Field decay; Field homogeneity.

Describes the superconducting NMR magnet developed at the Tsukuba Magnet Laboratory in Japan in 1999. Manufacture of the magnet with 15-percent tin-bronze-processed (Nb,Ti)[sub 3]Sn, Tantalum-reinforced (Nb,Ti)[sub 3]Sn and NbTi conductors; Cooling of coils used with pressurized superfluid helium.

Presents results of the engineering design and research and development studies on candidate superconductors for the inner coil of a one GHz superconducting nuclear magnetic resonance magnet at the Tsukuba Magnet Laboratory of the National Research Institute for Metals in Japan. Outer magnet and inner coils of the low temperature superconductor coils. generation.

As a milestone in the 1-GHz NMR magnet project that is being carried out at the Tsukuba Magnet Laboratory (TML), a 920-MHz high-resolution NMR magnet was successfully manufactured. It is made of 15%Sn-bronze-processed (Nb, Ti)aSh, Ta-reinforced (Nb, Ti)[sub 3]Sn, and NbTi conductors. The room-temperature bore of the cryostat is 54 mm in diameter. All the coils are cooled with pressurized superfluid helium at 1.55 K. The magnet was moved to a new building of the TML in December 2001. A persistent operation at 920 MHz started in April 2002. The field homogeneity after correcting with superconducting shim coils was less than 0.1 ppm in a sample volume. Field decay decreased to below 1.3 Hz/h at the beginning of July. NMR measurements using this magnet started in July. [ABSTRACT FROM AUTHOR]