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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]

After the successful test at the Takasago factory of Kobe Steel Ltd (KSL). 920 MHz magnet was transported and installed in Tsukuba Magnet Laboratory (TML), NIMS in April, 2002. To achieve a quick energization and long term operation with a minimum number of operators, the cryostat was equipped with an automated control and monitoring system. During the cooling process below 4.2 K and the energization procedure up to 21.6 T, the temperature of the magnet and He II bath was controlled automatically. Since the all installation procedure has completed in July 2002, the magnet has been continuously cooled to 1.545 K and the temperature variation has been kept within 0.01 K for over a year. [ABSTRACT FROM AUTHOR]

The first 920 MHz high-resolution NMR (Nuclear Magnetic Resonance) magnet was successfully installed at the Tsukuba Magnet Laboratory of the National Institute for Materials Science. A persistent operation at 21.6 T has continued since April 2002 without any problems. Excellent field stability of 0.31 Hz/h was observed from December 2002 to January 2003. Since July 2002, the magnet was used as an essential part of the only 920 MHz high-resolution NMR spectrometer in the world. The signal-to-noise ratio of 0.1 % ethylbenzene using a proton-selective probe was as high as 2981. An HCN triple-resonance probe is now attached to the spectrometer to contribute to the National Project on Protein Structural and Functional Analysis in Japan. The completion of the second 920 MHz-class NMR spectrometer is scheduled for spring 2004. [ABSTRACT FROM AUTHOR]