Persistent-mode operation of a 920 MHz high-resolution NMR magnet

Toko, Kiyoshi; Satô, Akio; Takeuchi, T.; Itoh, K.; Matsumoto, Shinji; Ozaki, Osamu; Fukushima, K.; Wada, Hitoshi; Yoshikawa, Masayuki; Kamikado, T.; Miki, Takashi; Hase, Takashi; Hamada, Mamoru; Hayashi, Seiji; Kawate, Yoshio; Hirose, R.

doi:10.1109/tasc.2002.1018500

Cited by 33 publications

(8 citation statements)

References 5 publications

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“…During the excitation, the two vacuum pumps were in operation. As reported earlier [1], [3], [5], voltage generations of a few mV in the -NbTi joints were often observed during the excitation of the first 920 MHz magnet. In contrast, no such phenomena took place in this magnet and we need not have decreased the operating current to eliminate such voltage generation.…”

Section: Operationsupporting

confidence: 78%

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Operation of a 930-MHz High-Resolution NMR Magnet at TML

Toko

Matsumoto

Satô

et al. 2005

IEEE Trans. Appl. Supercond.

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A 920-MHz high-resolution NMR spectrometer has been operating at the Tsukuba Magnet Laboratory (TML) since April 2002. It has proved its effectiveness by determining the 3-D structures of protein molecules. To accelerate studies in structural biology and solid-state NMR, a second high-field NMR magnet was developed and installed at TML. Although its basic design was the same as that of the first magnet, some improvements were made. For the innermost coil, a 16%Sn-bronze-processed (Nb Ti) 3 Sn conductor was employed. The increase in the critical current density above that of a 15%Sn-bronze-processed (Nb Ti) 3 Sn conductor made it possible to reduce the conductor size from 3.5 mm 1.75 mm in the first magnet to 2.80 mm 1.83 mm in the second. At the same operating current of the first magnet, the second magnet is expected to operate at 930 MHz. The liquid helium reservoir and the superfluid helium cooler, which were separated in the first system, were united in the same chamber in the new magnet. The latter magnet was energized up to 21.9 T without quenching in March 2004 and has operated in a persistent-mode at that field. It will be utilized mainly for solid-state NMR measurements.Index Terms-High magnetic field, NMR magnet, nuclear magnetic resonance, superconducting magnet.

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Section: Operationsupporting

confidence: 78%

“…As reported in a previous paper [5], the magnetic fields around the sample volume were measured with an NMR probe which rotated around the magnet center at a radius of 8.5 mm. The mapping data, plotted in Fig.…”

Section: Performances Of the Magnetmentioning

confidence: 99%

Operation of a 930-MHz High-Resolution NMR Magnet at TML

Toko

Matsumoto

Satô

et al. 2005

IEEE Trans. Appl. Supercond.

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“…Extensive efforts have been made continuously to develop a higher field NMR magnet [1,2,3,4], because higher magnetic fields can improve the NMR resolution and sensitivity. An example of the benefit can be seen for half-integer quadrupolar nuclei in solid-state NMR, because the line width due to the 2nd order quadrupole interactions becomes narrower with increasing the magnetic field.…”

Section: Introductionmentioning

confidence: 99%

“…Since the hybrid magnet has still the disadvantage in its magnetic field stability, homogeneity and running costs compared to superconducting NMR magnets, the hybrid magnet does not seem to come into general use right now. For superconducting NMR magnets, a break through in the magnetic field intensity was achieved for 920 MHz in 2001 [1,2], and 1 GHz (i.e. 1000 MHz) was reached in 2009 [4].…”

Section: Introductionmentioning

confidence: 99%

Achievement of 1020 MHz NMR

Hashi

Ohki

Matsumoto

et al. 2015

Journal of Magnetic Resonance

134

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We have successfully developed a 1020MHz (24.0T) NMR magnet, establishing the world's highest magnetic field in high resolution NMR superconducting magnets. The magnet is a series connection of LTS (low-Tc superconductors NbTi and Nb3Sn) outer coils and an HTS (high-Tc superconductor, Bi-2223) innermost coil, being operated at superfluid liquid helium temperature such as around 1.8K and in a driven-mode by an external DC power supply. The drift of the magnetic field was initially ±0.8ppm/10h without the (2)H lock operation; it was then stabilized to be less than 1ppb/10h by using an NMR internal lock operation. The full-width at half maximum of a (1)H spectrum taken for 1% CHCl3 in acetone-d6 was as low as 0.7Hz (0.7ppb), which was sufficient for solution NMR. On the contrary, the temporal field stability under the external lock operation for solid-state NMR was 170ppb/10h, sufficient for NMR measurements for quadrupolar nuclei such as (17)O; a (17)O NMR measurement for labeled tri-peptide clearly demonstrated the effect of high magnetic field on solid-state NMR spectra.

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“…The coil is wound with specially developed wires for use in high magnetic fields such as 920 MHz NMR magnet [1], [2]. The cryostat is an open neck Dewar vessel with a liquid nitrogen reservoir and radiation shield.…”

Section: Introductionmentioning

confidence: 99%

Development of a 20 Tesla Superconducting Magnet

Okui¹,

Hirose²,

Fukumizu³

et al. 2006

IEEE Trans. Appl. Supercond.

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A 20 T superconducting magnet was designed and developed for studying physical properties. The cryostat is an open neck Dewar vessel with a liquid nitrogen reservoir and radiation shield. A lambda plate is built into the magnet support assembly. The operating temperature can be reduced from 4.2 K to 2.2 K by pumping liquid helium through a throttle valve under the lambda plate.The central magnetic field is 20 T at 2.5 K (18 T at 4.2 K). The field homogeneity is less than + 0.1% in a 10 mm diameter sphere volume. The inner diameter of the cold clear bore is 52 mm. The outer diameter of the coil is 349 mm. The height of the coil, excluding the magnet protection circuit, is 560.5 mm. The coil is wound with the specially developed wires for use in high magnetic fields. In the case of Nb 3 Sn wires, a marked increase of the critical current density is achieved with higher tin content in the bronze matrix. The wires are more resistant to external stress with a rectangular cross section. We hung the magnet into the Dewar vessel and energized it. At first the magnet was operated at liquid helium temperature 4.2 K. As a result, the magnetic field rose to over 18 T with no training quench. The maximum magnetic field was 18.5 T. Then we energized the magnet after reducing the operating temperature to 2.2 K. Finally, the magnetic field rose to over 20 T with no quench.The result of this study shows that this magnet delivers a high magnetic field stably and easily.Index Terms-High magnetic field, Nb 3 Sn, superconducting magnet, 20 T.

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Persistent-mode operation of a 920 MHz high-resolution NMR magnet

Cited by 33 publications

References 5 publications

Operation of a 930-MHz High-Resolution NMR Magnet at TML

Operation of a 930-MHz High-Resolution NMR Magnet at TML

Achievement of 1020 MHz NMR

Development of a 20 Tesla Superconducting Magnet

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