Presentation Information
[ED5-04-INV]Development of RF Coil Using High-Temperature Superconductor for NMR
*Takanori Fujita1,2, Keita Sakuma1, Ryoji Tanaka2, Katsuyuki Toshima2, Naoto Sekiya1 (1. Yamanashi Univ. (Japan), 2. JEOL Ltd. (Japan))
Keywords:
NMR,HTS,RF coil
[Purpose]
The quality factor of the conventional high-temperature superconductor (HTS) radio frequency (RF) coil for nuclear magnetic resonance (NMR) decreased by 30% when a sample was loaded, and the static magnetic field was significantly distorted by the coil. Therefore, we developed the split-type HTS coil that solved these problems to improve the signal-to-noise ratio (SNR) for NMR signals.
[Method]
The coil consisted of four half-wavelength resonators and was designed using a three-dimensional electromagnetic field simulator. The HTS coil was fabricated using photolithography and ion milling. The HTS coil was implemented in an NMR probe and cooled to 14 K by using a commercial cooling system. The frequency response, Q when a sample was loaded, static magnetic field distribution, and SNR were measured.
[Results]
The Q of the split-type HTS coil was 10 times higher than that of the commercial copper coil. The Q decreased by only 11% when the sample was loaded. The maximum distortion of the static magnetic field was less than 20% compared to the conventional HTS coil. The SNR obtained with the HTS coil was 1.3 times higher than that of the copper coil.
[Consideration]
The HTS coil suppressed the decrease in the Q when the sample was loaded because the electric field concentration area was located far from the sample. The distortion of the static magnetic field was suppressed since the HTS is not located in the area of the coil substrate closest to the sample.
[Conclusion]
We developed the split-type HTS coil and realised a higher SNR than the commercial copper coil.
The quality factor of the conventional high-temperature superconductor (HTS) radio frequency (RF) coil for nuclear magnetic resonance (NMR) decreased by 30% when a sample was loaded, and the static magnetic field was significantly distorted by the coil. Therefore, we developed the split-type HTS coil that solved these problems to improve the signal-to-noise ratio (SNR) for NMR signals.
[Method]
The coil consisted of four half-wavelength resonators and was designed using a three-dimensional electromagnetic field simulator. The HTS coil was fabricated using photolithography and ion milling. The HTS coil was implemented in an NMR probe and cooled to 14 K by using a commercial cooling system. The frequency response, Q when a sample was loaded, static magnetic field distribution, and SNR were measured.
[Results]
The Q of the split-type HTS coil was 10 times higher than that of the commercial copper coil. The Q decreased by only 11% when the sample was loaded. The maximum distortion of the static magnetic field was less than 20% compared to the conventional HTS coil. The SNR obtained with the HTS coil was 1.3 times higher than that of the copper coil.
[Consideration]
The HTS coil suppressed the decrease in the Q when the sample was loaded because the electric field concentration area was located far from the sample. The distortion of the static magnetic field was suppressed since the HTS is not located in the area of the coil substrate closest to the sample.
[Conclusion]
We developed the split-type HTS coil and realised a higher SNR than the commercial copper coil.