title: Development of a 700 MHz low-/high- temperature superconductor nuclear magnetic resonance magnet: test results and spatial homogeneity improvement.
abstract: For the first time in nuclear magnetic resonance (NMR) magnet development, a magnet configuration comprising an insert wound with high-temperature superconductor (HTS) and a background-field magnet wound with low-temperature superconductor (LTS) has been proven viable for NMR magnets. This new LTS/HTS magnet configuration opens the way for development of 1 GHz and above NMR magnets. Specifically, a 700 MHz LTS/HTS NMR magnet (LH700), consisting of a 600 MHz LTS magnet (L600) and a 100 MHz HTS insert (H100), has been designed, built, and successfully tested, and its magnetic field characteristics were measured and analyzed. A field homogeneity of 172 ppm in a cylindrical mapping volume of 17 mm diameter by 30 mm long was measured at 692 MHz and corresponding 1H NMR signal with 1.9 kHz half-width was captured. Two techniques, room-temperature and ferromagnetic shimming, were analytically examined to investigate if they would be effective for further improving spatial field homogeneity of the LH700.
authors.affiliation: Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA. syhahn@mit.edu
authors.forename: S
authors.initials: S
authors.lastname: Hahn
authors.forename: J
authors.initials: J
authors.lastname: Bascuñán
authors.forename: H
authors.initials: H
authors.lastname: Lee
authors.forename: E S
authors.initials: ES
authors.lastname: Bobrov
authors.forename: W
authors.initials: W
authors.lastname: Kim
authors.forename: Y
authors.initials: Y
authors.lastname: Iwasa