title: An X0 shim coil for precise magic-angle adjustment.
abstract: A new method for precise setting of the spinning angle to the magic angle by using a saddle coil is described. The coil, which is referred to as an X0 shim coil, is wound to produce a uniform static magnetic field Bx perpendicular to the main magnetic field B0. The magnetic field felt by a sample is a vector sum of the main field B0 and the transverse field Bx produced by the X0 shim coil. Hence the angle between the spinner axis and the effective magnetic field can be controlled by current I supplied to the X0 shim coil, leading to precise angle adjustment without backlash accompanied with a mechanical system conventionally used. It is shown that the angle range achieved is ±0.05° for I=±5A at B0=7T.
authors.affiliation: Division of Chemistry, Graduate School of Science, Kyoto University, 606-8502 Kyoto, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Matsunaga
authors.affiliation: JEOL RESONANCE Inc., 196-8558 Akishima, Tokyo, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Mizuno
authors.affiliation: Division of Chemistry, Graduate School of Science, Kyoto University, 606-8502 Kyoto, Japan. Electronic address: takeyan@kuchem.kyoto-u.ac.jp.
authors.forename: K
authors.initials: K
authors.lastname: Takegoshi
keywords: High resolution solid state NMR; MAS; X(0) shim coil