Coil Assembly for Accurate Adjustment of Magic Angle in Solid-State NMR Apparatus and Method of Adjusting Magic Angle Using Such Coil Assembly

摘要

A specially shaped coil assembly for accurate adjustment of the magic angle is provided to permit accurate adjustment of an angle made between the direction of a static magnetic field and the axis of sample spinning without impairing the resolution of NMR signals. The sample is placed within the external static magnetic field B0. The coil assembly is for use in a solid-state NMR apparatus that performs NMR detection while spinning the sample about an axis tilted at the magic angle relative to the external static magnetic field B0. The coil assembly comprises a pair of arcuate conductor lines and a pair of straight conductor lines. Each of the arcuate lines has a diameter of 2a. Each of the straight lines has a length of 2L. The diameter 2a and the length 2L are so selected as to satisfy the relationship: 1.91≦2L/2a≦2.15.

主权项

1. A coil assembly for accurate adjustment of the magic angle, the coil assembly being for use in a solid-state NMR apparatus for performing NMR detection by spinning a sample at high speed about an axis tilted at the magic angle relative to an external static magnetic field B0 in which the sample is placed, said coil assembly comprising:
a pair of Helmholtz saddle coils arranged symmetrically with respect to a z axis of an xyz coordinate system on a cylindrical plane having a radius of a to produce a uniform magnetic field in the direction of an x axis when the axis of spinning of the sample is tilted relative to the z axis within a z-x plane, the cylindrical plane being centered at the z axis, the external static magnetic field B0 lying along the z axis, each of the Helmholtz saddle coils being made of at least one turn of coil; wherein the at least one turn of coil is composed of a pair of arcuate conductor lines arranged circumferentially of the cylindrical plane and a pair of straight conductor lines interconnecting the arcuate conductor lines and arranged lengthwise of the cylindrical plane, each of the arcuate conductor lines having a diameter of 2a, each of the straight conductor lines having a length of 2L; and wherein the diameter 2a of each of the arcuate conductor lines and the length 2L of each of the straight conductor lines are so selected as to satisfy the following relationship:
1.91≦2L/2a≦2.15