Patent ID: 9389287
Filing Date: 2016-07-12
CPC Classification: G01R

Claim Text:
1. A nuclear magnetic resonance spectrometer for spinning a sample about an axis tilted at a magic angle with respect to a static magnetic field and detecting a nuclear magnetic resonance signal, said nuclear magnetic resonance spectrometer comprising: a static magnetic field generating portion for producing the static magnetic field extending along a z-axis; a corrective magnetic field generating portion for producing a corrective magnetic field to correct the static magnetic field, comprising a shim coil set with plural shim coils arranged around the z-axis; a control portion for controlling the corrective magnetic field generating portion; and a probe for detecting a nuclear magnetic resonance signal emanating from the sample; wherein said control portion has a magnetic field distribution acquisition section for obtaining a distribution of the static magnetic field along said tilted axis by NMR measurements using the probe wherein the sample is spun about the tilted axis, an arithmetic unit for determining a first coefficient of a first-order magnetic field component of the corrective magnetic field, a second coefficient of a second-order magnetic field component of the corrective magnetic field, and a third coefficient of a third-order magnetic field component of the corrective magnetic field along the tilted axis based on the distribution of the static magnetic field, and a corrective magnetic field generating portion control section for controlling the corrective magnetic field generating portion based on the first, second, and third coefficients; wherein said corrective magnetic field is given by the following Eqs. (1), (2), and (3): where n is an integer equal to or greater than unity, m is an integer satisfying the relationship |m|≦n, z is an axis extending along the static magnetic field, b r,θ,φ are coordinate-axis components of polar coordinates, and P wherein said arithmetic unit uses at least one of B