University of California

Commissariat &#xc0; L'&#xc9;nergie Atomique Et Aux &#xc9;nergies Alternatives

Commissariat a L'energie Atomique

Dimitrios Sakellariou

Alexander Pines

Guy Aubert

Carlos A Meriles

Cédric Hugon

Rachel W Martin

Andreas H Trabesinger

Adam Moule

Jacques-François Jacquinot

Daniel Topgaard

Henrike Heise

The cylindrical permanent magnet device includes at least one basic structure () having a longitudinal axis (z) and a set () of coaxial magnetized structures () that are in the form of non-contiguous rings of axis that is the longitudinal axis (z) and that are disposed on the same side of the basic structure (), defining an exterior surface perpendicular to the longitudinal axis (z) to produce a magnetic field (B) outside the magnet device in an exterior area of interest () situated at a predetermined distance from the exterior surface along the longitudinal axis (z). At least one of the coaxial magnetized structures () in the form of rings is divided into components in the form of non-contiguous identical sectors. The basic structure () and the set () of coaxial magnetized structures () in the form of rings are magnetized in the same direction (M) to create in the exterior area of interest () an induced magnetic field (B) that is homogeneous or that has a constant gradient and that is oriented at a predetermined angle (&#x3b8;) relative to the longitudinal axis (z).

Cylindrical permanent magnet device generating a controlled magnetic field at a distance from the surface thereof

A magnetized structure that induces in a central area of interest a homogeneous magnetic field of predetermined orientation relative to a longitudinal axis (z) of the structure comprises at least two magnetized rings () disposed symmetrically relative to a plane (P) that is perpendicular to the longitudinal axis (z) and that contains the central area of interest, and at least one median annular magnetized structure disposed at least partly between the two magnetized rings () and also disposed symmetrically relative to the plane (P) of symmetry, one of the two magnetized rings () being magnetized radially relative to the longitudinal axis (z) with divergent magnetization and the other of the two magnetized rings () being magnetized radially relative to the longitudinal axis (z) with convergent magnetization, and the median annular magnetized structure being magnetized with an orientation different from that of the magnetization of the two magnetized rings (). The median annular magnetized structure comprises at least one magnetized ring () having a magnetization distribution of orientation that varies as in Halbach dipoles and the first two magnetized rings () and the median annular magnetized structure are each divided into individual components in the form of regularly distributed identical sectors.

Magnetised structure inducing a homogeneous field, in the centre thereof, with a pre-determined orientation

The magnetized structure that induces in a central area of interest a homogeneous magnetic field oriented along a longitudinal axis (z) of the structure comprises first and second magnetized rings () disposed symmetrically relative to a plane (P) that is perpendicular to said longitudinal axis (z) and that contains said central area of interest, and one median annular magnetized structure () disposed between the first and second magnetized rings () and also disposed symmetrically relative to the plane (P) of symmetry. The first magnetized ring () is magnetized radially relative to the longitudinal axis (z) with divergent magnetization, the second magnetized ring () is magnetized radially relative to the longitudinal axis (z) with convergent magnetization, and the median annular magnetized structure () is magnetized along the longitudinal axis (z). The median annular magnetized structure () is divided into at least two slices (A,B,A,B) along the longitudinal axis (z) and the first and second magnetized rings () and the various slices (A,B,A,B) of the median magnetized structure () are each divided into identical components in the form of regularly distributed sectors.

Assembly of magnetised coaxial structures inducing a longitudinal homogeneous field in the centre thereof

The present invention concerns an apparatus (') for NMR spectroscopy and/or NMR imaging of a sample. The apparatus comprises a static probe comprising an outer coil for excitation of nuclei of the sample by generating an incident radio frequency field at the Larmor frequency of the nuclei, and for reception of a return radio frequency field emitted by the sample, and a sensitive inner coil (&#x2032;) which is mounted closely around or in contact with the sample container and which is wirelessly coupled to the outer coil by an electromagnetic radio frequency field. The sensitive inner coil is embedded in an inner spinning rotor () which is rotatively mounted inside the static probe and which is integral with the sample container, so that the filling factor and the radio frequency field amplitude in the sensitive coil are maximized.

Apparatus for high-resolution NMR spectroscopy and/or imaging with an improved filling factor and RF field amplitude

A method and system of magnetic resonance imaging does not need a large homogenous field to truncate a gradient field. Spatial information is encoded into the spin magnetization by allowing the magnetization to evolve in a non-truncated gradient field and inducing a set of 180 degree rotations prior to signal acquisition.

Low field magnetic resonance imaging

Methods and systems for compensating for static magnetic field inhomogeneities during nuclear magnetic resonance detection are disclosed. Application of radio frequency pulses and/or magnetic field gradients may be used to correct for spin dephasing caused by the inhomogeneities. The methods and system may be used to improve signal-to-noise ratios in NMR and MRI systems where magnetic field inhomogeneity may have an effect.

Nuclear magnetic resonance detection in inhomogeneous magnetic fields

A method and apparatus for ex-situ nuclear magnetic resonance spectroscopy for use on samples outside the physical limits of the magnets in inhomogeneous static and radio-frequency fields. Chemical shift spectra can be resolved with the method using sequences of correlated, composite z-rotation pulses in the presence of spatially matched static and radio frequency field gradients producing nutation echoes. The amplitude of the echoes is modulated by the chemical shift interaction and an inhomogeneity free FID may be recovered by stroboscopically sampling the maxima of the echoes. In an alternative embodiment, full-passage adiabatic pulses are consecutively applied. One embodiment of the apparatus generates a static magnetic field that has a variable saddle point.

Growing community of inventors

Boulogne Billancourt, France

Dimitrios Sakellariou