JPS61176841A - Coil for nmr probe - Google Patents

Abstract

PURPOSE:To obtain a coil for an NMR probe of a small inductance in 1 turn by providing a pair of linear conductive members disposed approximately symmetrically to extend in the direction parallel with a cylindrical shaft with the cylindrical shaft in-between and arc-shaped conductive members for connecting the top ends of a pair of the linear conductive members and forming a coil. CONSTITUTION:The coil is constituted of the linear conductors L1, L2 parallel with the cylindrical shaft Z, the arc-shaped conductors L3, L4 for forming the coil by connecting the conductors L1, L2 in series, the 2nd arc-shaped conductors L5-L8 for compensation and leads L9, L10 for connecting the coil to the outside circuit. The conductor L4 is connected at the superposed part by, for example, soldering in the stage of forming the conductor into the cylindrical shape. The 2nd doncutors L5-L8 are provided in order to compensate the disturbance in the uniformity of the static magnetic field by disposing the conductors of the same shape as the shape of the 1st arc-shaped conductors in the position approximately symmetrical therewith with the central origin O of the cylindrical region where a sample is disposed in-between. The widths of the 1st and 2nd arc-shaped conductors are therefore both W and are made the same.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a sample coil used for a probe in a nuclear magnetic resonance (NMR) apparatus, and in particular, the present invention relates to a sample coil used for a probe in a nuclear magnetic resonance (NMR) apparatus, and in particular, the present invention relates to a sample coil used for a probe in a nuclear magnetic resonance (NMR) apparatus.
The present invention relates to the structure of a coil that can detect MR signals.

[Prior art] In an NMR apparatus, a probe containing a sample is placed in a uniform static magnetic field, and a high-frequency magnetic field for excitation is irradiated from a sample coil placed in the probe close to the sample, and the resonance of the sample is irradiated. A resonance signal from the sample coil is received by the sample coil, sent to a computer via a receiving circuit, and an NMR spectrum is obtained by Fourier transformation. At this time, great attention is paid to the shape and structure of the coil, since the sensitivity of the NMR apparatus is greatly influenced by the quality of the coupling between the coil and the resonator of the sample. In the case of an NMR apparatus using a superconducting magnet, a cylindrical saddle-shaped coil as shown in FIG. 4, for example, has been commonly used. The saddle-shaped coil shown in FIG.
Two spirally wound coil sections 1.2 are arranged symmetrically around the cylindrical axis 2. This spiral winding coil part is
It consists of straight portions IA, 2A parallel to the cylinder axis Z, and arcuate portions IB, 2B lying in a plane perpendicular to the cylinder axis 2. FIG. 5 shows a cross-sectional view of the linear portion A taken along a plane perpendicular to the cylindrical axis Z. The linear portions IA and 2A are arranged symmetrically on the circumference of the radius R with the Y plane in between. A high frequency magnetic field is generated in the X direction by the coil.

[Problems to be Solved by the Invention] The idea common to the conventional coils as described above is that two spirally wound coil portions 1°2 of the same shape are arranged facing each other from both sides with a cylindrical region in between. Therefore, the number of turns in the coil is 2°4.6.8. ...and it becomes an even number turn.

By the way, in recent years it has become possible to obtain strong static magnetic fields using superconducting magnets, and as a result, the observation frequency has increased to 40
From about 0MH2 to 500MHz.

It is about to be increased to 600MHz. In order to increase the observation frequency in this way, the sample coil is required to have a small inductance, a high tuning frequency, and a high Q.

In such cases, conventionally, a two-turn coil as shown in FIG. 1 is used because it has the smallest number of turns and can minimize inductance. However, even if such a coil is used, the inductance cannot be made sufficiently small, and conventionally, this coil has been used with the knowledge that it is undesirable.

The present invention has been made in view of this point, and provides a one-turn coil by arranging the winding ring on the Y plane, which would never be arranged based on the conventional concept described above, and reducing the inductance. The purpose is to provide a small coil and a coil with extremely high sensitivity.

[Means for solving flSlff1 point] In order to achieve this objective, the NMR probe coil according to the present invention is wound around a cylindrical sample region, and a high-frequency magnetic field in a direction perpendicular to the axis of the cylinder is applied. A coil for generating , the coil comprising: a pair of linear conductive parts extending in a direction parallel to the cylindrical axis and arranged approximately symmetrically across the cylindrical axis; and the pair of linear conductive parts. It is characterized by having an arcuate conductive piece for connecting the ends of the pieces to form a coil.

[Example] Hereinafter, one embodiment of the present invention will be described in detail using the drawings.

FIG. 1 shows an example of a coil embodying the present invention, (a)
(b) shows the shape when it is punched out from the conductor plate, and (b) shows the state when it is formed into a cylindrical shape.

In FIGS. 1(a) and 1(b), the coil consists of a straight conductor Ll, 12 parallel to the cylindrical axis Z, and a straight conductor L1 parallel to the cylindrical axis Z.
, L2 are connected in series to form a coil, and arc-shaped conductors L3 and L4, and a second arc-shaped conductor for compensation 5~
It consists of L8 and leads 9 and 11G for connecting the coil to an external circuit.

When the arc-shaped conductor L4 is punched out from the conductor plate, it is divided into two parts, and when molded into a cylindrical shape as shown in FIG. They are connected and integrated by soldering.

Further, the second arc-shaped conductors L5 to L8 do not have a role as a coil, as can be seen from the fact that they are not connected to each other, and the second arc-shaped conductors L5 to L8 do not have a role as a coil, but are connected to the first This is provided for the purpose of compensating for disturbances in the uniformity of the static magnetic field by arranging a conductor having approximately the same shape at a symmetrical position to the arc-shaped conductor. Therefore, its width is the first and second
W is made equal to both the arc-shaped conductors.

FIG. 2 shows a cross-sectional view of the coil shown in FIG. 1 taken at the center 0 of the cylindrical region along an XY plane perpendicular to the cylindrical axis 2. FIG. As you can see from this figure, a straight conductor 1. L2 is placed on the axis (Y axis) perpendicular to the axis of the high frequency magnetic field (X ring),
A one-turn coil has been realized. Therefore, according to the present invention, a one-turn coil having a smaller inductance than a conventional two-turn coil can be realized.

Moreover, the high-frequency magnetic field strength generated in the X-axis direction at the center origin O of the cylindrical area where the sample is placed by a straight conductor placed at this point If (on the Y plane) is different from that at any other position. Since it is stronger than when placed in the coil, it has a high Q as a coil. Therefore, according to the present invention, it is possible to irradiate a sample with a strong high-frequency magnetic field using a highly efficient coil with a high Q, and it is also possible to efficiently detect a strong resonance signal derived from the strong high-frequency magnetic field irradiation. The synergistic effect significantly increases the sensitivity of the NMR device.

In the above embodiment, the linear conductors L1 and L2 are replaced by two arcuate conductors L3. L4 is connected in parallel, but since it is only necessary to connect one side, it is not necessarily necessary to electrically connect the arc-shaped conductor L4, which is divided into two halves (leave them separated with a slight interval). However, it is not preferable to completely eliminate the arc-shaped conductor L4 because the presence of the conductor becomes asymmetrical.

FIG. 3 shows an example in which this point is taken into consideration and the lead extraction position is moved closer. The figure (a) shows the state in which it has been punched out from the conductor plate, and the figure (b) shows the state in which it has been formed into a cylindrical shape.

The coil of the present invention can be formed by pasting a conductor wire onto a bobbin, by forming it by vapor deposition technology on the surface of the bobbin, in addition to being punched out from the conductor plate as described above, or by forming a printed circuit on a substrate with or without flexibility. It can be manufactured by forming it as. If the conductor has sufficient strength, it is not necessary to support it with another support such as a bobbin, and the conductor can stand alone.

In the above embodiment, the linear conductors are arranged exactly symmetrically with respect to the two axes, but the linear conductors only need to be arranged substantially symmetrically, and a slight deviation is allowed.

[Effects of the Invention] As described in detail above, according to the present invention, a small coil for an NMR probe with small inductance can be realized in one turn, so that it can sufficiently cope with an increase in the observation frequency.

Furthermore, since the coil of the present invention has a high Q, it is possible to improve the sensitivity of the NMR apparatus.

[Brief explanation of the drawing]

Figures 1 and 3 are diagrams each showing an example of a coil embodying the present invention, Figure 2 is a diagram for explaining the arrangement of linear conductors around the Z-axis in the coil of Figure 1, and Figure 4 5 and 5 are diagrams for explaining a conventional saddle-shaped coil. Ll, L2: Straight conductor L3 to L10: Arc-shaped conductor

Claims (9)

[Claims] (1) A coil that is wound around a cylindrical sample area and generates a high-frequency magnetic field in a direction perpendicular to the axis of the cylinder, and extends in a direction parallel to the cylinder axis and extends approximately across the cylinder axis. a pair of linear conductive pieces arranged symmetrically;
1. A coil for an NMR probe, comprising: an arcuate conductive piece for connecting the ends of a pair of linear conductive pieces to form a coil. (2) At the other end of the linear conductive piece, a second conductive piece having symmetry with the arcuate conductive piece with respect to the center of the sample area.
The coil for an NMR probe according to claim 1, characterized in that the arcuate conductive pieces are connected to each other. (3) The NMR probe coil according to any one of claims 1 to 2, wherein the conductive piece is a conductive wire with a circular cross section. (4) The NMR probe coil according to any one of claims 1 to 2, wherein the conductive piece is formed of a plate-like conductor. (5) The NMR according to any one of claims 1 to 4, wherein the coil is supported by a hollow cylindrical bobbin.
Coil for probe. (6) The coil according to claim 5, wherein the coil is formed on the bobbin by vapor deposition. (7) The coil for an NMR probe according to any one of claims 1 to 2, wherein the coil comprises a printed circuit supported by an insulating substrate. (8) The coil according to claim 7, wherein the insulating substrate has flexibility and is bendable. (9) The coil for an NMR probe according to any one of claims 1 to 4, wherein the coil has sufficient strength to hold itself.