JPH0318451B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a coil used in a nuclear magnetic resonance apparatus (NMR apparatus), and particularly to a coil that is easy to manufacture and has excellent precision and sensitivity.

[Prior art] In an NMR device, 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 coil placed close to the sample in the probe, and resonance from the sample is emitted. A signal is received by this coil, sent to a computer via a receiving circuit, and an NMR spectrum is obtained by Fourier transform processing. At that time, the geometric symmetry of the coil and the quality of the coupling between the coil and the resonator of the sample are checked.
Great attention is paid to the manufacturing precision of the coil, as well as the shape and structure of the coil, as this greatly affects the sensitivity of the NMR device.

In the case of NMR devices using superconducting magnets, for example, a cylindrical saddle-shaped coil as shown in FIG. 4 has been commonly used. In the saddle-shaped coil shown in Fig. 4, two spirally wound coil parts 1 and 2 are arranged symmetrically around the cylindrical axis Z around a cylindrical region of radius R in which a sample tube containing a sample is arranged. has been done. This spirally wound coil portion consists of straight conductor portions 1A, 2A parallel to the cylindrical axis Z, and arcuate portions 1B, 2B lying in a plane perpendicular to the cylindrical axis Z.

Conventionally, such coils have been manufactured by winding a conductor wire with a circular cross section around the surface of a cylindrical bobbin, but this poses a problem in terms of manufacturing accuracy because the wire tends to shift.

FIG. 5 shows the original pattern of the coil proposed in Japanese Patent Application Laid-Open No. 57-147041. In this conventional example,
The coil pattern is manufactured as a printed circuit on a printed board or by punching out a wide flat conductor from a thin conductor plate, so it has excellent manufacturing accuracy. In addition, when a coil is made from a flat conductor like this, the surface area is larger than a coil made from a conductor wire with a circular cross-section of the same cross-sectional area, so the resistance to high-frequency current flowing through the surface layer is small, and the Q of the coil is significantly increased. Since the high-frequency magnetic field created by the high-frequency current flowing through the flat conductor runs parallel to the conductor surface, the excellent effect of increasing the uniformity of the high-frequency magnetic field irradiated onto the sample can be obtained.

[Problems to be Solved by the Invention] However, when making a coil using such a flat conductor, the so-called single-stroke coil pattern must be punched out or cut out from the conductor plate, so it is difficult to start winding the coil. The part S and the winding end part E cannot be taken out of the coil as they are, and the conductor wires for connecting to the external circuit are connected to S and E.
I had to solder the parts.

In this way, connecting to an external circuit within the coil winding is not only disadvantageous in terms of signal detection, but also requires careful consideration in manufacturing the coil.

The present invention has been made in view of this point,
The purpose is to provide a coil that is easy to manufacture and has excellent precision and sensitivity.

[Means for solving the problem] In order to achieve this objective, the present invention
Coils for NMR devices are made by cutting out a single-stroke coil pattern from a thin conductor plate along a predetermined fold line.
It is characterized by being folded back 180 degrees and formed into a cylindrical saddle-shaped coil with the winding start and winding ends located outside the coil.

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

FIG. 1a shows the original pattern of a two-turn coil for an NMR apparatus according to the present invention, which is produced by punching or cutting out a thin conductive plate.
1A and 2A in this pattern are straight conductors, 1
B and 2B correspond to arc-shaped conductors.

FIG. 1b shows the state when this coil pattern is folded in half along the fold line L. An insulating film F is inserted between the parts where the upper and lower conductors come into contact with each other due to the folding, thereby providing insulation.

FIG. 1c shows the state when the coil is further wound around the cylindrical bobbin 3, fixed, and formed into a coil. Needless to say, the dimensions l ₁ to l ₃ of the pattern are determined according to the diameter R and height of the bobbin so that the spiral winding portions 1 and 2 are symmetrical when formed into a coil.

In the coil of the present invention created in this way,
Since the coil is formed from one continuous flat conductor, and the coil winding start part S and winding end part E are outside the coil, it is disadvantageous in terms of signal detection compared to the conventional method where parts S and E were inside the coil. It is easy to manufacture.

Figure 2a shows the original pattern of the 3-turn coil according to the present invention, and if this is folded back along the fold line _L1 , the state shown in Figure 2b will be obtained.Furthermore, only the drawer portion 4 can be folded along the fold line _L2 . If it is returned, it will be in the state shown in Figure 2c.
Then, if it is further wound around a cylindrical bobbin and formed into a cylindrical shape, it becomes a three-turn coil. Incidentally, the arc-shaped conductor 1B is given a width commensurate with the width occupied by the arc-shaped conductor 2B, and the distribution of the conductor is made symmetrical.
This prevents a decrease in the uniformity of the static magnetic field.

Figure 3a shows the original pattern of the same 4-turn coil, and if you fold it back along the fold line _L1 , you will get the state shown in Figure 3b.
If you turn around at L ₂ , you will be in the situation shown in Figure 3c. Then, if you wrap it around a cylindrical bobbin and form it into a cylindrical shape, 4
It becomes a coil of turns.

In the embodiments shown in FIGS. 2 and 3, an insulating film F is also inserted in the portion where the upper and lower conductors come into contact.

Further, in the above-described embodiments, the coil is wound around a cylindrical bobbin and fixed, but as long as the flat conductor has sufficient strength, the coil itself can support itself, and a support such as a bobbin is not necessarily necessary.

[Effects of the Invention] As detailed above, according to the present invention, a coil that is easy to manufacture and has excellent precision and sensitivity is provided.

[Brief explanation of the drawing]

Figures 1, 2, and 3 each show an example of a coil for an NMR device embodying the present invention, Figure 4 shows a conventional cylindrical saddle-shaped coil, and Figure 5 shows the It is a figure showing the original pattern of the coil proposed in No. 57-147041. 1, 2: Spiral winding coil part, 1A, 2A:
Straight conductor part, 1B, 2B: arcuate conductor part,
3: Bobbin, 4: Drawer part, L ₁ , L ₂ : Folding line,
F: Insulating film.

Claims (1)

[Claims] 1 A single-stroke coil pattern cut from a thin conductor plate is folded back 180 degrees along a predetermined fold line, and the coil is made into a cylindrical saddle-shaped coil with the winding start and winding ends located outside the coil. A coil for NMR equipment formed by molding.