JPS59216045A - Slanting magnetic field coil - Google Patents

Abstract

PURPOSE:To obtain a slanting magnetic field coil which generates no strike noise by charging an elastic filler in the space formed of a bobbin for the coil for slanting magnetic field generation used for a nuclear magnetic resonance device, a coil fixing device, and a coil. CONSTITUTION:The slanting magnetic field generating coil consists of the bobbin 9, a Z-axial coil 10, and and an X-directional coil 11 and a Y-directional coil 12 arranged outside of the coil 10 while crossing each other at right angles. Those coils are fixed to the bobbin 9 by the coil fixing device 16 and then adhered by caking a filling adhesive 17 having proper elasticity, and packings 16a and 16b which are elastic are interposed between those coils. Thus, no strike noise is generated even in an intense static magnetic field.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a gradient magnetic field generating coil used in a calibration device using a nuclear magnetic resonance apparatus.

[Background of the invention]

Nuclear magnetic resonance (hereinafter referred to as NMR) is used for structural analysis and research on physical properties of organic compounds, and has become one of the important analysis tools.

In NMR, it is necessary to provide a magnetic field gradient to determine the irradiation observation surface.For this purpose, inside the static magnetic field,
Three sets of coils are attached to generate arbitrary gradient magnetic fields in each of the X, Y, and Z directions. These coils are called gradient magnetic field generating coils.

Each of these X, Y, and Z coils is connected to an independent dedicated power source and is excited with a controlled current (generally a pulsed current having a constant interval). However, since these coils are placed in a very strong static magnetic field (generally 1500 to 3000 Gauss), when an excitation current flows, when driven by a power source determined by the direction of the static magnetic field and the direction of the current flowing through the coil, Because a strong electromagnetic force is instantaneously applied, the coil vibrates, which is transmitted to the winding frame through the coil fixing device and becomes a source of noise.

1 to 3 show the structure of a conventionally used gradient magnetic field generating coil. FIG. 1 is an axial (Z-axis) view, and 10, 11, and 12 are arranged as shown and fixed to the winding frame 9 by a coil fixing device 13. FIG. 2 shows a cross-sectional view corresponding to FIG. Figure 3 shows the details of the coil fixing part, and each coil is made of non-magnetic material and has a spacer 13a made of electrical insulator (for example, phenol resin or FRP).
Its position is defined by 13d, and it is fixed to the winding frame 9 with a fixing screw 14 and a fixing nut 15. In this structure, there is no problem in mechanically positioning each coil with respect to the winding frame 9, but there is a problem in reducing electromagnetic vibration. However, since the holding distance of the spacer 13 becomes long, the mechanical fixation of the central part and the tip part becomes insufficient, and these parts vibrate, causing noise (hitting sound). In order to prevent these problems, it is possible to increase the number of spacers 13 and strengthen the mechanical connection between each coil and the winding frame 9, but this increases the complexity of the structure.
There were problems, such as the need to improve the accuracy of parts, which led to an increase in manufacturing and assembly man-hours.

Therefore, since this NMR is aimed at measuring the human body and the subject is placed inside a gradient magnetic field, the generation of these tapping sounds is undesirable as it gives a psychological feeling of pressure.

[Purpose of the invention]

The object of the present invention is to provide a gradient magnetic field coil that does not generate noise or hammering sounds.

[Summary of the invention]

In order to achieve such an object, the present invention provides a winding frame, a coil fixing device, and a backing having appropriate elasticity between the coils in a gradient magnetic field generating coil used in an inspection device using a nuclear magnetic resonance apparatus. The space between the winding frame, coil fixing device, and coils is filled with a filler having appropriate elasticity.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 4 shows the configuration of NMR. The control device 1 is configured to output various commands to each device at a constant timing. The output of the high frequency pulse generator 2 is amplified by a power amplifier 3 to excite a coil 4. coil 4
also serves as a receiving coil, and the signal components are passed through an amplifier 5, detected by a detector 6, and then converted into an image by a signal processing device 7. The gradient magnetic field generating coil 8 includes a winding frame 9, a Z-direction coil 10, and an X-direction coil 11. Each of the Y-direction coils 12 is driven by an excitation power source 14. A static magnetic field is generated by a coil 15 and driven by an excitation power source 16. The subject 17 is placed at the center of these magnets.

Figures 5 and 6 show the basic structure of the gradient @ field generating coil. FIG. 5 shows the installation of the Z-direction coil lo. Reference numeral 10 consists of two sets of coils wound in the circumferential direction at both ends of the winding frame 9, and terminals 10' are connected to the terminals of each coil for coupling with external wiring.

FIG. 6 shows the installation of the X-direction coil 11 and the Y-direction coil 12. 11 and 12 are saddle-shaped coils as shown in the figure.
It is mounted on the outside of the 0 and mechanically shifted by 90 degrees. Terminal 11'.

12' is connected to the terminal of each coil.

FIG. 7 is an axial view, FIG. 8 is a sectional view, and FIG. 9 is a detailed view of the coil fixing part. The same reference numerals as in FIGS. 1 to 3 indicate the same materials.

In FIGS. 7 and 8, coils 10, 11, and 12 are fixed to the winding frame 9 by a coil fixing device 16, and then hardened and bonded with a filler adhesive 17 having appropriate elasticity.

Figure 9 shows details of the coil fixing part, coil 10° 11.12
sandwich backings 16a and 16b having appropriate elasticity (for example, rubber) on the upper and lower sides, and spacers 16C and 1
6d and fixed at 9 at 14.15.

〔Effect of the invention〕

According to this structure, the vibration of each coil is 16a.

Since the vibrations 16b and 17 are regulated and attenuated, the intensity of the vibration transmitted to 9 can be significantly reduced. Furthermore, the number of parts for the coil fixing part is reduced, and a low-noise gradient magnetic field generating coil can be obtained without increasing the number of assembly steps.

[Brief explanation of the drawing]

1 to 3 are an axial view, a sectional view, and a detailed view of a coil fixing part showing an example of a conventional gradient magnetic field coil, respectively, and FIG. 4 is a nuclear magnetic resonance to which a gradient magnetic field coil according to the present invention is applied. 5 and 6 are diagrams showing the basic structure of the gradient magnetic field coil according to the present invention, and FIGS. 7 to 9 are axial diagrams each showing an embodiment of the gradient magnetic field coil according to the present invention. They are a perspective view, a sectional view, and a detailed view of a coil fixing part. 1... Control device, 2... High frequency pulse generator, 3.
... Power booster [1], 4... Coil, 5... Amplifier, 6... Detector, 7... No. 18 processing device, 8...
Gradient magnetic field generation coil, 9... Winding frame, 10... Z direction coil, 10'... terminal, 11... X direction coil, 11'... Pa terminal, 12... Y direction coil , 12'
...Terminal, 13...Coil fixing device, 13a...
Spacer, 13b...Spacer, 13C...Spacer, 13d...Spacer, 14...[lneL,,1
5... Fixing nut, 16... Coil fixing device, 16
a...Backing, 16b...Backing, 16c
... Spacer, 16d... Spacer, 17... Filling adhesive. Proxy Patent Attorney: Priest Akio Takahashi 1 (2) Funeral 2nd Funeral 3rd Illustration

Claims (1)

[Claims] 1. In a gradient magnetic field generating coil used in an inspection device using a nuclear magnetic resonance apparatus, a winding frame, a coil fixing device, and a backing having appropriate elasticity are interposed between the coils, and the winding frame, coil fixing device, A gradient magnetic field coil characterized in that the space between the coils is filled with a filler having appropriate elasticity.