JP2001178695A - Instrument for measuring biological magnetic field - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the transmission of a vibration from a floor, etc., during the measurement of a biological magnetic field. SOLUTION: A support board 28 for supporting a superconductive quantum interference flux meter and a bed 24 where an object to be inspected 25 being a living body is arranged via dampers 27 on the receiving board of a vibration isolating device in order to detect the feeble magnetic field of the living body by the superconductive quantum interference flux meter. The vibration isolating device for preventing the transmission of the vibration from the floor is provided with granular bodies inside a storing vessel, which consist of a large number of hard non-magnetic materials disposed on the floor and have a non-uniform shape, and the receiving board is arranged on the granular bodies. The dampers are non-metallic. Then the vibration from the floor is not transmitted to the flux meter, the dampers are arranged in the vicinity of the flux meter to attain miniaturization of a measuring instrument and the mutual span of the plurality of dampers is shortened. Then the vibration owing to the bending of the support board 28 is prevented or the vibration when the flux meter is vertically or horizontally moved is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for controlling vibration from a floor or the like.
The present invention relates to a biomagnetic field measuring device for preventing transmission to an object to be damped.

[0002]

2. Description of the Related Art Such a vibration isolator uses a superconductive quantum interference device (abbreviated as SQUID) magnetometer to detect weak magnetic fields generated from living bodies such as the human brain, arms, eyes and heart. Required to measure strength. In such a magnetometer, measurement accuracy is reduced by vibration from the floor or the like.

Conventionally, a vibration isolator used for industrial purposes is a spring made of a ferromagnetic material such as spring steel, and an end of a rubber piece is held by a member made of a ferromagnetic material, for example, iron. There is a configuration.

[0004] In such prior art, since the ferromagnetic material is contained, there is a problem that the measurement accuracy of the superconducting quantum interference fluxmeter is reduced. Further, in these prior arts, the natural frequency is usually around 5 Hz, whereas the frequency distribution of the magnetic field generated from the living body contains many components from DC to 200 Hz, particularly less than 40 Hz. The distribution of the frequency of the magnetic field of the living body and the natural frequency of the prior art vibration isolator partially overlap, so that the magnetometer
When vibrating at the natural frequency, the measurement accuracy of the magnetic field strength is significantly reduced.

Further, in such prior art, it is relatively easy to set a spring constant in a compression direction to a desired value, but it is difficult to set a spring constant in a lateral direction to a desired value. For this reason, there is a problem that a sufficient anti-vibration function cannot be achieved.

[0006] As another prior art for performing vibration isolation, a magnetometer to be subjected to vibration isolation is arranged on a large plate-like body such as marble, thereby blocking transmission of vibration from the floor of the magnetometer. . In such prior art, the plate-like body made of marble or the like has a large weight, for example, a value on the order of ton, and is difficult to handle and expensive.

Further, in order to prevent vibration from the floor, it is conceivable to lay a layer of sand to a desired thickness and arrange the magnetic flux meter or the like on the layer. Generally, a relatively large amount of iron powder is mixed in, and such iron powder mixed in the sand causes an error in a highly sensitive superconducting quantum interference magnetometer.

[0008] Yet another prior art is a so-called air damper that uses the elasticity of air, which comprises a cylinder and a piston made of a ferromagnetic material such as iron and austenitic stainless steel or a metal such as aluminum. There is a problem that the measurement accuracy of the magnetometer is reduced. Further, such a conventional air damper is made of metal as described above, and therefore, in order to minimize the measurement accuracy, the air damper is not installed near the magnetometer, and is separated from the magnetometer as much as possible. It is necessary to provide it at a different position. If it does so, the structure of the whole apparatus will become large and the installation area will become large.

Moreover, since it is necessary to mount such an air damper as far as possible from the magnetometer, it is necessary to increase the distance between the plurality of air dampers, that is, the span, so that the magnetometer and the biomagnetic field are increased. The support plate that supports the bed on which the object to be measured is to be measured is likely to bend, and the vibration of the support plate causes the measurement accuracy to decrease. Further, when the magnetometer moves horizontally on the support plate, the number of air dampers cannot be increased as described above, so that the magnetometer is likely to vibrate, and therefore, the measurement accuracy cannot be improved.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a biomagnetic field measuring apparatus capable of measuring a biomagnetic field with high accuracy using a superconducting quantum interference fluxmeter.

[0011]

SUMMARY OF THE INVENTION The present invention provides a superconducting quantum interference magnetometer, a bed on which an object to be measured is to be measured by the superconducting quantum interference magnetometer, a superconducting quantum interference magnetometer, and a bed. And a non-metallic damper provided below the support plate.

Further, the present invention provides a method in which a plurality of irregularly shaped hard non-magnetic materials are provided on a floor in a storage container, and a receiving plate is provided on the granular material. The biomagnetic field measuring apparatus according to claim 1, further comprising a vibration isolator provided with a lower portion of a damper thereon.

[0013] In the present invention, the granular material may be in a range of 0.5 to 0.5.
It has a particle size distribution within a range of a particle size of 5.0 mmφ.

Further, according to the present invention, a plurality of dampers are arranged, each damper is provided on a receiving plate 36, and a vertically extending cylindrical body 132 and a holding member 13 mounted on the cylindrical body 132 are provided.
8, a diaphragm 139 having a peripheral edge air-tightly fixed on the holding member 138 and on which the support plate 28 is mounted, an air chamber 135 in the cylindrical body 132, and a diaphragm chamber 143 in the diaphragm 139. And an air pressure source 148 for supplying compressed air to each air chamber 135 is provided.

According to the present invention, the dampers are grouped into a plurality of groups, and a plurality of pressure control valves 14 interposed between the air pressure source 148 and the air chamber 135 are provided for each group.
7, detecting means for detecting whether the support plate 28 is horizontal, and each pressure control valve 14 responsive to the output of the detecting means.
7 for operating the control plate 7 to keep the support plate 28 horizontal.

[0016]

According to the biomagnetic field measuring apparatus of the present invention, the support plate for supporting the superconducting quantum interference magnetometer and the bed is fixed at a fixed position via a non-metallic damper, for example, on the floor or the above-described vibration isolator. Since it is provided on the receiving plate on the apparatus, the measurement error of the superconducting quantum interference magnetometer can be suppressed.

According to the present invention, a vibration isolator provided with a damper has a granular body provided in a storage container, and the granular body is made of a large number of hard non-magnetic materials having irregular shapes.
For example, it is formed by grinding an inorganic material such as marble or glass. The granular material is formed into a layer, and a rigid, for example, wooden or flexible, for example, rubber receiving plate is provided thereon, and a biomagnetic field measuring device which is an object to be damped is provided on the receiving plate. Is provided. In this biomagnetic field measuring apparatus, a superconducting quantum interference magnetometer and a bed are supported on a support plate, and a lower portion of a non-metallic damper provided below the support plate is provided on a receiving plate. Thus, transmission of vibration from the floor or the like can be reliably blocked over a low frequency range. Small vibrations of the floor, for example, are absorbed by the minute frictional force of the granules and absorbed by the frictional force between the granules and the support plate. Thus, the small vibrations of the floor are converted into heat energy. And the transmission of vibration to the object to be damped is interrupted. Further, in the vibration isolator having such a configuration, even if the object to be damped is, for example, a high-sensitivity superconducting quantum interference magnetometer, there is no possibility that an error occurs in the measurement magnetic field.

Further, in such a vibration isolator, the natural frequency is extremely low, and therefore, it is possible to sufficiently shut off vibration of a low frequency.

Furthermore, according to the present invention, the particle size distribution of the granular material is in the range of the particle size of 0.5 to 5.0 mmφ, and thus the particle size is not uniform. The natural frequency can be made sufficiently small, for example, so that there is no resonance frequency.

According to the present invention, the compressed air from the air pressure source 148 is supplied to the air chamber 135 in the cylinder 132 on the receiving plate 36.
The compressed air in the air chamber 135 is supplied to the throttle 1
Via 36, it is supplied to the diaphragm chamber 143. As a result, the diaphragm 139 expands on the holding member 138, and the support plate 28 is held by the diaphragm 139.

The plurality of dampers are grouped into a plurality of groups, and a pressure control valve 147 is provided for each group. Each pressure control valve 147 is operated by the control means so that the support plate 28 detected by the detection means is horizontal. Thus, the support plate 28 is always kept horizontal, and the biomagnetic field can be measured with high accuracy.

[0022]

FIG. 1 is a perspective view of one embodiment of the present invention, FIG. 2 is a side view thereof, FIG. 3 is a plan view thereof, and FIG.
Is a front view thereof. Referring to these drawings, a biomagnetic field measuring device 21 is provided via a vibration isolator 23 provided on a floor 22 at a fixed position. An inspection object 25 which is a human body is mounted on a bed 24 having a horizontal mounting surface. On a rigid horizontal receiving plate 26 of, for example, wooden, of the vibration isolator 23, a horizontal wooden supporting plate 28 is provided, which is spaced upwardly by a damper 27 according to the invention. On this support plate 28, a mounting piece 29
A pair of aluminum or wooden rails 30 extending in the X direction is fixed on the mounting piece 29. On the support plate 28, another aluminum or wooden rail 31 is fixed. Wooden moving body 3
6 is provided with an aluminum roller 33 sandwiching the rail 30 up and down by a support piece 32.
A roller 34 running above is attached to a wooden moving body 36 by a support piece 35. The wooden moving body 36 is elongated in the Y direction, and a pair of aluminum or wooden rails 38 extending in the Y direction is fixed on the moving body 36.
The rail 38 has a substantially inverted L-shaped section perpendicular to the axis. The support piece 39 of the bed 24 is provided with a roller 40 that runs along the rail 38 while sandwiching the rail 38 vertically. Thus, the bed 24 is provided movably in the X direction and the Y direction that are orthogonal to each other in the horizontal plane.

In order to move the moving body 36 in the X direction, pulleys 42 and 43 are provided on the support plate 28, and the pulleys 42 and 43 are belts, which are endless ropes made of a material such as rubber. A part 44 a of the belt 44 is fixed to the moving body 36. A belt 44 made of a material such as rubber, which is an endless rope, is wound between a pulley 45 fixed to the pulley 43 and a pulley 45 fixed to the pulley 43 and a pulley 46 provided on the support plate 28. The pulley 46 is driven by a servomotor 48 as a drive source and a speed reduction unit 49 having a gear train. Therefore, the belt 47 is driven by the rotation of the servo motor 48, and the belt 44 is driven accordingly, so that the moving body 36 is moved in the X direction.

In order to drive the bed 24 in the Y direction, a driving source 53 including a servomotor 51 and a deceleration means 52 is attached to the moving body 36 as clearly shown in FIG. The pulley 54 is rotationally driven by the speed reduction means 52, and another pulley 55 is provided on the moving body 36, and a belt 56 made of rubber or the like, which is an endless cable, is wound between the pulleys 54 and 55. Can be
A portion 56a of the belt 56 is fixed to the bed 24. By driving the motor 51 in this manner, the belt 56 runs, and accordingly, the bed 24
It is moved in the direction and travels.

The magnetic field measuring means 58 is a superconducting quantum interference magnetometer, and is a living body, for example, a human body.
5 to measure the strength of a weak magnetic field such as a magnetocardiogram. The magnetic field measuring means 58 is provided above the bed 24. The magnetic field measuring means 58 is vertically driven up and down by the lifting drive means 60.

In the lifting / lowering drive means 60, a wooden support 62 erected on the support plate 28 is reinforced by a reinforcing plate 63. The support 62 includes a brass screw rod 64.
Is rotatably supported about a vertical axis by a bearing 65 (see FIG. 8) at a lower portion and a bearing 66 (see FIG. 13) at an upper end portion. A single screw rod 64 extends vertically.
A pair of guide rods 67 are provided on both sides of the screw rod 64 in the Y direction. A holding body 68 is inserted into the guide rod 67 and can be moved up and down.

FIG. 6 is a sectional view showing the vicinity of the lower portion of the screw rod 64, and FIG. 7 is a rear view as seen from behind. Screw rod 64
A pulley 69 is fixed to the lower part of. A pulley 70 is rotatably provided on the support 62 by bearings 71 and 72, and an endless belt 73 made of rubber or the like is wound between the pulley 70 and the above-described pulley 69. . A spur gear 74 is fixed to the pulley 70.

The rotation driving means 75 for driving the gear 74 is detachably mounted on a mounting plate 76 of the support 62 by a bolt 137 having a knob. The mounting plate 76 is fixed to a base 79, and the base 79 is
It is fixed to 8. The rotation drive unit 75 has a gear 80 that meshes with the gear 74, and is driven to rotate around the vertical axis by manual rotation of the handle 82 around the axis 83 via the gear reduction unit 81. The gear 80 may be rotationally driven by a servomotor 110 as shown in FIGS. 12 to 14 as a second embodiment described later.

Referring to FIG. 8, a nut member 84 made of a material such as stainless steel or brass made of a non-magnetic material is screwed into the screw rod 64. Accordingly, when the handle 82 is rotationally driven, the power is transmitted to the screw rod 64 via the gear reduction means 81, the gears 80 and 74, and the belt 73, and the screw rod 64 is rotationally driven around its axis. Accordingly, the nut member 84 moves up and down along the axis of the screw rod 64. Nut member 84
Is fixed to the holder 68.

By making the rotation driving means 75 detachable from the mounting plate 76, when a magnetic field is measured by the magnetic field measuring means 58, an adverse effect of the member made of a ferromagnetic material constituting the rotation driving means 75 is prevented. Measurement accuracy can be improved. The gear reduction unit 81 of the rotation driving unit 75 includes a gear made of a material such as iron, which is a ferromagnetic material. Therefore, the rotation driving means 75 including members such as gears made of such a ferromagnetic material.
When the magnetic flux is measured by the magnetic flux measuring means 58, the bolt 137 is loosened and removed from the mounting plate 76 as described above, so that the intensity of the weak magnetic field generated from the inspection object 25 can be reliably measured. And the measurement error can be reduced.

The gears 74 and 80 are spur gears, so that the gears 74 and 80 can be easily screwed and unfastened when the rotation driving means 75 is attached and detached. When the gear reduction unit 81 is removed from the mounting plate 76, the holding body 68 does not descend by its own weight, and the screw bar 64 does not rotate around its axis. Therefore, the upper and lower positions of the magnetic field measuring means 58 are kept. It should be noted that only a part of the rotation driving means 75 such as a gear made of a ferromagnetic material may be detachable.

FIG. 9 is a partially cutaway sectional view of the magnetic field measuring means 58 and its vicinity as viewed from the front, and FIG. 10 is a sectional view as viewed from the side. The magnetic field measuring means 58 is composed of a superconducting quantum interference magnetometer as described above,
Immerse in. The low temperature oven 87 is fastened by a screw of a connecting rod 92 between a lower support cylinder 89 having a bottom 88 and an upper support cylinder 91 covering a lid 90 of the low temperature oven 87. On both sides of the lower support cylinder 89, the free ends 93a of the pair of support arms 93 are arranged, and around the axis 94a of the shaft 94,
The lower support cylinder 89, and thus the magnetic field measuring means 58,
It can be angularly displaced as shown. The shaft 94 has an external thread 96
And screwed into the screw hole of the lower support cylinder 89. This shaft 94
, A knob 97 is formed. The axes of the pair of shafts 94 intersect perpendicularly with the axis 98 of the magnetic field measuring means 54. By tightening the shaft 94 with the knob 97, the oblique angle position of the arrow 95 can be fixed.

Referring again to FIG. 8, the base end 93b of the support arm 93 is fixed to the base 100.
0 is fixed to the end of a swing shaft 103 having a rotation axis 102 extending horizontally and horizontally, of the angular displacement driving means 101. The swing shaft 103 is supported by the holding body 68 by a bearing 104.

By loosening the screw of the connecting rod 92,
In the upper and lower support cylinders 91, 89, the low temperature constant temperature chamber 87, and thus the magnetic field measuring means 58, can be angularly displaced around its axis 98 as indicated by the arrow 106 in FIG.

FIG. 11 is a rear view of the angular displacement driving means 101. The mounting plate 107 is provided with gear reduction means 121 detachably by bolts 137, and a handle 122 which is manually driven to rotate. This handle 122
, The output shaft 123 of the gear reduction means 121 is rotated, and the output shaft 123 is connected to the swing shaft 103 by a detachable shaft joint 124, whereby the swing shaft 103 is swung to change the angular displacement. Is done. At the time of magnetic field measurement, the bolt 137 is loosened and the gear reduction means 121 is removed, and at this time, the shaft coupling 124 is detached, so that the measurement accuracy of the gear reduction means 121 due to the ferromagnetic material is prevented from lowering.

The axis 102 of the oscillating shaft 103 corresponds to the shaft 9 supporting the magnetic field measuring means 58 of the free end 93a of the support arm 93.
4 is higher than the axis 94a. Thus, the height of the ceiling of the room in which the present magnetic field measuring apparatus having the vertically elongated magnetic field measuring means 58 and the low temperature constant temperature chamber 87 is installed does not need to be increased unnecessarily, and the holding body 68, and therefore the low temperature constant temperature chamber, is not required. 87 and the magnetic field measuring means 58 can be displaced upward. Furthermore, it is possible to easily perform an operation of removing the lid 90 and supplying a cryogenic gas such as liquid helium into the low temperature constant temperature chamber 87 by removing the lid 90.

Further, the magnetic field measuring means 58 is displaced sufficiently downward to come close to the device under test 25, so that the measurement of a weak magnetic field can be performed with high accuracy. Furthermore,
The space 127 (see FIG. 1) between the magnetic field detecting means 58 and the holder 68 is made sufficiently large, and the bed 24 is moved to the vicinity of the support 62, and the object 25 on the bed 24 is spread over a wide range. Of the magnetic field can be measured.

In order to prevent the magnetic field measuring means 58 from being adversely affected by the ferromagnetic material, the support plate 28, the moving body 36, the bed 24
The support 62 and the like are made of wood, and the other members are made of a non-magnetic material such as aluminum, brass, rubber and leather.

FIG. 12 is a plan view of the lifting / lowering driving means 60a according to another embodiment of the present invention, and FIG.
FIG. 14 is a rear view of FIG.
13 is a left side view of FIG. Referring to these drawings, in lifting drive unit 60a, base 108 is detachably provided on mounting plate 107 fixed to holding body 68 by manually operated bolt 109. On this base 108, a servomotor 110 is fixed. The pulley 111 is driven by the servomotor 110.
A pulley 113 is fixed to an input shaft of the gear reduction unit 112. A belt 114 made of a nonmagnetic material such as endless rubber is wound around the pulleys 111 and 113. A handle 116 for manual operation is attached to the input shaft 115 of the gear reduction unit 112. The output gear 80 is rotated by the gear reduction means 112, and the screw bar 64 is rotated.

As another embodiment of the present invention, the magnetic field measuring means 58 may have another configuration instead of the superconducting quantum interference magnetometer.

Referring again to FIGS. 2 and 4, in order to cut off vibration from the floor 22 to the magnetic field measuring device 21,
In the vibration isolator 23 provided on the upper part 2, a storage container 130 made of a transparent material such as a synthetic resin and opened upward is
A powder 131 made of many hard non-magnetic materials is stored. The powder 131 has an irregular shape and is made of, for example, marble or glass, and is manufactured by being crushed. The thickness d1 of the layer filled with the powder 131 is:
It is about 3 cm or more, and desirably 5 cm or more. If it is less than 3 cm, the vibration-proof effect is low. The particle size of the granular material 131 has a particle size distribution in the range of 0.5 to 5.0 mmφ,
For example, (a) 25% by weight of a granular material having a particle size of 0.5 mmφ or more and less than 1.0 mmφ, (b) 1.0 mmφ
As described above, 25% by weight of a granular material having a diameter of less than 2.0 mmφ, (c)
It is configured to include 25 parts by weight of a granular material having a diameter of 2.0 mmφ or more and less than 3.0 mmφ and (d) 25% by weight of a granular material having a diameter of 3.0 mmφ or more and less than 5.0 mmφ. In this manner, the resonance frequency can be sufficiently lowered or the resonance frequency can be made zero because not only the shape is irregular but also the particle size distribution is wide. Therefore, the direct current generated from the inspection object 25 which is a human body ~ 2
A magnetic field having a frequency component of 00 Hz, particularly less than 40 Hz, can be measured with high accuracy, and the measurement of the magnetic field of such a frequency component does not include an error caused by vibration from a floor or the like. Becomes possible. Further, such a granular material 131 does not contain iron powder or the like, and therefore does not adversely affect the magnetic field measuring means 58. According to the particles 131 having such irregular shapes, the particles 131 are displaced as indicated by arrows in FIG.
2 is prevented from being transmitted to the receiving plate 26.

FIG. 16 is a sectional view showing a specific configuration of the damper 27 with a part thereof cut away. This damper 27
Is interposed between the support plate 28 and the receiving plate 26. The upper and lower ends of the straight cylindrical body 132 are
134, the air chamber 1
35 are formed. An aperture 136 such as an oil fiss is formed on the upper flange 133. This upper flange 13
3, a holding member 138 is mounted via an O-ring 137, and an elevating member 140 is disposed on the holding member 138 via a diaphragm 139. The periphery of the diaphragm 139 is air-tightly fixed to an outer cylinder 142 fixed to the outer peripheral portion of the holding member 138 by bolts 141, and the diaphragm chamber 143 has a gas passage hole 144 formed in the holding member 138. The orifice communicates with the air chamber 135 from the throttle 136 as an orifice. The throttle 136 provided in the damper 27 is useful for suppressing the fluctuation of the air pressure in the diaphragm chamber 143 as much as possible. The diaphragm 139 is made of an elastic material such as rubber, for example, and the other components 132, 133, 134, 138, 140, and 14 are provided.
1,142 may be made of engineering plastics such as polycarbonate, polyacetal, nylon 66 and polyimide, may be made of a material such as fiber reinforced plastic (abbreviated as FRP), or may be made of a material such as rubber. And other non-metallic materials. A positioning projection 145 is provided upright on the elevating member 140, and the projection 145 is
8, the relative displacement between the lifting member 140 and the support plate 28 is prevented. The protrusion 145 is also made of a non-metallic material as described above. Lifting member 14
The guide tube portion 146 formed in the cylindrical member 142 partially fits outside the tube member 142, whereby the elevating member 140 and the tube member
2, thus holding member 138 and upper flange 133
The displacement in the horizontal plane is prevented, and only vertical displacement is allowed.

FIG. 17 is a diagram showing the position of the damper 27 disposed below the support plate 28. As shown in FIG. The support plate 28 is divided into a plurality of (two in this embodiment) support plate portions 28a and 28b having the same size and shape to facilitate transportation, and each of the support plate portions 28a and 28b is provided in this embodiment. In this case, a total of six dampers 27 are arranged. The dampers 27 are grouped and connected to the air pressure source 148 via the pressure control valve 147 for each group. The air pressure source 148 is, for example, 3.5 kgG /
cm ² . The pressure control valve 147 is connected to the support plate 2
The secondary pressure is controlled so that 8 is kept at the same position in the vertical direction, and is always kept horizontal.

As another embodiment of the present invention, the pressure control valve 1
47 responds to a detecting means for detecting the vertical position of the support plate 28 and whether or not it is horizontal, and controls the plurality of pressure control valves 147 so that the support plate 28 is always kept horizontal at the same vertical position. It may be configured to operate to change the secondary pressure.

FIG. 18A is a graph showing an experimental result of one embodiment of the present invention. It is understood that the use of the damper 27 suppresses vibration transmitted from the receiving plate 26 to the support plate 28 over a wide frequency range. On the other hand, FIG. 18B shows an experimental result when the support plate 28 is placed on the receiving plate 26 without the interposition of the damper 27. In this comparative example, a large vibration from the receiving plate 26 is transmitted to the supporting plate 28 as it is. As described above, according to the present invention, it is understood that the use of the damper 27 can suppress the vibration particularly in the range of DC to 200 Hz.

FIG. 19A shows an output waveform of the magnetic field measuring means 58 which is a superconducting quantum interference device due to the vibration of the floor 22 in the experiment of the present inventor. The floor 22 contains white noise over a wide frequency range. In this state, the receiving plate 26 is placed directly on the floor 22 and the receiving plate 26
When the damper 27 is interposed between the magnetic field measuring means 58 and the supporting plate 28 and the magnetic field measuring means 58 moves horizontally, the output waveform obtained from the magnetic field measuring means 58 includes It is confirmed that there is almost no adverse effect of vibration due to the vibration. On the other hand, in the comparative example in which the damper 27 is omitted in the above-described configuration, as shown in FIG. 19C, when the magnetic field measuring means 58 is moved horizontally, the output of the magnetic field measuring means 58 is: It was confirmed that a large waveform disturbance was caused by the horizontal movement, and the measurement accuracy was deteriorated. Therefore, it is understood that the damper 27 is indispensable for measuring the biomagnetic field with high accuracy.

As still another embodiment of the present invention, the vibration isolator 23 may be omitted and the damper 27 may be directly mounted on the floor 22.

In the above embodiment, the damper 27 is an air damper using air pressure. However, other gas such as N2 may be used instead of such air, or hydraulic oil may be used instead of gas. There may be.

[0049]

According to the present invention, the support plate for supporting the superconducting quantum interference fluxmeter and the bed on which the object is placed is held by the damper, so that the vibration-proof effect can be achieved well. Since this damper is made of a nonmetal, it is possible to suppress a measurement error of the superconducting quantum interference magnetometer.

In particular, since the damper is made of non-metal as described above, such a damper can be installed near the superconducting quantum interference magnetometer, and therefore, the size of the entire device including the support plate can be reduced. It is possible to reduce the installation area of the apparatus. Further, since the damper is made of a non-metal as described above, it is not necessary to install the damper away from the superconducting quantum interference magnetometer, and therefore, the distance between the plurality of dampers supporting the support plate, that is, the span is shortened. This can prevent vibration due to deflection of the support plate. Furthermore, by using this damper, even if the superconducting quantum interference magnetometer moves horizontally or vertically, the movement does not cause a measurement error of the superconducting quantum interference magnetometer, so that the superconducting quantum interference magnetometer is moved. Highly accurate measurement can be performed.

According to the present invention, by using the vibration isolator, the transmission of vibration from the floor to the object to be damped can be sufficiently blocked, and the granular material can be prevented from being transmitted. Even if the object made of non-magnetic material and thus to be damped is a highly sensitive superconducting quantum interference magnetometer,
There is no adverse effect such as lowering the accuracy of the magnetic field to be measured.

According to the present invention, the compressed air from the air pressure source 148 is supplied from the air chamber 135 in the cylinder 132 to the throttle 13.
6, through the diaphragm chamber 14 in the diaphragm 139.
3, the pressure in the diaphragm chamber 143 can be kept stable by the resistance of the throttle 136, and the support plate 28 can be kept stable.

A pressure control valve 147 is provided for each of a plurality of groups of dampers. Each pressure control valve 1 is controlled so that the support plate 28 detected by the detecting means is horizontal.
Since the operating plate 47 is operated and controlled, the support plate 28 is always kept horizontal, so that the biomagnetic field can be measured with higher accuracy.

[Brief description of the drawings]

FIG. 1 is a perspective view of one embodiment of the present invention.

FIG. 2 is a side view of the embodiment.

FIG. 3 is a plan view of the embodiment.

FIG. 4 is a front view of the embodiment.

FIG. 5 is a side view of the vicinity of a driving source 53.

FIG. 6 is a cross-sectional view of the vicinity of the lifting drive means 60.

FIG. 7 is a rear view of the vicinity of the elevation driving means 60.

FIG. 8 is a sectional view of the angular displacement driving means 101.

FIG. 9 is a sectional view of the vicinity of the magnetic field measuring means 58 as viewed from the front.

FIG. 10 is a cross-sectional view of the vicinity of the magnetic field measuring means 58 as viewed from the side.

11 is a rear view of the angular displacement driving unit 101. FIG.

FIG. 12 is a plan view of a lifting drive means 60a according to another embodiment of the present invention.

FIG. 13 is a rear view of the lifting drive means 60a.

FIG. 14 is a left side view of the elevation drive means 60a.

FIG. 15 is an enlarged view showing a granular material 131;

FIG. 16 is a cross-sectional view showing a damper 27 with a part cut away.

FIG. 17 is a plan view showing an arrangement of a damper 27.

FIG. 18 is a graph showing experimental results of the present inventor.

FIG. 19 is a graph showing another experimental result of the present inventor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 Magnetic field measuring device 22 Floor 23 Vibration isolator 24 Bed 25 Inspection object 26 Receiving plate 27 Damper 28 Supporting plate 36 Moving body 48, 51 Motor 58 Magnetic field measuring means 64 Screw rod 67 Guide rod 68 Holder 75 Rotation driving means 93 Support Arm 101 angular displacement driving means 131 powder

Claims (5)

[Claims] 1. A superconducting quantum interference magnetometer, a bed on which an object to be inspected is to be measured by the superconducting quantum interference magnetometer, a support plate supporting the superconducting quantum interference magnetometer and the bed, A biomagnetic field measuring apparatus, comprising: a non-metallic damper provided at a lower portion of the plate. 2. A granule made of a large number of hard non-magnetic materials having irregular shapes provided on a floor is provided in a storage container, a receiving plate is provided on the granule, and a granule is provided on the granule. The biomagnetic field measuring apparatus according to claim 1, further comprising a vibration isolator provided with a lower portion of the damper. 3. The biomagnetic field measuring apparatus according to claim 2, wherein the granular material has a particle size distribution in a range of a particle size of 0.5 to 5.0 mmφ. 4. A plurality of dampers are arranged, each of which is provided on a receiving plate 36 and extends vertically, a holding member 138 mounted on the cylinder 132, and a holding member 138. A diaphragm 139 having a peripheral edge fixed thereon in an air-tight manner and on which the support plate 28 is mounted, an air chamber 135 in the cylindrical body 132, and a diaphragm 136 interposed between the diaphragm chamber 143 in the diaphragm 139.
The biomagnetic field measuring apparatus according to any one of claims 1 to 3, further comprising an air pressure source 148 that supplies compressed air to each of the air chambers 135. 5. The dampers are grouped into a plurality of groups, a plurality of pressure control valves 147 interposed between the air pressure source 148 and the air chamber 135 are provided for each group, and the support plate 28 is horizontally 5. The living body according to claim 4, further comprising: detecting means for detecting whether or not the detecting means is in operation, and control means for operating each pressure control valve 147 in response to an output of the detecting means to keep the support plate 28 horizontal. Magnetic field measuring device.