JP2013217690A - Magnetic field correction device and magnetic field measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce influences by a magnetic field in respective areas of a plurality of cells.SOLUTION: A plurality of cells 11 are provided with correction coil bodies 13 respectively. A current supply part supplies the correction coil bodies 13 with current. A controller measures magnetic fields in the respective areas of the plurality of cells 11 by using a cell array 10 and controls supply of the current by the current supply part so that an AC magnetic field which cancels the magnetic fields measured is generated by the plurality of correction coil bodies 13.

Description

  The present invention relates to a technique for correcting a magnetic field.

  When measuring a weak magnetic field generated by a living body using a magnetic sensor, a magnetic shield is used to reduce the influence of an external magnetic field. For example, Patent Document 1 describes a magnetic shield that is provided between an outer wall and an inner wall of a magnetic shielding chamber and in which three sets of coils are arranged in three axial directions. Patent Document 2 describes a magnetic shielding device that is provided so as to cover a shield room and in which three sets of coils are arranged in three axial directions. Patent Document 3 describes a technique for controlling a magnetic field distribution in a target space for each region in a magnetic shield in which a coil is arranged in each region obtained by dividing the inner surface of the target space.

JP 2002-232182 A Japanese Patent No. 2864095 JP 2011-82444 A

In an optical pumping type magnetic sensor, a plurality of small cells may be used. In the techniques described in Patent Documents 1 to 3, the magnetic field distribution in a wide space such as a room can be improved, but the magnetic field in a minute region of each cell cannot be made completely uniform.
An object of the present invention is to reduce the influence of a magnetic field in each region of a plurality of cells.

A magnetic field correction apparatus according to the present invention includes a plurality of coil bodies provided in each of a single cell or adjacent cells with respect to a plurality of cells in which atoms that are spin-polarized by being excited by light are enclosed, and the plurality of coil bodies A current supply unit that supplies current to the coil body and a magnetic sensor to measure a magnetic field in each region of the plurality of cells, and an alternating magnetic field that cancels the measured magnetic field is generated from the plurality of coil bodies. And a control unit that controls supply of current by the current supply unit.
According to this configuration, the influence of the magnetic field in each region of the plurality of cells can be reduced.

Each of the plurality of coil bodies includes a pair of first coils disposed on a first axis across the single cell, and a second crossing the first axis across the single cell. A pair of second coils arranged on the axis of the first and a pair of third coils arranged on a third axis intersecting the first axis and the second axis across the single cell You may have a coil.
According to this configuration, the three-axis component of the magnetic field in each region of the plurality of cells can be canceled out.

The plurality of cells are two-dimensionally arranged, and the magnetic field measurement apparatus includes a plurality of partition plates formed of a material having a magnetic permeability higher than a threshold value and provided between adjacent cells in the plurality of cells. May be.
According to this structure, the process which reduces the influence of a magnetic field can be performed in a short time.

The control unit measures the magnetic fields in the regions of the plurality of cells at a time, and supplies current to the plurality of coil bodies provided in the plurality of cells such that an alternating magnetic field that cancels the measured magnetic fields is generated. May be.
According to this structure, the influence of the magnetic field generated from the coil body of the adjacent cell can be corrected.

The plurality of cells are two-dimensionally arranged, and the control unit sequentially selects the plurality of cells one by one, measures the magnetic field in the region of the selected cells, and cancels the measured magnetic field. A current that causes the generation of the current may be supplied to the coil body provided in the selected cell.
According to this structure, the influence of the magnetic field generated from the coil body of the adjacent cell can be corrected.

The plurality of cells are arranged in a matrix, and the control unit sequentially selects the plurality of cells one by one or one row, measures a magnetic field in a region of the selected cell, and determines the measured magnetic field. A current that generates a magnetic field to be canceled may be supplied to the coil body provided in the selected cell.
According to this configuration, it is possible to suppress magnetic field interference between adjacent cells.

The magnetic field measurement device according to the present invention includes the magnetic field correction device, a plurality of cells in which atoms that are spin-polarized and excited by light are enclosed, an irradiation unit that irradiates the plurality of cells with light, and the plurality of cells A detection unit that detects a rotation angle of a polarization plane of the light transmitted through the cell, and the control unit detects a magnetic field of each region of the plurality of cells based on the rotation angle detected by the detection unit. Is measured.
According to this configuration, the magnetic field measurement accuracy can be improved.

Diagram showing the configuration of the magnetic field measurement device Block diagram showing the configuration of the control device Plan view of cell array Cell perspective view Flow chart showing magnetic field correction processing Diagram showing correction table The figure which shows ID allocated to the cell which concerns on a modification Front view of first cell array and second cell array according to modification The perspective view of the 1st cell which concerns on a modification, and a 2nd cell

  FIG. 1 is a diagram illustrating a configuration of a magnetic field measurement apparatus 1 according to the embodiment. The magnetic field measuring apparatus 1 is an optical pumping type magnetic sensor that measures a magnetic field generated by a living body. The magnetic field measuring apparatus 1 is used, for example, in a magnetocardiograph that measures a magnetic field (magnetomagnetic field) generated from the heart or a magnetoencephalometer that measures a magnetic field (magnetomagnetic field) generated from the brain.

  The magnetic field measurement apparatus 1 includes a cell array 10, a pump light irradiation unit 20, a probe light irradiation unit 30 (an example of an irradiation unit), a detection unit 40, a control device 50 (an example of a control unit), and a current supply unit 60. With. The cell array 10 includes a plurality of cells 11. The cell 11 is a cubic container formed of a light-transmitting material such as glass. An atom is enclosed in the cell 11. An atom is an alkali metal atom (cesium etc.), for example.

  The pump light irradiation unit 20 irradiates each cell 11 with pump light L1 having a circularly polarized component. When the pump light L1 is irradiated, the outermost electrons of the atoms in the cell 11 are excited and spin polarization occurs. Spin-polarized atoms precess by a magnetic field. The probe light irradiation unit 30 irradiates each cell 11 with probe light L2 having a linearly polarized light component. At this time, the probe light irradiation unit 30 irradiates the probe light L2 so as to be orthogonal to the pump light L1. The plane of polarization of the probe light L2 is rotated by atoms in the cell 11 when passing through the cell 11 (Faraday effect). The rotation angle of this polarization plane becomes a magnitude according to the magnetic field. The probe light L2 that has passed through the cell 11 is incident on the detection unit 40. The detection unit 40 detects the rotation angle of the polarization plane of the incident probe light L2.

  FIG. 2 is a block diagram illustrating a configuration of the control device 50. The control device 50 includes a CPU (Central Processing Unit) 51, a memory 52, an operation unit 53, and a display unit 54. The CPU 51 controls each unit of the magnetic field measurement apparatus 1 by executing a program stored in the memory 52. Further, the CPU 51 calculates the magnitude of the magnetic field based on the rotation angle detected by the detection unit 40. Thereby, the magnetic field is measured. The operation unit 53 includes a keyboard and a mouse, for example. The operation unit 53 is used for operation of the magnetic field measurement apparatus 1. The display unit 54 is a liquid crystal display, for example. The display unit 54 displays magnetic field measurement results under the control of the CPU 51.

  FIG. 3 is a plan view of the cell array 10. The cell array 10 includes 25 cells 11 arranged in a matrix of 5 rows and 5 columns. Between adjacent cells 11, a partition plate 12 made of a material with high magnetic permeability is provided. The “high magnetic permeability” means that the magnetic permeability is higher than a threshold value.

  FIG. 4 is a perspective view of the cell 11. The x axis (an example of the first axis), the y axis (an example of the second axis), and the z axis (an example of the third axis) illustrated in FIG. 4 are orthogonal to each other. All the cells 11 included in the cell array 10 have the same configuration. The cell 11 is provided with a correction coil body 13 (an example of a coil body). The correction coil body 13 includes an x-axis correction coil 14 (an example of a first coil 14), a y-axis correction coil 15 (an example of a second coil 14), and a z-axis correction coil 16 (a third coil 15). Example).

  The x-axis correction coil 14 includes a pair of first coil 14h and second coil 14i. The first coil 14h and the second coil 14i are disposed on the x-axis with the cell 11 interposed therebetween. The first coil 14h and the second coil 14i are provided so that their coil surfaces are parallel to each other. The y-axis correction coil 15 includes a pair of third coil 15h and fourth coil 15i. The third coil 15h and the fourth coil 15i are arranged on the y axis with the cell 11 in between. The third coil 15h and the fourth coil 15i are provided such that their coil surfaces are parallel to each other. The z-axis correction coil 16 includes a pair of fifth coil 16h and sixth coil 16i. The fifth coil 16h and the sixth coil 16i are arranged on the z-axis with the cell 11 in between. The fifth coil 16h and the sixth coil 16i are provided so that their coil surfaces are parallel to each other. Each of the first coil 14h to the sixth coil 16i has a hollow rectangular shape. The pump light L1 and the probe light L2 are irradiated to the cell 11 through any one of the hollow portions of the first coil 14h to the sixth coil 16i.

  The magnetic field measuring device 1 is disposed in the magnetic shield 2. The magnetic shield 2 is made of a magnetic material, and suppresses intrusion of a magnetic field from the outside. However, even if the magnetic shield 2 is provided, a magnetic field from the outside may enter the magnetic shield 2 depending on the performance of the magnetic shield 2 and the magnetic field environment. In the following description, a magnetic field that has entered the magnetic shield 2 from the outside is referred to as an “intrusive magnetic field”. If an intruding magnetic field exists, the magnetic field in the region of the cell array 10 becomes non-uniform, and the magnetic field measurement accuracy of the magnetic field measuring apparatus 1 is deteriorated.

  The current supply unit 60 supplies a current to the correction coil body 13 under the control of the control device 50 to generate a cancel magnetic field that cancels the intrusion magnetic field. Specifically, the current supply unit 60 supplies a current in the same direction to the first coil 14h and the second coil 14i, and generates a cancel magnetic field that cancels the x-axis component of the intrusion magnetic field. The current supply unit 60 supplies current in the same direction to the third coil 15h and the fourth coil 15i, and generates a cancel magnetic field that cancels the y-axis component of the intrusion magnetic field. The current supply unit 60 supplies a current in the same direction to the fifth coil 16h and the sixth coil 16i, and generates a cancel magnetic field that cancels the z-axis component of the intrusion magnetic field.

  FIG. 5 is a flowchart showing magnetic field correction processing. This process is performed before the magnetic field of the living body is measured using the magnetic field measuring apparatus 1. When this processing is performed, the cell array 10 is placed in a magnetic field environment within the magnetic shield 2. The operator uses the operation unit 53 to perform an operation for instructing execution of an operation for correcting the intrusion magnetic field. When this operation is performed, the controller 50 uses the cell array 10 to measure the intrusion magnetic field in each region of the plurality of cells 11 (step S11).

  Specifically, the control device 50 controls the pump light irradiation unit 20 to irradiate each cell 11 with the pump light L1 to spin-polarize the atoms. The control device 50 controls the probe light irradiation unit 30 to irradiate each cell 11 with the probe light L2 so as to be orthogonal to the pump light L1. When the probe light L2 is irradiated from the probe light irradiation unit 30, the detection unit 40 detects the rotation angle of the polarization plane of the probe light L2 that has passed through each cell 11. The control device 50 calculates the magnitude of the intrusion magnetic field in the area of each cell 11 based on the rotation angle detected by the detection unit 40. Thereby, the penetration magnetic field in the area of each cell 11 is measured.

  The control device 50 calculates a cancel magnetic field that cancels the intrusion magnetic field in the area of each cell 11 based on the intrusion magnetic field measured in step S11 (step S12). This canceling magnetic field is an alternating magnetic field having the same magnitude as the intrusion magnetic field and in the reverse direction. The control device 50 stores the calculated canceling magnetic field in the correction table T for each cell 11 and stores it in the memory 52.

  FIG. 6 is a diagram showing the correction table T. Numbers 1 to 25 are assigned in advance as IDs to the plurality of cells 11 included in the cell array 10. In the correction table T, the ID of the cell 11 and the cancel magnetic field are stored in association with each other. For example, when the cancel magnetic field M1 is calculated for the area of the cell 11 with ID “1”, the ID “1” and the cancel magnetic field M1 are stored in association with each other.

  The control device 50 supplies current to the correction coil body 13 of each cell 11 from the current supply unit 60 based on the cancel magnetic field calculated in step S12 (step S13). For example, in the correction table T shown in FIG. 6, ID “1” is associated with the cancel magnetic field M1. In this case, the control device 50 controls the current supply unit 60 to supply the correction coil body 13 of the cell 11 with ID “1” with a current for generating the cancel magnetic field M1. Similarly, the control device 50 controls the current supply unit 60 for the correction coil bodies 13 provided in the other cells 11 to supply a current for generating a canceling magnetic field.

  When a current is supplied from the current supply unit 60, the correction coil body 13 of each cell 11 generates a cancel magnetic field. Thereby, the penetration magnetic field in the area of each cell 11 is canceled. Note that “cancel” means that the penetration magnetic field becomes a value within a range that can be regarded as zero. This range is, for example, a range of ± several nanotesla (nT) centered on 0.

  Moreover, as shown in FIG. 3, between the adjacent cells 11, the partition plate 12 formed with the material with high magnetic permeability is provided. Thereby, when the correction | amendment coil body 13 of each cell 11 generate | occur | produces a cancellation magnetic field, the interference of the magnetic field between the adjacent cells 11 can be suppressed.

  In the present embodiment, the correction coil body 13, the current supply unit 60, and the control device 50 cooperate to function as a magnetic field correction device. In this embodiment, since the correction coil body 13 is provided in each cell 11, the influence of the intrusion magnetic field in each region of the plurality of cells 11 can be reduced. Thereby, the measurement precision of the magnetic field of the magnetic field measuring apparatus 1 can be improved. Moreover, in this embodiment, since the penetration | invasion magnetic field of each area | region of the several cell 11 is measured at once, the magnetic field correction process can be performed in a short time.

  The present invention is not limited to the above-described embodiment, and may be modified as follows. Further, the following modifications may be combined with each other.

(1) Modification 1
In the embodiment described above, the magnetic field correction processing is performed on all the cells 11 included in the cell array 10 together. However, this correction processing may be performed for each single cell 11 or each of the plurality of cells 11.

  FIG. 7 is a diagram showing IDs assigned to the cells 11 according to this modification. Numbers 1 to 5 are assigned to the cells 11 in the first column in order from the top as IDs. Numbers 6 to 10 are assigned to the cells 11 in the second column in order from the top as IDs. Similarly, the numbers 11 to 25 are assigned as IDs to the cells 11 in the third to fifth columns.

  For example, the magnetic field correction process may be performed for each cell 11. At this time, the control device 50 sequentially selects the plurality of cells 11 included in the cell array 10 one by one. This order may be, for example, from the smallest ID number to the largest order. When the cell 11 is selected by the control device 50, the processes of steps S11 to S13 described above are performed for the selected cell 11. Here, it is assumed that the cells 11 are selected in ascending order of ID numbers. In this case, first, the cell 11 with ID “1” is selected, the intrusion magnetic field in the area of the cell 11 with ID “1” is measured (step S11), and the canceling magnetic field of this intrusion magnetic field is calculated (step S12). A current is supplied to the correction coil body 13 of the cell 11 of “1” (step S13). Next, the cell 11 with ID “2” is selected, the intrusion magnetic field in the area of the cell 11 with ID “2” is measured (step S11), and the canceling magnetic field of this intrusion magnetic field is calculated (step S12). A current is supplied to the correction coil body 13 of the cell 11 of “2” (step S13). The same processing is performed in order for the cells 11 with IDs “3” to “25”. Further, this process may be repeated until the magnetic fields in all the cell 11 regions become values within a range that can be regarded as zero.

  As shown in FIG. 7, since the cell 11 with ID “1” and the cell 11 with ID “2” are adjacent to each other, the cell 11 with ID “2” is the correction coil body of the cell 11 with ID “1”. 13 is affected by a canceling magnetic field generated from 13. However, in this modification, the magnetic field in the region of the cell 11 with ID “2” is corrected after the magnetic field in the region of the cell 11 with ID “1” is corrected. Therefore, for the cell 11 with ID “2”, an intrusion magnetic field affected by the cancel magnetic field generated from the correction coil body 13 of the cell 11 with ID “1” is measured, and a cancel magnetic field that cancels this intrusion magnetic field is calculated. The Therefore, when the magnetic field in the region of the cell 11 with ID “2” is corrected, the influence of the magnetic field generated from the correction coil body 13 of the cell 11 with ID “1” adjacent to the cell 11 can also be corrected.

  Further, the magnetic field correction process may be performed for each column or for each row. At this time, the control device 50 selects the plurality of cells 11 in order of one column or one row. This order may be, for example, the order close to the left end, right end, upper end, or lower end in FIG. When the cell 11 is selected by the control device 50, the processes of steps S11 to S13 described above are performed for the selected cell 11. Here, it is assumed that the cells 11 are selected one by one in order from the left end in FIG. In this case, first, the cell 11 in the first column is selected, the intrusion magnetic field in the area of the cell 11 in the first column is measured (step S11), and the canceling magnetic field of this intrusion magnetic field is calculated (step S12). A current is supplied to the correction coil body 13 of the cell 11 (step S13). Next, the cell 11 in the second column is selected, the intrusion magnetic field in the area of the cell 11 in the second column is measured (step S11), and the cancellation magnetic field of this intrusion magnetic field is calculated (step S12). A current is supplied to the correction coil body 13 of the cell 11 (step S13). The same processing is performed in order for the cells 11 in the third column to the fifth column. Further, this process may be repeated until the magnetic fields in all the cell 11 regions become values within a range that can be regarded as zero.

  As shown in FIG. 7, since the cell 11 in the first column and the cell 11 in the second column are adjacent to each other in the x-axis direction, the cell 11 in the second column is the correction coil body of the cell 11 in the first column. 13 is affected by a canceling magnetic field generated from 13. However, in this modification, the magnetic field in the region of the cells 11 in the second column is corrected after the magnetic field in the region of the cells 11 in the first column is corrected. Therefore, for the cells 11 in the second row, an intrusion magnetic field affected by the cancel magnetic field generated from the correction coil body 13 of the cell 11 in the first row is measured, and a cancel magnetic field for canceling out the intrusion magnetic field is calculated. Therefore, when the magnetic field in the region of the cells 11 in the second column is corrected, the influence of the magnetic field generated from the correction coil bodies 13 in the cells 11 in the adjacent first column can also be corrected.

(2) Modification 2
The magnetic field measurement apparatus 1 may have a gradiometer type configuration. For example, when a primary gradiometer-type configuration is provided, the magnetic field measurement apparatus 1 includes a first cell array 10A and a second cell array 10B.

  FIG. 8 is a front view of the first cell array 10A and the second cell array 10B according to this modification. The first cell array 10A and the second cell array 10B are arranged so as to overlap in the z-axis direction. The first cell array 10A includes a plurality of first cells 11A. The second cell array 10B includes a plurality of second cells 11B. The configuration of the first cell 11A and the second cell 11B is the same as that of the cell 11 described in the above-described embodiment. In this gradiometer type configuration, the influence of the environmental magnetic field can be removed by taking the difference between the measurement results in the first cell array 10A and the second cell array 10B.

  FIG. 9 is a perspective view of the first cell 11A and the second cell 11B according to this modification. In the gradiometer type configuration, since the distance between the first cell 11A and the second cell 11 adjacent in the z-axis direction is small, in the region of the first cell 11A and the region of the second cell 11B, It can be considered that the magnitude of the invading magnetic field is the same. Therefore, in this modification, one correction coil body 13A is provided for the first cell 11A and the second cell 11B. That is, in this modification, one correction coil body 13A is provided for the first cell 11A and the second cell 11B adjacent in the z-axis direction. The correction coil body 13A includes a first x-axis correction coil 17A, a second x-axis correction coil 17B, a first y-axis correction coil 18A, a second y-axis correction coil 18B, and a z-axis correction. A coil 19.

  The first x-axis correction coil 17A is composed of a pair of first coil 17h and second coil 17i. The first coil 17h and the second coil 17i are arranged on the x-axis with the first cell 11A interposed therebetween. The second x-axis correction coil 17B is composed of a pair of first coil 17j and second coil 17k. The first coil 17j and the second coil 17k are disposed on the x-axis with the second cell 11B interposed therebetween.

  The first y-axis correction coil 18A is composed of a pair of a third coil 18h and a fourth coil 18i. The third coil 18h and the fourth coil 18i are arranged on the y-axis with the first cell 11A interposed therebetween. The second y-axis correction coil 18B is composed of a pair of third coil 18j and fourth coil 18k. The third coil 18j and the fourth coil 18k are arranged on the y-axis with the second cell 11B interposed therebetween.

  The z-axis correction coil 19 includes a pair of fifth coil 19h and sixth coil 19i. The fifth coil 19h and the sixth coil 19i are arranged on the z-axis with the first cell 11A and the second cell 11B interposed therebetween. No coil is provided between the first cell 11A and the second cell 11B. Thereby, it can suppress that a magnetic field interferes between the cells 11 adjacent in az-axis direction. Note that FIG. 9 illustrates a configuration in which no coil is provided between the first cell 11A and the second cell 11B, but between the first cell 11A and the second cell 11B. A coil may be provided. In this case, magnetic field interference can be suppressed by ensuring a sufficient distance between the first cell 11A and the second cell 11B.

  When a gradiometer type configuration is employed, the magnetic field correction process may be performed for each cell array. At this time, the control apparatus 50 selects the cell array 10 in the order arrange | positioned near a biological body, when measuring the magnetic field of a biological body. In the example of FIG. 8, first the first cell array 10A is selected, and then the second cell array 10B is selected. When the cell array 10 is selected by the control device 50, the processes of steps S11 to S13 are performed on the selected cell array 10 in the same manner as the first modification described above.

  As shown in FIG. 8, since the first cell array 10A and the second cell array 10B are adjacent to each other in the z-axis direction, the second cell array 10B is generated from the correction coil body 13 of the first cell array 10A. Canceled by magnetic field. However, in this modification, the magnetic field in the region of the second cell array 10B is corrected after the magnetic field in the region of the first cell array 10A is corrected. Therefore, for the second cell array 10B, an intrusion magnetic field affected by the cancel magnetic field generated from the correction coil body 13 of the first cell array 10A is measured, and a cancel magnetic field for canceling out this intrusion magnetic field is calculated. Therefore, when the magnetic field in the region of the second cell array 10B is corrected, the influence of the magnetic field generated from the correction coil body 13 of the adjacent first cell array 10A can also be corrected.

(3) Modification 3
The correction coil body 13 is not limited to the one that corrects the three-axis component of the intrusion magnetic field. The correction coil body 13 may correct only the biaxial component or the uniaxial component of the intrusion magnetic field. For example, when only the z component of the intrusion magnetic field is corrected, the correction coil body 13 is composed of only the z-axis correction coil 16.
The shape of the correction coil body 13 is not limited to the cubic shape shown in FIG. For example, the correction coil body 13 may have a rectangular parallelepiped or spherical shape.
The shape of the first coil 14h to the sixth coil 16i is not limited to a rectangle. For example, the first coil 14h to the sixth coil 16i may have a shape such as a circle, an ellipse, or a polygon.

(4) Modification 4
In the above-described embodiment, the cell array 10 is used as a magnetic sensor that measures the intrusion magnetic field in each region of the plurality of cells 11. However, this magnetic sensor is not limited to the cell array 10. For example, the penetration magnetic field of each region of the plurality of cells 11 may be measured using a fluxgate magnetometer. In this case, a fluxgate magnetometer is provided in the vicinity of the plurality of cells 11.

(5) Modification 5
The magnetic field measurement apparatus 1 may measure the x-axis component, the y-axis component, and the z-axis component of the penetration magnetic field in the area of each cell 11. In this case, the pump light L1 and the probe light L2 are each irradiated from three axial directions.
The magnetic field measurement apparatus 1 is not limited to a two-beam magnetic sensor using the pump light L1 and the probe light L2. For example, the magnetic field measuring apparatus 1 may be a one-beam magnetic sensor that uses a single light as both pump light and probe light. In this case, the magnetic field measurement apparatus 1 includes a configuration other than the pump light irradiation unit 20 among the configurations described in the embodiment.

(6) Modification 6
The magnetic shield 2 is not necessarily provided. For example, when the magnetic field in the area of each cell 11 can be sufficiently corrected with only the correction coil body 13, the magnetic shield 2 need not be provided.

(7) Modification 7
The arrangement of the plurality of cells 11 is not limited to a matrix. The plurality of cells 11 may be two-dimensionally arranged in a shape other than a matrix. For example, the plurality of cells 11 may be two-dimensionally arranged in a radial pattern. The plurality of cells 11 may be arranged in a line. Alternatively, the plurality of cells 11 may be arranged along the shape of the surface of the living body.
The shape of the cell 11 is not limited to a cube. For example, the cell 11 may have a shape such as a rectangular parallelepiped, a polyhedron, a sphere, or a cylinder.
The atoms in the cell 11 may be introduced into the cell 11 in any state of solid, liquid, or gas. The atoms need only be gasified at the time of measurement, and need not always be in a gas state.

(8) Modification 8
The program executed by the CPU 51 may be provided in a state of being recorded on a recording medium such as a magnetic tape, a magnetic disk, a flexible disk, an optical disk, a magneto-optical disk, or a memory, and may be installed in the control device 50. The program may be downloaded to the control device 50 via a communication line such as the Internet.

DESCRIPTION OF SYMBOLS 1 ... Magnetic field measuring apparatus, 10 ... Cell array, 11 ... Cell, 12 ... Partition plate, 13 ... Correction coil body, 20 ... Pump light irradiation part, 30 ... Probe light irradiation part, 40 ... Detection part, 50 ... Control apparatus, 60 ... Current supply unit

Claims (7)

A plurality of coil bodies provided in each of a single cell or adjacent cells with respect to a plurality of cells in which atoms that are spin-polarized by being excited by light are enclosed;
A current supply unit for supplying current to the plurality of coil bodies;
Control that measures the magnetic field of each region of the plurality of cells using a magnetic sensor, and controls the supply of current by the current supply unit so that an alternating magnetic field that cancels the measured magnetic field is generated from the plurality of coil bodies And a magnetic field correction apparatus. Each of the plurality of coil bodies includes a pair of first coils disposed on a first axis across the single cell, and a second crossing the first axis across the single cell. A pair of second coils arranged on the axis of the first and a pair of third coils arranged on a third axis intersecting the first axis and the second axis across the single cell The magnetic field correction apparatus according to claim 1, further comprising: a coil. The plurality of cells are two-dimensionally arranged,
The magnetic field correction apparatus according to claim 1, further comprising a plurality of partition plates that are formed of a material having a magnetic permeability higher than a threshold value and are provided between adjacent cells in the plurality of cells. The control unit measures magnetic fields in the regions of the plurality of cells at a time, and supplies currents that generate an alternating magnetic field that cancels the measured magnetic fields to the plurality of coil bodies provided in the plurality of cells. The magnetic field correction apparatus according to claim 1, wherein the magnetic field correction apparatus is a magnetic field correction apparatus. The plurality of cells are two-dimensionally arranged,
The control unit sequentially selects the plurality of cells one by one, measures the magnetic field in the region of the selected cell, and provides the selected cell with a current that generates a magnetic field that cancels the measured magnetic field. The magnetic field correction apparatus according to claim 1, wherein the magnetic field correction apparatus is supplied to the coil body. The plurality of cells are arranged in a matrix,
The control unit sequentially selects the plurality of cells one by one or one row, measures the magnetic field in the region of the selected cell, and supplies the selected cell with a current that generates a magnetic field that cancels the measured magnetic field. It supplies to the provided coil body. The magnetic field correction apparatus of any one of Claim 1 to 3 characterized by the above-mentioned. The magnetic field correction apparatus according to any one of claims 1 to 6,
A plurality of cells in which atoms that are spin-polarized and excited by light are enclosed;
An irradiation unit for irradiating light to the plurality of cells;
A detection unit that detects a rotation angle of a polarization plane of the light transmitted through the plurality of cells,
The said control part measures the magnetic field of each area | region of these cells based on the said rotation angle detected by the said detection part. The magnetic field measuring apparatus characterized by the above-mentioned.

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