Superconducting magnet system and magnetic field manifestation method

Abstract

To provide a superconducting magnet system and the like that appropriately indicate the state of magnetic field generation state.SOLUTION: A superconducting magnet system 1 includes a superconducting magnet 2, a magnetic field region indicating device 5 and a warning sound device 6 that indicate the magnetic field generation status, and a control device 4 that controls an excitation power source 3 of the superconducting magnet 2 and controls the magnetic field region indicating device 5 and the warning sound device 6, and the magnetic field region indicating device 5 and the warning sound device 6 emit light and / or sound that change on the basis of the magnitude or rate of change of the current of the superconducting magnet 2.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a superconducting magnet system and the like. [Background technology]

[0002] There is a known technology for alerting people in the vicinity of the strong magnetic field generated by a superconducting magnet. For example, Patent Document 1 describes a magnetic characteristic warning device that includes "magnetic characteristic measuring means for measuring magnetic characteristics, computing means for performing numerical calculations on the measurement results of the magnetic characteristic measuring means, and control means for calculating and determining the degree of magnetic danger by the computing means and controlling the operation of issuing a warning." [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-44975 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology described in Patent Document 1, a magnetic characteristic warning device is installed on an object to be brought into a specified space, and a warning is issued if the magnetic flux density (measured value) at that position exceeds a specified value. However, there is room for improvement in that people in the vicinity cannot know whether the magnetic flux density exceeds the specified value at positions where the magnetic characteristic warning device is not installed.

[0005] Therefore, an object of the present invention is to provide a superconducting magnet system etc. that properly indicates the generation status of a magnetic field. [Means for solving the problem]

[0006] In order to solve the above problems, a superconducting magnet system according to the present invention comprises a superconducting magnet; A light source is provided.The present invention is provided with an indicating means for indicating the generation state of a magnetic field, and a control means for controlling an excitation power supply of the superconducting magnet and controlling the indicating means, the indicating means emitting light and / or sound that changes based on the magnitude or rate of change of the current of the superconducting magnet. The control means changes an irradiation position when light from the light source is irradiated onto a floor surface around the superconducting magnet, or a light emitting area of ​​the light source on the floor surface, based on a magnitude of a current in the superconducting magnet. It is characterized by: Effect of the Invention

[0007] According to the present invention, it is possible to provide a superconducting magnet system etc. that properly indicates the generation state of a magnetic field. [Brief description of the drawings]

[0008] [Figure 1] 1 is a functional block diagram of a superconducting magnet system according to a first embodiment. [Diagram 2] FIG. 1 is a circuit diagram of a superconducting magnet system according to a first embodiment. [Figure 3A] 1 is an explanatory diagram showing an installation position of a magnetic field region specifying device in a superconducting magnet system according to a first embodiment. FIG. [Figure 3B] 4 is an explanatory diagram showing the irradiation position of light when the excitation power supply is ON and the energizing current of the superconducting magnet is zero in the superconducting magnet system according to the first embodiment. FIG. [Figure 3C] 3 is an explanatory diagram showing the irradiation position of light when a current flows through the superconducting magnet and the current value is smaller than that during rated operation in the superconducting magnet system according to the first embodiment. FIG. [Figure 3D] FIG. 2 is an explanatory diagram showing the irradiation position of light when the superconducting magnet is in rated operation in the superconducting magnet system according to the first embodiment. [Figure 4] 2 is a plan view showing a position where light is irradiated by a magnetic field region specifying device in the superconducting magnet system according to the first embodiment. FIG. [Diagram 5] 3 is an explanatory diagram showing the relationship between the distance from the center position of the superconducting magnet to the position irradiated with light and the current flowing through the superconducting magnet in the superconducting magnet system according to the first embodiment. FIG. [Figure 6] 4 is a time chart showing ON / OFF of an excitation power supply, energizing current, light irradiation position, ON / OFF of an alarm sound, and frequency of the alarm sound in the superconducting magnet system according to the first embodiment. [Figure 7A] FIG. 11 is an explanatory diagram showing the irradiation position of light when the excitation power supply is ON and no current flows through the superconducting magnet in the superconducting magnet system according to the second embodiment. [Figure 7B] FIG. 11 is an explanatory diagram showing the irradiation position of light when a current starts to flow through a superconducting magnet in a superconducting magnet system according to a second embodiment. [Figure 7C] FIG. 11 is an explanatory diagram showing the irradiation position of light when a current flows through the superconducting magnet and the current value is smaller than that during rated operation in the superconducting magnet system according to the second embodiment. [Figure 7D] FIG. 11 is an explanatory diagram showing the irradiation position of light when the superconducting magnet is in rated operation in the superconducting magnet system according to the second embodiment. [Figure 8] 10 is a time chart showing ON / OFF of an excitation power supply, a current flow, a first irradiation position, and a second irradiation position in a superconducting magnet system according to a second embodiment. [Figure 9] 13 is a time chart showing ON / OFF of an excitation power supply, a current flow, a light irradiation position, ON / OFF of a warning sound, and a pattern of the warning sound in a superconducting magnet system according to a third embodiment. [Figure 10] FIG. 11 is a circuit diagram of a superconducting magnet system according to a fourth embodiment. [Figure 11] 13 is a time chart showing ON / OFF of an excitation power supply, a current flow, a first irradiation position, a second irradiation position, and an alarm sound in a superconducting magnet system according to a fourth embodiment. [Figure 12A] FIG. 13 is an explanatory diagram showing a light emission state when an excitation power supply is ON and no current flows through a superconducting magnet in a superconducting magnet system according to a fifth embodiment. [Figure 12B]FIG. 13 is an explanatory diagram of light emission showing a state when a current starts to flow through a superconducting magnet in a superconducting magnet system according to a fifth embodiment. [Figure 12C] FIG. 13 is an explanatory diagram showing a light emission state when a current flows through a superconducting magnet and the current value is smaller than that during rated operation in a superconducting magnet system according to a fifth embodiment. [Figure 12D] FIG. 13 is an explanatory diagram showing a light emission state when a superconducting magnet is in rated operation in a superconducting magnet system according to a fifth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Each embodiment of the present invention will be described in detail with reference to the drawings as appropriate.

[0010] (First embodiment) FIG. 1 is a functional block diagram of a superconducting magnet system 1 according to the first embodiment. The superconducting magnet system 1 shown in Fig. 1 has a function of generating a predetermined magnetic field in a superconducting magnet 2 and a function of indicating the magnetic field generation status with light and sound. As shown in Fig. 1, the superconducting magnet system 1 includes the superconducting magnet 2, an excitation power supply 3, a control device 4 (control means), a magnetic field region indicating device 5 (indicating means, light source), and an alarm sound device 6 (indicating means, sound source).

[0011] The superconducting magnet 2 generates a predetermined magnetic field by passing a current through a superconducting coil 20 (see FIG. 2) made of a superconducting material (also called a superconducting substance). Here, a superconducting material is a material whose electrical resistance becomes nearly zero (that is, which causes a superconducting phenomenon) at or below a superconducting critical temperature, which is an extremely low temperature. Examples of such superconducting materials include niobium titanium (NbTi), niobium tin (Nb 3 Sn) can be used as a low-temperature superconductor. Other superconducting materials include magnesium diboride (MgB 2 It is also possible to use high-temperature superconductors such as yttrium (Y)-based and bismuth (Bi)-based superconductors.

[0012] Conventional low-temperature superconducting magnets are used at extremely low temperatures, where the specific heat of the constituent materials is less than 1 / 1000 of room temperature, and so are prone to temperature rise with even the slightest disturbance, making them thermally unstable. Even in the superconducting state, where electrical resistance is nearly zero, heat is often generated by eddy currents that are generated locally in the superconducting wire due to magnetic field fluctuations. Therefore, with conventional low-temperature superconducting magnets, there has been a tendency to avoid operations in which the magnetic field is switched on and off in short periods of time, except in cases where it is possible to adopt special cooling methods such as forced cooling using supercritical helium.

[0013] On the other hand, in recent years, high-temperature superconductors (e.g., Bi-based, Y-based, MgB 2 ), it has become possible to operate in a temperature range where the specific heat is 20 times larger than that of a conventional low-temperature superconducting magnet. High-temperature superconductors are also thermally stable, so it is becoming possible to operate them by turning the magnetic field on and off in a short time such as several tens of seconds to several minutes. However, this means that a strong magnetic field is rapidly generated and disappeared around the superconducting magnet 2. Therefore, in the first embodiment, in order to prevent problems such as malfunction of cardiac pacemakers, damage to magnetic cards, and attraction of magnetic bodies, the magnetic field region indicating device 5 and the warning sound device 6 are configured to successively indicate the generation status of the magnetic field to the surroundings. The superconducting material constituting the superconducting magnet 2 is not limited to a high-temperature superconductor, and may be a low-temperature superconductor as described above.

[0014] 1 is a DC power supply for supplying a current to the superconducting magnet 2. The excitation power supply 3 is provided with a current sensor (not shown) for detecting the current supplied to the superconducting magnet 2. The momentary measured value (current measurement value) of the current sensor is output to the control device 4.

[0015] Although not shown, the control device 4 is configured to include electronic circuits such as a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and various interfaces. The CPU reads out a program stored in the ROM and expands it in the RAM, and executes various processes. The control device 4 controls the excitation power supply 3, as well as the magnetic field region indicating device 5 and the warning sound device 6. That is, the control device 4 outputs a predetermined control command value to the excitation power supply 3 and adjusts the current supplied from the excitation power supply 3 to the superconducting magnet 2. This controls the ON / OFF of the magnetic field in the superconducting magnet 2. The control device 4 also changes command signals (indication position command value and warning sound command value) to the magnetic field region indicating device 5 and the warning sound device 6 based on the magnitude or rate of change of the current of the superconducting magnet 2. Details of the processing by the control device 4 will be described later.

[0016] The magnetic field region indicating device 5 (indicating means) is a light source that indicates the state of magnetic field generation by the superconducting magnet 2, and emits light based on an indication position command value from the control device 4. As such a magnetic field region indicating device 5, for example, a laser pointer is used. The warning sound device 6 (indicating means) is a sound source that indicates the state of magnetic field generation by the superconducting magnet 2, and emits a predetermined warning sound based on a voice command value from the control device 4. As such a warning sound device 6, for example, a speaker is used.

[0017] FIG. 2 is a circuit diagram of the superconducting magnet system 1. The superconducting magnet system 1 includes, as an excitation circuit, an excitation power supply 3, a superconducting coil 20, a protective resistor 21, a diode 22, and a circuit breaker 23, all of which are shown in Fig. 2. As shown in Fig. 2, the excitation power supply 3, the circuit breaker 23, and the superconducting coil 20 are connected in sequence to form a predetermined closed circuit.

[0018] A series connection of a protective resistor 21 and a diode 22 is connected in parallel to the excitation power supply 3 and also to the superconducting coil 20. A circuit breaker 23, which separates the excitation power supply 3 from the superconducting coil 20 in an emergency, is provided between the cathode of the diode 22 and the positive electrode of the excitation power supply 3. The protective resistor 21 is a resistor for consuming current when the excitation power supply 3 and the superconducting coil 20 are separated by the circuit breaker 23. The diode 22 serves to prevent current from flowing through the protective resistor 21 during normal excitation. A cryostat 19, shown by a dashed line in Fig. 2, keeps the superconducting coil 20 at an extremely low temperature.

[0019] FIG. 3A is an explanatory diagram showing the installation position of the magnetic field region specifying device 5. As shown in FIG. 3A shows a front view of superconducting magnet 2. In the example of FIG. 3A, superconducting magnet 2 is cylindrical and is installed so that its central axis is approximately parallel to floor surface 31 of room 30. Support base 7 is a base that supports superconducting magnet 2 and is placed on floor surface 31. The position of a plane that passes through the central axis of cylindrical superconducting magnet 2 and is perpendicular to floor surface 31 is called center position 10 (see also FIG. 4).

[0020] As shown in FIG. 3A, a pair of magnetic field region indicating devices 5 are provided on the superconducting magnet 2. To explain in more detail, a magnetic field region indicating device 5 is provided on one side of the outer circumferential surface of the superconducting magnet 2, and another magnetic field region indicating device 5 is provided on the other side of the outer circumferential surface of the superconducting magnet 2, sandwiching the above-mentioned central position 10. The pair of magnetic field region indicating devices 5 may be directly provided on the outer circumferential surface of the superconducting magnet 2, or may be provided via a predetermined fixture (not shown). The pair of magnetic field region indicating devices 5 indicate the outer circumferential edge (boundary line) of a predetermined strong magnetic field region 40 (see FIG. 4) by a light emitting means such as a laser pointer. The strong magnetic field region 40 (see FIG. 4) is a region in which the magnetic field is relatively strong around the superconducting magnet 2.

[0021] FIG. 3B shows the position R of light irradiation when the excitation power supply is ON and the current passing through the superconducting magnet 2 is zero. S FIG. When the excitation power supply 3 (see FIG. 1) is ON and the current flowing through the superconducting magnet 2 is zero, the control device 4 (see FIG. 1) performs, for example, the following process. That is, the control device 4 aligns the irradiation position R of the laser light with the edge of the projection plane when the area of ​​the superconducting magnet 2 is projected vertically onto the floor surface 31. S The laser light is scanned in a predetermined manner by the magnetic field region specifying device 5 so that the laser light approximately coincides with the magnetic field region specifying device 5. This allows personnel in the vicinity to easily understand that preparations are complete for passing a current through the superconducting magnet 2. Note that, as a technology for scanning and irradiating the laser light in a predetermined manner, for example, a laser scanner and LIDAR (LIDAR) are known.

[0022] FIG. 3C shows the position R of light irradiation when a current flows through the superconducting magnet 2 and the current value is smaller than that during rated operation. T FIG. The control device 4 (see FIG. 1 ) detects the position R of the light irradiated by the magnetic field region revealing device 5 as the current passing through the superconducting magnet 2 increases. T However, the control device 4 is configured to move away from the center position 10 of the superconducting magnet 2. In other words, the control device 4 expands the strong magnetic field region 40 (see FIG. 4) as the energizing current increases, and the light irradiation position R T and the superconducting magnet 2 in a plan view are made longer.

[0023] In this case, the light irradiation position R T The linear irradiation position (by the laser light scanning) may surround the superconducting magnet 2 in a plan view. The inside of the circular line shown by such light scanning is a predetermined strong magnetic field region 40 (see FIG. 4). This allows surrounding personnel to know at a glance that they must not approach the superconducting magnet 2 while wearing a magnetic body or the like (in particular, they must not enter the inside of the strong magnetic field region 40).

[0024] In this way, the control device 4 determines the irradiation position R when the light from the magnetic field region specifying device 5 (light source) is irradiated onto the floor surface 31 (see FIG. 3C) around the superconducting magnet 2 based on the magnitude of the current in the superconducting magnet 2. T As the current of the superconducting magnet 2 increases, the control device 4 changes the irradiation position R T The magnetic field domain specifying device 5 is controlled so that the magnetic field domain moves away from the superconducting magnet 2.

[0025] FIG. 3D shows the position of light irradiation R when the superconducting magnet 2 is in rated operation. O FIG. During rated operation of the superconducting magnet 2, the light from the magnetic field region indicating device 5 is incident on a predetermined irradiation position R O This irradiation position R O indicates the outer edge of the strong magnetic field region 40 (see FIG. 4) during rated operation. The control device 4 detects the position R of the light irradiated by the magnetic field region indicating device 5 during rated operation of the superconducting magnet 2. O The rated operation is an operating state in which a desired magnetic field is generated near the center of the superconducting magnet 2.

[0026] FIG. 4 is a plan view showing the position where light is irradiated by the magnetic field region specifying device 5. As shown in FIG. For example, the control device 4 controls the magnetic field region specifying device 5 so that the light irradiation position on the floor surface 31 (see Figs. 3C and 3D) surrounds the superconducting magnet 2 in a plan view. This allows surrounding personnel to know at a glance that they must not approach the strong magnetic field region 40 while wearing a magnetic body or the like.

[0027] In this way, by clearly showing how the strong magnetic field changes in response to the current flow, the generation status of the magnetic field can be recognized by personnel staying near the superconducting magnet 2. In other words, the presence or absence of a strong magnetic field can be clearly recognized by the surrounding personnel, and the increase or decrease in the magnetic field strength can also be recognized.

[0028] FIG. 5 is an explanatory diagram showing the relationship between the distance from the center position of the superconducting magnet to the position irradiated with light and the current flowing through the superconducting magnet. The horizontal axis of FIG. 5 indicates the current flowing through the superconducting magnet 2. The vertical axis of FIG. 5 indicates the distance (distance in plan view) from the center position 10 (see FIG. 3A) of the superconducting magnet 2 to the position of light irradiation. As shown in FIG. 5, the magnetic field region indicating device 5 is controlled so that the distance from the center position of the superconducting magnet 2 to the position of light irradiation increases as the current flowing through the superconducting magnet 2 increases. In other words, the magnetic field region indicating device 5 emits light that changes based on the magnitude (or rate of change) of the current through the superconducting magnet 2. Such a relationship between the current flowing through the superconducting magnet 2 and the position of light irradiation is stored in advance in the control device 4. Next, the operation of the magnetic field region indicating device 5 as well as the warning sound device 6 will be described with reference to FIG. 6.

[0029] FIG. 6 is a time chart showing ON / OFF of the excitation power supply, the energizing current, the light irradiation position, ON / OFF of the warning sound, and the frequency of the warning sound (also refer to FIG. 1 as appropriate). 6, the ON / OFF state of the excitation power supply 3, the energizing current of the superconducting magnet 2, the position of light irradiation by the magnetic field region indicating device 5 (the distance from the center of the superconducting magnet 2), the ON / OFF state of the warning sound by the warning sound device 6, and the frequency of the warning sound are shown. In the example of FIG. 6, the excitation power supply 3 is in the OFF state from time t0 to t1, and is in the ON state from time t1 to t6. The energizing current of the superconducting magnet 2 increases over time from time t2, and reaches the rated current value I at time t3. O The rated current I O is a current value that makes the magnetic field strength at the center position 10 of the superconducting magnet 2 a predetermined target value, and is set in advance.

[0030] During the time t0 to t1 when the excitation power supply 3 is in the OFF state, no light is emitted from the magnetic field region indicating device 5, and no warning sound is emitted from the warning sound device 6. During the time t1 to t2 when the excitation power supply 3 is in the ON state and no current flows through the superconducting magnet 2, the magnetic field region indicating device 5 indicates a predetermined irradiation position R S (See also FIG. 3B.) Furthermore, at times t1 to t2, the warning sound device 6 outputs a value f S A warning sound of the same frequency will be emitted.

[0031] As the energizing current increases, the light irradiation position changes (see also FIG. 3C), and the frequency of the warning sound increases. In the example of FIG. 6, the frequency of the warning sound increases from time t2 to time t3. S to value f O In this way, the control device 4 changes the frequency of the sound from the warning sound device 6 (sound source) based on the magnitude and rate of change of the current in the superconducting magnet 2. In other words, the warning sound device 6 emits a sound that changes based on the magnitude and rate of change of the current in the superconducting magnet 2. This makes it possible to make surrounding personnel aware that the magnetic field strength is increasing.

[0032] The current passing through superconducting magnet 2 is the rated current value I O When the light reaches a certain irradiation position R O In addition, the frequency of the warning sound is kept at a value f O This makes it possible for personnel in the vicinity to be aware that the plant has entered rated operation.

[0033] When the control device 4 ends the rated operation and turns off the magnetic field, the order is reversed from that when it turned on. In other words, as the current passing through the superconducting magnet 2 decreases, the predetermined irradiation position R O (See Fig. 3D) from another irradiation position R S (See Figure 3B) and the frequency of the warning sound is reduced. This makes it possible to notify surrounding personnel that the magnetic field strength is decreasing.

[0034] Then, when the current passing through the superconducting magnet 2 becomes zero (the excitation power supply 3 is in an ON state), the light reaches a predetermined irradiation position R S and the frequency of the warning sound is kept at a predetermined value f S This makes it possible to inform surrounding personnel that the magnetic field strength has become zero. Thereafter, when the excitation power supply 3 is turned off based on a command from the control device 4, the light from the magnetic field region indicating device 5 is no longer emitted and the warning sound is also turned off. As described above, the operating state of the superconducting magnet 2 can be made known to surrounding personnel by the position of the light irradiation as well as the presence or absence and frequency of the warning sound.

[0035] In this way, in this embodiment, the command signal output from the control device 4 to the magnetic field region indicating device 5 and the warning sound device 6 changes in response to the magnitude and rate of change of the current of the superconducting magnet 2. In other words, the control device 4 changes the irradiation position of the light from the magnetic field region indicating device 5 (light source) based on the magnitude of the current of the superconducting magnet 2. Also, the control device 4 changes the sound of the warning sound device 6 (sound source) based on the magnitude and rate of change of the current of the superconducting magnet 2. This not only makes it possible for personnel entering the vicinity of the superconducting magnet 2 to recognize the presence or absence of a magnetic field, but also makes it possible to recognize the operating state of the superconducting magnet 2 by expanding and contracting the area indicated by the magnetic field region indicating device 5. Also, by changing the frequency of the warning sound generated with the increase and decrease of the current supplied to the superconducting magnet 2, it becomes possible to recognize the operating state of the superconducting magnet 2. Therefore, for example, even if the magnetic field of the superconducting magnet 2 is frequently switched ON / OFF, the surrounding personnel can easily grasp the generation state of a strong magnetic field.

[0036] Second Embodiment The second embodiment differs from the first embodiment in that the magnetic field region indicating device 5 indicates the outer peripheral position of the strong magnetic field region during rated operation when the excitation power supply 3 is switched ON and preparations for generating a magnetic field are complete. Note that other points (such as the configuration of the superconducting magnet system 1: see FIG. 1) are the same as those of the first embodiment. Therefore, only the points that differ from the first embodiment will be described, and explanations of overlapping points will be omitted.

[0037] FIG. 7A is an explanatory diagram showing the light irradiation position when the excitation power supply is ON and no current flows through superconducting magnet 2 (also see FIG. 1 as appropriate). For example, when the excitation power supply 3 is turned on by a command from the control device 4 and preparations for generating a magnetic field are completed, the outer edge of the strong magnetic field region during rated operation is indicated by laser light (dashed line in Figure 7A) from the magnetic field region indicating device 5, as shown in Figure 7A.

[0038] In this way, when the excitation power supply 3 is in an on state, even when no current flows through the superconducting magnet 2, the control device 4 controls the first irradiation position R O The magnetic field region indicating device 5 (light source) continues to irradiate light of the first emission color. This indicates a strong magnetic field region 40 (see FIG. 4) during rated operation before the start of energizing the superconducting magnet 2. Therefore, if a person in the vicinity of the superconducting magnet 2 is carrying a magnetic body or a magnetic card, he or she can easily know how far away they should move away from the superconducting magnet 2.

[0039] FIG. 7B is an explanatory diagram showing the irradiation position of light when a current starts to flow through superconducting magnet 2. As shown in FIG. When starting to pass a current through the superconducting magnet 2, the control device 4 controls the irradiation position R S For example, the control device 4 controls the magnetic field region specifying device 5 so that the light of the second emission color is irradiated to the edge of the projection plane when the region of the superconducting magnet 2 is projected perpendicularly onto the floor surface 31. SThe control device 4 scans the laser light (solid line in FIG. 7B) in a predetermined manner so that the first and second irradiation positions R O By irradiating the area with light, the strong magnetic field region during rated operation can be continuously indicated.

[0040] FIG. 7C is an explanatory diagram showing the irradiation position of light when a current flows through superconducting magnet 2 and the current value is smaller than that during rated operation. The control device 4 adjusts the irradiation position R of the laser light of the second emission color as the current value of the superconducting magnet 2 increases. T In other words, when the excitation power supply 3 is on and a current flows through the superconducting magnet 2, the control device 4 controls the irradiation position R of the light of the second emission color from the magnetic field region indicating device 5 (light source) based on the magnitude of the current through the superconducting magnet 2. T In addition, the control device 4 continues to indicate the strong magnetic field region during rated operation with light of the first emission color (dashed line in FIG. 7C).

[0041] FIG. 7D is an explanatory diagram showing the irradiation position of light when superconducting magnet 2 is operating at rated power. When the current flowing through the superconducting magnet 2 reaches the rated current, the control device 4 changes the color of the light emitted when irradiating the position of the outer periphery of the strong magnetic field region to the second color. O The color of the light emitted from the sensor is changed from the first color (dashed line in FIG. 7C) to the second color (solid line in FIG. 7D). In this way, the light irradiation position indicating the outer edge of the actual strong magnetic field region is the same as the irradiation position R during rated operation. O When this occurs, it is possible to inform nearby personnel that rated operation is taking place.

[0042] FIG. 8 is a time chart showing ON / OFF of the excitation power supply, the energizing current, the first irradiation position, and the second irradiation position. 8, there are shown, from the top to the bottom, the ON / OFF state of the excitation power supply 3, the current passing through the superconducting magnet 2, the first irradiation position (distance from the center position of the superconducting magnet 2) and the second irradiation position by the magnetic field region specifying device 5. The first irradiation position is the irradiation position of light (e.g., the dashed line in FIG. 7B) that indicates in advance the outer edge of the strong magnetic field region during rated operation. The second irradiation position is the irradiation position of light (e.g., the solid line in FIG. 7B) that changes with the current value of the superconducting magnet 2.

[0043] As shown in FIG. 8, when the excitation power supply 3 is in the ON state, regardless of the magnitude of the current value of the superconducting magnet 2, the outer edge of the strong magnetic field region during rated operation is located at the first irradiation position (predetermined irradiation position R O ) In addition, the second irradiation position changes in a predetermined manner with the change in the energizing current of the superconducting magnet 2. Note that the warning sound emitted from the warning sound device 6 (see FIG. 1) is the same as that in the first embodiment (see FIG. 6), and therefore a description thereof will be omitted.

[0044] According to the second embodiment, the control device 4 clearly indicates the strong magnetic field area during rated operation before starting the current supply to the superconducting magnet 2, thereby making it possible to make surrounding personnel aware of the area where items such as magnetic materials and magnetic cards should be evacuated.

[0045] (Third embodiment) The third embodiment differs from the first embodiment in that the pattern (sound quality) of the sound emitted from the warning sound device 6 (see FIG. 1) is changed in accordance with a change in the current flowing through the superconducting magnet 2. Other aspects (such as the configuration of the superconducting magnet system 1: see FIG. 1) are similar to those of the first embodiment. Therefore, only the parts that differ from the first embodiment will be described, and a description of the overlapping parts will be omitted.

[0046] FIG. 9 is a time chart showing the ON / OFF of the excitation power supply, the energizing current, the light irradiation position, the ON / OFF of the warning sound, and the pattern of the warning sound in the superconducting magnet system according to the third embodiment (also see FIG. 1 if necessary). 9, when the excitation power supply 3 is ON and no current flows through the superconducting magnet 2 (times t1 to t2, t5 to t6), a sound of a predetermined pattern A is emitted from the warning sound device 6. Furthermore, while the current passing through the superconducting magnet 2 is increasing (times t2 to t3), a sound of a different pattern B is emitted from the warning sound device 6. During rated operation (times t3 to t4), a sound of pattern C is emitted, and while the current passing through the superconducting magnet 2 is subsequently decreasing (times t4 to t5), a sound of a different pattern D is emitted.

[0047] That is, the pattern (sound quality) of the warning sound emitted from the warning sound device 6 changes according to the magnitude and rate of change of the current in the superconducting magnet 2. The pattern (sound quality) of the warning sound here includes not only the temporal continuity of the sound (continuous sound, intermittent sound) and frequency, but also different music pieces, etc.

[0048] According to the third embodiment, the control device 4 changes the pattern of the warning sound (sound) of the warning sound device 6 (sound source) based on the magnitude of the current in the superconducting magnet 2. Therefore, it becomes possible to confirm the presence or absence of a magnetic field by the pattern (sound quality) of the warning sound. Also, by changing the pattern (sound quality) of the warning sound according to the change in the magnetic field strength (e.g., increase, decrease, constant), the surrounding personnel can recognize the change in the magnetic field strength.

[0049] (Fourth embodiment) The fourth embodiment differs from the second embodiment in that the superconducting magnet system 1A (see FIG. 10) includes a persistent current switch 24 (see FIG. 10) and performs persistent current operation in which the superconducting magnet 2 continues to generate a magnetic field even when the superconducting magnet 2 is disconnected from the excitation power supply 3. The rest of the fourth embodiment is similar to the second embodiment. Therefore, only the parts that differ from the second embodiment will be described, and the description of the overlapping parts will be omitted.

[0050] FIG. 10 is a circuit diagram of a superconducting magnet system 1A according to the fourth embodiment. The superconducting magnet system 1A includes an excitation power supply 3, a superconducting coil 20, a protective resistor 21, a diode 22, and a circuit breaker 23 as shown in FIG. 10, as well as a persistent current switch 24 and a heater 25.

[0051] The persistent current switch 24 is a coil with a superconducting wire wound thereon, and is connected in parallel to the superconducting magnet 2 and to the excitation power supply 3. The heater 25 is a heat source for changing the temperature of the persistent current switch 24, and is provided near the persistent current switch 24. When performing persistent current operation, the control device 4 (see FIG. 1) supplies current to the superconducting coil 20 from the excitation power supply 3 while the persistent current switch 24 is in a normal conducting state by heating it with the heater 25 or the like. Thereafter, the control device 4 stops heating by the heater 25, and stops the supply current from the excitation power supply 3 while the persistent current switch 24 is in a superconducting state. As a result, a closed circuit in a superconducting state including the superconducting coil 20 and the persistent current switch 24 is formed, and a persistent current operation is performed in which a current continues to flow through this closed circuit. This makes it possible to continue generating a magnetic field even when the superconducting magnet 2 is separated from the excitation power supply 3.

[0052] FIG. 11 is a time chart showing ON / OFF of the excitation power supply, energizing current, the first irradiation position, the second irradiation position, and a warning sound pattern. 11 are the same as those in the second embodiment. That is, the first irradiation position indicates a strong magnetic field region during rated operation, and the second irradiation position changes with the current flowing through the superconducting magnet 2.

[0053] 11, during persistent current operation, the current supplied from the excitation power supply 3 to the superconducting magnet 2 becomes substantially zero. Based on the state of the excitation power supply 3 before entering persistent current operation (times t1 to t4) and the history of the current flowing through the superconducting magnet 2, the control device 4 determines that persistent current operation is being performed from time t4 to t5.

[0054] That is, even in a state where no current is supplied from the excitation power supply 3 to the superconducting magnet 2, the control device 4 determines that a predetermined current is flowing through the superconducting magnet 2 from time t4 to t5. Then, the control device 4 outputs a predetermined indicating position command value to the magnetic field region indicating device 5 from time t4 to t5, and transmits a predetermined warning sound command value to the warning sound device 6. In the example of FIG. 11, a predetermined irradiation position R corresponding to the persistent current operation is determined from time t4 to t5. O In addition to being irradiated with laser light, a warning sound of a predetermined pattern C is emitted.

[0055] Thus, during persistent current operation in which current flows through a closed circuit including the superconducting magnet 2 and the persistent current switch 24, the control device 4 adjusts the irradiation position (or light emission area) of the magnetic field area indicating device 5 (light source) so as to indicate a strong magnetic field area during rated operation of the superconducting magnet 2. Also, during persistent current operation, the control device 4 controls the warning sound device 6 (sound source) so as to emit a predetermined sound corresponding to the magnetic field strength during rated operation of the superconducting magnet 2.

[0056] 11 is a detection value of a current sensor (not shown) built into the excitation power supply 3. From time t4 to t5, the detection value of the current (energization current) in the excitation power supply 3 is zero, but a predetermined permanent current flows in the superconducting magnet 2.

[0057] According to the fourth embodiment, even in the persistent current mode in which the superconducting magnet 2 continues to generate a magnetic field even when it is disconnected from the excitation power supply 3, it becomes possible for personnel approaching the vicinity of the superconducting magnet 2 to recognize the presence or absence of a magnetic field and changes in the strength of the magnetic field.

[0058] Fifth embodiment The fifth embodiment differs from the second embodiment in that a lighting device provided on the floor surface 31 is used as the magnetic field region specifying device 5B (see FIG. 12A). The rest is the same as the second embodiment (see FIG. 7 and FIG. 8). Therefore, only the parts that are different from the second embodiment will be described, and the description of the overlapping parts will be omitted.

[0059] FIG. 12A is an explanatory diagram showing a light emission state when the excitation power supply is ON and no current flows through the superconducting magnet 2. As shown in FIG. As shown in Fig. 12A, a lighting facility (e.g., LED: Light Emitting Diode) provided on the floor surface 31 of the room 30 in which the superconducting magnet 2 is installed is used as the magnetic field region specifying device 5B (light source). In the example of Fig. 12A, the magnetic field region specifying device 5B is provided in the entire area surrounded by the outer edge of the strong magnetic field region during rated operation.

[0060] For example, when the excitation power supply 3 (see FIG. 1) is in an on state, the control device 4 (see FIG. 1) continues to cause the magnetic field region manifesting device 5B (light source) to emit light in a first emission color in a first emission region including the outer edge of the strong magnetic field region during rated operation, even when no current flows through the superconducting magnet 2. In this case, the outer edge of the emission region of the magnetic field region manifesting device 5B may surround the superconducting magnet 2 in a plan view. The magnetic field region manifesting device 5B may also be configured by arbitrarily arranging an organic EL lighting device or a liquid crystal device, which is a surface light source, on the floor surface 31.

[0061] FIG. 12B is an explanatory diagram of light emission showing a state when a current starts to flow through superconducting magnet 2. As shown in FIG. In the example of FIG. 12B, the magnetic field region specifying device 5B is a projection surface portion (position R S 12A) emits light in the second emission color, and the remaining part emits light in the first emission color (the same color as in FIG. 12A). This allows people in the vicinity to know at a glance that they must not approach the superconducting magnet 2 while wearing a magnetic body or the like.

[0062] FIG. 12C is an explanatory diagram showing a light emission state when a current flows through superconducting magnet 2 and the current value is smaller than that during rated operation. As the current passing through the superconducting magnet 2 increases, the area in which the magnetic field region indicating device 5B emits light in a predetermined color expands, and the outer edge of the area expands to a predetermined position R. OIn this way, the control device 4 determines the position of the light emitting area (position R T For example, when the excitation power supply 3 is on and a current flows through the superconducting magnet 2, the control device 4 changes the light emitting area of ​​the second light emitting color in the magnetic field region manifestation device 5B based on the magnitude of the current through the superconducting magnet 2.

[0063] FIG. 12D is an explanatory diagram showing the light emission state when the superconducting magnet 2 is operated at the rated power. As shown in Figure 12D, during rated operation, position R O The magnetic field region indicating device 5B of the region having the outer edge thereof illuminates in the second luminous color. The control device 4 maintains the light emitting region of the magnetic field region indicating device 5B in a predetermined state during rated operation of the superconducting magnet 2. This allows surrounding personnel to know at a glance that the superconducting magnet 2 is in a rated operation state and that they must not approach the strong magnetic field region. Note that the control of the warning sound device 6 is the same as in the first embodiment, and therefore a description thereof will be omitted.

[0064] According to the fifth embodiment, the light from the magnetic field region specifying device 5B is not blocked by objects placed around the superconducting magnet 2, so that the strong magnetic field generation region can be specified by the magnetic field region specifying device 5B.

[0065] (Modification) Although the superconducting magnet systems 1, 1A, etc. according to the present invention have been described in the above in terms of the respective embodiments, the present invention is not limited to these descriptions and various modifications can be made. For example, in each embodiment, the superconducting magnet 2 (see FIG. 3A) is described as being cylindrical, but it may have a shape other than cylindrical. Furthermore, there is no particular limitation on the use of the superconducting magnet system 1. For example, each embodiment can be applied to various devices such as MRI (Magnetic Resonance Imaging) and NMR (Nuclear Magnetic Resonance), as well as magnetic separation magnets and magnetic refrigerators.

[0066] In each embodiment, the control device 4 controls the magnetic field region indicating device 5 and the warning sound device 6 based on the current measurement value in the excitation power supply 3 (see FIG. 1), but this is not limiting. That is, the control device 4 may control the magnetic field region indicating device 5 and the warning sound device 6 based on a current command value to the excitation power supply 3.

[0067] In the first to fourth embodiments, a configuration has been described in which a pair of magnetic field region specifying devices 5 (specifying means, light source) are provided on the superconducting magnet 2, but the present invention is not limited to this. That is, the number and installation positions of the magnetic field region specifying devices 5 can be changed as appropriate. The magnetic field region specifying device 5 may also be provided near the superconducting magnet 2. For example, one or more magnetic field region specifying devices 5 may be provided on the ceiling or wall of the room in which the superconducting magnet 2 is provided.

[0068] In addition, in each embodiment, the magnetic field region specifying device 5 is used to irradiate light onto the floor surface 31 (or to cause the floor surface to emit light), but this is not limited thereto. For example, a three-dimensional display may be performed that surrounds the periphery of the superconducting magnet 2 in a cylindrical shape. In addition, the magnetic field region specifying device 5 may be used to appropriately display predetermined characters or patterns on the floor surface 31.

[0069] Furthermore, the control device 4 may control the magnetic field region manifestation device 5 (light source) so that the outer edge of the light emission region of the magnetic field region manifestation device 5 moves away from the superconducting magnet 2 as the current in the superconducting magnet 2 increases. In addition, in each embodiment, the warning sound device 6 (indicating means, sound source) is provided near the superconducting magnet 2, but this is not limiting. For example, the warning sound device 6 may be provided in the superconducting magnet 2.

[0070] In the first embodiment and the like, the case where the laser light is scanned so that the irradiation position of the laser light surrounds the superconducting magnet 2 in a plan view has been described, but the present invention is not limited to this. For example, the magnetic field region specifying device 5 may specify a plurality of points or lines included in the outer edge of a predetermined strong magnetic field region by using the laser light or the like. In the first embodiment and the like, a case has been described in which the control device 4 changes the position of light irradiation by the magnetic field region specifying device 5 based on the magnitude of the current in the superconducting magnet 2, but this is not limiting. For example, the control device 4 may be configured to appropriately change the range of light irradiation by the magnetic field region specifying device 5. In this case, the matter of the control device 4 changing the range of light irradiation by the magnetic field region specifying device 5 is included in the matter of changing the position of light irradiation.

[0071] In addition, in each embodiment, the magnetic field region indicating device 5 indicates a predetermined strong magnetic field region, but this is not limited to the above. In other words, it is sufficient to change the light irradiation position so that the surrounding personnel can understand the operating state of the superconducting magnet system 1, and there is no particular need to make the region indicated by the magnetic field region indicating device 5 coincide with the outer edge of the strong magnetic field region.

[0072] In each embodiment, the control device 4 changes the position of light irradiation and the light emission area of ​​the magnetic field region indicating device 5 based on the magnitude of the current of the superconducting magnet 2, but the present invention is not limited to this. For example, the control device 4 may appropriately change the position of light irradiation and the light emission area of ​​the magnetic field region indicating device 5 based on the rate of change of the current of the superconducting magnet 2.

[0073] In each embodiment, the control device 4 changes the frequency and pattern of the sound from the warning sound device 6 (sound source) based on the magnitude and rate of change of the current in the superconducting magnet 2, but this is not limiting. For example, the control device 4 may change the frequency and pattern of the sound from the warning sound device 6 (sound source) based on the magnitude or rate of change of the current in the superconducting magnet 2. For example, the frequency and pattern of the sound may be different when the rate of change of the current in the superconducting magnet 2 is positive, when the rate of change is zero, and when the rate of change is negative.

[0074] Furthermore, the control device 4 may change the volume of the warning sound based on the magnitude or rate of change of the current in the superconducting magnet 2. For example, the control device 4 may increase the volume of the warning sound as the current flowing through the superconducting magnet 2 increases. Also, the change in the frequency and the change in the volume of the warning sound may be appropriately combined. That is, the control device 4 may change the frequency and / or the volume of the sound of the warning sound device 6 (sound source) based on the magnitude or rate of change of the current of the superconducting magnet 2.

[0075] In each embodiment, the magnetic field region indicating device 5 and the warning sound device 6 are both used as means for notifying the generation status of the magnetic field of the superconducting magnet 2, but one of them may be omitted. The magnetic field region indicating device 5 (indicating means, light source) and the warning sound device 6 (indicating means, sound source) may emit light and / or sound that changes based on the magnitude or rate of change of the current of the superconducting magnet 2.

[0076] In addition, in each embodiment, the superconducting magnet system 1 (see FIG. 1) is described as having one control device 4, but the present invention is not limited to this. That is, a plurality of control devices connected in a predetermined manner via signal lines may be used as the control device 4. Also, the control device 4 may include a predetermined server.

[0077] Moreover, the respective embodiments may be combined as appropriate. For example, the second embodiment may be combined with the third embodiment, the first embodiment may be combined with the fourth embodiment, or the first embodiment may be combined with the fifth embodiment. Furthermore, the processes executed by the superconducting magnet system 1 and the like (for example, the magnetic field manifestation method described in each embodiment) may be executed as a predetermined program of a computer. The program may be provided via a communication line, or may be written on a recording medium such as a CD-ROM and distributed.

[0078] In addition, each embodiment has been described in detail to clearly explain the present invention, and is not necessarily limited to having all of the configurations described. In addition, it is possible to add, delete, or replace part of the configuration of an embodiment with other configurations. Furthermore, the above-mentioned mechanisms and configurations are those considered necessary for the explanation, and do not necessarily show all mechanisms and configurations of the product. [Explanation of symbols]

[0079] 1,1A superconducting magnet system 2. Superconducting magnet 3 Excitation power supply 4 Control device (control means) 5,5B Magnetic field area clarifying device (clarifying means, light source) 6. Warning sound device (means of indication, sound source) 20 Superconducting coil 24 Persistent current switch 30 rooms 31 Floor

Claims

1. A superconducting magnet, A display means having a light source and indicating the occurrence of a magnetic field; A control means for controlling an excitation power supply of the superconducting magnet and for controlling the indicating means, the indicating means emits light and / or sound that changes based on the magnitude or rate of change of the current in the superconducting magnet; A superconducting magnet system characterized in that the control means changes the irradiation position when light from the light source is irradiated onto a floor surface around the superconducting magnet, or the light emitting area of ​​the light source on the floor surface, based on the magnitude of the current in the superconducting magnet.

2. The indicating means is provided on the superconducting magnet or in the vicinity of the superconducting magnet.

2. The superconducting magnet system according to claim 1 .

3. The control means changes a command signal to the indicating means based on the magnitude or rate of change of the current in the superconducting magnet.

2. The superconducting magnet system according to claim 1 .

4. The indicating means has a sound source, The control means changes the sound of the sound source based on the magnitude or rate of change of the current of the superconducting magnet.

2. The superconducting magnet system according to claim 1 .

5. The control means controls the light source so that the irradiation position or the outer edge of the light-emitting region surrounds the superconducting magnet in a plan view.

2. The superconducting magnet system according to claim 1 .

6. The control means controls the light source so that the irradiation position or the outer edge of the light emitting region moves away from the superconducting magnet as the current of the superconducting magnet increases.

6. The superconducting magnet system according to claim 5,

7. The control means maintains the irradiation position or the light-emitting area in a predetermined state during rated operation of the superconducting magnet.

7. The superconducting magnet system according to claim 6,

8. The control means When the excitation power supply is in an on state, even when no current flows through the superconducting magnet, the light source continues to irradiate a first irradiation position corresponding to an outer edge of a strong magnetic field region during rated operation with light of a first emission color; When the excitation power supply is in an on state and a current flows through the superconducting magnet, the irradiation position of the light of the second emission color from the light source is changed based on the magnitude of the current through the superconducting magnet.

2. The superconducting magnet system according to claim 1 .

9. The control means When the excitation power supply is in an on state, even when no current flows through the superconducting magnet, the light source continues to emit light of a first emission color in a first emission region including an outer edge of a strong magnetic field region during rated operation; When the excitation power supply is in an on state and a current flows through the superconducting magnet, a light emitting area of ​​a second light emission color in the light source is changed based on a magnitude of the current through the superconducting magnet.

2. The superconducting magnet system according to claim 1 .

10. The control means changes the frequency and / or volume of the sound of the sound source based on the magnitude or rate of change of the current of the superconducting magnet.

5. The superconducting magnet system according to claim 4,

11. The control means changes the sound pattern of the sound source based on the magnitude or rate of change of the current of the superconducting magnet.

5. The superconducting magnet system according to claim 4,

12. a persistent current switch connected in parallel to the superconducting magnet and to the excitation power supply; During persistent current operation in which a current flows through a closed circuit including the superconducting magnet and the persistent current switch, the control means adjusts the irradiation position or the light emission area so as to indicate a strong magnetic field area during rated operation of the superconducting magnet.

2. The superconducting magnet system according to claim 1 .

13. a persistent current switch connected in parallel to the superconducting magnet and to the excitation power supply; During persistent current operation in which a current flows through a closed circuit including the superconducting magnet and the persistent current switch, the control means controls the sound source so as to generate a predetermined sound corresponding to a magnetic field strength during rated operation of the superconducting magnet.

5. The superconducting magnet system according to claim 4,

14. the light source is provided on the floor of a room in which the superconducting magnet is installed, The control means changes the light emitting area of ​​the light source on the floor surface based on the magnitude of the current of the superconducting magnet.

2. The superconducting magnet system according to claim 1 .

15. A magnetic field indicating method for indicating a magnetic field generation state of a superconducting magnet, comprising: The device has a light source and is provided with an indication means for emitting light and / or sound to indicate the generation of a magnetic field; changing the light and / or sound of the indicating means based on the magnitude or rate of change of the current in the superconducting magnet; A magnetic field manifestation method that changes the irradiation position when light from the light source is irradiated onto a floor surface surrounding the superconducting magnet, or the light emitting area of ​​the light source on the floor surface, based on the magnitude of the current in the superconducting magnet.

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