Superconducting electromagnet device, particle beam therapy system, and method for controlling superconducting electromagnet device

Abstract

A superconducting electromagnet device is provided with: a first superconducting coil; a second superconducting coil; a first power source that supplies current to the first superconducting coil and does not supply current to the second superconducting coil; a second power source that does not supply current to the first superconducting coil and supplies current to the second superconducting coil; a first detector that detects quenching of the first superconducting coil; and a control unit that, in response to the quench of the first superconducting coil detected by the first detector, executes a first adjustment process for adjusting the current supplied to the second superconducting coil by the second power source.

Description

Technical Field

[0001] The present invention relates to a superconducting electromagnet device, a particle beam therapy system, and a control method for a superconducting electromagnet device. Background Art

[0002] Conventionally, particle beam therapy has been performed to treat malignant tumors such as cancer by irradiating the malignant tumors with charged particle beams accelerated to high energies. In the devices used for particle beam therapy, an electromagnet capable of generating a strong magnetic field is sometimes used to deflect the charged particle beams so that the charged particle beams are emitted from an arbitrary angle to the isocenter in the treatment room. Moreover, the use of superconducting coils in such electromagnets has been proposed (for example, Patent Documents 1 to 3).

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2021-159267

[0006] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2017-162896

[0007] Patent Document 3: Japanese Unexamined Patent Application Publication No. 2021-93440 Summary of the Invention

[0008] Problems to be Solved by the Invention

[0009] In a superconducting coil, a quench may occur in which the superconducting state disappears and becomes a normal conduction state. When a quench occurs, the magnetic flux density of the superconducting coil changes, generating eddy currents, which may cause heating in other superconducting coils or an induced electromotive force in the power supply that supplies current to the coil, resulting in an overvoltage. Thus, a quench in a superconducting coil may affect other superconducting coils and peripheral devices. As a result, the recovery of the device may take time.

[0010] An embodiment of the present invention provides a technique for reducing the influence of a quench in a superconducting coil on other components.

[0011] Solutions to the Problems

[0012] The present invention includes the following solutions.

[0013] [Solution 1]

[0014] A superconducting electromagnet device, the superconducting electromagnet device comprising:

[0015] A first superconducting coil;

[0016] A second superconducting coil;

[0017] A first power supply that supplies current to the first superconducting coil and does not supply current to the second superconducting coil;

[0018] A second power supply that does not supply current to the first superconducting coil and supplies current to the second superconducting coil;

[0019] A first detector that detects a quench of the first superconducting coil; and

[0020] A control unit that, in response to the quench of the first superconducting coil detected by the first detector, performs a first adjustment process of adjusting the current supplied by the second power supply to the second superconducting coil.

[0021] [Solution 2]

[0022] The superconducting electromagnet device according to Solution 1, wherein

[0023] In the first adjustment process, the control unit makes the current supplied by the second power supply to the second superconducting coil lower than the current before the execution of the first adjustment process.

[0024] [Solution 3]

[0025] The superconducting electromagnet device according to any one of Solutions 1 to 2, wherein

[0026] In the first adjustment process, the control unit sets the current supplied by the second power supply to the second superconducting coil to 0 [A].

[0027] [Solution 4]

[0028] The superconducting electromagnet device according to any one of Solutions 1 to 3, wherein

[0029] The superconducting electromagnet device further includes a first circuit breaker that cuts off the current supplied from the first power supply to the first superconducting coil,

[0030] When the first detector detects a quench of the first superconducting coil, the control unit uses the first circuit breaker to cut off the current supplied to the first superconducting coil.

[0031] [Solution 5]

[0032] The superconducting electromagnet device according to any one of Solutions 1 to 4, wherein

[0033] The superconducting electromagnet device further includes:

[0034] A second detector that detects a quench of the second superconducting coil; and

[0035] A second circuit breaker that cuts off the current supplied from the second power source to the second superconducting coil

[0036] When the control unit detects a quench of the second superconducting coil by the second detector during the execution of the first adjustment process, the control unit cuts off the current supplied to the second superconducting coil by using the second circuit breaker.

[0037] [Solution 6]

[0038] The superconducting electromagnet device according to Solution 5, wherein

[0039] The control unit executes the first adjustment process in response to detecting a quench of the first superconducting coil by the first detector and the temperature of the second superconducting coil becoming equal to or higher than a first threshold value, the first threshold value being a value lower than the superconducting transition temperature of the second superconducting coil.

[0040] [Solution 7]

[0041] The superconducting electromagnet device according to any one of Solutions 5 to 6, wherein

[0042] The control unit executes the first adjustment process in response to detecting a quench of the first superconducting coil by the first detector and the temperature gradient of the second superconducting coil being equal to or higher than a specified value.

[0043] [Solution 8]

[0044] The superconducting electromagnet device according to any one of Solutions 1 to 7, wherein

[0045] The control unit ends the first adjustment process when the temperature of the quenched first superconducting coil becomes equal to or lower than a second threshold value.

[0046] [Solution 9]

[0047] The superconducting electromagnet device according to any one of Solutions 1 to 8, wherein

[0048] The superconducting electromagnet device further includes a cryostat that houses the first superconducting coil and the second superconducting coil.

[0049] [Solution 10]

[0050] The superconducting electromagnet device according to Solution 9, wherein

[0051] The superconducting electromagnet device further includes a heat conduction mechanism in the cryostat that thermally connects the first superconducting coil and the second superconducting coil.

[0052] [Solution 11]

[0053] The superconducting electromagnet device according to any one of Solutions 9 to 10, wherein,

[0054] The superconducting electromagnet device further includes:

[0055] A third superconducting coil accommodated in the cryostat; and

[0056] A third power supply that does not supply current to the first superconducting coil and the second superconducting coil, but supplies current to the third superconducting coil,

[0057] The second superconducting coil, the first superconducting coil, and the third superconducting coil are arranged in sequence in the cryostat,

[0058] In response to the quench of the first superconducting coil detected by the first detector, the control unit further performs a second adjustment process of adjusting the current supplied by the third power supply to the third superconducting coil.

[0059] [Solution 12]

[0060] The superconducting electromagnet device according to any one of Solutions 9 to 10, wherein,

[0061] The superconducting electromagnet device further includes:

[0062] A third superconducting coil accommodated in the cryostat; and

[0063] A third power supply that does not supply current to the first superconducting coil and the second superconducting coil, but supplies current to the third superconducting coil,

[0064] The first superconducting coil, the second superconducting coil, and the third superconducting coil are arranged in sequence in the cryostat,

[0065] In response to the quench of the first superconducting coil detected by the first detector, the control unit further performs a second adjustment process of adjusting the current supplied by the third power supply to the third superconducting coil.

[0066] [Solution 13]

[0067] The superconducting electromagnet device according to any one of Solutions 9 to 10, wherein,

[0068] The superconducting electromagnet device further includes:

[0069] A third superconducting coil, the third superconducting coil being accommodated in a cryostat different from the cryostat accommodating the first superconducting coil and the second superconducting coil; and

[0070] A third power supply, the third power supply not supplying current to the first superconducting coil and the second superconducting coil, but supplying current to the third superconducting coil,

[0071] The second superconducting coil, the first superconducting coil, and the third superconducting coil are arranged in sequence,

[0072] The control unit, in response to the quench of the first superconducting coil detected by the first detector, further performs a second adjustment process of adjusting the current supplied by the third power supply to the third superconducting coil.

[0073] [Solution 14]

[0074] The superconducting magnet device according to any one of Solutions 11 or 13, wherein

[0075] The control unit can execute a first control mode and a second control mode. In the first control mode, the first power supply and the second power supply supply current to the first superconducting coil and the second superconducting coil respectively. In the second control mode, the first power supply and the third power supply supply current to the first superconducting coil and the third superconducting coil respectively.

[0076] When the control unit detects the quench of the first superconducting coil by the first detector during the execution of the first control mode, the control unit executes the first adjustment process.

[0077] When the control unit detects the quench of the first superconducting coil by the first detector during the execution of the second control mode, the control unit executes the second adjustment process.

[0078] [Solution 15]

[0079] The superconducting electromagnet device according to any one of Solutions 1 to 14, wherein

[0080] The first superconducting coil is adjacent to the second superconducting coil.

[0081] [Solution 16]

[0082] The superconducting electromagnet device according to any one of Solutions 1 to 15, wherein

[0083] The first detector detects the quench of the first superconducting coil by detecting the voltage of the first superconducting coil.

[0084] [Solution 17]

[0085] A particle beam therapy system, the particle beam therapy system comprising:

[0086] The superconducting electromagnet device according to any one of Aspects 1 to 16;

[0087] An accelerator that generates and emits a charged particle beam; and

[0088] A beam delivery system that delivers the charged particle beam emitted from the accelerator to the superconducting electromagnet device.

[0089] [Aspect 18]

[0090] The particle beam therapy system according to Aspect 17, wherein

[0091] The accelerator does not emit a charged particle beam during the current adjustment by the control unit.

[0092] [Aspect 19]

[0093] A control method, which is a control method of a superconducting magnet device, the superconducting magnet device comprising:

[0094] A first superconducting coil;

[0095] A second superconducting coil;

[0096] A first power supply that supplies current to the first superconducting coil and does not supply current to the second superconducting coil; and

[0097] A second power supply that does not supply current to the first superconducting coil and supplies current to the second superconducting coil, wherein the control method includes:

[0098] Detecting a quench of the first superconducting coil; and

[0099] In response to detecting a quench of the first superconducting coil through the detection, adjusting the current supplied by the second power supply to the second superconducting coil.

[0100] Advantageous Effects of the Invention

[0101] According to an embodiment of the present invention, the influence of a quench of a superconducting coil on other constituent parts can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0102] Figure 1 It is a schematic diagram of a superconducting electromagnet device according to an embodiment.

[0103] Figure 2 It is a flowchart showing an example of processing of a control unit.

[0104] Figure 3 It is a diagram showing the time variations of the current and temperature of a superconducting coil when a quench occurs in the superconducting coil.

[0105] Figure 4 It is a schematic diagram of a superconducting electromagnet device of an embodiment.

[0106] Figure 5 It is a flowchart showing a processing example of the control unit.

[0107] Figure 6 It is a diagram showing the time variation of the temperature of a superconducting coil when a quench occurs in the superconducting coil.

[0108] Figure 7 It is a flowchart showing a processing example of the control unit.

[0109] Figure 8 It is a flowchart showing a processing example of the control unit.

[0110] Figure 9 It is a device configuration diagram of a particle beam therapy system of an embodiment. Detailed implementation manners

[0111] <First Embodiment>

[0112] <Configuration of the Superconducting Electromagnet Device>

[0113] Figure 1 It is a schematic diagram of a superconducting electromagnet device 100 of an embodiment. For example, the superconducting electromagnet device 100 is a device that can generate a strong magnetic field to emit a charged particle beam from an arbitrary angle to the isocenter in the treatment room during particle beam therapy. The superconducting electromagnet device 100 includes circuits 110A, 110B, cryostats 120A, 120B, and a control unit 130.

[0114] The circuit 110A includes a power supply 111A, a superconducting coil 112A, a protection resistor 113A, and a circuit breaker 114A. The power supply 111A supplies current to the superconducting coil 112A. The superconducting coil 112A generates a magnetic field in response to the current supplied from the power supply 111A. The superconducting electromagnet device 100 deflects the charged particle beam through this magnetic field. Although not shown, a core can be assembled inside the superconducting coil 112A. The protection resistor 113A attenuates the current flowing in the superconducting coil 112A when a quench occurs in the superconducting coil 112A. The protection resistor 113A is connected in parallel with the superconducting coil 112A with respect to the power supply 111A. The circuit breaker 114A cuts off the current flowing from the power supply 111A to the superconducting coil 112A. The circuit breaker 114A is connected in series with the superconducting coil 112A with respect to the power supply 111A.

[0115] The cryostat 120A is a heat-insulating cooler that maintains the superconducting coil 112A at an extremely low temperature and houses the superconducting coil 112A. By using the cryostat 120A to keep the superconducting coil 112A in an extremely low temperature state, the superconducting coil 112A can maintain the superconducting state. The cryostat 120A uses a refrigerant such as helium gas, liquid helium, or liquid nitrogen, for example.

[0116] The control unit 130 controls the operation of the superconducting electromagnet device 100. The control unit 130 includes a control general unit 131 and power supply control units 132A and 132B. The control general unit 131 controls the entire superconducting electromagnet device 100 in an overall manner. The power supply control unit 132A controls the power supply 111A and the circuit breaker 114A in the circuit 110A and adjusts the current flowing through the superconducting coil 112A.

[0117] The control general unit 131 and the power supply control units 132A and 132B can each be a control circuit including one or more processors such as a CPU (Central Processing Unit) and a memory. These functions can be realized by the processor operating using a program (software) stored in the memory in a readable manner. The program can be stored, for example, in a storage device inside the superconducting electromagnet device 100.

[0118] It should be noted that the control general unit 131 and the power supply control units 132A and 132B can also be constituted by replacing the processor and the memory respectively or including hardware such as integrated circuits represented by FPGA (Field Programmable Gate Array) or ASIC (Application Specific Integrated Circuit) on the basis of them.

[0119] In addition, here, a scheme in which the control general unit 131 and the power supply control units 132A and 132B are each an independent control circuit is exemplified. However, the control unit 130 can also be constituted by a single control circuit as described above to realize the respective functions of the control general unit 131 and the power supply control units 132A and 132B.

[0120] Detector 140A detects that a quench has occurred in superconducting coil 112A. In the present embodiment, detector 140A detects the voltage of superconducting coil 112A. The detection result of detector 140A is output to power supply control unit 132A. Power supply control unit 132A can determine that a quench has occurred in superconducting coil 112A when the voltage of superconducting coil 112A detected by detector 140A is equal to or higher than a specified value. It should be noted that as a method for detecting a quench in superconducting coil 112A based on detector 140A, well-known techniques can be appropriately used. For example, detector 140A can also detect the temperature of superconducting coil 112A. In this case, power supply control unit 132A can determine that a quench has occurred in superconducting coil 112A when the temperature of superconducting coil 112A detected by detector 140A is equal to or higher than the superconducting transition temperature.

[0121] Circuit 110B, power supply 111B, superconducting coil 112B, protection resistor 113B, circuit breaker 114B, cryostat 120B, power supply control unit 132B, and detector 140B are the same as circuit 110A, power supply 111A, superconducting coil 112A, protection resistor 113A, circuit breaker 114A, cryostat 120A, power supply control unit 132A, and detector 140A, respectively, and thus the description thereof is omitted.

[0122] In the present embodiment, superconducting electromagnet device 100 has two circuits 110A and 110B. Moreover, power supply 111A included in circuit 110A supplies current to superconducting coil 112A also included in circuit 110A, but does not supply current to superconducting coil 112B included in circuit 110B. On the other hand, power supply 111B included in circuit 110B supplies current to superconducting coil 112B also included in circuit 110B, but does not supply current to superconducting coil 112A included in circuit 110A. That is to say, superconducting coil 112A and superconducting coil 112B are neither in series connection nor in parallel connection with respect to power supply 111A or power supply 111B. It can also be said that superconducting coil 112A and superconducting coil 112B are in a relation of being independent of each other in the circuit. In addition, in the present embodiment, superconducting coil 112B is adjacent to superconducting coil 112A.

[0123] <Actions during quench occurrence>

[0124] Next, the operation on the circuit 110A side when a quench occurs in the superconducting coil 112A will be described. When the power supply control unit 132A determines that a quench has occurred in the superconducting coil 112A, it operates the circuit breaker 114A to cut off the current supply from the power supply 111A to the superconducting coil 112A. Then, the circuit 110A becomes a closed circuit of the superconducting coil 112A and the protection resistor 113A. As a result, the current flowing in the superconducting coil 112A decays. After that, as time passes, when the temperature of the superconducting coil 112A drops below the superconducting transition temperature, i.e., the temperature T1 (refer to Figure 3 ), the superconducting coil 112A can return to the superconducting state.

[0125] Next, in the case where a plurality of superconducting coils 112A and 112B are provided as in the present embodiment, sometimes the state change of one superconducting coil may affect the other superconducting coil. For example, when a quench occurs in the superconducting coil 112A, sometimes the magnetic flux density of the superconducting coil 112A changes due to the change in the current of the superconducting coil 112A, causing a quench in the superconducting coil 112B. In addition, sometimes an induced electromotive force caused by electromagnetic induction is generated in the superconducting coil 112B due to the change in the magnetic flux density of the superconducting coil 112A. Moreover, it is possible that the superconducting coil 112B becomes overvoltage due to this induced electromotive force, causing a failure in the power supply 111B connected to the superconducting coil 112B. In this way, the quench of the superconducting coil sometimes affects other components of the device. As a result, in the case of a quench of the superconducting coil, it may take time for the device to recover until it can perform a specified operation again (for example, the operation of emitting a charged particle beam from an arbitrary angle in particle beam therapy). Therefore, in the present embodiment, the following control is performed to reduce the influence of the quench of the superconducting coil on other components.

[0126] Figure 2 It is a flowchart showing a processing example of the control unit 130. For example, this process is executed during a specified operation such as the following operations of the superconducting electromagnet device 100, for example, the operation of generating a strong magnetic field to emit a charged particle beam from an arbitrary angle in particle beam therapy.

[0127] In S101, the control unit 130 closes the circuit breakers 114A and 114B to be in a state where current can be supplied from the power supplies 111A and 111B to the superconducting coils 112A and 112B. Specifically, the control general unit 131 instructs the power supply control unit 132A to close the circuit breaker 114A and instructs the power supply control unit 132B to close the circuit breaker 114B. The received power supply control units 132A and 132B close the circuit breakers 114A and 114B, respectively. It should be noted that when the circuit breakers 114A and 114B are already closed, the control unit 130 maintains this state.

[0128] In S102, the control unit 130 supplies a set current to the superconducting coils 112A and 112B. Specifically, the power supply control units 132A and 132B that receive instructions from the overall control unit 131 respectively control the power supplies 111A and 111B to supply the set current to the superconducting coils 112A and 112B. It should be noted that the set current of the superconducting coil 112A and the set current of the superconducting coil 112B may be the same or different.

[0129] In S103, the control unit 130 confirms whether a quench of the superconducting coil 112A is detected. If detected, it proceeds to S104; if not detected, it proceeds to S108. The power supply control unit 132A confirms whether a quench occurs in the superconducting coil 112A based on the detection result of the detector 140A. In addition, when the power supply control unit 132A detects a quench of the superconducting coil 112A by the detector 140A, it sends information indicating the detection of the quench of the superconducting coil 112A to the overall control unit 131.

[0130] In S104, the control unit 130 opens the circuit breaker 114A. As a result, the current supply from the power supply 111A to the superconducting coil 112A is cut off, and the circuit 110A becomes a closed circuit of the superconducting coil 112A and the protection resistor 113A. As a result, the current flowing in the superconducting coil 112A decays, and the energy stored in the superconducting coil 112A is consumed by the protection resistor 113A. Thus, the superconducting coil 112A that has quenched can be protected from damage.

[0131] In S105, the control unit 130 starts the current adjustment process for the superconducting coil 112B. When the overall control unit 131 receives information indicating the detection of a quench of the superconducting coil 112A from the power supply control unit 132A, it instructs the power supply control unit 132B to adjust the current of the superconducting coil 112B. The received power supply control unit 132B adjusts the current supplied from the power supply 111B to the superconducting coil 112B. In the present embodiment, the power supply control unit 132B adjusts the current supplied to the superconducting coil 112B by controlling the output current of the power supply 111B. Specifically, the power supply control unit 132B adjusts by setting the current supplied from the power supply 111B to the superconducting coil 112B to 0 [A] so that the current supplied to the superconducting coil 112B is 0 [A]. That is, in a state where the circuit breaker 114B is closed and the power supply 111B is connected to the superconducting coil 112B in the circuit, the current supplied to the superconducting coil 112B is adjusted. It should be noted that the current adjustment process (S105) of the superconducting coil 112B may be performed simultaneously with the opening operation (S104) of the circuit breaker 114A, or as soon as possible after the opening operation of the circuit breaker 114A.

[0132] Note that, in this embodiment, the power supply control unit 132B sets the current supplied from the power supply 111B to the superconducting coil 112B to 0 [A] during the current adjustment process, but other solutions can also be adopted. For example, the power supply control unit 132B can also set the current supplied from the power supply 111B to the superconducting coil 112B to a specified current (>0 [A]) lower than the set current during the current adjustment process. Compared with the case where no current adjustment process is performed, the temperature rise of the superconducting coil 112B can also be suppressed by this solution. In addition, by making the supply current to the superconducting coil 112B greater than 0 [A], the time required for the device to recover can be shortened.

[0133] Here, when a quench occurs in the superconducting coil 112A, it is also considered to continue maintaining the current supplied to the superconducting coil 112B. However, in this case, the power supply 111B and the superconducting coil 112B may become overvoltage due to the influence of the induced electromotive force caused by the electromagnetic induction of the superconducting coil 112A, causing the power supply 111B to malfunction. In contrast, in this embodiment, the current supplied to the superconducting coil 112B is adjusted when a quench occurs in the superconducting coil 112A, so the influence of the overvoltage caused by the electromagnetic induction caused by the quench of the superconducting coil 112A can be reduced.

[0134] In S106, the control unit 130 confirms that the current supplied to the superconducting coil 112B is 0 [A]. Then, in S107, the control unit 130 confirms that the superconducting coil 112A is at a temperature of T1 [K] or lower. Here, the temperature T1 can be the superconducting transition temperature of the material constituting the superconducting coil 112A. In addition, for example, the temperature T1 can be a temperature lower than the superconducting transition temperature. After that, the control unit 130 returns to S101. That is, the control unit 130 ends the current adjustment process of the superconducting coil 112B and supplies the set current to the superconducting coil 112A and the superconducting coil 112B again.

[0135] On the other hand, when entering S108 from S103, the control unit 130 confirms whether the specified operation has ended. If it has ended, it enters S109. If it has not ended, it returns to S103. The specified operation is, for example, an operation in which the superconducting electromagnet device 100 generates a strong magnetic field so that a charged particle beam can be emitted from an arbitrary angle during particle beam therapy.

[0136] In S109, the control unit 130 ends the supply of the set current to the superconducting coils 112A and 112B.

[0137] Figure 3 It is a graph showing the time variation of the current and temperature of the superconducting coils 112A and 112B when a quench occurs in the superconducting coil 112A. Before the quench occurs, the temperatures of the superconducting coils 112A and 112B are less than the superconducting transition temperature (temperature T1).

[0138] When the superconducting coil 112A experiences a quench, the temperature of the superconducting coil 112A begins to rise. Thereafter, when the detector 140A detects the quench of the superconducting coil 112A, the circuit breaker 114A is opened ( Figure 2 , S104). The temperature of the superconducting coil 112A also temporarily rises after the circuit breaker 114A is opened. The reason is that an induced current is generated due to the change in magnetic flux density with current interruption, resulting in a large AC loss, and the temperature change per unit time of the superconducting coil 112A, i.e., the temperature gradient, becomes large. However, thereafter, it gradually decreases in response to the energy stored in the superconducting coil 112A being consumed by the protection resistor 113A.

[0139] On the other hand, in the superconducting coil 112B, in response to the occurrence of the quench of the superconducting coil 112A, the supplied current is decreased by the current adjustment performed by the control unit 130 ( Figure 2 , S105). As a result, even if the temperature of the superconducting coil 112B rises due to the influence of the change in the magnetic flux density of the superconducting coil 112A or the like, the temperature gradient of the superconducting coil 112B becomes gentle. Therefore, the superconducting state can be maintained, and the current supplied to the superconducting coil 112B can be decreased. Thereby, the occurrence of a quench in the superconducting coil 112B and the damage to the power supply 111B and the superconducting coil 112B due to overvoltage can be suppressed.

[0140] Here, in the case of a quench in the superconducting coil 112A, for the superconducting coil 112B, it is also considered to open the circuit breaker 114B to cut off the current from the power supply 111B. In this case, although the damage to the power supply 111B and the superconducting coil 112B can be suppressed, since the current flows through the protection resistor 113B, the temperature of the superconducting coil 112B may rise, resulting in a quench in the superconducting coil 112B. As a result, it may take more time for both the superconducting coil 112A and the superconducting coil 112B to return to the superconducting state. In contrast, in the present embodiment, as described above, the occurrence of a quench in the superconducting coil 112B can be suppressed, and the damage to the power supply 111B and the superconducting coil 112B due to overvoltage can be suppressed.

[0141] It should be noted that in the present embodiment, the process of adjusting the current of the superconducting coil 112B in the case of a quench in the superconducting coil 112A has been described. The process of adjusting the current of the superconducting coil 112A in the case of a quench in the superconducting coil 112B can also be executed in parallel with this process.

[0142] <Second Embodiment>

[0143] Figure 4It is a schematic diagram of a superconducting electromagnet device 200 according to an embodiment. The superconducting electromagnet device 200 of this embodiment is mainly different from the superconducting electromagnet device 100 of the first embodiment in that two superconducting coils are accommodated in the same cryostat. Hereinafter, the same reference numerals are given to the same elements as those of the superconducting electromagnet device 100 of the first embodiment, and the description is appropriately omitted. In addition, the modification examples and the like described in the description of the superconducting electromagnet device 100 can also be appropriately applied to the superconducting electromagnet device 200.

[0144] In the superconducting electromagnet device 200, the superconducting coils 112A and 112B are accommodated in the same cryostat 220. Moreover, the superconducting coil 112A and the superconducting coil 112B are thermally connected by a heat conduction mechanism 250. As the heat conduction mechanism 250, for example, a plate or a wire mesh made of aluminum or the like having a high thermal conductivity at low temperatures can be cited. By thermally connecting the superconducting coils 112A and 112B, they can be uniformly cooled, and the cooling efficiency can be improved. It should be noted that, when the superconducting coils 112A and 112B are accommodated in the same cryostat 220, a configuration in which the heat conduction mechanism 250 is omitted may also be adopted. It should be noted that, even when the heat conduction mechanism 250 is omitted, in terms of being accommodated in the same cryostat 220, it can be said that the superconducting coils 112A and 112B of the superconducting electromagnet device 200 are in a thermally connected relationship. On the other hand, the superconducting coils 112A and 112B of the superconducting electromagnet device 100 are respectively accommodated in different cryostats 120A and 120B, and therefore can be said to be in a thermally independent relationship.

[0145] In the superconducting electromagnet device 200, as a process when a quench occurs in the superconducting coil 112A, the same flowchart as Figure 2 can be adopted. In the superconducting electromagnet device 200, the superconducting coils 112A and 112B are accommodated in the same cryostat 220 and are thermally connected. Therefore, compared with the superconducting electromagnet device 100 of the first embodiment, when a quench occurs in the superconducting coil 112A in the superconducting electromagnet device 200, it is easy for the temperature of the superconducting coil 112B to rise. Even in this case, overvoltages of the power supply 111B and the superconducting coil 112B caused by electromagnetic induction due to the quench of the superconducting coil 112A can be suppressed, and the occurrence of a quench in the superconducting coil 112B can be suppressed.

[0146] <Third Embodiment>

[0147] In the superconducting electromagnet device 100 of the first embodiment or the superconducting electromagnet device 200 of the second embodiment, as a process when a quench occurs in the superconducting coil 112A, it is possible to execute the same as Figure 2The processes shown in the flowcharts are different processes. Hereinafter, other processing examples when a quench occurs in the superconducting coil 112A in the superconducting electromagnet device 100 or the superconducting electromagnet device 200 will be described.

[0148] Figure 5 It is a flowchart showing a processing example of the control unit 130. In Figure 2 In the flowchart, when a quench occurs in the superconducting coil 112A, a current adjustment process of the superconducting coil 112B is executed. On the other hand, it is also considered that a quench occurs in the superconducting coil 112B during the current adjustment process of the superconducting coil 112B due to differences in the positional relationship between the superconducting coil 112A and the superconducting coil 112B and the temperature condition of the superconducting coil 112A. Therefore, in this flowchart, when a quench also occurs in the superconducting coil 112B, the current is cut off using the circuit breaker 114B. It should be noted that the same reference numerals are assigned to the same processes as those in Figure 2 the flowchart, and the description is appropriately omitted.

[0149] In this flowchart, the control unit 130 enters S201 after S105. That is, Figure 2 similar to the flowchart of

[0150] when a quench of the superconducting coil 112A is detected (S103: Yes), the circuit breaker 114A is opened (S104), and a current adjustment process of the superconducting coil 112B is performed (S105). After that, in S105, the control unit 130 confirms whether a quench of the superconducting coil 112B is detected. If detected, it enters S202, and if not detected, it enters S106. The control unit 130 confirms whether a quench has occurred in the superconducting coil 112B based on the detection result of the detector 140B. Figure 2 In the case where a quench of the superconducting coil 112B is not detected, the subsequent processing is the same as that of

[0151] the flowchart (S106, S107).

[0152] Based on the above processing, when the superconducting coil 112A experiences a quench, the control unit 130 performs a current adjustment process for the superconducting coil 112B (S105). Moreover, when the temperature rise of the superconducting coil 112B can be suppressed through the current adjustment process, after confirming that the temperature of the superconducting coil 112A has dropped to the temperature T1 [K], the circuit 310A and the circuit breaker 114A are closed. Thus, it is possible to recover from the quench of the superconducting coil 112A without causing a quench in the superconducting coil 112B. As a result, the time from the quench of the superconducting coil 112A to recovery can be shortened.

[0153] On the other hand, even if the current adjustment process for the superconducting coil 112B is performed when the superconducting coil 112A experiences a quench, a quench may sometimes occur in the superconducting coil 112B. In this case, by opening the circuit breaker 114B to cut off the supply current to the superconducting coil 112B (S202), the influence of damage caused by the quench on the superconducting coil 112B can be reduced.

[0154] Figure 6 It is a graph showing the time variation of the temperatures of the superconducting coils 112A and 112B when the superconducting coil 112A experiences a quench. Before the quench occurs, the temperatures of the superconducting coils 112A and 112B are lower than the superconducting transition temperature (temperature T1).

[0155] When the superconducting coil 112A experiences a quench, the temperature of the superconducting coil 112A starts to rise. After that, when the detector 140A detects the quench of the superconducting coil 112A, the circuit breaker 114A1 is opened ( Figure 5 , S104). The temperature of the superconducting coil 112A also temporarily rises after the circuit breaker 114A is opened. The reason is that an induced current is generated due to the change in magnetic flux density with current interruption, resulting in a large AC loss, and the temperature gradient of the superconducting coil 112A per unit time becomes larger. However, afterwards, it gradually decreases in response to the energy stored in the superconducting coil 112A being consumed by the protection resistor 113A.

[0156] On the other hand, as the temperature of the thermally connected superconducting coil 112A rises, the temperature of the superconducting coil 112B also rises. In this example, although the temperature gradient during the temperature rise is suppressed through the current adjustment process of the superconducting coil 112B ( Figure 5 , S105), the temperature of the superconducting coil 112B is still higher than the superconducting transition temperature (temperature T1). Therefore, the detector 140B detects the quench of the superconducting coil 112B ( Figure 5, S201). After that, the breaker 114B is opened and the current flows through the protection resistor 113B. Therefore, when the temperature rises, the temperature gradient temporarily increases. However, in response to the consumption of the stored energy in the protection resistor, the temperature of the superconducting coil 112B will gradually decrease.

[0157] In this embodiment, when a quench occurs in the superconducting coil 112A, first, the current adjustment process of the superconducting coil 112B is performed. When a quench still occurs in the superconducting coil 112B even after the current adjustment process, the breaker 114B is opened. In this way, by processing the superconducting coil 112B step by step, it is possible to seek a balance between shortening the time from the occurrence of the quench in the superconducting coil 112A to recovery and protecting the superconducting coil 112B.

[0158] <Fourth Embodiment>

[0159] Hereinafter, another processing example when a quench occurs in the superconducting coil 112A in the superconducting electromagnet device 100 or the superconducting electromagnet device 200 will be described. In this processing example, when a quench occurs in the superconducting coil 112A, the current adjustment process of the superconducting coil 112B is not immediately performed, but the set current of the superconducting coil 112B is maintained under certain conditions. By maintaining the set current of the superconducting coil 112B, it is possible to accelerate the recovery of the device when the superconducting coil 112A relatively quickly recovers from the quench state to the superconducting state.

[0160] Figure 7 is a flowchart showing a processing example of the control unit 130. It should be noted that for the processes the same as those in Figure 2 or Figure 5 the flowchart, the same reference numerals are used and the description is appropriately omitted.

[0161] In this flowchart, the control unit 130 enters S301 after S104. In S301, the control unit 130 maintains the set current of the superconducting coil 112B.

[0162] In S302, the control unit 130 confirms whether the temperature of the superconducting coil 112A is below T1 [K]. If it is below T1 [K], it returns to S101. If it is not below T1 [K], it enters S303. Then, in S303, the control unit 130 confirms whether the temperature of the superconducting coil 112B is below the temperature T2 [K]. If it is above the temperature T2 [K], it enters S105. If it is not above the temperature T2 [K], it enters S302. Here, the temperature T2 is a specified temperature lower than the superconducting transition temperature, that is, the temperature T1 (T2 < T1). The processing after S105 is the same as that in Figure 5 the flowchart.

[0163] According to this processing example, even when a quench occurs in the superconducting coil 112A, the control unit 130 maintains the set current of the superconducting coil 112B (S301) when the temperature of the superconducting coil 112B is equal to or lower than the temperature T2 (< temperature T1). Thereby, when the superconducting coil 112A recovers from the normal conduction state to the superconducting state during the period of maintaining the set current of the superconducting coil 112B, the recovery of the device can be accelerated.

[0164] On the other hand, when the temperature of the superconducting coil 112B exceeds the temperature T2 while maintaining the set current of the superconducting coil 112B, by performing the current adjustment process of the superconducting coil 112B, the temperature rise of the superconducting coil 112B can be suppressed (S105). Furthermore, when the temperature of the superconducting coil 112B exceeds the temperature T1 and a quench occurs in the superconducting coil 112B even after performing the current adjustment process of the superconducting coil 112B, the circuit breaker 114B can be opened to protect the superconducting coil 112B.

[0165] <Fifth Embodiment>

[0166] Hereinafter, a further processing example when a quench occurs in the superconducting coil 112A in the superconducting electromagnet device 100 or the superconducting electromagnet device 200 will be described. In this processing example, when a quench occurs in the superconducting coil 112A, the aspect of maintaining the set current of the superconducting coil 112B without immediately performing the current adjustment process of the superconducting coil 112B under certain conditions is the same as that of the fourth embodiment. On the other hand, in this embodiment, the temperature gradient of the superconducting coil 112B is also considered to determine whether to perform the current adjustment process of the superconducting coil 112B. Thereby, the current adjustment process of the superconducting coil 112B can be more appropriately executed.

[0167] Figure 8 It is a flowchart showing a processing example of the control unit 130. It should be noted that for the same processes as those in the Figure 2 , Figure 5 or Figure 7 flowcharts, the same reference numerals are assigned and the description is appropriately omitted.

[0168] In this flowchart, when the temperature of the superconducting coil 112B is equal to or higher than the temperature T2 [K] in S303, the control unit 130 proceeds to S401. In S401, the control unit 130 confirms whether the temperature gradient (dT / dt) of the superconducting coil 112B is greater than a specified value. If it is equal to or greater than the specified value, it proceeds to S202 to open the circuit breaker 114B. If it is not equal to or greater than the specified value, it proceeds to S105. The subsequent processes are the same as those in the Figure 7 flowchart.

[0169] The specified value of the temperature gradient can be appropriately set. For example, the specified value can be a positive value. That is to say, when the temperature of the superconducting coil 112B is above temperature T2 and the temperature gradient is above the specified value (>0), the control unit 130 can open the circuit breaker 114B without performing the current adjustment process of the superconducting coil 112B. Thus, in the case of a temperature gradient such that even if the current adjustment process of the superconducting coil 112B is performed, the superconducting coil 112B will exceed temperature T1, by quickly opening the circuit breaker 114B, damage to the superconducting coil 112B can be suppressed. On the other hand, when the temperature gradient is such that as long as the current adjustment process of the superconducting coil 112B is performed, the temperature of the superconducting coil 112B can be maintained below temperature T1, the control unit 130 can perform the current adjustment process of the superconducting coil 112B. Thus, the recovery of the device in the case where the superconducting coil 112A recovers from the normal conduction state to the superconducting state can be accelerated.

[0170] It should be noted that in Figure 8 the flowchart, based on the temperature and temperature gradient of the superconducting coil 112B, the current supplied to the superconducting coil 112B and the operation of the circuit breaker 114B are controlled. However, it is also possible to control the current supplied to the superconducting coil 112B and the operation of the circuit breaker 114B only based on the temperature gradient of the superconducting coil 112B. For example, in Figure 7 the flowchart, the conditional branch of S401 in Figure 8 can be adopted to replace the conditional branch of S303.

[0171] <Sixth Embodiment>

[0172] Figure 9 is a configuration diagram of the device of a particle beam therapy system 10 of an embodiment. The particle beam therapy system 10 is a device for treating malignant tumors such as cancer by irradiating a charged particle beam accelerated to a high energy to perform particle beam therapy on the malignant tumors. The particle beam therapy system 10 includes an accelerator 20, a beam delivery system 30, an acceleration control unit 40, and a superconducting electromagnet device 300.

[0173] The accelerator 20 is a device that generates and emits a charged particle beam, such as a synchrotron, a cyclotron, or a linear accelerator. The charged particle beam generated by the accelerator 20 passes through the beam delivery system 30 and is guided to the superconducting electromagnet device 300.

[0174] The beam delivery system 30 delivers the charged particle beam generated by the accelerator 20 to the superconducting electromagnet device 300. The beam delivery system 30 includes a beam adjustment unit 31 and a vacuum pipe 32.

[0175] The beam adjustment unit 31 adjusts the shape, dose, traveling direction, etc. of the charged particle beam. For example, in the beam adjustment unit 31, according to the specifications, it appropriately includes a beam slit for adjusting the beam shape and / or dose, an electromagnet for adjusting the traveling direction of the charged particle beam, a quadrupole electromagnet for adjusting the beam shape of the charged particle beam, and a guide electromagnet for finely adjusting the beam position of the charged particle beam, etc.

[0176] The vacuum pipe 32 is configured to allow the charged particle beam to pass through, so as to avoid or reduce the attenuation of the charged particle beam generated and accelerated by the accelerator 20. The charged particle beam passes through the vacuum pipe 32 while being adjusted by the beam adjustment unit 31, and is guided to the superconducting electromagnet device 300 at a specified deflection angle (for example, φ1).

[0177] The superconducting electromagnet device 300 to which the charged particle beam is guided uses the magnetic field generated by a superconducting coil (for example, superconducting coil 312A) to further deflect the charged particle beam, so that the charged particle beam is irradiated to the isocenter O (the affected part of the patient) at a specified irradiation angle (for example, θ1). The charged particle beam deflected by the superconducting electromagnet device 300 is emitted from an irradiation nozzle (not shown) toward the isocenter O. The irradiation nozzle is provided in a treatment room having a treatment table for carrying the patient.

[0178] The acceleration control unit 40 controls the accelerator 20 and the beam delivery system 30. For example, the acceleration control unit 40 performs operations such as allowing the charged particle beam to be emitted and setting the current values of the electromagnets provided in the accelerator 20 and the beam delivery system 30. The acceleration control unit 40 is communicably connected to the control unit 330 of the superconducting electromagnet device 300 described later.

[0179] Next, the superconducting electromagnet device 300 will be described. The superconducting electromagnet device 300 includes circuits 310A to 310F, cryostats 320A, 320D, and a control unit 330.

[0180] The circuit 310A includes a power supply 311A and a superconducting coil 312A. The power supply 311A may have the same configuration as the power supply 111A of the superconducting electromagnet device 100, and the superconducting coil 312A may have the same configuration as the superconducting coil 112A of the superconducting electromagnet device 100. The circuits 310B to 310F, the power supplies 311B to 311F, and the superconducting coils 312B to 312F may respectively have the same configurations as the circuit 310A, the power supply 311A, and the superconducting coil 312A.

[0181] In addition, although not shown, the circuits 310A to 310F include protection resistors and circuit breakers corresponding to the protection resistor 113A and the circuit breaker 114A of the superconducting electromagnet device 100. In addition, for the superconducting coils 312A to 312F, detectors (not shown) corresponding to the detector 140A of the superconducting electromagnet device 100 are provided respectively.

[0182] In the present embodiment, the power supply 311A included in the circuit 310A supplies current to the power supply 311A also included in the circuit 310A, and does not supply current to the superconducting coils 312B to 312F included in the other circuits 310B to 310F. Similarly, the power supplies 311B to 311F supply current to the superconducting coils included in the same circuit, and do not supply current to the superconducting coils included in the other circuits. That is, the superconducting coils 312A to 312F are neither in series connection nor in parallel connection with respect to the power supplies 311A to 311F. It can also be said that the superconducting coils 312A to 312F are in a relation of being independent of each other electrically.

[0183] In addition, in the present embodiment, the superconducting coils 312A to 312C are accommodated in the same cryostat 320A. That is, the superconducting coils 312A to 312C are in a relation of being independent of each other electrically and are in a thermally connected relation. In addition, the superconducting coils 312A to 312C can also be connected to each other through a heat conduction mechanism such as the heat conduction mechanism 250 of the superconducting electromagnet device 200. Similarly, the superconducting coils 312D to 312F are accommodated in the same cryostat 320D, and thus are in a relation of being independent of each other electrically and are in a thermally connected relation.

[0184] The control unit 330 controls the operation of the superconducting electromagnet device 300. Specifically, the control unit 330 controls the current supplied from the power supplies 311A to 311F of the circuits 310A to 310F to the superconducting coils 312A to 312F. The control unit 330 can be a control circuit including one or more processors such as a CPU (Central Processing Unit) and a memory. These functions can be realized by the processor operating using a program stored in the memory in a readable manner. The program can be stored, for example, in a storage device inside the superconducting electromagnet device 100.

[0185] It should be noted that the control unit 330 may also be configured to replace the processor and the memory or include hardware such as integrated circuits represented by FPGA (Field Programmable Gate Array) or ASIC (Application Specific Integrated Circuit) on the basis of them. The control unit 330 may be implemented by a single control circuit or by a plurality of control circuits that share the functions of the control unit 330. In addition, the control unit 330 may have a power supply control unit corresponding to each power supply and a control summary unit that summarizes them, similar to the control unit 130 of the superconducting electromagnet device 100.

[0186] For example, during treatment, currents of the respective power supplies are set in the control unit 330 so that the charged particle beam is irradiated toward the isocenter O at a desired irradiation angle θ. Then, when the current setting on the control unit 330 side is completed, a treatment start signal is sent from the control unit 330 to the acceleration control unit 40. In this state, for example, when an operator presses a treatment start button (not shown), the acceleration control unit 40 receives this signal, and the acceleration control unit 40 issues an instruction to allow the emission of the charged particle beam to the accelerator 20, and the treatment starts. In the case of the end of treatment, a treatment end signal is sent from the control unit 330 to the acceleration control unit 40, and the acceleration control unit 40 that has received this signal stops the emission of the charged particle beam. It should be noted that the sharing of functions between the acceleration control unit 40 and the control unit 330 can be appropriately changed. Alternatively, the functions of the acceleration control unit 40 and the control unit 330 may be implemented by a single control unit, or a control unit that undertakes a part of the functions may be further provided. In addition, the acceleration control unit 40 does not allow the emission of the charged particle beam during the current adjustment process of the superconducting coil by the control unit 330. That is, during the current adjustment process of the superconducting coil, the superconducting electromagnet device 300 does not emit the charged particle beam.

[0187] Here, a case where quench occurs in any one of the superconducting coils 312A to 312F will be described. For example, regarding the current adjustment of the superconducting coil 312B in the case where quench occurs in the superconducting coil 312A, it is possible to execute the same processing as the Figure 2 , Figure 5 , Figure 7 , or Figure 8 shown flowchart. In addition, regarding which superconducting coil's current adjustment process is performed in the case of quench in which superconducting coil, it can be appropriately selected according to the magnitude of the influence received from the quenched superconducting coil. The magnitude of the influence received from the quenched superconducting coil changes according to the positional relationship, thermal connection relationship, etc. of the superconducting coils. An example of the relationship between the quenched superconducting coil and the superconducting coil for which the current adjustment process is performed is shown in Table 1.

[0188] Table 1

[0189]

[0190] An example of current adjustment processing for a superconducting coil adjacent to and thermally connected to a quenched superconducting coil is shown in Table 1. It should be noted that here, when a plurality of superconducting coils are arranged in a specified direction, adjacent superconducting coils are referred to as mutually adjacent superconducting coils. The arrangement direction of the plurality of superconducting coils is, for example, the direction of a plane orthogonal to the direction of the magnetic field generated by the superconducting coil. It should be noted that other constituent parts (such as a support member, a wall portion of a cryostat, etc.) may be interposed between adjacent superconducting coils.

[0191] For example, when the superconducting coil 312A quenches, in accordance with Figure 2 , Figure 5 , Figure 7 , or Figure 8 the flowchart, current adjustment processing is performed on the superconducting coil 312B adjacent to and thermally connected to the superconducting coil 312A. On the other hand, for the superconducting coil 312D adjacent to but not thermally connected to the superconducting coil 312A, no current adjustment processing is performed. The reason is that the superconducting coil 312B is affected by both the overvoltage caused by electromagnetic induction from the superconducting coil 312A and the thermal influence as the temperature of the superconducting coil 312A rises, so the possibility of quenching occurrence is higher than that of the superconducting coil 312D not affected by thermal influence. In addition, when the superconducting coil 312B or the superconducting coil 312E thermally connected to the superconducting coils on both sides quenches, current adjustment processing is performed on the superconducting coils on both sides thereof. Thus, by limiting the object of current adjustment processing to the superconducting coil adjacent to and thermally connected to the quenched superconducting coil, current adjustment processing can be performed on the superconducting coil with a relatively high possibility of quenching occurrence.

[0192] Next, another example of the relationship between the quenched superconducting coil and the superconducting coil on which current adjustment processing is performed is shown in Table 2.

[0193] Table 2

[0194]

[0195] An example of current adjustment processing for a superconducting coil thermally connected to a quenched superconducting coil is shown in Table 2. For example, when the superconducting coil 312A quenches, in addition to the superconducting coil 312B, in accordance with Figure 2 , Figure 5 , Figure 7 , or Figure 8The flowchart performs current adjustment processing on superconducting coil 312C that is not adjacent to but thermally connected to superconducting coil 312A. Superconducting coils that are thermally connected while being housed in the same cryostat as a quenched superconducting coil are likely to have their temperatures rise due to the temperature rise of the quenched superconducting coil. Therefore, by setting the object of the current adjustment processing to the superconducting coil that is thermally connected to the quenched superconducting coil, it is possible to perform current adjustment processing on the superconducting coil that is likely to be thermally affected by the quenched superconducting coil.

[0196] Next, another example of the relationship between the quenched superconducting coil and the superconducting coil on which the current adjustment processing is performed is shown in Table 3.

[0197] Table 3

[0198]

[0199] Examples of performing current adjustment processing on superconducting coils adjacent to or thermally connected to the quenched superconducting coil are shown in Table 3. For example, when superconducting coil 312A has quenched, according to Figure 2 , Figure 5 , Figure 7 , or Figure 8 's flowchart, current adjustment processing is performed on superconducting coils 312B, 314D adjacent to superconducting coil 312A, and superconducting coil 312C thermally connected to superconducting coil 312A. Superconducting coil 312D is not thermally connected to superconducting coil 312A but is adjacent to it, so it is likely to be affected by the induced electromotive force caused by electromagnetic induction. Therefore, in this example, current adjustment processing is performed on the superconducting coil that is not thermally connected to the quenched superconducting coil but is adjacent to it. Thus, it is possible to perform current adjustment processing on the superconducting coil that is not thermally connected to the quenched superconducting coil but is likely to be affected by it.

[0200] It should be noted that the relationships shown in Tables 1 to 3 are examples, and the method of selecting the superconducting coil as the object of the current adjustment processing is not limited to the above. For example, regardless of whether there is thermal connection, current adjustment processing can be performed on the superconducting coil adjacent to the quenched superconducting coil.

[0201] Next, in superconducting electromagnet device 300, power supplies 311A to 311F are respectively provided for superconducting coils 312A to 312F. During operation, current can be supplied to superconducting coils 312A to 312F simultaneously from each of power supplies 311A to 311F, but the power supply for which current is supplied can also be selected as needed. That is, when irradiating the isocenter O with a charged particle beam at a specified irradiation angle θ, it may not always be necessary to supply current to all superconducting coils 312A to 312F. Therefore, for example, as shown in Table 4, the superconducting coils for which power supply is performed can also be selected according to the irradiation angle θ toward the isocenter O.

[0202] Table 4

[0203]

[0204] For example, in the case where the charged particle beam only passes through the magnetic field region generated by the superconducting coil 312A, only the superconducting coil 312A is supplied with current (mode I). In addition, for example, in the case where the charged particle beam passes through the magnetic field region generated by the superconducting coil 312A and the magnetic field region generated by the superconducting coil 312B, the superconducting coil 312A and the superconducting coil 312B are supplied with current (mode II). In this way, the superconducting coil to which power is supplied is selected according to the passing region of the charged particle beam (as a result, the irradiation angle θ), thereby suppressing unnecessary current supply to the superconducting coil and reducing power consumption.

[0205] Moreover, when appropriately selecting the superconducting coil to which current is supplied, for example, as shown in Table 5, the superconducting coil for performing the current adjustment process can also be selected according to the selection status thereof.

[0206] Table 5

[0207]

[0208] For example, in the case where the superconducting coil 312B quenches in mode II, the control unit 130 performs the current adjustment process of the superconducting coil 312A according to the flowchart of Figure 2 , Figure 5 , Figure 7 , or Figure 8 . On the other hand, in the case where the superconducting coil 312B quenches in mode III, the control unit 130 performs the current adjustment process of the superconducting coil 312C according to the flowchart of Figure 2 , Figure 5 , Figure 7 , or Figure 8 . In this way, even in the case where the same superconducting coil 312B quenches, the control unit 130 can determine the object of the current adjustment process according to the current supply status of each superconducting coil at this time.

[0209] The dimensions, materials, shapes, relative positions of the components, etc. described above can also be changed according to the structure or various conditions of the device to which the present invention is applied. It is not intended to be limited to the specific terms and embodiments used in the description. Those skilled in the art can use other equivalent components, and the above embodiments can also be subjected to other deformations and changes without departing from the gist or scope of the present invention. In addition, even if the features described in connection with one embodiment of the present invention are not explicitly described above, they can also be used together with other embodiments.

[0210] Description of Reference Numerals

[0211] 10: Particle beam therapy system;

[0212] 20: Accelerator;

[0213] 30: Beam delivery system;

[0214] 100: Superconducting electromagnet device;

[0215] 111A, 111B: Power supply;

[0216] 112A, 112B: Superconducting coil;

[0217] 130: Control unit;

[0218] 140A, 140B: Detector.

Claims

1. A superconducting electromagnet device, the superconducting electromagnet device comprising: A first superconducting coil; A second superconducting coil; A first power supply that supplies current to the first superconducting coil and does not supply current to the second superconducting coil; A second power supply that does not supply current to the first superconducting coil and supplies current to the second superconducting coil; A first detector that detects a quench of the first superconducting coil; And A control unit that, in response to the quench of the first superconducting coil detected by the first detector, performs a first adjustment process of adjusting the current supplied by the second power supply to the second superconducting coil.

2. The superconducting electromagnet device according to claim 1, wherein In the first adjustment process, the control unit makes the current supplied by the second power supply to the second superconducting coil lower than the current before the execution of the first adjustment process.

3. The superconducting electromagnet device according to claim 1, wherein In the first adjustment process, the control unit sets the current supplied by the second power supply to the second superconducting coil to 0 A.

4. The superconducting electromagnet device according to claim 1, wherein The superconducting electromagnet device further comprises a first circuit breaker that cuts off the current supplied from the first power supply to the first superconducting coil, When the first detector detects a quench of the first superconducting coil, the control unit uses the first circuit breaker to cut off the current supplied to the first superconducting coil.

5. The superconducting electromagnet device according to claim 1, wherein The superconducting electromagnet device further comprises: A second detector that detects a quench of the second superconducting coil; And A second circuit breaker that cuts off the current supplied from the second power supply to the second superconducting coil, When the second detector detects a quench of the second superconducting coil during the execution of the first adjustment process, the control unit uses the second circuit breaker to cut off the current supplied to the second superconducting coil.

6. The superconducting electromagnet device according to claim 1, wherein The control unit performs the first adjustment process in response to the quench of the first superconducting coil detected by the first detector and the temperature of the second superconducting coil becoming equal to or higher than a first threshold value, the first threshold value being a value lower than the superconducting transition temperature of the second superconducting coil.

7. The superconducting electromagnet device according to claim 1, wherein The control unit performs the first adjustment process in response to the quench of the first superconducting coil detected by the first detector and the temperature gradient of the second superconducting coil being equal to or higher than a specified value.

8. The superconducting electromagnet device according to claim 1, wherein The control unit ends the first adjustment process when the temperature of the quenched first superconducting coil becomes equal to or lower than a second threshold value.

9. The superconducting electromagnet device according to claim 1, wherein The superconducting electromagnet device further comprises a cryostat that houses the first superconducting coil and the second superconducting coil.

10. The superconducting electromagnet device according to claim 9, wherein, the superconducting electromagnet device further includes a heat conduction mechanism in the cryostat, and the heat conduction mechanism thermally connects the first superconducting coil and the second superconducting coil.

11. The superconducting electromagnet device according to claim 9, wherein, the superconducting electromagnet device further includes: a third superconducting coil, which is accommodated in the cryostat; and a third power supply, which does not supply current to the first superconducting coil and the second superconducting coil, but supplies current to the third superconducting coil, the second superconducting coil, the first superconducting coil, and the third superconducting coil are arranged in sequence in the cryostat, in response to the quench of the first superconducting coil detected by the first detector, the control unit further performs a second adjustment process of adjusting the current supplied by the third power supply to the third superconducting coil.

12. The superconducting electromagnet device according to claim 9, wherein, the superconducting electromagnet device further includes: a third superconducting coil, which is accommodated in the cryostat; and a third power supply, which does not supply current to the first superconducting coil and the second superconducting coil, but supplies current to the third superconducting coil; the first superconducting coil, the second superconducting coil, and the third superconducting coil are arranged in sequence in the cryostat, in response to the quench of the first superconducting coil detected by the first detector, the control unit further performs a second adjustment process of adjusting the current supplied by the third power supply to the third superconducting coil.

13. The superconducting electromagnet device according to claim 9, wherein, the superconducting electromagnet device further includes: a third superconducting coil, which is accommodated in a cryostat different from the cryostat that accommodates the first superconducting coil and the second superconducting coil; and a third power supply, which does not supply current to the first superconducting coil and the second superconducting coil, but supplies current to the third superconducting coil; the second superconducting coil, the first superconducting coil, and the third superconducting coil are arranged in sequence, in response to the quench of the first superconducting coil detected by the first detector, the control unit further performs a second adjustment process of adjusting the current supplied by the third power supply to the third superconducting coil.

14. The superconducting magnet device according to any one of claims 11 or 13, wherein, the control unit can execute a first control mode and a second control mode. In the first control mode, the first power supply and the second power supply supply current to the first superconducting coil and the second superconducting coil respectively. In the second control mode, the first power supply and the third power supply supply current to the first superconducting coil and the third superconducting coil respectively. when the first detector detects the quench of the first superconducting coil during the execution of the first control mode, the control unit performs the first adjustment process. When the control unit detects a quench of the first superconducting coil by the first detector during the execution of the second control mode, the second adjustment process is executed.

15. The superconducting electromagnet device according to any one of claims 1 to 13, wherein the first superconducting coil is adjacent to the second superconducting coil.

16. The superconducting electromagnet device according to any one of claims 1 to 13, wherein the first detector detects a quench of the first superconducting coil by detecting the voltage of the first superconducting coil.

17. A particle beam therapy system, the particle beam therapy system comprising: the superconducting electromagnet device according to any one of claims 1 to 13; an accelerator that generates and emits a charged particle beam; and a beam delivery system that delivers the charged particle beam emitted from the accelerator to the superconducting electromagnet device.

18. The particle beam therapy system according to claim 17, wherein the accelerator does not emit a charged particle beam during the current adjustment by the control unit.

19. A control method, the control method being a control method of a superconducting magnet device, the superconducting magnet device comprising: a first superconducting coil; a second superconducting coil; a first power supply that supplies current to the first superconducting coil and does not supply current to the second superconducting coil; and a second power supply that does not supply current to the first superconducting coil and supplies current to the second superconducting coil, wherein the control method includes: detecting a quench of the first superconducting coil; and responding to the detection of the quench of the first superconducting coil by the detection, adjusting the current supplied by the second power supply to the second superconducting coil.

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