JP2013251182A - Cyclotron and quench back method of superconducting coil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cyclotron capable of realizing highly reliable quench back and a quench back method of a superconducting coil.SOLUTION: A cyclotron 1 is provided with superconducting coils 2,3 arranged inside a vacuum chamber 4 and a refrigerator 7 which cools down the superconducting coils 2,3, and also provided with a control section 11 which detects quench of the superconducting coils 2,3, and controls supply of quenching gas for quenching the superconducting coils 2,3, and a gas flow passage 13 for sending the quenching gas to the vicinity of the superconducting coils 2,3. In the case where the control section 11 detects the quench of one superconducting coil and does not detect the quench of the other superconducting coil out of the superconducting coils 2,3, the control section quenches the other superconducting coil by supplying the quenching gas to the vicinity of the other superconducting coil through the gas flow passage 13 to raise the temperature of the coil.

Description

  The present invention relates to a cyclotron and a method of quenching back a superconducting coil provided in the cyclotron.

  Conventionally, for example, Patent Document 1 is known as a technical document related to a cyclotron. Patent Document 1 includes a hollow yoke, a vacuum container disposed in the interior space of the yoke, two superconducting coils disposed in the vacuum container, a refrigerator that cools these superconducting coils, A cyclotron with is described.

JP 2002-43117 A

  By the way, in a cyclotron equipped with a plurality of superconducting coils, when one superconducting coil is quenched, an unbalanced magnetic field occurs, and the remaining unquenched superconducting coils are attracted to the yoke, causing deformation or damage to the superconducting coils. May occur. In this case, even if the current supply to the superconducting coil is stopped, it is not enough to prevent attraction, and therefore it is preferable to quickly quench the remaining superconducting coils that have not been quenched.

  However, quenching by raising the temperature of the superconducting coil with a resistance heater is unreliable, and it is difficult to quench the superconducting coil by setting the magnetic field or current above the critical point in a short time. .

  SUMMARY OF THE INVENTION An object of the present invention is to provide a cyclotron and a superconducting coil quench-back method capable of realizing a highly reliable quench-back.

  In order to solve the above problems, the present invention provides a cyclotron comprising a plurality of superconducting coils disposed in a vacuum vessel and a cooling means for cooling the plurality of superconducting coils, wherein the plurality of superconducting coils are quenched. A quench detection means for detecting the gas, a gas supply means for supplying a quenching gas for quenching the superconducting coil, a control means for controlling the gas supply means, and sending the quenching gas to the vicinity of the plurality of superconducting coils And the control means detects the quench of at least one superconducting coil among the plurality of superconducting coils and does not detect the quench of the remaining superconducting coils. In addition, quenching the remaining superconducting coil by supplying a quenching gas to the vicinity of the remaining superconducting coil through the gas flow path and raising the temperature. And features.

  According to the cyclotron according to the present invention, when the quench is detected from at least one of the plurality of superconducting coils and the quench of the remaining superconducting coils is not detected, the vicinity of the remaining superconducting coils through the gas channel is detected. By supplying the quenching gas, the temperature of the superconducting coil can be raised to the superconducting transition temperature or higher to quench. Therefore, according to this cyclotron, by supplying the quenching gas, the temperature of the superconducting coil can be quickly raised and reliably quenched, so that a highly reliable quench back can be realized.

The cyclotron according to the present invention may include a flow path that passes through the inside of the vacuum vessel and partially passes through the vicinity of the superconducting coil.
According to this cyclotron, the target superconducting coil can be quenched by the temperature rise through the gas flow path without releasing the quenching gas into the vacuum vessel, so the quench released into the vacuum vessel It is possible to reduce the labor and time for collecting the working gas and returning it to the vacuum. Also, according to this cyclotron, it is possible to quench the superconducting coil while maintaining the vacuum in the vacuum vessel.

In the cyclotron according to the present invention, the gas flow path may be formed on the outer peripheral side of the superconducting coil in the vacuum vessel.
According to this cyclotron, the gas flow path can be shortened as compared with the case where the gas flow path is formed up to the inner peripheral side of the superconducting coil, which is advantageous for simplification of the cyclotron structure and cost reduction. .

In the cyclotron according to the present invention, the gas flow path may include a plurality of flow paths respectively corresponding to the plurality of superconducting coils.
According to this cyclotron, the target superconducting coil can be appropriately quenched by selecting the gas flow path for supplying the quenching gas. Also, according to this cyclotron, the quenching gas reaches the target superconducting coil in a short time compared to the case where one gas flow path passes all the superconducting coils. Back can be realized.

In the cyclotron according to the present invention, a vacuum pump may be connected to the gas flow path.
According to this cyclotron, the inside of the gas channel can be evacuated in a normal time when no quench occurs, so that it is possible to effectively suppress the transfer of external heat to the superconducting coil through the gas channel. it can. This is advantageous for maintaining the superconducting state of the superconducting coil.

  The present invention relates to a quench back method for a superconducting coil in a cyclotron comprising a plurality of superconducting coils disposed in a vacuum vessel and a cooling means for cooling the plurality of superconducting coils, When quenching of at least one superconducting coil is detected and quenching of the remaining superconducting coils is not detected, the quenching gas is supplied to the vicinity of the remaining superconducting coils through the gas flow path to raise the temperature. Thus, the remaining superconducting coil is quenched.

  According to the quench back method for a superconducting coil according to the present invention, when the quench is detected from at least one of the plurality of superconducting coils and the quench of the remaining superconducting coils is not detected, the remaining through the gas flow path. By supplying the quenching gas to the vicinity of the superconducting coil, the temperature of the superconducting coil can be raised to the superconducting transition temperature or more to quench. Therefore, according to this quenchback method, by supplying the quenching gas, the temperature of the superconducting coil can be quickly raised and reliably quenched, so that a highly reliable quenchback can be realized. it can.

In the quench back method of the superconducting coil according to the present invention, the gas flow path includes a flow path that passes through the vicinity of the superconductive coil while passing through the inside of the vacuum vessel, and the quenching gas flowing through the gas flow path is: The remaining superconducting coil may be quenched by raising the temperature via the gas flow path.
According to this quench-back method, the target superconducting coil can be quenched by the temperature rise through the gas flow path without releasing the quenching gas into the vacuum vessel, so that it is released into the vacuum vessel. It is possible to reduce the time and effort for recovering the quenching gas and returning it to a vacuum. Further, according to this quench back method, it is possible to quench the superconducting coil while maintaining the vacuum in the vacuum vessel.

In the quench back method for a superconducting coil according to the present invention, the gas flow path may be formed on the outer peripheral side of the superconducting coil in the vacuum vessel.
According to this quench-back method, the gas flow path can be shortened as compared with the case where the gas flow path is formed up to the inner peripheral side of the superconducting coil, so that the structure of the cyclotron can be simplified and the cost can be reduced. It is done.

In the quench back method for a superconducting coil according to the present invention, the gas flow path includes a plurality of flow paths respectively corresponding to the plurality of superconducting coils, and the quenching gas is supplied to the flow paths corresponding to the remaining superconducting coils. May be.
According to this quench-back method, the target superconducting coil can be appropriately quenched by selecting the gas flow path for supplying the quenching gas. Also, according to this quenchback method, the quenching gas reaches the target superconducting coil in a short time compared to the case where one gas flow path passes near all the superconducting coils. Quenchback can be achieved.

In the quench back method for a superconducting coil according to the present invention, a vacuum pump is connected to the gas flow path, and the inside of the gas flow path may be evacuated by driving the vacuum pump.
According to this quench-back method, the inside of the gas flow path can be evacuated in a normal time when no quench occurs, so that external heat is effectively prevented from being transmitted to the superconducting coil through the gas flow path. be able to. This is advantageous for maintaining the superconducting state of the superconducting coil.

  ADVANTAGE OF THE INVENTION According to this invention, the quenchback method of the cyclotron which can implement | achieve highly reliable quenchback and a superconducting coil can be provided.

It is a schematic sectional drawing which shows one Embodiment of the cyclotron which concerns on this invention. It is a figure for demonstrating the relationship of the gas flow path with respect to a superconducting coil. It is a flowchart which shows the quench back method of the superconducting coil with which the cyclotron was equipped. It is a schematic sectional drawing which shows the cyclotron which concerns on other embodiment.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the same or an equivalent part, and the overlapping description is abbreviate | omitted.

[First Embodiment]
A cyclotron 1 of the first embodiment shown in FIG. 1 is a circular accelerator that accelerates charged particles supplied from an ion source (not shown) and outputs a charged particle beam (charged particle beam). Examples of the charged particles include protons, heavy particles (heavy ions), and electrons.

  The cyclotron 1 includes superconducting coils 2 and 3 arranged around the central axis C, an annular vacuum vessel 4 that accommodates the superconducting coils 2 and 3, and an air core portion of the first superconducting coil 2. Refrigerator for cooling the upper pole (upper magnetic pole) 5 arranged on the lower pole, the lower pole (lower magnetic pole) 6 arranged at the air core part of the second superconducting coil 3, and the superconducting coils 2 and 3 (Cooling means) 7 and a yoke 8 are provided. The yoke 8 is a hollow disk-shaped block, and the vacuum vessel 4, the upper pole 5 and the lower pole 6 are disposed therein.

  In the cyclotron 1, a strong magnetic field is formed by flowing a current through the superconducting coils 2 and 3 that are brought into a superconducting state by the refrigerator 7 after the vacuum vessel 4 is evacuated. The charged particles supplied from the ion source are accelerated by the influence of the magnetic field in the space G between the upper pole 5 and the lower pole 6 and output as a charged particle beam.

  The first superconducting coil 2 and the second superconducting coil 3 are integrally held in the vacuum vessel 4 by a coil holding member (not shown). A refrigerator 7 is provided so as to be in contact with the coil holding member or in contact with the superconducting coils 2 and 3, and the superconducting coils 2 and 3 can be directly cooled by the refrigerator 7 in a vacuum state. Done. As the refrigerator 7, for example, a small GM refrigerator can be adopted.

  As shown in FIGS. 1 and 2, the cyclotron 1 forces one of the first superconducting coil 2 and the second superconducting coil 3 to quench the other superconducting coil. A quench-back system 10 is provided.

  In the quenchback system 10, when one superconducting coil is quenched, the quenching gas is supplied in the vicinity of the other superconducting coil to increase the temperature of the other superconducting coil to a superconducting transition temperature or higher. Force quench.

  The quenching gas is a gas having a temperature sufficient to raise the temperature of the superconducting coil to the superconducting transition temperature or higher, and for example, a normal temperature gas is used. The quenching gas is preferably a stable gas having a low freezing point. Specifically, a rare gas or the like can be used as the quenching gas, and helium gas is particularly preferable.

  The quenchback system 10 includes a control unit 11 that controls the quenchback system 10, a gas tank 12 in which the quenching gas is stored, and the quenching gas to the vicinity of the first superconducting coil 2 or the second superconducting coil 3. , And a condenser 14 for condensing the quenching gas that has given heat to the superconducting coil 2 or the superconducting coil 3.

  The gas tank 12 is a tank in which a normal temperature quenching gas is stored. The gas tank 12 is connected to the gas flow path 13, and the quenching gas in the gas tank 12 flows into the gas flow path 13 by opening the first electromagnetic valve 15 or the second electromagnetic valve 16.

  The gas channel 13 includes a first gas channel 13A corresponding to the first superconducting coil 2, a second gas channel 13B corresponding to the second superconducting coil 3, and a quenching gas in the gas tank 12. A recovery channel 13C for recovering the gas. The gas flow path 13 can be configured by a pipe made of steel or stainless steel.

  The first gas flow path 13 </ b> A is a flow path from the gas tank 12 to the condenser 14, and a part thereof enters the vacuum vessel 4 and passes through the vicinity of the first superconducting coil 2. The quenching gas in the gas tank 12 flows into the first gas flow path 13A by opening the first electromagnetic valve 15.

  The first gas flow path 13A is formed so as to pass through the vacuum container 4, and a seal member 4a for maintaining a vacuum state is provided between the first gas flow path 13A and the vacuum container 4. . The first gas flow path 13 </ b> A is formed outside the first superconducting coil 2 (on the yoke 8 side) in the vacuum vessel 4.

  A part of the first gas flow path 13 </ b> A forms a first heat exchange unit 130 that is in contact with the first superconducting coil 2 in the vacuum vessel 4. The quenching gas at room temperature that has flowed into the first heat exchange unit 130 exchanges heat with the first superconducting coil 2 in the superconducting state, and raises the temperature of the first superconducting coil 2.

  The quenching gas heat-exchanged with the first superconducting coil 2 is condensed in the condenser 14 and recovered to the gas tank 12 through the recovery channel 13C. A recovery pump 17 for recovering the quenching gas to the gas tank 12 is provided in the recovery channel 13C.

  The first gas channel 13A is provided with a evacuation channel 131 for evacuating the first gas channel 13A. A vacuum pump 18 and a vacuuming electromagnetic valve 19 are arranged in the vacuuming flow path 131. In the first gas flow path 13A, after the quenching gas is collected, the vacuum pump 18 is driven in a state in which the evacuation electromagnetic valve 19 is opened, thereby bringing the first gas flow path 13A into a vacuum state. .

  The second gas flow path 13 </ b> B is a flow path from the gas tank 12 to the condenser 14, and a part thereof enters the vacuum vessel 4 and passes near the second superconducting coil 3. The quenching gas in the gas tank 12 flows into the second gas flow path 13B by opening the electromagnetic valve 16.

  The second gas channel 13B is formed so as to pass through the vacuum vessel 4, and a seal member 4a for maintaining a vacuum state is provided between the second gas channel 13B and the vacuum vessel 4. . The second gas flow path 13B is formed outside the second superconducting coil 3 (on the yoke 8 side) in the vacuum vessel 4.

  A part of the second gas flow path 13 </ b> B forms a second heat exchange unit 132 that is in contact with the second superconducting coil 3 in the vacuum vessel 4. The quenching gas at room temperature that has flowed into the second heat exchanging section 132 exchanges heat with the second superconducting coil 3 in the superconducting state, and raises the temperature of the second superconducting coil 3. The quenching gas heat-exchanged with the second superconducting coil 3 is condensed in the condenser 14 and recovered to the gas tank 12 through the recovery channel 13C.

  The second gas flow path 13B is also provided with a evacuation flow path 133 for making the second gas flow path 13B in a vacuum state. A vacuum pump 20 and a vacuuming electromagnetic valve 21 are arranged in the vacuuming flow path 133. The vacuum pump 20 does not need to be provided separately from the vacuum pump 18 of the first gas flow path 13A, and the vacuum pump 20 is shared by the first gas flow path 13A and the second gas flow path 13B. Also good.

  The control unit 11 illustrated in FIG. 1 is an electronic control unit including a CPU [Central Processing Unit], a ROM [Read Only Memory], a RAM [Random Access Memory], and the like. The control unit 11 controls the first electromagnetic valve 15, the second electromagnetic valve 16, the recovery pump 17, the vacuuming electromagnetic valves 19 and 21, and the vacuum pumps 18 and 20. The control unit 11 functions as a gas supply unit described in the claims together with the gas tank 12. The control unit 11 also functions as control means described in the claims.

  Further, the control unit 11 detects the voltages of the first superconducting coil 2 and the second superconducting coil 3. Since the controller 11 changes the voltage of the superconducting coil when it is quenched, it detects the quench based on the voltage change of the superconducting coils 2 and 3. The control unit 11 functions as a quench detection unit described in the claims.

  When the control unit 11 detects the quench of one of the first superconducting coil 2 and the second superconducting coil 3 and does not detect the quenching of the other superconducting coil, the control unit 11 A quench-back control for forcibly quenching the conductive coil is executed.

  Next, a quench back method for the superconducting coils 2 and 3 provided in the cyclotron 1 will be described. FIG. 3 is a flowchart showing a quench-back method for the superconducting coils 2 and 3.

  As shown in FIG. 3, first, in the control unit 11 of the cyclotron 1, quench detection of the superconducting coils 2 and 3 is performed as step S1. The controller 11 detects the quench from the change in the voltage of the superconducting coils 2 and 3.

  Next, as step S2, the control unit 11 determines whether or not the quench of the other superconducting coil has been detected for one superconducting coil that has detected the quench.

  When the quench of the other superconducting coil is also detected (NO in step S2), the control unit 11 terminates the control because there is no need to perform quench back.

  On the other hand, when the control unit 11 detects quenching of one superconducting coil and determines not to detect quenching of the other superconducting coil (YES in step S2), the control unit 11 proceeds to step S3.

  In step S3, the control unit 11 causes quenching gas to be supplied to the flow path corresponding to the superconducting coil that has not been quenched in the first gas flow path 13A or the second gas flow path 13B.

  Specifically, the control unit 11 opens the first electromagnetic valve 15 or the second electromagnetic valve 16 so that the quenching gas in the gas tank 12 is transferred to the first gas flow path 13A or the second gas flow. Supply to path 13B. The supplied quenching gas heats the superconducting coil that has not been quenched, and raises the temperature of the superconducting coil to be higher than the superconducting transition temperature to achieve quenching back.

  Thereafter, in step S4, the control unit 11 collects the quenching gas. The control unit 11 recovers the quenching gas condensed by the condenser 14 into the gas tank 12 by the recovery pump 17.

  After substantially recovering the quenching gas in the gas flow path 13, the controller 11 performs a vacuum state in the gas flow path 13 in step S <b> 5. The control unit 11 opens the evacuation solenoid valves 19 and 21 corresponding to the used first gas channel 13A or the second gas channel 13 and drives the vacuum pumps 18 and 20 to drive the gas channel. 13 is evacuated. Thereby, it is possible to suppress external heat from being transmitted to the superconducting coils 2 and 3 through the gas flow path 13.

  According to the cyclotron 1 and the quench back method according to the first embodiment described above, when the quench is detected from one of the superconducting coils 2 and 3 and the quench of the other superconducting coil is not detected, By supplying the quenching gas to the vicinity of the other superconducting coil through the gas flow path 13, the temperature of the superconducting coil can be raised and quenched. Therefore, according to the cyclotron 1 and the quenchback method, by supplying the quenching gas, the temperature of the superconducting coil can be quickly raised and reliably quenched, thereby realizing a highly reliable quenchback. can do.

  Further, according to the cyclotron 1 and the quench back method, the gas flow path 13 is configured to pass through without being opened in the vacuum container 4, so that the gas flow path is not released into the vacuum container 4. The target superconducting coil can be quenched by the temperature rise via 13. Therefore, according to the cyclotron 1 and the quench-back method, the superconducting coil can be quenched while maintaining the vacuum in the vacuum vessel 4, so that the time and effort for returning the vacuum vessel 4 to the vacuum can be reduced.

  Further, according to the cyclotron 1 and the quenchback method, the gas flow path 13 is formed outside the superconducting coils 2 and 3 in the radial direction of the superconducting coils 2 and 3 in the vacuum vessel 4. Compared with the case where the gas flow path is formed up to the inside of the conductive coils 3, 4, the gas flow path 13 can be shortened. This is advantageous in simplifying the structure of the cyclotron 1 and reducing the cost.

  In addition, according to the cyclotron 1 and the quenchback method, the first gas flow path 13A and the second gas flow path 13B corresponding to the first superconducting coil 2 and the second superconducting coil 3 are provided. By doing so, the target superconducting coil can be appropriately quenched by selecting the gas flow path for supplying the quenching gas. Moreover, according to the cyclotron 1 and the quenchback method, the quenching gas reaches the vicinity of the target superconducting coil in a short time compared to the case where one gas flow path passes near all the superconducting coils. Therefore, quick quench back can be realized.

  Further, according to the cyclotron 1 and the quench back method, the gas flow path 13 is evacuated in a normal state where the quench back is not necessary (when both the superconducting coils 2 and 3 are superconducting). It is possible to effectively suppress external heat from being transmitted to the superconducting coil through the flow path. This is advantageous for maintaining the superconducting state of the superconducting coils 2 and 3.

  The present invention is not limited to the embodiment described above. FIG. 4 is a schematic cross-sectional view showing a cyclotron 31 according to another embodiment. The cyclotron 31 shown in FIG. 4 is greatly different from the cyclotron 1 described above in that the quenching gas is directly discharged into the vacuum vessel 4. In addition, about the same component as the cyclotron 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  The quenchback system 32 of the cyclotron 31 includes a control unit 33 that controls the quenchback system 32, a gas tank 34 that stores the quenching gas, and a gas flow path 35 that supplies the quenching gas to the vicinity of the superconducting coils 2 and 3. have.

  The control unit 33 is an electronic control unit that controls the electromagnetic valve 36, the vacuum pump 37, and the vacuuming electromagnetic valve 38 provided in the gas flow path 35. The controller 33 detects the quench from the voltage change of the superconducting coils 2 and 3.

  When the control unit 33 detects the quenching of one of the first superconducting coil 2 and the second superconducting coil 3 and does not detect the quenching of the other superconducting coil, the control valve 33 Is opened, the quenching gas is supplied into the gas flow path 35.

  The gas flow path 35 is a flow path that connects the gas tank 34 and the vacuum vessel 4. The quenching gas supplied into the gas flow path 35 is quenched into the vacuum vessel 4 by raising the temperature of the superconducting coils 2 and 3 in the vacuum vessel 4 to the superconducting transition temperature or higher. . Thereby, quick and reliable quench back can be realized.

  After that, the control unit 33 opens the evacuation electromagnetic valve 38 provided in the evacuation passage 35 a of the gas passage 35 and drives the vacuum pump 37, so that the inside of the vacuum container 4 and the gas passage 35. To a vacuum. Thereby, it is possible to prevent external heat from being transmitted to the superconducting coils 2 and 3 through the gas flow path 35 and the like.

  According to the cyclotron 31 described above, by supplying the quenching gas into the vacuum vessel 4, it is possible to quickly raise the temperature of the superconducting coil for quenching, thereby realizing a highly reliable quench back. Can do.

  In addition, in the cyclotrons 1 and 31 described above, the number of superconducting coils is not limited to two, and may be three or more. Moreover, the shape of the gas flow paths 13 and 35 is not restricted to what was mentioned above, Various shapes can be employ | adopted. Specifically, the gas flow path 13 is not a gas flow path 13A or 13B corresponding to each of the superconducting coils 2 and 3, but a single flow path that passes through the vicinity of both superconducting coils 2 and 3. It may be configured. Further, the gas flow path 13 may be formed up to the inner peripheral side of the superconducting coils 2 and 3.

  Furthermore, the gas flow path 13 does not necessarily need to be in direct contact with the superconducting coils 2 and 3, and may be in contact via a coil holding member or the like. Further, the gas flow path 13 may be separated from the superconducting coils 2 and 3 in the vacuum vessel 4. In this case, the heat of the quenching gas flowing in the gas flow path 13 can be indirectly given to the superconducting coils 2 and 3 by slightly putting air or the like into the vacuum vessel 4 to break the vacuum state.

  Further, the gas flow path 13 is not necessarily formed so as to circulate so that the quenching gas can be recovered. Further, it is not always necessary to evacuate the gas flow path 13.

  Moreover, the gas tank 12 does not necessarily need to store the quenching gas at room temperature, and may be stored at a temperature sufficient to quench the superconducting coil. The gas tank 12 may store the quenching gas in a high pressure state.

  DESCRIPTION OF SYMBOLS 1,31 ... Cyclotron 2 ... 1st superconducting coil 3 ... 2nd superconducting coil 4 ... Vacuum container 4a ... Sealing member 5 ... Upper pole 6 ... Lower pole 7 ... Refrigerator 8 ... Yoke 10, 32 ... Quench back System 11, 33 ... Control unit (quenching detection means, gas supply means, control means) 12, 34 ... Gas tank (gas supply means) 13, 35 ... Gas flow path 13A ... First gas flow path 13B ... Second gas Flow path 13C ... Recovery flow path 130 ... First heat exchange section 131, 133, 35a ... Vacuum evacuation flow path 132 ... Second heat exchange section 14 ... Condenser 15 ... First solenoid valve 16 ... Second Solenoid valve 17 ... Recovery pump 18, 20, 37 ... Vacuum pump 19, 21, 38 ... Vacuum valve solenoid valve C ... Center axis G ... Space

Claims (10)

A cyclotron comprising a plurality of superconducting coils disposed in a vacuum vessel and a cooling means for cooling the plurality of superconducting coils,
Quench detecting means for detecting quenching of the plurality of superconducting coils;
Gas supply means for supplying a quenching gas for quenching the superconducting coil;
Control means for controlling the gas supply means;
A gas flow path for sending the quenching gas to the vicinity of the plurality of superconducting coils;
With
The control means detects the gas flow when the quench detection means detects quenching of at least one superconducting coil of the plurality of superconducting coils and does not detect quenching of the remaining superconducting coils. A cyclotron that quenches the remaining superconducting coil by supplying the quenching gas to the vicinity of the remaining superconducting coil through a path and raising the temperature.   2. The cyclotron according to claim 1, wherein the gas flow path includes a flow path that passes through the inside of the vacuum vessel and partially passes through the vicinity of the superconducting coil.   The cyclotron according to claim 2, wherein the gas flow path is formed on the outer peripheral side of the superconducting coil in the vacuum vessel.   The cyclotron according to claim 1, wherein the gas flow path includes a plurality of flow paths respectively corresponding to the plurality of superconducting coils.   The cyclotron according to claim 1, wherein a vacuum pump is connected to the gas flow path. A quenchback method for the superconducting coil in a cyclotron comprising a plurality of superconducting coils disposed in a vacuum vessel and a cooling means for cooling the plurality of superconducting coils,
When quenching of at least one superconducting coil of the plurality of superconducting coils is detected and quenching of the remaining superconducting coils is not detected, to the vicinity of the remaining superconducting coils through a gas flow path A quench back method for a superconducting coil, wherein the remaining superconducting coil is quenched by supplying a quenching gas to raise the temperature. The gas flow path includes a flow path that passes through the vacuum vessel and a part of the gas flow path passes near the superconducting coil.
The quench back method for a superconducting coil according to claim 6, wherein the quenching gas flowing through the gas flow path is quenched by raising the temperature of the remaining superconductive coil through the gas flow path.   The method of quenching back a superconducting coil according to claim 7, wherein the gas flow path is formed on the outer peripheral side of the superconducting coil in the vacuum vessel. The gas flow path includes a plurality of flow paths respectively corresponding to the plurality of superconducting coils,
The quenchback method for a superconducting coil according to any one of claims 6 to 8, wherein the quenching gas is supplied to a flow path corresponding to the remaining superconducting coil.   The superconducting coil according to any one of claims 6 to 9, wherein a vacuum pump is connected to the gas flow path, and the gas flow path is evacuated by driving the vacuum pump. Quenchback method.

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