Device for cooling object in vacuum chamber

Abstract

The invention relates to a device (1) for cooling an object (100) contained in a vacuum chamber (200), for example a superconducting magnet. The cooling device is insertable into and removable from a shield (300) housed by the vacuum chamber, the shield or a portion of the shield being in thermal contact with the object to be cooled. The distal end portion (4) of the cooling device comprises a first cold station (10) and a first coupling (20) thermally connected to the first cold station, the first coupling comprising at least two moving contacts (22, 60) thermally connected to the first cold station. The cooling device comprises a drive device (50) and a mechanical actuator connecting the drive device to the at least two moving contacts, the drive device and the mechanical actuator are configured for moving each of the at least two moving contacts radially inward and outward so as to release or form thermally conductive contact between the first cold station and the shield or a portion thereof, respectively.

Description

Field of the Invention

[0001] The present disclosure relates to a device for cooling an object contained in a vacuum chamber, such as for cooling a superconducting magnet enclosed in a vacuum chamber. Background Art

[0002] Such devices are generally known in the art. For example, in the field of charged particle therapy, systems are known for generating a charged particle beam and delivering the charged particle beam from a particle accelerator to a patient to be treated with the particle beam. A particle accelerator used in a charged particle therapy system (such as a cyclotron or a synchrocyclotron) may include a superconducting magnet to generate a main magnetic field in the accelerator. The superconducting magnet is an electromagnet whose coils are made of superconducting wire, and the superconducting wire must be cooled to a low temperature during operation. In a particle accelerator, the main superconducting magnet is housed in a thermally insulated container (sometimes referred to as a cryostat) maintained under vacuum. Optionally, the main superconducting magnet may be surrounded by a heat shield for intercepting the heat radiated from the container before it reaches the superconducting magnet. The main superconducting magnet (or its coils) is thermally connected to a cryogenic refrigerator (sometimes referred to as a cryocooler).

[0003] Such cryostats and cryocoolers are known in the art. A cryocooler is generally an independent device that can be inserted into a separate chamber or shield of a cryostat and removed from the chamber or shield of the cryostat for maintenance and / or repair.

[0004] US 8,29,717 discloses a cryocooler for cooling a superconducting magnet contained in a cryostat and allowing replacement or repair without the need to break the cryostat vacuum or heat the superconducting magnet. After the cryocooler is inserted into the shield of the cryostat, a drive device establishes a thermo-mechanical coupling between the cold station of the cryocooler and the superconducting magnet by laterally-axially pushing the cold station of the cryocooler into contact with the inner wall or a part thereof of the shield, via the wall of the shield.

[0005] However, the maintenance and / or repair of such a system is inconvenient, especially since the drive device cannot be easily removed or accessed when it is connected to the shield. After the cryocooler is inserted into the shield, it is not easy to center the cryocooler in the shield, and expensive bellows may be required, which significantly increases the complexity of the cryocooler support structure. The detachment and retraction of the cryocooler from the shield of the cryostat may also be problematic, especially if the thermo-mechanical coupling between the cold station of the cryocooler and the shield becomes stuck due to frozen condensation.

[0006] US 10495261 discloses another example of a removable cryocooler for cooling a superconducting magnet contained in a cryostat. In this device, the cryocooler has a clamping ring made of PTFE, which, due to its radial contraction upon cooling, presses the cup-shaped part of the cold head of the cryocooler against the cylindrical terminal of the heat conduction link of the superconducting magnet. The clamping ring is surrounded by a heating wire to heat the clamping ring so that the clamping ring can expand radially to release the pressure on the cup-shaped part and hopefully release the thermal contact between the cup-shaped part of the cryocooler and the cylindrical terminal of the heat conduction link.

[0007] However, it may take some time to cool and / or heat the clamping ring before the clamping ring sufficiently increases or releases its pressure on the cup-shaped part, and thus before the cryocooler can be effectively used or removed from the protective cover. It may also be problematic to know when the thermal contact is sufficiently established or when the thermal contact is sufficiently released. Detaching and retracting the cryocooler from the protective cover of the cryostat may also be problematic, especially if the connection between the cup-shaped part of the cryocooler and the cylindrical terminal of the heat link becomes stuck due to frozen condensation. In addition, in the case of a failure of the heating system of the cryocooler, the thermal contact will no longer be released and the cryocooler will no longer be disconnected from the protective cover without preheating the entire system, which takes a significant amount of time during which it cannot be operatively used. SUMMARY OF THE INVENTION

[0008] The object of the present disclosure is to solve the problems of existing cooling devices (such as cryocoolers). More specifically, the object of the present disclosure is to provide a cooling device that can be inserted into or removed from a vacuum chamber or inserted into the protective cover of a vacuum chamber, and the cooling device can be easily and / or quickly repaired and / or maintained, especially for its moving parts.

[0009] According to the present disclosure, there is provided a cooling device for cooling an object contained in a vacuum chamber, the cooling device being insertable into and removable from a protective cover accommodated in the vacuum chamber, the cooling device extending along a longitudinal axis and having a proximal part, an intermediate part, and a distal part, the distal part including a first cold head and a first coupler thermally connected to the first cold head. The first coupler includes at least two moving contacts thermally connected to the first cold head. And the cooling device includes a driving device and a mechanical transmission connecting the driving device to the at least two moving contacts, the driving device and the mechanical transmission being configured to move the at least two moving contacts radially inward and / or outward.

[0010] In the context of the present disclosure, "thermally connected" means that there is a heat conduction link between the connecting parts such that heat can be transmitted by conduction between the connecting parts.

[0011] In the context of the present disclosure, and as is commonly known in the mechanical and control arts, a drive device is a component that is adapted to generate a force or torque on a moving contact via a mechanical transmission when input power is supplied to the drive device, or to displace the moving contact in a controlled or controllable manner. For example, the input power can be electrical power, or pneumatic power, or hydraulic power, or human power (i.e., power applied by a human).

[0012] Since the drive device and the mechanical transmission are part of the cooling device, it becomes easy to maintain or replace the drive device and / or parts of the mechanical transmission when the cooling device is removed from the shield of the vacuum chamber. Due to the presence of the drive device, a controlled force can also be applied on these moving contacts such that these moving contacts move radially inwards and / or outwards in a controlled manner and are independent of any type of heating or cooling of any component.

[0013] In some embodiments, the drive device is a manually driven device such as a crank or a lever or a wheel, and the manually driven device can be operated by a person.

[0014] In some embodiments, the drive device is a motor such as an electric motor, or an electromagnet, or a hydraulic motor, or a pneumatic motor, or a hydraulic cylinder, or a pneumatic cylinder.

[0015] In some embodiments, the drive device and the mechanical transmission are configured to drive and move each of at least two moving contacts radially inwards to a thermally disconnected configuration, and to drive and move each of at least two moving contacts radially outwards to a thermally connected configuration, or vice versa.

[0016] In some embodiments, the drive device is configured to simultaneously and radially inwards drive and / or move each of at least two moving contacts to a thermally disconnected configuration, and to simultaneously and radially outwards drive and / or move each of at least two moving contacts to a thermally connected configuration, or vice versa. Simultaneously means that the moving contacts all move together and move synchronously from their respective initial starting positions (outwards or inwards). This allows for good centering of the cooling device after the cooling device has been inserted into the shield of the vacuum chamber and upon actuation of the drive device.

[0017] In some embodiments, the drive device is arranged at a proximal portion of the cooling device, and the mechanical transmission includes a drive shaft that connects the drive device to a first coupler. This allows for easy access to the drive device from the outside of the vacuum chamber when the cooling device is inserted into the shield of the vacuum chamber.

[0018] According to the present disclosure, there is also provided a charged particle accelerator, which includes: a vacuum chamber, a main superconducting magnet, a protective shield, one or more thermal links, and a cooling device as described herein; the main superconducting magnet is disposed within the vacuum chamber, the protective shield is received within the vacuum chamber and presents an opening to the surrounding environment, and the one or more thermal links are located between the superconducting magnet and the protective shield or a portion thereof. Description of the Drawings

[0019] These and further aspects will be explained in more detail by way of example and with reference to the drawings, in which:

[0020] Figure 1 A general cross-sectional view schematically shows the cooling device according to the present disclosure in an operating position inside the protective shield of the vacuum chamber;

[0021] Figure 2 Schematically shows Figure 1 a general cross-sectional view of the cooling device when partially retracted from the protective shield;

[0022] Figure 3 A partial cross-sectional view schematically shows a first embodiment of the cooling device according to the present disclosure in an operating position inside the protective shield of the vacuum chamber;

[0023] Figure 4 Shows Figure 3 a cross-sectional view of the cooling device;

[0024] Figure 5 A partial cross-sectional view schematically shows a second embodiment of the cooling device according to the present disclosure in an operating position inside the protective shield of the vacuum chamber;

[0025] Figure 6 Shows Figure 5 a cross-sectional view of the cooling device;

[0026] Figure 7 Schematically shows Figure 3 a cross-sectional view of a preferred embodiment of the cooling device;

[0027] Figure 8 Schematically shows Figure 5 a cross-sectional view of a preferred embodiment of the cooling device;

[0028] Figure 9 A cross-sectional view schematically shows another embodiment of the cooling device according to the present disclosure.

[0029] Figure 10 A partial view schematically shows a third embodiment of the cooling device according to the present disclosure in an operating position inside the protective shield of the vacuum chamber;

[0030] Figure 11 Schematically shows Figure 7 a cross-sectional view of a preferred embodiment of the cooling device;

[0031] Figure 12 Schematically shows a cross-sectional view of a fourth embodiment of the cooling device according to the present disclosure when in an operating position inside a protective cover of a vacuum chamber;

[0032] Figure 13 Schematically shows a cross-sectional view of a fifth embodiment of the cooling device according to the present disclosure when in an operating position inside a protective cover of a vacuum chamber;

[0033] Figure 14 Schematically shows a charged particle accelerator including an embodiment of the cooling device according to the present disclosure;

[0034] Figure 15 Schematically shows a charged particle accelerator including another embodiment of the cooling device according to the present disclosure.

[0035] The figures are neither drawn to scale nor in proportion. Generally, similar or identical components are denoted by the same reference numerals in the figures. Detailed description of the invention

[0036] Figure 1 Schematically shows an overall cross-sectional view of a cooling device 1 (hereinafter sometimes also referred to as a "cryocooler") according to the present disclosure, for example, when inserted into an operating position in a protective cover 300 housed in a vacuum chamber 200 (hereinafter sometimes also referred to as a "cryostat"), the vacuum chamber containing an object 100 cooled by the cooling device. The object to be cooled in the vacuum chamber can be, for example, a superconducting magnet, such as the main magnet of a particle accelerator, such as the main magnet of a cyclotron (e.g., a synchrocyclotron).

[0037] Figure 2 Schematically shows Figure 1 an overall cross-sectional view of the cooling device 1 in the vacuum chamber 200 when partially retracted from the protective cover 300. As can be seen in this figure, the entire cooling device 1 can be longitudinally removed without breaking the vacuum of the vacuum chamber 200.

[0038] As can be seen in Figure 1 and Figure 2 the cooling device 1 can be longitudinally inserted into and removed from the protective cover 300 housed in the vacuum chamber 200. In Figure 1 and Figure 2 the vacuum chamber 200 and the protective cover 300 are shown in dashed lines and are not part of the cooling device 1.

[0039] The cooling device 1 extends along a longitudinal axis L and has a proximal portion 2, an intermediate portion 3, and a distal portion 4. The proximal portion 2 is the portion of the cooling device 1 that is located outside the vacuum chamber 200 when the cooling device 1 is inserted into the protective housing 300, and this portion may include, for example, a flange and a connector to provide an airtight connection between the cooling device 1 and the protective housing 300 when the cooling device 1 is inserted into the protective housing 300. In the case of a cryocooler, the proximal portion 2 is sometimes referred to as the head of the cryocooler. The distal portion 4 includes a first cold station 10 and a first coupler 20 that is thermally connected to the first cold station 10. In operation, the cooling device 1 cools the first cold station 10, which in turn allows the object 100 to be cooled to enter the cryostat through a thermal link (shown by three serpentine dashed lines) between the first cold station 10 and the object 100 to be cooled via the first coupler 20 and the protective housing 300 or a part thereof.

[0040] This is well known in the art and will not be described further.

[0041] Now, a plurality of exemplary embodiments of the cooling device 1 according to the present invention will be described in more detail.

[0042] A cross-sectional view of a first embodiment of the cooling device 1 (or cryostat) according to the present disclosure is shown in Figure 3 and a sectional view is shown in Figure 4 It is the same as the cooling device shown in Figure 1 and Figure 2 but has more details of its distal portion, which includes the first coupler 20 and its drive device 50 as well as a mechanical transmission.

[0043] In this first embodiment, the first coupler 20 includes a cup-shaped part 21 that is attached to and thermally connected to the first cold station 10. The cup-shaped part 21 may alternatively form an integral part of the first cold station 10.

[0044] The cup-shaped part 21 has at least two flexible extensions 22 that extend longitudinally and are arranged radially opposite to each other. In this example, the cup-shaped part 21 includes two flexible extensions. The flexible extensions 22 are adapted to deform flexibly (i.e., elastically deform) and deform radially outward or inward (upward and / or downward in the cross-sectional views of Figure 3 and Figure 4 ). These flexible extensions constitute the moving contacts 22, which can be in thermally conductive contact with the protective housing 300 when the moving contacts 22 are deformed, as will be explained below.

[0045] The first connector 20 further includes at least two pusher 60 respectively arranged in front of at least two moving contacts 22. In this example, the first connector 20 includes two pushers 60 which are respectively arranged in front of the two moving contacts 22 to cooperate with the two moving contacts 22 respectively.

[0046] When the two pushers 60 move radially outward, as Figure 3 and Figure 4 shown by the two arrows in, they will respectively push the two moving contacts 22 and deform the two moving contacts 22 until they form thermal contact with the inner wall of the protective cover 300. When this thermal contact is established, heat can be conducted from the wall of the protective cover 300 through the two moving contacts 22 to the first cold station 10, thereby allowing the object 100 to be cooled to enter the cryostat. Since in this example these moving contacts 22 are arranged opposite to each other, their radially outward movement will additionally help to center the cooling device 1 in the protective cover 300 after the cooling device 1 has been inserted into the protective cover 300. When the two pushers 60 then move radially inward, they will release the pressure against the two moving contacts 22, such that the two moving contacts 22 will elastically return to their initial positions, or at least will loosen the contact with the inner wall of the protective cover 300. When this contact is loosened, the cooling device 1 can be withdrawn from the protective cover 300 for, for example, repair or maintenance.

[0047] The cooling device 1 may further include guiding means (not shown) for guiding each of the two pushers 60 in only the radial direction (with only one degree of freedom).

[0048] The cooling device 1 further includes a drive device 50 and a mechanical transmission connecting the drive device 50 to at least two moving contacts 22, the drive device 50 and the mechanical transmission being configured to move each of the at least two moving contacts 22 radially inward and / or outward.

[0049] In Figure 3 and Figure 4 example, the drive device 50 includes a motor (such as an electric motor), and the mechanical transmission includes a drive shaft 81, a gear train 82 and two pushers 60, all arranged at the distal portion 4 of the cooling device 1. The drive shaft 81 connects the motor to the gear train 82.

[0050] The gear train 82 has a gear ratio R. In some examples, the value of R is greater than 1, preferably greater than 5, and preferably greater than 10. This allows an increase in the torque applied to the driven wheel 83 of the gear train 82 and thus an increase in the force applied to the pusher 60. In the present example, the drive shaft 81 is mounted on a first bearing which is mounted on the disc-shaped portion of the cup-shaped part 21, and the shaft of the driven wheel 83 of the gear train 82 is mounted on a second bearing which is mounted on the central portion of the disc-shaped portion of the cup-shaped part 21. In this example, the motor is attached to the disc-shaped portion of the cup-shaped part 21, but it could also be attached to another fixed part of the cooling device 1.

[0051] The driven wheel 83 of the gear train 82 is configured to cooperate with two pushers 60 to radially move two moving contact members 22 of the first coupler 20 inwardly and / or outwardly. To obtain such cooperation and movement, the driven wheel 83 of the gear train 82 may for example include two arcuate holes 84, each arcuate hole having one end at a first distance from the center of the driven wheel 83 and an opposite end at a second distance from the center of the driven wheel 83, the second distance being different from the first distance, and the two pushers 60 each include an axially extending portion 85, such as a rod respectively cooperating with a corresponding one of the two arcuate holes 84. Thus, when the motor is controlled to rotate in one direction, the driven wheel 83 of the gear train 82 will force the two pushers 60 to move radially outward, thereby pushing the moving contact members 22 to establish a thermal connection between the moving contact members and the protective cover 300. When the motor is controlled to rotate in the opposite direction, the driven wheel 83 of the gear train 82 will force the pushers 60 to move radially inward, thereby releasing the connection between the moving contact members 22 and the protective cover 300.

[0052] Figure 4 A cross-sectional view of the Figure 3 cooling device is shown. In this figure, the two arcuate holes 84 of the driven wheel 83 of the gear train 82 and how they cooperate with the pushers 60 and their axially extending portions 85 can be better seen. In the present example, both the moving contact members 22 and the distal portions 60a of the pushers 60 have an arcuate shape corresponding to the shape of the inner wall of the protective cover 300 at their contact zones in order to obtain good thermal contact. Alternatively, in the case where the inner wall of the protective cover 300 presents a flat or planar portion at the contact zone, the distal portions 60a and the moving contact members 22 of the pushers 60 may all have a flat shape. For example, this may occur when the inner wall of the protective cover 300 has a square or rectangular or polygonal cross-section at the contact zone (as seen in the example described Figure 9 below). By "contact zone" or "contact area", one must understand the zone or area where a thermal contact is formed between the first coupler 20 and the protective cover 300 when the drive device 50 of the cooling device 1 is actuated.

[0053] In some examples, each movable contact is mechanically connected to its corresponding pusher 60, for example, by a flexible mechanical link or a hinged mechanical link therebetween. Thus, when the drive device 50 pulls the pusher 60 to move the pusher radially inwardly, each pusher 60 will also pull its corresponding movable contact to move the corresponding movable contact inwardly. This has the advantage that it forces the contact between each movable contact 22 and the protective cover 300 to be broken, which may be useful, for example, in cases where such contact becomes frozen.

[0054] In Figure 3 and Figure 4 examples, the drive device 50 and the mechanical transmission are configured herein to drive and / or move each of at least two movable contacts 22 radially inwardly to a thermally disconnected configuration, and to drive and / or move each of at least two movable contacts 22 radially outwardly to a thermally connected configuration.

[0055] Figure 5 and Figure 6 show a cross-sectional view of a second embodiment of a cooling device (or cryostat) according to the present disclosure. In this second embodiment, except that the first coupler 20 is slightly different, it is the same as the Figure 3 and Figure 4 shown cooling device 1. In this second embodiment, the cup-shaped part 21 of the first coupler 20 does not have a flexible extension arranged around the pusher as in the case of the first embodiment, but has a longitudinal guiding extension 23, as Figure 5 and Figure 6 shown. Each guiding extension includes, for example, a groove, and each pusher 60 passes freely and tightly through the groove respectively, so that each pusher 60 is in sliding thermal contact with each corresponding guiding extension respectively. In other words, in this second embodiment, the pusher 60 is a movable contact. Alternatively or complementarily, flexible thermal links may be arranged between the two guiding extensions 23 and the two pushers 60 respectively, as Figure 5 and Figure 6As shown by the two dashed lines thereon. Thus, when the two moving contact members (the two pusher 60) are in contact with the protective cover 300, heat can be transferred through conduction between the protective cover 300 and the first cold station 10 via the two moving contact members (the two pusher 60). The driving device 50 here is the same as the driving device 50 in the first embodiment. When powered on, the driving device 50 will thus also move the pusher 60 radially outward and / or inward. When controlling the driving device 50 to move the pusher 60 radially outward, the pusher 60 will directly contact the inner wall of the protective cover 300, such that when the cooling device 1 operates, heat will be transferred from the object to be cooled 100 to the first cold station 10 through the protective cover 300 (or a part thereof) and the first coupler 20. When controlling the driving device 50 to move the pusher 60 radially inward, the pusher 60 will move away from the inner wall of the protective cover 300, such that the thermal connection will be loosened and the cooling device 1 can be pulled out from the protective cover 300.

[0056] Figure 6 shows Figure 5 a cross-sectional view of the cooling device. In this figure, another view of the guiding extension 23 can be seen. In this second embodiment, the distal end portion 60a of the moving contact member (the pusher 60) also has an arc shape corresponding to the shape of the inner wall of the protective cover 300 at its contact area, so as to obtain good thermal contact. Alternatively, in the case where the inner wall of the protective cover 300 presents a flat or planar portion at the contact area, the distal end portion 60a of the moving contact member (the pusher 60) can all have a flat shape. For example, as Figure 9 shown, this may occur when the inner wall of the protective cover 300 has a square or rectangular or polygonal cross-section at the contact area.

[0057] Figure 7 schematically shows Figure 3 a cross-sectional view of a preferred embodiment of the cooling device. Except that the driving device 50 is arranged at the proximal portion 2 of the cooling device 1 (i.e., on the left side of the cooling device, as Figure 7 shown), this device is the same as the Figure 3 embodiment. In this example, the driving device 50 is more precisely arranged outside the portion of the cooling device that will be inserted into the protective cover 300, such that when the cooling device 1 is inserted into the protective cover 300, the driving device 50 is accessible from the outside of the protective cover 300 or from the outside of the vacuum chamber 200.

[0058] Figure 8 schematically shows Figure 5 a cross-sectional view of a preferred embodiment of the cooling device. Except that the driving device 50 is arranged at the proximal portion 2 of the cooling device 1 (i.e., on the left side of the cooling device, as Figure 8 shown), it is the same as the Figure 5is the same as the embodiment. In this example, the drive device 50 is more specifically arranged outside the part of the cooling device that is to be inserted into the protective cover 300.

[0059] In Figure 7 and Figure 8 's embodiments, the drive device 50 can be a motor or a manually driven device 50, such as a crank or a lever or a wheel, and when the cooling device 1 is inserted into the protective cover 300 of the vacuum chamber 200 in the operating position, the drive device 50 can be operated by a person from outside the vacuum chamber 200.

[0060] In the embodiments described so far, there are two moving contact members 22, but there can also be more. In each embodiment, there can be two to sixteen moving contact members 22. In some examples, there is a pair of moving contact members 22, and more preferably there are eight moving contact members 22.

[0061] In each embodiment, at least two moving contact members 22 are angularly evenly spaced around the longitudinal axis L of the cooling device 1 and are arranged equidistant from the longitudinal axis L.

[0062] Figure 9 A cross-sectional view schematically shows yet another embodiment of the cooling device according to the present invention. It is the same as Figure 3 or Figure 7 's embodiments, except that the coupler counts six moving contact members 22 and six pusher members 60 instead of two, and except that the distal portions 60a of the moving contact members 22 and the pusher members 60 all have a flat or planar shape so as to contact each other and the inner surface of the protective cover 300 when the protective cover 300 has a hexagonal cross-section. As Figure 9 can be seen, the moving contact members 22 are angularly evenly spaced around the longitudinal axis L of the cooling device 1. In this example, there is an angle of 60° between each pair of adjacent moving contact members 22. These moving contact members 22 are also arranged equidistant from the longitudinal axis L of the cooling device 1.

[0063] Obviously, the coupler can include more or fewer than six moving contact members 22, and the inner wall of the protective cover 300 can have other polygonal cross-sections with corresponding arrangements of the moving contact members 22 and the pusher members 60.

[0064] Figure 10 A cross-sectional view shows a third embodiment of the cooling device according to the present invention. Except for some differences on the first coupler side, it is the same as Figure 1 and Figure 3The cooling devices shown are the same. In this third embodiment, the cup-shaped part 21 of the coupler is still in thermal contact with the first cold station 10 of the cooling device 1, but it is arranged more centrally between the pusher 60s that surround the flexible extension (the moving contact 22) of the cup-shaped part 21 of the first coupler. This configuration is particularly suitable when the protective cover 300 has a centrally arranged thermal port 310 (such as a cylinder) at its distal end. The drive device 50 is substantially the same as in other embodiments. Here, the drive device 50 is configured to drive and / or move each of at least two moving contacts 22 radially inwards to a thermal connection configuration, and to drive and / or move each of the at least two moving contacts 22 radially outwards to a thermal disconnection configuration.

[0065] In some examples, each moving contact 22 is mechanically connected to its corresponding pusher 60, for example, by a flexible mechanical link or a hinged mechanical link therebetween. Thus, when the drive device 50 drives the pushers 60 to move them in one radial direction or in the opposite radial direction, the pushers 60 will also drive their corresponding moving contacts 22 in the same direction.

[0066] In Figure 10 the example of, the drive device 50 and the mechanical transmission are thus configured to drive and / or move each of at least two moving contacts 22 radially inwards to a thermal connection configuration, and to drive and / or move each of at least two moving contacts 22 radially outwards to a thermal disconnection configuration.

[0067] Figure 11 is schematically shown Figure 7 a cross-sectional view of a preferred embodiment of the cooling device of. Except that the middle part 3 of the cooling device 1 includes a second cold station 90 and a second coupler 91 thermally connected to the second cold station 90, it is the same as the Figure 7 cooling device of. The second coupler 91 can be the same as the first coupler 20 described herein. In this case, the second coupler also has a drive device and a mechanical transmission as described herein (although a separate drive device), or the second coupler can be a passive device as shown in Figure 11 In Figure 11 the example of, the second coupler 91 includes a series of passive elements arranged around and in thermal contact with the second cold station 90. The size and arrangement of these passive elements are determined such that they form a sliding contact with the inner wall of the protective cover 300 when the cooling device 1 is installed in the protective cover 300. Due to the sliding contact, heat can be transferred from the object 100 to be cooled to the second cold station 90 via the protective cover 300 and the passive elements. These passive elements can be, for example, annular springs, such as the Bal The second cold station 90 and the second coupler 91 can be used to cool another object in the vacuum chamber 200, such as cooling a heat shield 400 including corresponding heat-conducting portions included in the vacuum chamber 200 and thermally connected to the protective cover 300, for example regarding Figure 15 as shown.

[0068] Figure 12 A cross-sectional view is schematically shown of a fourth embodiment of the cooling device according to the present disclosure in an operating position inside the protective cover 300 of the vacuum chamber 200. This embodiment is the same as the other embodiments described herein, except that the pusher 60 is differently arranged and moves differently when driven by the drive device 50. In the present example, the distal portion 60a of the pusher 60 is rotatably mounted on the cooling device (e.g., on the cup-shaped part 21) via a hinge 61, for example, the hinge 61 is arranged at one end portion of the distal portion 60a ( Figure 12 the right portion on the top pusher 60 in), and the axis of the hinge 61 is parallel to the longitudinal axis L of the cooling device. The other end portion of the distal portion 60a opposite to the hinge 61 ( Figure 12 the left portion on the top pusher 60 in) is arranged to cooperate with one end of the radial portion of the pusher 60 ( Figure 12 one end of the vertical portion on the top pusher 60 in). The distal portion 60a of the pusher 60 can be a flexible portion attached to one end of the radial portion of the pusher 60 or flexibly connected to one end of the radial portion of the pusher 60. Thus, when the drive device 50 is actuated, the radial portion of the pusher 60 will push and / or pull on its distal portion 60a, thereby establishing or disconnecting thermal contact with the protective cover 300 via the corresponding movable contact 22. The same applies to other pushers 60. It is obvious that the same arrangement can be used without the movable contact 22, for example, in the case of the embodiments shown in Figure 5 , Figure 6 and Figure 8 shown.

[0069] Figure 13 A cross-sectional view is schematically shown of a fifth embodiment of the cooling device according to the present disclosure in an operating position inside the protective cover 300 of the vacuum chamber 200. This embodiment is the same as the embodiments described herein regarding, for example Figure 3 , Figure 4 , Figure 7 and Figure 9 described, except that the pusher 60 is differently arranged and moves differently when driven by the drive device 50. In the present example, two pushers 60 are fixedly attached to the driven wheel 83 of the gear train 82 and thus rotate about the axis of the driven wheel 83 when the drive device 50 is actuated, as Figure 13as indicated by the double arrows. Each of these actuators 60 has a circular distal portion that contacts the respective moving contact 22 and thus radially outwardly pushes the moving contact 22 when the driven wheel 83 rotates clockwise until Figure 13 the position shown in. When the driven wheel 83 then rotates counterclockwise (or further clockwise in this case) until the angle at which the actuator 60 no longer contacts the moving contact 22, the pressure on the moving contact 22 will be released, thereby loosening the thermal contact between the moving contact 22 and the protective cover 300.

[0070] Regardless of the embodiment, the mechanical transmission has a transmission ratio of R, where R is greater than 1, or greater than 5, or greater than 10. As is well known, the transmission ratio R of a mechanical transmission is the ratio Wi / Wo, where Wi is the input speed of the mechanical transmission and Wo is the output speed of the mechanical transmission.

[0071] In some examples, the cooling device 1 is adapted to cool the first cold station 10 to a temperature between 1°K and 100°K or between 1°K and 25°K during operation, and in some examples, to a temperature between 2°K and 10°K.

[0072] In some examples, the cooling device 1 is adapted to cool the second cold station 90 to a temperature between 30°K and 100°K during operation, and in some examples, to a temperature between 30°K and 60°K.

[0073] The present disclosure also provides a charged particle accelerator 1000, comprising:

[0074] a vacuum chamber 200;

[0075] a main superconducting magnet 100 disposed in the vacuum chamber;

[0076] a protective cover 300 received in the vacuum chamber 200 and presenting an opening to the surrounding environment;

[0077] one or more thermal links located between the superconducting magnet 100 and the protective cover 300 or a portion of the protective cover 300; and

[0078] a cooling device as described herein, disposed in the protective cover 300.

[0079] As is known in the field of particle accelerators, the vacuum chamber 200 is sometimes referred to as a cryostat, the cooling device 1 is sometimes referred to as a cryocooler, and the main superconducting magnet is an electromagnet that imposes the trajectory of charged particles when they are gradually accelerated into the accelerator.

[0080] The thermal link is, for example, a heat conduction link, such as made of copper or aluminum, or a liquid link (such as liquid helium), or a combination of these.

[0081] Figure 14 Schematically shown is an exemplary charged particle accelerator 1000 including an embodiment of a cooling device 1 according to the present disclosure. Figure 14 The illustrated cooling device 1 is, for example, with respect to Figures 7 to 10 or Figures 12 to 13 the described cooling device. Thus, when the cryocooler operates, heat will be transferred from the superconducting magnet 100 via the first thermal link 501, the distal portion 4 of the shield 300, and the first coupler 20 to the first cold station 10 of the cryocooler. In this configuration, the cooling device is, for example, adapted to cool the first cold station 10 to a temperature between 1°K and 100°K during operation, or to a temperature between 1°K and 10°K, preferably to a temperature between 3°K and 6°K.

[0082] Figure 15 Schematically shown is an exemplary charged particle accelerator 1000 including another embodiment of a cooling device according to the present disclosure. Figure 15 The illustrated cooling device 1 is, for example, with respect to Figure 11 the described cooling device. In this case, the vacuum chamber 200 also houses a thermal shield 400 at least surrounding the superconducting magnet. Thus, when the cryocooler operates, heat will be transferred from the superconducting magnet 100 via the first thermal link 501, the distal portion 4 of the shield 300, and the first coupler 20 to the first cold station 10 of the cryocooler, and heat will also be transferred from the thermal shield via the second thermal link 502, the intermediate portion 3 of the shield 300, and the second coupler 91 to the second cold station 90 of the cryocooler. In this configuration, the cooling device 1 is, for example, adapted to cool the first cold station 10 to a temperature between 1°K and 100°K during operation, or to a temperature between 1°K and 10°K, and to cool the second cold station 90 to a temperature between 15°K and 100°K, or to a temperature between 20°K and 60°K.

[0083] In some examples, the charged particle accelerator 1000 is a cyclotron or a synchrocyclotron.

[0084] In Figure 14 and Figure 15 examples, the superconducting magnet is thermally linked to these first thermal links 501.

[0085] In other examples, the superconducting magnet may be arranged, for example, in an enclosure containing liquid helium, which enclosure is accommodated in the vacuum chamber 200, preferably inside the thermal shield 400. In this case, the first thermal link 501 is thermally connected to a condenser arranged in the enclosure in order to condense the helium after it has evaporated due to being heated by the superconducting magnet.

[0086] The device has been described according to specific embodiments which are illustrative and should not be construed as restrictive. The reference signs in the claims, if any, do not limit their scope of protection. The use of the verbs “to comprise”, “to include”, “to consist of” or any other variants and their corresponding conjugates does not exclude the presence of elements other than those stated. The use of the article “a”, “an” or “the” before an element does not exclude the presence of a plurality of such elements.

[0087] The device according to the present disclosure may also be described as follows: A device for cooling an object 100 accommodated in a vacuum chamber 200, which object is, for example, a superconducting magnet. The cooling device 1 can be inserted into and removed from a protective shield 300 accommodated by the vacuum chamber 200, and the protective shield or a part thereof is in thermal contact conduction and / or convection with the object 100 to be cooled. The distal portion 4 of the cooling device 1 includes a first cold station 10 and a first coupler 20 thermally connected to the first cold station 10, the first coupler 20 including at least two movable contacts 22, 60 which are thermally connected to the first cold station 10. And the cooling device 1 includes a drive device 50 and a mechanical transmission connecting the drive device 50 to the at least two movable contacts 22, 60, the drive device 50 and the mechanical transmission being configured to radially move each of the at least two movable contacts 22, 60 inwards and outwards in order to form or release a thermally conductive contact between the first cold station 10 and the protective shield 300 or a part thereof.

Claims

1. A cooling device (1) for cooling an object contained in a vacuum chamber (200), the cooling device being insertable into and removable from a protective cover (300) accommodated by the vacuum chamber (200), the cooling device extending along a longitudinal axis (L) and having a proximal portion (2), an intermediate portion (3) and a distal portion (4), the distal portion (4) including a first cold station (10) and a first coupler (20) thermally connected to the first cold station (10). Among them, The first coupler (20) includes at least two moving contacts (22, 60), the at least two moving contacts being thermally connected to the first cold station (10), and wherein the cooling device includes a drive device (50) and a mechanical transmission, the mechanical transmission connecting the drive device (50) to the at least two moving contacts (22, 60), the drive device (50) and the mechanical transmission being configured to move each of the at least two moving contacts (22, 60) radially inwards and outwards.

2. The cooling device according to claim 1, wherein, The drive device (50) is a motor or a manually operated drive device.

3. The cooling device according to claim 1, wherein, The drive device (50) and the mechanical transmission are configured to drive and / or move each of the at least two moving contacts (22) radially inwards to a thermally disconnected configuration, and to drive and / or move each of the at least two moving contacts (22) radially outwards to a thermally connected configuration, and vice versa.

4. The cooling device according to claim 1, wherein, The drive device (50) is arranged at the proximal portion (2) of the cooling device (1), and wherein the mechanical transmission includes a drive shaft (81) connecting the drive device (50) to the first coupler (20).

5. The cooling device according to claim 1, wherein The mechanical transmission has a transmission ratio R, where R is greater than 1.

6. The cooling device according to claim 5, wherein, The mechanical transmission includes a gear train (82) arranged at the distal portion (4) of the cooling device (1), and wherein a driven wheel (83) of the gear train (82) is configured to cooperate with the at least two moving contacts (22) of the first coupler (20).

7. The cooling device according to claim 6, wherein, The driven wheel (83) of the gear train (82) includes at least two arcuate holes (84), each arcuate hole having one end spaced a first distance from the center of the driven wheel (83) and an opposite end spaced a second distance from the center of the driven wheel (83), the second distance being different from the first distance, and wherein the mechanical transmission includes at least two pushers (60) arranged in front of the at least two moving contacts (22) respectively, the at least two pushers (60) each having an axially extending portion (85) cooperating with a corresponding one of the at least two arcuate holes (84).

8. The cooling device according to claim 6, wherein, The driven wheel (83) of the gear train (82) includes at least two arcuate holes (84), each arcuate hole having one end spaced a first distance from the center of the driven wheel (83) and an opposite end spaced a second distance from the center of the driven wheel (83), the second distance being different from the first distance, and wherein the at least two moving contact members (60) each have an axially extending portion (85) that mates with a corresponding one of the at least two arcuate holes (84).

9. The cooling device according to claim 1, wherein The at least two moving contact members (22, 60) are angularly evenly spaced about the longitudinal axis (L) of the cooling device (1).

10. The cooling device according to claim 9, wherein, The at least two moving contact members (22, 60) are between two and sixteen moving contact members, preferably a pair of moving contact members, more preferably six or eight moving contact members.

11. The cooling device according to claim 1, wherein, The cooling device (1) is adapted to cool the first cold station (10) to a temperature between 1°K and 100°K or between 1°K and 10°K during operation.

12. The cooling device according to claim 1, wherein, The intermediate portion (3) includes a second cold station (90) and a second coupler (91) thermally connected to the second cold station (90).

13. The cooling device according to claim 12, wherein, The second coupler (91) includes a series of passive elements disposed around the second cold station (90) and in thermal contact with the second cold station (90).

14. The cooling device according to claim 13, wherein, The passive element is an annular spring.

15. The cooling device according to claim 12, wherein, The cooling device (1) is adapted to cool the second cold station (90) to a temperature between 15°K and 100°K or between 20°K and 60°K during operation.

16. A charged particle accelerator (1000) comprising: A vacuum chamber (200); A main superconducting magnet (100), the main superconducting magnet (100) being disposed in the vacuum chamber (200); A protective shield (300), the protective shield (300) being received in the vacuum chamber (200) and presenting an opening to the surrounding environment; One or more thermal links (501, 502) between the superconducting magnet (100) and the protective shield (300) or a portion of the protective shield (300); and The cooling device according to claim 1, the cooling device being disposed in the protective shield (300).

17. The charged particle accelerator (1000) according to claim 16, wherein, The accelerator is a cyclotron or a synchrocyclotron.

Images