Device for cooling object in vacuum chamber

Abstract

To provide a cooling device that can be inserted into and removed from a vacuum chamber.SOLUTION: A cooling device 1 for cooling an object 100 in a vacuum chamber 200 can be inserted into and removed from a boot 300 in the vacuum chamber 200, and the boot 300 or a portion thereof is in thermal contact with the object 100. A distal portion 4 of the cooling device, comprises: a first cold station 10; and a first coupler 20 thermally connected to a first cold station. The first coupler 20 comprises at least two movable contacts 22, 60 thermally connected to the first cold station 10. The cooling device comprises: driving means 50; and a mechanical transmission device connecting the driving means to the movable contacts 22 and 60. The driving means and the mechanical transmission device move each of the movable contacts 22 and 60 radially inwardly and outwardly to loosen or make conductive thermal contact between the first cold station 10 and the boot 300 or a portion thereof.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a device for cooling an object placed in a vacuum chamber, for example, 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 beam therapy, a system for generating a charged particle beam and transporting it from a particle accelerator to a patient to be treated with the particle beam is known. For example, a particle accelerator for use in a charged particle beam therapy system, such as a cyclotron or a synchrocyclotron, may include a superconducting magnet that generates a main magnetic field within the accelerator. A superconducting magnet is an electromagnet made of superconducting wire that must cool its coil to cryogenic temperatures during operation. In a particle accelerator, the main superconducting magnet is housed in a thermally insulated container maintained in a vacuum state, sometimes referred to as a cryostat. Optionally, the main superconducting magnet may be surrounded by a thermal shield that serves to block the heat released by the container before it reaches the superconducting magnet. The main superconducting magnet (or its coil) is thermally linked to a cryogenic cooling device, 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 boot of a cryostat and removed from the chamber or boot of the cryostat for maintenance and / or repair.

[0004] No. 8,291,717 discloses a cryocooler for cooling a superconducting magnet encased in a cryostat, which allows replacement or repair to be performed without the need to break the cryostat vacuum or warm the superconducting magnet. After the cryocooler is inserted into the boot of the cryostat, a drive means pushes the cryocooler's cold station across the axis, causing contact with the inner wall of the boot or a portion thereof, thereby establishing a thermomechanical coupling between the cryocooler's cold station and a conductive thermal link to the superconducting magnet through the wall of the boot. However, such systems are difficult to maintain and / or repair, particularly because the drive means is connected to the boot and the drive means cannot be easily removed or accessed. Centering the cryocooler within the boot after insertion into the boot is also difficult and can require the use of expensive bellows for centering, which significantly increases the complexity of the cryocooler support structure. Release and retraction of the cryocooler from the cryostat boot can also be problematic, particularly if the thermomechanical coupling between the cryocooler's cold station and the boot becomes stuck due to freezing.

[0005] U.S. Patent No. 10,495,261 discloses another example of a removable cryocooler for cooling a superconducting magnet encased in a cryostat. In this device, the cryocooler has a clamp ring made of PTFE. When cooled, the clamp ring contracts radially, thereby pressing the cup-shaped portion of the cryocooler's cold station against the cylindrical terminal of a conductive heat link for the superconducting magnet. The clamp ring is surrounded by a heating wire that heats the clamp ring, allowing it to expand radially to release pressure on the cup-shaped portion and, potentially, break thermal contact between the cryocooler's cup-shaped portion and the cylindrical terminal of the conductive heat link. However, it may take a certain amount of time to cool and / or heat the clamp ring until the pressure on the cup-shaped portion is sufficiently increased or released, and thus until the cryocooler can be effectively used or removed from the boot. Also, it may be a problem to know when the thermal contact is sufficiently established or when the thermal contact is sufficiently released. Especially when the connection between the cup-shaped portion of the cryocooler and the cylindrical terminal of the thermal link becomes immovable due to freezing, the release and retraction of the cryocooler from the boot of the cryostat can also be a problem. Furthermore, if the heating system of the cryocooler fails, the thermal contact can no longer be released, and the cryocooler can no longer be disconnected from the boot unless the entire system is warmed up, which takes a lot of time and during which the cryocooler cannot be used.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] An object of the present disclosure is to address the problems of current cooling devices, such as cryocoolers. More specifically, an 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 boot of a vacuum chamber, and that can be easily and / or quickly repaired and / or maintained, particularly with respect to its movable members.

Means for Solving the Problems

[0008] According to the present disclosure, a cooling device for cooling an object placed in a vacuum chamber is provided. The cooling device can be inserted into and removed from a boot housed by the vacuum chamber, extends along a longitudinal axis, and has a proximal portion, an intermediate portion, and a distal portion. The distal portion includes a first cryogenic station and a first coupler thermally connected to the first cryogenic station. The first coupler includes at least two movable contacts thermally connected to the first cryogenic station. The cooling device includes a driving means and a mechanical transmission device connecting the driving means to the at least two movable contacts. The driving means and the mechanical transmission device are configured to move the at least two movable contacts radially inward and / or outward.

[0009] In the context of the present disclosure, "thermally connected" means that there is a conductive thermal link between the connected members, and as a result, heat is transmitted by conduction between the connected members.

[0010] In the context of the present disclosure, and as generally known in the field of mechanical control, the driving means is a component adapted to generate a force or torque or displacement of the movable contact for the movable contact through a mechanical transmission device in a controlled or controllable manner when input power is supplied to the driving means. The input power can be, for example, electric power, or pneumatic power, or hydraulic power, or human power (i.e., power applied by a person).

[0011] Since the driving means and the mechanical transmission device are part of the cooling device, when the cooling device is removed from the boot of the vacuum chamber, maintenance or replacement of the driving means and / or each member of the mechanical transmission device becomes easier. The presence of the driving means further enables applying a controlled force to the movable contact. Thus, such movable contacts move radially inward and / or outward in a controlled manner and without depending on any kind of heating or cooling of any member.

[0012] In some embodiments, the driving means is a manually operable manual driving means such as a crank, a lever, or a wheel.

[0013] In some embodiments, the driving means is a motor such as an electric motor, or an electromagnet, or a pneumatic motor, or a hydraulic motor, or a pneumatic cylinder, or a hydraulic cylinder.

[0014] In some embodiments, the driving means and the mechanical transmission are configured to drive and move each of at least two movable contacts radially inward to thermally disconnect them, and to drive and move each of at least two movable contacts radially outward to thermally connect them, or vice versa.

[0015] In some embodiments, the driving means is configured to drive and / or move each of at least two movable contacts radially inward simultaneously to thermally disconnect them, and to drive and / or move each of at least two movable contacts radially outward simultaneously to thermally connect them, or vice versa. By "simultaneously" it is meant that each movable contact is moved outward or inward from its respective initial starting position, all together and in synchronization. This enables proper centering of the cooling device following the actuation of the driving means after the cooling device has been inserted into the boot of the vacuum chamber.

[0016] In some embodiments, the driving means is arranged at the proximal portion of the cooling device, and the mechanical transmission comprises a drive shaft connecting the driving means to a first coupler. This enables easy access to the driving means from outside the vacuum chamber when the cooling device is inserted into the boot of the vacuum chamber.

[0017] According to the present disclosure, there is also provided a charged particle accelerator including a vacuum chamber, a main superconducting magnet disposed within the vacuum chamber, a boot accommodated within the vacuum chamber and having an opening to the environment, one or more thermal links between the superconducting magnet and the boot or a part of the boot, and a cooling device described herein.

[0018] These aspects and further aspects will be described in more detail with reference to the accompanying drawings using examples.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Mode for Carrying Out the Invention

[0020] Each figure in the drawings is neither drawn to a fixed scale nor drawn proportionally. Generally in the drawings, similar or identical components are indicated by the same reference numerals.

[0021] FIG. 1 schematically shows an overall cutaway view of a cooling device (1) (hereinafter sometimes referred to as a “cryocooler”) according to the present disclosure when inserted in an operating position inside a boot (300) housed in a vacuum chamber (200) (hereinafter sometimes referred to as a “cryostat”). The vacuum chamber contains an object (100) cooled by the cooling device. The object cooled inside the vacuum chamber can be, for example, a superconducting magnet, such as the main magnet of a particle accelerator, a cyclotron, such as the main magnet of a synchrocyclotron.

[0022] FIG. 2 schematically shows an overall cutaway view of the cooling device (1) of FIG. 1 when partially retracted from the boot (300). As can be seen in this figure, it is possible to remove the entire cooling device (1) longitudinally without interrupting the vacuum in the vacuum chamber (200).

[0023] As can be seen in FIGS. 1 and 2, the cooling device (1) can be inserted longitudinally into and removed from a boot (300) housed by a vacuum chamber (200). In FIGS. 1 and 2, the vacuum chamber (200) and the boot (300) are shown in dotted lines and are not part of the cooling device (1).

[0024] 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 boot (300), and can be provided with, for example, a flange and a joint so as to provide an airtight connection between the cooling device (1) and the boot (300) when the cooling device (1) is inserted into the boot (300). In the case of a cryocooler, the proximal portion (2) may also be called the head of the cryocooler. The distal portion (4) comprises a first cryogenic station (10) and a first coupler (20) thermally connected to the first cryogenic station (10). During operation, the cooling device (1) cools the first cryogenic station (10), thereby enabling the cooling of an object (100) to be cooled within the cryostat through a thermal link (shown by three serpentine dotted lines) between the first cryogenic station (10) and the object (100) to be cooled via the first coupler (20) and the boot (300) or a part thereof.

[0025] This is generally known in the art and will not be described in detail accordingly.

[0026] Next, some exemplary embodiments of the cooling device (1) according to the present disclosure will be described in more detail.

[0027] A cutaway view of a first embodiment of a cooling device (1) (or cryostat) according to the present disclosure is shown in FIG. 3, and a cross-sectional view is shown in FIG. 4. The first embodiment is similar to the cooling device shown in FIGS. 1 and 2, but its distal portion is further detailed and the distal portion includes a first coupler (20), its drive means (50), and a mechanical transmission ().

[0028] In this first embodiment, the first coupler (20) comprises a cup-shaped member (21) attached to and thermally connected to the first cryogenic station (10). Alternatively, the cup-shaped member (21) may form a member that is part of the first cryogenic station (10).

[0029] This cup-shaped member (21) has at least two flexible extensions (22) extending in the longitudinal direction and arranged on opposite sides in the radial direction. In this example, the cup-shaped member (21) comprises two flexible extensions. The flexible extensions (22) are adapted to be deformed elastically (i.e., flexibly) radially outward or inward (upward and / or downward in the cutaway views of FIGS. 3 and 4). As will be explained later, when such flexible extensions are deformed, they constitute movable contacts (22) capable of making thermal conductive contact with the boot (300).

[0030] The first coupler (20) also includes at least two pushers (60) each disposed in front of at least two movable contacts (22). In this example, the first coupler (20) includes two pushers (60) each disposed in front of two movable contacts (22) so as to cooperate with the two movable contacts (22) respectively. As indicated by the two arrows in FIGS. 3 and 4, when the two pushers (60) are moved radially outward, they each push the two movable contacts (22) and deform the movable contacts (22) until they are in thermal contact with the inner wall of the boot (300). When such thermal contact is established, heat is transferred from the wall of the boot (300) through the two movable contacts (22) to the first cryogenic station (10), thereby making it possible to cool the cooled object (100) within the cryostat. In this example, since the movable contacts (22) are disposed on opposite sides of each other, their radial outward movement further assists in centering the cooling device (1) within the boot (300) of the cooling device (1) after the cooling device (1) is inserted into the boot (300). Thereafter, when the two pushers (60) are moved radially inward, the pressure on the two movable contacts (22) is released, and as a result, the two movable contacts (22) elastically return to their initial positions or at least loosen their contact with the inner wall of the boot (300). When this contact is loosened, it becomes possible to retract the cooling device (1) from the boot (300), for example, for repair or maintenance.

[0031] The cooling device (1) may also include guiding means (not shown) for guiding each of the two pushers (60) only radially (i.e., with only one degree of freedom).

[0032] The cooling device (1) may also include driving means (50) and a mechanical transmission connecting the driving means (50) to at least two movable contacts (22), and the driving means (50) and the mechanical transmission are configured to move each of the at least two movable contacts (22) radially inward and / or outward.

[0033] In the examples of FIGS. 3 and 4, the driving means (50) comprises a motor such as an electric motor, and the mechanical transmission device comprises a drive shaft (81), a gear train (82), and two pushers (60), all of which are arranged in the distal portion (4) of the cooling device (1). The drive shaft (81) connects the motor to the gear train (82). 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 makes it possible to increase the torque applied to the driven wheel (83) of the gear train (82), and thus the force applied to the pusher (60). In this example, the drive shaft (81) is installed in a first bearing installed in the disk-shaped portion of the cup-shaped member (21), and the shaft of the driven wheel (83) of the gear train (82) is installed in a second bearing installed in the central portion of the disk-shaped portion of the cup-shaped member (21). In this example, the motor is attached to the disk-shaped portion of the cup-shaped member (21), but it may also be attached to another fixed member of the cooling device (1).

[0034] The driven gear (83) of the gear train (82) is configured to cooperate with the two pushers (60) to move the two movable contacts (22) of the first coupler (20) radially inwardly and / or outwardly. To achieve such cooperation and movement, the driven gear (83) of the gear train (82) may include, for example, two arcuate holes (84), each of the arcuate holes having one end at a first distance from the center of the driven gear (83) and the opposite end at a second distance from the center of the driven gear (83), the second distance being different from the first distance. Also, each of the two pushers (60) includes an axial extension (85), such as a rod, that cooperates respectively with a corresponding one of the two arcuate holes (84). Thus, when the motor is controlled to rotate in one direction, the driven gear (83) of the gear train (82) moves the two pushers (60) radially outwardly, thereby pushing the movable contacts (22) to establish a thermal connection with the boots (300) of the movable contacts (22). When the motor is controlled to rotate in the opposite direction, the driven gear (83) of the gear train (82) moves the pushers (60) radially inwardly, thereby loosening the connection with the boots (300) of the movable contacts (22).

[0035] Figure 4 shows a cross-sectional view of the cooling device of FIG. 3. In this figure, it is possible to better understand the two arcuate holes (84) of the driven wheel (83) of the gear train (82), and how they cooperate with the pusher (60) and its axial extension (85). In this example, in order to obtain good thermal contact, all of the movable contact (22) and the distal member (60a) of the pusher (60) have an arcuate shape corresponding to the shape of the inner wall of the boot (300) in their contact area. Alternatively, if the inner wall of the boot (300) has a flat or planar portion in the contact area, all of the distal member (60a) of the pusher (60) and the movable contact (22) may have a flat shape. This can be the case, for example, when the inner wall of the boot (300) has a square, rectangular, or polygonal cross-section in the contact area (as seen in the example of FIG. 9 described later). The "contact range" or "contact area" should be understood as the range or area in which thermal contact is generated between the first coupler (20) and the boot (300) when the driving means (50) of the cooling device (1) is actuated.

[0036] In some examples, each movable contact is mechanically connected to its corresponding pusher (60), for example, through a flexible mechanical link or a linkage-type mechanical link between the two. Thus, when the driving means (50) pulls the pusher (60) and moves them radially inward, each pusher (60) also pulls its corresponding movable contact and moves it inward. This has the advantage of forcibly interrupting the contact between each movable contact (22) and the boot (300), which can be useful, for example, when such contacts freeze.

[0037] Thus, in the examples of FIGS. 3 and 4, the driving means (50) and the mechanical transmission are configured to drive and / or move each of at least two movable contacts (22) radially inward to a thermally disconnected configuration, and to drive and / or move each of at least two movable contacts (22) radially outward to a thermally connected configuration.

[0038] A cut-away view of a second embodiment of a cooling device (or cryostat) according to the present disclosure is shown in FIGS. 5 and 6. This second embodiment is similar to the cooling device (1) shown in FIGS. 3 and 4, except that the first coupler (20) is slightly different. In this second embodiment, the cup-shaped member (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 shown in FIGS. 5 and 6. Each guiding extension is provided with a groove or hole through which each pusher (60) can pass freely and precisely, for example, so that each pusher (60) makes thermal contact while sliding with the corresponding guiding extension. In other words, in this second embodiment, the pusher (60) becomes the movable contact. Alternatively or additionally, as shown by two dotted lines in FIGS. 5 and 6 respectively, a flexible thermal link may be arranged between the two guiding extensions (23) and the two pushers (60) respectively. Thus, when the two movable contacts (two pushers (60)) are brought into contact with the boot (300), heat can be conducted between the boot (300) and the first cryogenic station (10) through the two movable contacts (two pushers (60)). In this case, the driving means (50) is the same as the driving means (50) of the first embodiment. Thus, when power is applied, the driving means (50) also moves the pusher (60) radially outward and / or inward. When the driving means (50) is controlled to move the pusher (60) radially outward, the pusher (60) comes into direct contact with the inner wall of the boot (300), and thus, when the cooling device (1) is in an operating state, heat is transferred from the object (100) to be cooled to the first cryogenic station (10) through the boot (300) (or a part thereof) and the first coupler (20). When the driving means (50) is controlled to move the pusher (60) radially inward, the pusher (60) is moved away from the inner wall of the boot (300), and as a result, the thermal connection is loosened and the cooling device (1) can be withdrawn from the boot (300).

[0039] FIG. 6 shows a cross-sectional view of the cooling device of FIG. 5. In this figure, another perspective of the guiding extension portion (23) can be seen. Also in this second embodiment, in order to obtain good thermal contact, the distal members (60a) of the movable contacts (pushers (60)) have an arcuate shape corresponding to the shape of the inner wall of the boot (300) in their contact area. Alternatively, if the inner wall of the boot (300) has a flat or planar portion in the contact area, all of the distal members (60a) of the movable contacts (pushers (60)) may have a flat shape. This can be the case, for example, as shown in FIG. 9, where the inner wall of the boot (300) has a square, rectangular, or polygonal cross-section in the contact area.

[0040] FIG. 7 schematically shows a cut-away view of a preferred embodiment of the cooling device of FIG. 3. This embodiment is the same as the embodiment of FIG. 3, except that the drive means (50) is arranged in the proximal portion (2) of the cooling device (1) (i.e., the left side of the cooling device as shown in FIG. 7). More specifically, in this example, the drive means (50) is arranged outside the portion of the cooling device that is inserted into the boot (300) of the cooling device, and thus, when the cooling device (1) is inserted into the boot (300), access to the drive means (50) can be obtained from the outside of the boot (300) or from the outside of the vacuum chamber (200).

[0041] FIG. 8 schematically shows a cut-away view of a preferred embodiment of the cooling device of FIG. 5. This embodiment is the same as the embodiment of FIG. 5, except that the drive means (50) is arranged in the proximal portion (2) of the cooling device (1) (i.e., the left side of the cooling device as shown in FIG. 8). More specifically, in this example, the drive means (50) is arranged outside the portion of the cooling device that is inserted into the boot (300) of the cooling device.

[0042] In the embodiments of FIGS. 7 and 8, the driving means (50) may be a motor or a manual driving means (50) that can be manually operated from the outside of the vacuum chamber (200), such as a crank, a lever, or a wheel, while the cooling device (1) is inserted into the boot (300) of the vacuum chamber (200) and is in the operating position.

[0043] The embodiments described so far have two movable contacts (22), but there may be more movable contacts (22). In each embodiment, there may be from two to sixteen movable contacts (22). In some examples, there are an even number of movable contacts (22), more preferably eight movable contacts (22).

[0044] In each embodiment, at least two movable contacts (22) are arranged at equal angular intervals around the longitudinal axis (L) of the cooling device (1) and are equidistant from the longitudinal axis (L).

[0045] FIG. 9 schematically shows a cross-sectional view of yet another embodiment of a cooling device according to the present disclosure. This embodiment is similar to the embodiment of FIG. 3 or FIG. 7, except that the coupler includes six movable contacts (22) and six pushers (60) instead of two, and when the boot (300) has a hexagonal cross-section, the distal members (60a) of the movable contacts (22) and the pushers (60) all have a flat or planar shape so as to contact each other and the inner surface of the boot (300). As can be seen in FIG. 9, in this example having an angle of 60° between each pair of adjacent movable contacts (22), each movable contact (22) is arranged at equal angular intervals around the longitudinal axis (L) of the cooling device (1). Each movable contact (22) is also equidistant from the longitudinal axis (L) of the cooling device (1).

[0046] It will be apparent that the coupler may comprise more or less than six movable contacts (22), and that there may also be other polygonal cross-sections on the inner wall of the boot (300) with corresponding arrangements of the movable contacts (22) and the pushers (60).

[0047] A cutaway view of a third embodiment of the cooling device according to the present disclosure is shown in FIG. 10. This embodiment is similar to the cooling devices shown in FIGS. 1 and 3, except for some differences on the first coupler side. In this third embodiment, the cup-shaped member (21) of the coupler is also in thermal contact with the first low-temperature station (10) of the cooling device (1), but is disposed more centrally and between pushers (60) that surround the flexible extension (movable contact (22)) of the cup-shaped member (21) of the first coupler. This configuration is particularly suitable when the boot (300) has a thermal port (310) centrally disposed at its distal end, such as a cylinder or the like. The drive means (50) is substantially the same as in the other embodiments. In this case, the drive means (50) is configured to drive and / or move each of at least two movable contacts (22) radially inward to form a thermally connected configuration, and to drive and / or move each of at least two movable contacts (22) radially outward to form a thermally disconnected configuration.

[0048] In some examples, each movable contact (22) is mechanically connected to its corresponding pusher (60), for example through a flexible mechanical link or a linkage-type mechanical link between the two. Thus, when the drive means (50) drives the pushers (60) to move them in one radial direction or the opposite radial direction, the pushers (60) also drive their corresponding movable contacts (22) in the same direction.

[0049] Thus, in the example of FIG. 10, the drive means (50) and the mechanical transmission are configured to drive and / or move each of at least two movable contacts (22) radially inward to form a thermally connected configuration, and to drive and / or move each of at least two movable contacts (22) radially outward to form a thermally disconnected configuration.

[0050] Figure 11 schematically shows a cutaway view of a preferred embodiment of the cooling device of FIG. 7. This embodiment is similar to the cooling device of FIG. 7, except that the intermediate portion (3) of the cooling device (1) comprises a second cryogenic station (90) and a second coupler (91) thermally connected to the second cryogenic station (90). The second coupler (91) may be similar to the first coupler (20) described herein, in which case it also comprises the drive means and mechanical transmission described herein (although separate), or it may be a passive device as shown in FIG. 11. In the example of FIG. 11, the second coupler (91) comprises a series of passive elements arranged in thermal contact therewith around the second cryogenic station (90). The dimensions and arrangement of these passive elements are defined such that when the cooling device (1) is installed within the boot (300), the passive elements form a sliding contact with the inner wall of the boot (300). By means of the sliding contact, heat is transferred from the object (100) to be cooled to the second cryogenic station (90) via the boot (300) and the passive elements. The passive elements can be, for example, annular springs such as Bal Springs® from Bal Seal. This second cryogenic station (90) and second coupler (91) may be used, for example, to cool another object within the vacuum chamber (200), such as to cool a heat shield (400) contained within the vacuum chamber (200) and thermally connected to a corresponding heat conducting portion of the boot (300), as shown in connection with FIG. 15 for example.

[0051] FIG. 12 schematically shows a cross-sectional view of a fourth embodiment of a cooling device according to the present disclosure when in an operating position inside a boot (300) of a vacuum chamber (200). This embodiment is similar to the other embodiments described herein, except that the pusher (60) is arranged in a different form and moves in a different form when driven by the driving means (50). In this example, the distal member (60a) of the pusher (60) is rotatably installed on the cooling device (e.g., a cup-shaped member (21)) through a hinge (61) arranged at one end of the distal member (60a) (the right side portion of the upper pusher (60) in FIG. 12), and the axis of the hinge (61) is parallel to the longitudinal axis (L) of the cooling device. The other end of the distal member (60a) on the opposite side of the hinge (61) (the left side portion of the upper pusher (60) in FIG. 12) is arranged to cooperate with one end of the radial portion of the pusher (60) (the end of the vertical portion of the upper pusher (60) in FIG. 12). The distal member (60a) of the pusher (60) can be a flexible member attached to the one end of the radial portion of the pusher (60), or can be flexibly linked to the one end of the radial portion of the pusher (60). Thus, when the driving means (50) is actuated, the radial portion of the pusher (60) pushes and / or pulls its distal member (60a), thereby establishing or interrupting the thermal contact with the boot (300) via the corresponding movable contact (22) respectively. The same applies to the other pushers (60). It will be apparent that the same arrangement can be used even without the movable contact (22), as in the case of the embodiments shown in FIGS. 5, 6, and 8.

[0052] FIG. 13 schematically shows a cross-sectional view of a fifth embodiment of a cooling device according to the present disclosure when in an operating position inside a boot (300) of a vacuum chamber (200). This embodiment is similar to the embodiments described herein in connection with FIGS. 3, 4, 7, and 9, except that the pusher (60) is arranged in a different form and moves in a different form when driven by the driving means (50). In this example, two pushers (60) are fixedly attached to the driven wheel (83) of the gear train (82), and thus, when the driving means (50) is actuated, the two pushers (60) rotate about the axis of the driven wheel (83) as indicated by the double arrows in FIG. 13. Each pusher (60) has a rounded distal member that contacts the corresponding movable contact (22), and thus, when the driven wheel (83) is rotated clockwise to the position shown in FIG. 13, the movable contact (22) is pushed radially outward. Thereafter, when the driven wheel (83) is rotated counterclockwise (or, in this case, further clockwise) to an angle at which the pusher (60) no longer contacts the movable contact (22), the pressure on the movable contact (22) is released, thereby loosening the thermal contact between the movable contact (22) and the boot (300).

[0053] In any of the embodiments, the mechanical transmission has a speed transmission ratio R, where R is greater than 1, or greater than 5, or greater than 10. As is well known, the speed 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.

[0054] The cooling device (1) is adapted to cool a first low-temperature station (10) to a temperature between 1°K and 100°K, or between 1°K and 25°K, or in some examples, to a temperature between 2°K and 10°K during operation.

[0055] The cooling device (1) is adapted to cool a second cryogenic station (90) during operation to a temperature between 30°K and 100°K in some examples and between 30°K and 60°K in some other examples.

[0056] The present disclosure also provides a charged particle accelerator (1000). The charged particle accelerator (1000) includes - a vacuum chamber (200), and - a main superconducting magnet (100) disposed within the vacuum chamber (200), and - a boot (300) housed within the vacuum chamber (200) and having an opening to the environment, and - one or more thermal links between the superconducting magnet (100) and the boot (300) or a part of the boot (300), and - the cooling device described herein disposed within the boot (300) and comprises.

[0057] As is known in the field of particle accelerators, the vacuum chamber (200) may be referred to as a cryostat, and the cooling device (1) may be referred to as a cryocooler. Also, the main superconducting magnet is an electromagnet that determines the path of charged particles while the charged particles are gradually accelerated within the accelerator.

[0058] The thermal link is, for example, a thermally conductive link made of, for example, copper or aluminum, or a liquid link such as liquid helium, or a combination thereof.

[0059] FIG. 14 schematically shows an exemplary charged particle accelerator device (1000) including an embodiment of a cooling device (1) according to the present disclosure. The cooling device (1) shown in FIG. 14 is the cooling device described in connection with FIGS. 7 to 10 or FIGS. 12 to 13, for example. Thus, when the cryocooler is in an operating state, heat is transferred from the superconducting magnet (100) to the first cryogenic station (10) of the cryocooler via the first heat link (501), the distal portion (4) of the boot (300), and the first coupler (20). In this configuration, the cooling device is adapted to cool the first cryogenic station (10) to a temperature between 1°K and 100°K, or to a temperature between 1°K and 10°K, preferably to a temperature between 3°K and 6°K, for example during operation.

[0060] FIG. 15 schematically shows an exemplary charged particle accelerator device (1000) including another embodiment of a cooling device (1) according to the present disclosure. The cooling device (1) shown in FIG. 15 is the cooling device described in connection with FIG. 11, for example. In this case, the vacuum chamber (200) also houses a thermal shield (400) that at least surrounds the superconducting magnet. Thus, when the cryocooler is in an operating state, heat is transferred from the superconducting magnet (100) to the first cryogenic station (10) of the cryocooler via the first heat link (501), the distal portion (4) of the boot (300), and the first coupler (20), and the heat is further transferred from the thermal shield to the second cryogenic station (90) of the cryocooler via the second heat link (502), the intermediate portion (3) of the boot (300), and the second coupler (91). In this configuration, the cooling device (1) is adapted to cool the first cryogenic station (10) to a temperature between 1°K and 100°K, or to a temperature between 1°K and 10°K, and to cool the second cryogenic station (90) to a temperature between 15°K and 100°K, or to a temperature between 20°K and 60°K, for example during operation.

[0061] In some examples, the charged particle accelerator device (1000) is a cyclotron or a synchrocyclotron.

[0062] In the examples of FIGS. 14 and 15, the superconducting magnet is linked by heat conduction to a first heat link (501).

[0063] In other examples, the superconducting magnet may be disposed within an enclosure containing, for example, liquid helium, the enclosure being housed within a vacuum chamber (200), preferably inside a thermal shield (400). In such a case, the first heat link (501) is thermally connected to a condenser disposed within the enclosure to condense helium after it has vaporized due to heating by the superconducting magnet.

[0064] Although the device has been described with respect to specific examples, the examples are illustrative and should not be construed as limiting. Even if reference numerals are present in the claims, the reference numerals do not limit the scope of protection. The use of the verbs "to comprise", "to include", "to be composed of", or any other variants, and their conjugations, does not exclude the presence of elements other than those described. The use of the articles "a", "an", or "the" preceding an element does not exclude the presence of a plurality of such elements.

[0065] The device according to the present disclosure can also be described as follows: a device for cooling an object (100), such as a superconducting magnet, placed in a vacuum chamber (200). This cooling device (1) can be inserted into and removed from a boot (300) housed by the vacuum chamber (200), and the boot or a part thereof is in thermal contact (conductivity and / or transmissivity) with the object (100) to be cooled. The distal portion (4) of the cooling device (1) comprises a first cryogenic station (10) and a first coupler (20) thermally connected to the first cryogenic station (10). The first coupler (20) comprises at least two movable contacts (22, 60) thermally connected to the first cryogenic station (10), and the cooling device (1) comprises drive means (50) and a mechanical transmission connecting the drive means (50) to at least two movable contacts (22, 60), and the drive means (50) and the mechanical transmission are configured to move each of the at least two movable contacts (22, 60) radially inwards and outwards in order to create or relieve a conductive thermal contact between the first cryogenic station (10) and the boot (300) or a part thereof.

Claims

Claim 1 A cooling device (1) for cooling an object (100) placed in a vacuum chamber (200), which can be inserted into and removed from a boot (300) accommodated by the vacuum chamber (200), extends along a longitudinal axis (L), and has a proximal portion (2), an intermediate portion (3), and a distal portion (4), and in the cooling device, the distal portion (4) comprises a first cryogenic station (10) and a first coupler (20) thermally connected to the first cryogenic station (10), wherein the first coupler (20) comprises at least two movable contacts (22, 60) thermally connected to the first cryogenic station (10), the cooling device comprises drive means (50) and a mechanical transmission connecting the drive means (50) to the at least two movable contacts (22, 60), and the drive means (50) and the mechanical transmission are configured to move each of the at least two movable contacts (22, 60) radially inward and / or outward, a cooling device (1). Claim 2 The cooling device according to claim 1, wherein the drive means (50) is a motor or a manually operated drive means. Claim 3 The cooling device according to claim 1, wherein the drive means (50) and the mechanical transmission are configured such that each of the at least two movable contacts (22) is driven and / or moved radially inward to be thermally disconnected, and each of the at least two movable contacts (22) is driven and / or moved radially outward to be thermally connected, or vice versa. Claim 4 The cooling device according to claim 1, wherein the drive means (50) is arranged in the proximal portion (2) of the cooling device (1), and the mechanical transmission comprises a drive shaft (81) connecting the drive means (50) to the first coupler (20). Claim 5 The cooling device according to claim 1, wherein the mechanical transmission has a speed transmission ratio R, and R is greater than 1. Claim 6 The cooling device according to claim 5, wherein the mechanical transmission comprises a gear train (82) arranged in the distal portion (4) of the cooling device (1), and a driven gear (83) of the gear train (82) is configured to cooperate with the at least two movable contacts (22) of the first coupler (20). Claim 7 The driven wheel (83) of the gear train (82) comprises at least two arcuate holes (84), each of the arcuate holes having one end at a first distance from the center of the driven wheel (83) and the opposite end at a second distance from the center of the driven wheel (83), the second distance being different from the first distance, the mechanical transmission means comprising at least two pushers (60) arranged in front of the at least two movable contacts (22) respectively, each of the at least two pushers (60) having an axial extension (85) which cooperates respectively with a corresponding one of the at least two arcuate holes (84). The cooling device according to claim 6.

8. The driven wheel (83) of the gear train (82) comprises at least two arcuate holes (84), each of the arcuate holes having one end at a first distance from the center of the driven wheel (83) and the opposite end at a second distance from the center of the driven wheel (83), the second distance being different from the first distance, each of the at least two movable contacts (60) having an axial extension (85) which cooperates respectively with a corresponding one of the at least two arcuate holes (84). The cooling device according to claim 6.

9. The at least two movable contacts (22, 60) are arranged at equal angular intervals around the longitudinal axis (L) of the cooling device (1). The cooling device according to claim 1.

10. The at least two movable contacts (22, 60) are movable contacts between 2 and 16, preferably an even number of movable contacts, more preferably 6 or 8 movable contacts. The cooling device according to claim 9.

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

12. The intermediate part (3) comprises a second low-temperature station (90) and a second coupler (91) thermally connected to the second low-temperature station (90). The cooling device according to claim 1.

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

14. The cooling device of claim 13 , wherein the passive element is an annular spring.

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

16. a vacuum chamber (200), a main superconducting magnet (100) located within said vacuum chamber (200); a boot (300) housed in said vacuum chamber (200) and having an opening to the environment; - one or more thermal links (501, 502) between said superconducting magnet (100) and said boot (300) or parts of said boot (300); - a cooling device according to claim 1, arranged in said boot (300); A charged particle accelerator (1000) comprising:

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

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