CN113470844A

CN113470844A - Target device

Info

Publication number: CN113470844A
Application number: CN202110293440.0A
Authority: CN
Inventors: 村上喜信; F·圭拉
Original assignee: Sumitomo Heavy Industries Ltd
Current assignee: Sumitomo Heavy Industries Ltd
Priority date: 2020-03-30
Filing date: 2021-03-19
Publication date: 2021-10-01
Also published as: JP7445491B2; CA3112871A1; EP3890450A1; JP2021162318A

Abstract

The invention provides a target device capable of improving cooling performance based on a cooling mechanism. According to the target device (100), the target container (3) has a 1 st region (E1) for containing the target liquid (101) and a 2 nd region (E2) for receiving the gas-liquid mixture (102) of the boiling target liquid. On the other hand, the cooling mechanism (4) is provided with a 1 st cooling part (30A) for cooling at least the 1 st region (E1) and a 2 nd cooling part (30B) for cooling at least the 2 nd region (E2). In addition, the 2 nd cooling unit (30B) forms a flow of the refrigerant from the upper side toward the lower side in the 2 nd region (E2) (flow F2 in fig. 2). The cooling performance by the refrigerant flowing from the upper side to the lower side can be improved as compared with the cooling performance when the refrigerant used in cooling unit 1a is used as it is.

Description

Target device

The present application claims priority based on japanese patent application No. 2020-. The entire contents of this Japanese application are incorporated by reference into this specification.

Technical Field

The present invention relates to a target device.

Background

Radioisotopes used in examination medicines for PET examination using Positron Emission Tomography (PET) are produced using a radiation source such as a cyclotron installed near an examination room in a hospital. Specifically, radiation (for example, a particle beam such as a proton beam or a deuteron beam) from a radiation source is introduced into a target device, and passes through a target liquid (for example, a target liquid) contained in the target device¹⁸O water)) to produce radioisotopes. In-line with the aboveThen, the produced radioisotope is incorporated into a predetermined compound (for example, Fluorodeoxyglucose (FDG) or partially substituted to synthesize the compound, thereby preparing a test drug.

As an apparatus for containing a target liquid for producing such a radioisotope, there is known an apparatus provided with a cooling mechanism for cooling, from the back side, a portion containing the target liquid and a portion receiving a gas-liquid mixture of the boiled target liquid (for example, refer to patent document 1).

Patent document 1: japanese patent laid-open publication No. 2011-220930

Here, when the intensity of the radiation irradiated to the target liquid is increased, a high cooling performance is required for the cooling portion that cools the target accommodating portion. The cooling mechanism of the target device injects a refrigerant coaxially with the radiation to the back surface (heat transfer wall portion) of the portion containing the target liquid. Then, the cooling mechanism of the target device cools the target accommodating portion from the back surface of the portion receiving the gas-liquid mixture of the target liquid by the refrigerant (upward flow from the portion receiving the liquid toward the portion receiving the gas-liquid mixture) that is radially diffused after contacting the heat transfer wall portion by the jetting. However, in this structure, sufficient cooling performance may not be obtained. Therefore, a target device capable of improving the cooling performance of the cooling mechanism is required.

Disclosure of Invention

The present invention has been made in view of the above problems, and an object thereof is to provide a target device capable of improving cooling performance by a cooling mechanism.

In order to achieve the above object, a target device according to an aspect of the present invention includes: a target accommodating portion having a 1 st region for accommodating a target liquid and a 2 nd region located above the 1 st region and receiving a gas-liquid mixture of the boiling target liquid; and a cooling mechanism for cooling the target accommodating portion by the refrigerant on the side opposite to the irradiation direction of the beam irradiated to the target liquid, wherein the cooling mechanism comprises a 1 st cooling portion for cooling at least the 1 st region and a 2 nd cooling portion for cooling at least the 2 nd region, and the 2 nd cooling portion forms a flow of the refrigerant from the upper side to the lower side in the 2 nd region.

According to the above target device, the target accommodating portion has the 1 st region for accommodating the target liquid and the 2 nd region located above the 1 st region and receiving the gas-liquid mixture of the boiling target liquid. On the other hand, the cooling mechanism includes a 1 st cooling unit for cooling at least the 1 st region and a 2 nd cooling unit for cooling at least the 2 nd region. The 2 nd cooling unit forms a flow of the refrigerant from the upper side to the lower side in the 2 nd region. The cooling performance by the refrigerant flowing from the upper side to the lower side can be improved as compared with the cooling performance when the refrigerant used in the 1 st cooling unit is used as it is. With the above configuration, the cooling performance by the cooling mechanism can be improved.

The following may be used: the 1 st cooling unit includes a 1 st nozzle portion for injecting the refrigerant to the partition wall between the 1 st and 2 nd regions, the 2 nd cooling unit includes a 2 nd nozzle portion for injecting the refrigerant to the partition wall between the 2 nd and 2 nd regions, and the 2 nd cooling unit forms a flow of the refrigerant from above to below an injection portion of the 2 nd nozzle portion. The cooling by spraying has a high heat transfer coefficient and a good cooling efficiency as compared with other forced convection. Therefore, the cooling performance of the cooling mechanism can be further improved by cooling the 2 nd region by injection from the 2 nd nozzle part in addition to cooling the 1 st region by injection from the 1 st nozzle part.

The following may be used: the 1 st inner space through which the refrigerant in the 1 st cooling part flows and the 2 nd inner space through which the refrigerant in the 2 nd cooling part flows are partitioned from each other. In this case, the cooling can be performed in a state where the 1 st cooling unit and the 2 nd cooling unit are independently opened from each other. In this case, it is possible to suppress the flow of the refrigerant of one of the cooling portions from interfering with the flow of the refrigerant of the other cooling portion.

Effects of the invention

According to the present invention, a target device capable of improving cooling performance by a cooling mechanism can be provided.

Drawings

Fig. 1 is a sectional view of a target device according to the present embodiment.

Fig. 2 is a sectional view of the target device in a state where the target liquid is irradiated with the beam.

Fig. 3 is a view of the target device as viewed from the rear surface side.

Fig. 4 is a diagram showing a detailed structure of the target accommodating portion.

In the figure: 3-target accommodating section, 4-cooling mechanism, 30A-1 st cooling section, 30B-2 nd cooling section, 31A-1 st internal space, 31B-2 nd internal space, 32A-1 st nozzle section, 32B-2 nd nozzle section, 34-heat transfer wall section (partition wall), 100-target device.

Detailed Description

Hereinafter, a mode for carrying out the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

Fig. 1 is a sectional view of a target device 100 according to the present embodiment. Fig. 1 is a sectional view of the target apparatus 100 taken at the position of the irradiation axis RL. Fig. 1 shows a state before irradiation of a target liquid 101 with a beam B. Fig. 2 is a cross-sectional view of the target apparatus 100 in a state where the target liquid 101 is irradiated with the beam B. Fig. 3 is a view of the target apparatus 100 as viewed from the rear surface side.

As shown in fig. 1, the target device 100 according to the present embodiment includes a beam introduction unit 1, a foil 2, a target housing unit 3, and a cooling mechanism 4. The radioisotope production apparatus includes the target device 100 and an accelerator, not shown. As the accelerator, for example, a cyclotron or the like is used, which generates a charged particle beam (hereinafter, referred to as a "beam"), and irradiates the target apparatus 100 with the generated beam B (see fig. 2) along an irradiation axis RL. Examples of the beam B to be irradiated to the target apparatus 100 include a particle beam such as a proton beam and a deuteron beam. The target device 100 is attached to a discharge port through which the beam B of the accelerator is discharged, via a manifold (not shown) disposed between the accelerator and the target device. In the following description, the direction in which the irradiation axis RL extends may be referred to as a depth direction D1 of the target device 100. The side of the depth direction D1 on which the beam B is irradiated (the upstream side in the beam traveling direction) may be referred to as the front side of the target device 100, and the opposite side may be referred to as the rear side of the target device 100. A direction perpendicular to the depth direction D1 and the vertical direction of the target device 100 may be referred to as a width direction D2.

The target device 100 has, for example, a quadrangular prism shape. The target device 100 includes a front flange 11 mainly for forming the beam introduction part 1, a target container 12 mainly for forming the target housing part 3, and a flow path forming member 13 mainly for forming the cooling mechanism 4. The front flange 11, the target container 12, and the flow path forming member 13 are made of metal blocks. The front flange 11, the target container 12, and the flow path forming member 13 are sequentially overlapped from the front side toward the rear side in the depth direction D1.

The target device 100 includes a front surface 100a and a rear surface 100b that are parallel to each other in the depth direction D1, a side surface 100c and a side surface 100D (see fig. 3) that are parallel to each other in the width direction D2, and an upper surface 100e and a lower surface 100f that are parallel to each other in the vertical direction. The front surface 100a is formed by a front side surface of the front surface flange 11 in the depth direction D1. Further, a ring member 14 for introducing the beam B is attached to the front surface 100a at a position corresponding to the irradiation axis RL. The rear surface 100b is a surface of the flow path forming member 13 on the rear side in the depth direction D1. The side surfaces 100c and 100D are formed by a combination of the front flange 11, the target container 12, and the end surfaces of the flow path forming member 13 in the width direction D2. The upper surface 100e is formed by a combination of the front surface flange 11, the target container 12, and the upper surface of the flow channel forming member 13. The lower surface 100f is formed by a combination of the front surface flange 11, the target container 12, and the lower surface of the flow channel forming member 13.

The beam introducing section 1 is a portion for introducing the beam B into the target apparatus 100. The beam introducing section 1 is constituted by an introducing hole 21 centered on the irradiation axis RL of the beam B. The introduction hole 21 is formed by a combination of a through hole formed in the ring member 14 and a through hole formed in the front flange 11. The foil 2 is exposed at the opening portion on the rear side of the introduction hole 21. Therefore, the beam B introduced into the introduction hole 21 of the beam introduction part 1 is irradiated to the foil 2. The ring member 14 and the front flange 11 constituting the beam introducing section 1 may be formed of, for example, an aluminum alloy.

The foil 2 is a member for separating the beam introduction part 1 from the target accommodating part 3. The foil 2 is sandwiched between the front surface flange 11 and the target container 12. The foil 2 is fixed by pressing the front surface flange 11 against the target container 12. The foil 2 allows the beam B to pass through, and on the other hand, cuts off the passage of the fluid such as the target liquid 101 and He gas. Therefore, the beam B is irradiated to the foil 2, and then is irradiated to the target liquid 101 through the foil 2. He gas, for example, is blown to the front surface of the foil 2 and used as a cooling gas for the foil 2. The foil 2 is a thin foil made of a metal such as Ti or an alloy, and has a thickness of about 10 to 50 μm. The foil 2 is arranged to cover at least the entire introduction aperture 21 of the beam introduction part 1. The foil 2 is provided so as to cover the entire opening of a recess 22 described later of the target accommodating portion 3.

The target accommodating portion 3 is a portion for accommodating the target liquid 101. The target accommodating portion 3 is constituted by a space surrounded by the recess 22 formed in the target container 12 and the foil 2. The target container 12 can be formed of Nb, for example. Is sealed as a target liquid 101 in the target accommodating portion 3¹⁸O (target solution). The recess 22 is recessed from the rear side in the depth direction D1 of the front surface of the target container 12, for example, the fixing surface 12a sandwiching the foil 2. The recess 22 has a bottom surface 22a and a peripheral surface 22b extending from the outer peripheral edge of the bottom surface 22a toward the front side in the depth direction D1. The target accommodating portion 3 (except for the point where the heat sink 29 described later is provided) has a shape symmetrical with respect to the center line CL1 of the target device 100 when viewed from the width direction D2.

The target container 12 is formed with a gas introduction hole 23 for introducing an inert gas (e.g., He gas) into the target accommodating portion 3. The gas introduction hole 23 communicates with the target accommodating portion 3, and extends to an opening portion 24a provided on the rear surface of the target container 12. A pipe path 24 extending further rearward is connected to the opening 24a on the rear surface of the target container 12. The inert gas is introduced into the target accommodating portion 3 through the piping path 24 and the gas introduction hole 23. By introducing the inert gas at a high pressure (for example, 3MPa) into the target accommodating portion 3 in this manner, the boiling temperature of the target liquid 101 can be increased by setting the inside of the target accommodating portion 3 at a high pressure.

The target container 12 is formed with a flow hole 26 used when filling the target container 3 with the target liquid 101 and used when discharging the target liquid 101 in the target container 3. The circulation hole 26 communicates with the target accommodating portion 3 and extends to an opening 27a provided on the rear surface of the target container 12. A pipe path 27 extending further rearward is connected to the opening 27a on the rear surface of the target container 12. Thereafter, the target liquid 101 is introduced into the target accommodating portion 3 through the piping path 27 and the flow hole 26. The target liquid 101 in the target accommodating portion 3 is discharged through the flow hole 26 and the pipe path 27.

The target container 3 has a 1 st region E1 that contains the target liquid 101 and a 2 nd region E2 that is located above the 1 st region E1 and receives the gas-liquid mixture 102 (refer to fig. 2) of the boiling target liquid 101. The state where the region 2E 2 receives the boiling gas-liquid mixture 102 means a state where the gas-liquid mixture 102 is contained during irradiation of the beam B, instead of containing the target liquid 101 before irradiation of the beam B. The 2 nd region E2 is continuously formed on the upper side of the 1 st region E1. The liquid surface of the target liquid 101 before boiling is set at a boundary between the 1 st region E1 and the 2 nd region E2. In the present embodiment, the boundary portion is set above the irradiation axis RL and below the center line CL 1. Therefore, the volume of the 2 nd region E2 is greater than the volume of the 1 st region E1. However, the relationship between the volume of the 1 st region E1 and the volume of the 2 nd region E2 is not particularly limited, and the volumes of both may be the same or the volume of the 1 st region E1 may be larger. The gas-liquid mixture 102 rises in liquid level due to the generation of bubbles therein, and reaches the 2 nd region E2 (see fig. 2).

A more detailed structure of the target accommodating portion 3 will be described with reference to fig. 4. As shown in fig. 4 (a), the target accommodating portion 3 has a track shape with semicircular upper and lower end portions. A plurality of fins 29 are provided in the 2 nd area E2. The plurality of fins 29 extend upward from the vicinity of the boundary with the 1 st region E1 to the upper end of the 2 nd region E2. The plurality of fins 29 are arranged at predetermined intervals in the width direction W1. The fins 29 extend from the bottom surface 22a of the recess 22 to the front side in the depth direction D1. The heat sink 29 is fixed to the bottom surface 22 a. The height of the heat sink 29 is not particularly limited, and may extend to the position of the foil 2 (see fig. 4 (b)). In the 1 st region E1, the heat radiation fins 29 are not provided, and the bottom surface 22a is spread flat.

As described above, when the fins 29 are provided in the 2 nd region E2, the contact area between the gas-liquid mixture 102 and the cooling surface can be increased, and therefore, the cooling performance of the 2 nd cooling portion 30B can be improved. On the other hand, in the 1 st region E1, the heat sink 29 is not provided in order to prevent the beam B from contacting the heat sink 29. In addition, since the gas component generated by evaporation is large in the 2 nd region E2, the cooling effect by providing the heat radiation fins 29 is high. In contrast, if the heat sink 29 is provided in the 1 st region E1 where the liquid component is large, the volume for accommodating the target liquid 101 must be secured accordingly. The influence of the increase in the outer shape of the entire target accommodating portion 3 may be larger than the influence of the improvement in the cooling performance. Therefore, the heat radiation fins 29 are not provided in the 1 st region E1.

Referring again to fig. 1, the cooling mechanism 4 cools the target accommodating portion 3 with a refrigerant on the side opposite to the irradiation direction of the beam B irradiated to the target liquid 101 (i.e., the rear surface side). The cooling mechanism 4 includes a 1 st cooling unit 30A that cools the 1 st section E1 and a 2 nd cooling unit 30B that cools the 2 nd section E2. The 1 st cooling unit 30A includes a nozzle portion 32A disposed in the 1 st internal space 31A. The 2 nd cooling unit 30B includes a nozzle portion 32B disposed in the 2 nd internal space 31B.

The 1 st internal space 31A and the 2 nd internal space 31B are spaces for flowing the refrigerant therein. The 1 st internal space 31A is formed on the rear side in the depth direction D1 with respect to the 1 st region E1 of the target accommodating portion 3. The 2 nd internal space 31B is formed on the rear side in the depth direction D1 with respect to the 2 nd region E2 of the target accommodating portion 3. That is, the 2 nd internal space 31B is provided above the 1 st internal space 31A. A heat transfer wall portion 34 (partition wall) is provided between the internal spaces 31A, 31B and the target accommodating portion 3.

The 1 st internal space 31A and the 2 nd internal space 31B are partitioned by a partition wall 36. Thus, the inner spaces 31A and 31B have a rail-like shape (the upper end corresponds to the inner space 31B, and the lower end corresponds to the inner space 31A) in which the upper end and the lower end are semicircular in section at the center in the vertical direction when viewed from the front (see fig. 3). The internal spaces 31A and 31B have the above-described shape and extend parallel to the depth direction D1. The partition wall 36 is provided at the position of the center line CL1 of the target device 100. Therefore, the 1 st internal space 31A is close to a part of the 2 nd area E2 on the lower end side. In addition, the target container 12 has a recess 37 on the rear surface. The flow path forming member 13 has

concave portions

38A and 38B on the front surface. A partition wall 36 is provided between the recess 38A and the recess 38B. The 1 st internal space 31A is formed by a combination of the recess 37 of the target container 12 and the recess 38A of the flow path forming member 13. The 2 nd internal space 31B is formed by a combination of the recess 37 of the target container 12 and the recess 38B of the flow path forming member 13.

The 1 st nozzle portion 32A is a member that injects the refrigerant into the heat transfer wall portion 34 between the 1 st region E1. The 1 st nozzle portion 32A vertically injects the refrigerant against the heat transfer wall portion 34. The 1 st nozzle portion 32A injects the refrigerant to a position (a position facing the introduction hole 21 and coaxial with the beam B) of the heat transfer wall portion 34 that intersects the irradiation axis RL. At this time, the nozzle center of the 1 st nozzle portion 32A is arranged within the diameter of the beam B as viewed from the depth direction D1. The 1 st nozzle portion 32A is a cylindrical member extending parallel to the depth direction D1. The 1 st nozzle portion 32A is provided on the bottom surface of the recess 38A. The 1 st nozzle portion 32A is separated from the heat transfer wall portion 34. An enlarged diameter portion 32A having an enlarged diameter is formed at the front end portion (the front end portion in the depth direction D1) of the 1 st nozzle portion 32A. The outer peripheral surface of the enlarged diameter portion 32a is separated from the recess 37, the inner peripheral surface of the recess 38A, and the partition wall 36.

The 2 nd nozzle portion 32B is a member that injects the refrigerant into the heat transfer wall portion 34 between the 2 nd region E2. The 2 nd nozzle portion 32B vertically injects the refrigerant against the heat transfer wall portion 34. The portion to be injected by the 2 nd nozzle portion 32B is preferably in the vicinity of the interface of the gas-liquid mixture 102. The 2 nd nozzle portion 32B is a cylindrical member extending parallel to the depth direction D1. The 2 nd nozzle portion 32B is provided on the bottom surface of the recess 38B. The 2 nd nozzle portion 32B is separated from the heat transfer wall portion 34. An enlarged diameter portion 32B having an enlarged diameter is formed at the front end portion (the front end portion in the depth direction D1) of the 2 nd nozzle portion 32B. The outer peripheral surface of the enlarged diameter portion 32B is separated from the inner peripheral surfaces of the recess 37 and the recess 38B and the partition wall 36.

The cooling mechanism 4 has a flow mechanism 40 for ejecting the refrigerant from the nozzle portions 32A and 32B. First, the supply pipe 41 for supplying the refrigerant is inserted into the rear surface 100 b. The supply pipe 41 communicates with the ejection port of the 2 nd nozzle portion 32B via a flow path 42 formed in the flow path forming member 13. A flow path 43 for collecting the refrigerant in the 2 nd internal space 31B opens at the bottom surface of the recess 38B of the 2 nd internal space 31B. The flow path 43 extends in the flow path forming member 13 and communicates with the ejection port of the 1 st nozzle portion 32A. A flow path 44 for collecting the refrigerant in the 1 st internal space 31A opens at the bottom surface of the recess 38A of the 1 st internal space 31A. The flow path 44 is connected to a recovery pipe 46 inserted into the rear surface of the flow path forming member 13. The recovery pipe 46 extends to one side in the width direction D2 (see fig. 3), and the refrigerant is recovered by a recovery pipe 47 provided above the target device 100 through a pipe (not shown).

Next, the flow of the refrigerant in the cooling mechanism 4 when the beam B is irradiated will be described in detail with reference to fig. 2 and 3. If the beam B is irradiated to the target liquid 101 (refer to fig. 1), the target liquid 101 is boiled, so that the gas-liquid mixture 102 is introduced into the 2 nd region E2. Thus, F-18 is generated in the 1 st region E1. At this time, the refrigerant is supplied from the supply pipe 41, whereby the 2 nd nozzle portion 32B injects the refrigerant to a position (specifically, the vicinity of the interface) of the heat transfer wall portion 34 corresponding to the 2 nd region E2 (flow F1). The refrigerant colliding with heat transfer wall 34 is radially diffused from the collision portion. Thereby, a flow of the refrigerant from the upper side to the lower side is formed in the 2 nd region E2 between the 2 nd nozzle portion 32B and the heat transfer wall portion 34 (flow F2). In addition, in the 2 nd region E2, a flow of the refrigerant is also formed from below toward above (flow F3). The refrigerant diffused in the heat transfer wall portion 34 is folded back in the diameter-enlarged portion 32b, flows toward the opening 43a of the flow path 43, and is collected (flow F4). The refrigerant collected from the 2 nd internal space 31B flows through the flow path 43 to the 1 st nozzle portion 32A (flow F5). Thereby, the 1 st nozzle portion 32A injects the refrigerant (flow F6) to a position of the heat transfer wall portion 34 corresponding to the 1 st region E1 (specifically, a position coaxial with the beam B).

The refrigerant colliding with heat transfer wall 34 is radially diffused from the collision portion. Thereby, a flow of the refrigerant from the upper side to the lower side is formed in the 1 st region E1 between the 1 st nozzle portion 32A and the heat transfer wall portion 34 (flow F7). In the 1 st region E1, a flow of the refrigerant is also formed from below toward above (flow F8). In addition, since the 2 nd region E2 is also close to a part of the 1 st internal space 31A, a part of the upper side of the flow F8 is also close to the 2 nd region E2 (refer to fig. 2). The refrigerant diffused in the heat transfer wall portion 34 turns back at the diameter-enlarged portion 32a, flows toward the opening 44a of the flow path 44, and is collected (flow F9). The refrigerant recovered from the 1 st internal space 31A flows through the flow path 44 to the recovery pipe 46 (flow F10). The refrigerant is recovered by the recovery pipe 47 (flow F11).

Next, the operational effects of the target device 100 according to the present embodiment will be described.

According to the target apparatus 100 of the present embodiment, the target container 3 has the 1 st region E1 in which the target liquid 101 is contained and the 2 nd region E2 (region in which the target liquid 101 is not contained before the irradiation with the beam B) in which the gas-liquid mixture 102 of the boiling target liquid 101 is received. On the other hand, the cooling mechanism 4 includes the 1 st cooling unit 30A that cools at least the 1 st region E1 and the 2 nd cooling unit 30B that cools at least the 2 nd region E2. In addition, the 2 nd cooling unit 30B forms a flow of the refrigerant from the upper side toward the lower side in the 2 nd region E2 (flow F2 in fig. 2). The cooling performance by the refrigerant flowing from the upper side to the lower side can be improved as compared with the cooling performance when the refrigerant used in cooling unit 1a is used as it is. With the above configuration, the cooling performance of the cooling mechanism 4 can be improved.

In the target accommodating portion 3, the vapor component of the target liquid which gradually rises as a result of heating is present in the upper part of the 2 nd region E2 in many cases, but it is expected that more heat will be taken away by condensation heat transfer at these parts. Therefore, the 2 nd cooling portion 30B can keep the temperature of the heat transfer wall 34 lower by bringing the refrigerant into contact with the heat transfer wall 34 above the 2 nd region E2. Therefore, the cooling performance can be improved.

The 1 st cooling portion 30A includes a 1 st nozzle portion 32A that injects the refrigerant into the heat transfer wall portion 34 between the 1 st region E1. The 2 nd cooling unit 30B includes a 2 nd nozzle portion 32B that injects the refrigerant into the heat transfer wall portion 34 between the 2 nd region E2. In the 2 nd cooling portion 30B, a flow of the refrigerant from the upper side to the lower side may be formed below the injection portion of the 2 nd nozzle portion 32B (flow F2 in fig. 2). The cooling by spraying has a high heat transfer coefficient and a good cooling efficiency as compared with other forced convection. Therefore, the 2 nd nozzle portion 32B cools the 2 nd zone E2 by injection in addition to the 1 st zone E1 by injection of the 1 st nozzle portion 32A, whereby the cooling performance of the cooling mechanism 4 can be further improved.

The 1 st inner space 31A through which the refrigerant flows in the 1 st cooling part 30A and the 2 nd inner space 31B through which the refrigerant flows in the 2 nd cooling part 30B may be partitioned from each other. In this case, cooling can be performed in a state where the 1 st cooling unit 30A and the 2 nd cooling unit 30B are independent from each other. In this case, it is possible to suppress the flow of the refrigerant of one of the cooling portions from interfering with the flow of the refrigerant of the other cooling portion.

When cooling is performed by spraying, the heat transfer coefficient near the nozzle center is large and the thermal efficiency is good, but the heat transfer coefficient becomes small at a portion distant from the nozzle center. Therefore, the flow meter of the refrigerant with 5-10 liters per minute for the part which can be effectively cooled is limited to about 2cm in radius. For example, as in a comparative example described later, when the 2 nd zone E2 is also cooled by the refrigerant from the 1 st cooling part 30A, the 2 nd zone E2 is radially distant from the 1 st nozzle part 32A, and therefore sufficient cooling may not be performed. In contrast, when the 1 st cooling unit 30A and the 2 nd cooling unit 30B are independent of each other and the flow of the refrigerant dedicated to the 2 nd area E2 is formed by the 2 nd cooling unit 30B, the cooling efficiency for the 2 nd area E2 can be greatly improved.

As a comparative example, a target apparatus was prepared in which the 2 nd cooling unit 30B and the partition wall 36 were removed from the target apparatus 100 according to the above embodiment. The target device according to the comparative example cools the 2 nd zone by the upward flow of the refrigerant (corresponding to the flow F8 in fig. 2) generated by the injection from the 1 st nozzle portion 32A. In the target device according to this comparative example, when the target liquid 101 was irradiated with the 18MeV beam B having an average 95. mu.A for 2 hours, the maximum pressure of the target container 3 reached 3.5MPa, and 416GBq of F-18 was generated. If the beam current is increased more, the pressure of the target accommodating portion 3 may exceed the recommended upper limit of 4.2MPa, and the target may be damaged. In contrast, in the target apparatus 100 according to the present embodiment, when the target liquid 101 is irradiated with the 18MeV beam B having an average 95 μ A for 2 hours, the target container 3 reaches 2.3MPa at maximum, and F-18 having a grain size of 450GBq is generated. When the target liquid 101 was irradiated with the beam B of 167. mu.A on average for 2 hours, the target container 3 reached 3.4MPa at maximum, and F-18 of 755GBq was generated. As described above, the cooling mechanism 4 of the target apparatus 100 of the present embodiment has high cooling performance, and thus the intensity of the beam B can be increased as compared with the comparative example.

The present invention is not limited to the above embodiments.

For example, the 2 nd cooling unit includes a 2 nd nozzle unit that sprays the refrigerant to the partition wall between the 2 nd area and the 2 nd area. However, the 2 nd cooling unit need only form a flow of the refrigerant from the upper side to the lower side in the 2 nd region, and need not necessarily have the 2 nd nozzle unit. For example, the flow of the refrigerant flowing from the upper side to the lower side may be formed in the heat transfer wall portion 34 from the upper end of the 2 nd internal space. That is, in the above embodiment, the 2 nd cooling unit also forms a flow from the lower side toward the upper side by injection (flow F3 in fig. 2), but may form only a flow from the upper side toward the lower side.

The mechanism for circulating the refrigerant in the cooling mechanism is not limited to the above embodiment. For example, in the above embodiment, only one supply pipe of the refrigerant is used, and the refrigerant used for the injection of the 2 nd cooling unit is also used for the injection of the 1 st cooling unit. Alternatively, a dedicated supply pipe may be provided for the 1 st cooling unit and a dedicated supply pipe may be provided for the 2 nd cooling unit. The flow path and piping of the refrigerant may be appropriately changed in structure.

Claims

1. A target device is provided with:

a target accommodating portion having a 1 st region for accommodating a target liquid and a 2 nd region located above the 1 st region and receiving a gas-liquid mixture of the boiling target liquid; and

a cooling mechanism for cooling the target accommodating portion by a refrigerant on a side opposite to an irradiation direction of the beam irradiated to the target liquid,

the cooling mechanism is provided with a 1 st cooling part for cooling at least the 1 st area and a 2 nd cooling part for cooling at least the 2 nd area,

the 2 nd cooling unit forms a flow of the refrigerant from above to below in the 2 nd region.

2. The target apparatus according to claim 1,

the 1 st cooling unit includes a 1 st nozzle portion for injecting the refrigerant to a partition wall between the 1 st region and the first cooling unit,

the 2 nd cooling unit includes a 2 nd nozzle portion for injecting the refrigerant to a partition wall between the 2 nd area and the 2 nd area,

in the 2 nd cooling unit, the flow of the refrigerant from the upper side to the lower side is formed below the ejection portion of the 2 nd nozzle portion.

3. The target device according to claim 1 or 2,

a 1 st inner space through which the refrigerant flows in the 1 st cooling part and a 2 nd inner space through which the refrigerant flows in the 2 nd cooling part are partitioned from each other.