Mixer and charged particle beam apparatus equipped therewith

Abstract

To effectively suppress temporal temperature variation of cooling water with a simple configuration.SOLUTION: A mixer includes a container 34 of which internal space is partitioned by a partition wall 36 into a first stirring chamber 38 and a second stirring chamber 40. A nozzle 70 discharges a jet flow 48 to generate a rotational flow 50 in the first stirring chamber 38. The partition wall 36 includes a plurality of through-holes for sampling the rotational flow 50, thereby generating a plurality of sampling flows 54. The first stirring chamber 38 and the second stirring chamber 40 stir cooling water step-by-step.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a mixer and a charged particle beam apparatus including the same, and particularly to the structure of the mixer.

Background Art

[0002] A mixer is a device for mixing liquids. A mixer is used when it is desired to equalize the temperature of a liquid or when it is desired to equalize the concentration of a liquid. As such mixers, a dynamic mixer having a moving member for stirring and a static mixer not having such a moving member are known. From the viewpoint of suppressing size and cost, adoption of a static mixer is desirable.

[0003] In charged particle beam apparatuses such as electron microscopes, electron beam lithography apparatuses, and ion beam processing apparatuses, it is necessary to cool many facilities such as lenses and electronic circuits. In that case, if the temperature of the cooling water, which is a refrigerant, changes over time, it has a great influence on the formation of charged particle beams. Therefore, it is necessary to suppress the temporal temperature change of the cooling water as much as possible. For example, it is necessary to suppress the temperature change range of the cooling water to 0.5°C or less, or 0.25°C or less. In particular, in a high-precision charged particle beam apparatus, for example, it is necessary to suppress the temperature change range of the cooling water to 0.1°C or less.

[0004] When controlling the temperature of the cooling water by electrical feedback control, the controllable frequency band is determined by the response characteristics of the cooling water and the like. It is impossible to suppress periodic changes exceeding the upper limit of that frequency band. In addition to electrical feedback control, it is required to effectively suppress temporal temperature changes by a static mixer.

[0005] <00神仙道<3000018>Patent Document 1, Patent Document 2, and Patent Document 3 disclose mixers. However, none of the patent documents disclose a mixer in which a combination of a plurality of stirring methods is implemented, particularly a mixer that generates a plurality of sampling flows from a rotational flow.

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] Japanese Patent Publication No. 2008-1428701 [Patent Document 2] Japanese Patent Application Laid-Open No. 63-107736 [Patent Document 3] Japanese Patent Publication No. 2016-44876 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] The object of the present invention is to increase the degree of liquid mixing in a mixer without using a complex structure. Alternatively, the object of the present invention is to precisely equalize the temperature of the refrigerant in a charged particle beam apparatus. [Means for solving the problem]

[0008] The mixer according to the present invention includes a container having an internal space, a partition wall intersecting the central axis of the container and dividing the internal space into a first stirring chamber and a second stirring chamber, the partition wall having a plurality of through holes connecting the first stirring chamber and the second stirring chamber, an inlet for introducing liquid into the first stirring chamber, an outlet for discharging liquid from the second stirring chamber, and an injection structure that injects the liquid introduced through the inlet into the first stirring chamber, thereby generating a rotating flow in the first stirring chamber that rotates around the central axis of the container, wherein a plurality of sampling flows are generated by sampling the rotating flow through the plurality of through holes, and the plurality of sampling flows flow into the second stirring chamber.

[0009] The charged particle beam apparatus according to the present invention includes a cooling target for irradiating a sample with a charged particle beam, a cooling device for cooling a refrigerant returned from the cooling target, and a mixer provided between the cooling device and the cooling target to suppress temperature changes of the refrigerant sent from the cooling device toward the cooling target, wherein the mixer includes a container having an internal space, a partition wall intersecting the central axis of the container and dividing the internal space into a first stirring chamber and a second stirring chamber, the partition wall having a plurality of through holes connecting the first stirring chamber and the second stirring chamber, an inlet for introducing the refrigerant into the first stirring chamber, an outlet for discharging the refrigerant from the second stirring chamber, and an injection structure that injects the refrigerant introduced through the inlet into the first stirring chamber, thereby generating a rotating flow in the first stirring chamber that rotates around the central axis of the container, wherein a plurality of sampling flows are generated by sampling the rotating flow through the plurality of through holes, and the plurality of sampling flows flow into the second stirring chamber. [Effects of the Invention]

[0010] According to the present invention, the degree of mixing of liquids can be increased in a mixer without using a complex structure. Alternatively, according to the present invention, the refrigerant temperature can be made uniform with high precision in a charged particle beam apparatus. [Brief explanation of the drawing]

[0011] [Figure 1] Block diagram showing a charged particle beam apparatus according to an embodiment. [Figure 2] This is a perspective view of the mixer. [Figure 3] This is a perspective view of a mixer. [Figure 4] This is a cross-sectional view of the hollow case. [Figure 5] This diagram shows jet flow and rotational flow. [Figure 6] This is a cross-sectional view of the mixer. [Figure 7] This figure shows the experimental results. [Figure 8] This figure shows the results of another experiment. [Figure 9]It is a diagram showing another arrangement of the hollow case. [Figure 10] It is a diagram showing a first modification example of the partition wall. [Figure 11] It is a diagram showing a second modification example of the partition wall.

Mode for Carrying Out the Invention

[0012] Hereinafter, embodiments will be described based on the drawings.

[0013] (1) Outline of Embodiment The mixer according to the embodiment has a container, a partition wall, an inlet, an outlet, and an injection structure. The container is a hollow container having an internal space. The partition wall intersects the central axis of the container and partitions the internal space of the container into a first stirring chamber and a second stirring chamber. The partition wall has a plurality of through holes connecting the first stirring chamber and the second stirring chamber. The inlet is for introducing liquid into the first stirring chamber. The outlet is for discharging liquid from the second stirring chamber. The injection structure injects the liquid introduced through the inlet into the first stirring chamber, thereby generating a rotating flow that rotates around the central axis of the container in the first stirring chamber. A plurality of sampling flows are generated by sampling the rotating flow through the plurality of through holes. The plurality of sampling flows flow into the second stirring chamber.

[0014] According to the above configuration, in the first stirring process, a rotating flow is generated by the injection flow, and the injection flow is mixed with the rotating flow. In the subsequent second stirring process, the plurality of sampling flows generated by the plurality of through holes are mixed with the liquid in the second stirring chamber. Thus, by combining a plurality of stirring methods, the mixing degree of the liquid can be increased in the container with a simple configuration. Therefore, temporal temperature fluctuations or concentration fluctuations of the liquid can be significantly suppressed.

[0015] The rotational flow generated in the first stirring chamber is a flow that rotates around the central axis of the container, and includes vortex flow, spiral flow, etc. In the first stirring chamber, when the injection flow ejected from the injection structure collides with the inner surface of the container and generates a flow different from the rotational flow, that different flow also contributes to the improvement of the stirring efficiency. In the second stirring chamber, when a rotational flow is generated by a plurality of sampling flows, that rotational flow also contributes to the improvement of the stirring efficiency. In the first stirring chamber, the liquid gradually moves toward the second stirring chamber while rotating. In the second stirring chamber, the liquid gradually moves toward the outlet side.

[0016] In an embodiment, the injection structure includes a nozzle protruding from the container into the first stirring chamber. The nozzle generates an injection flow that spreads in the width direction intersecting the central axis of the container. According to this configuration, it is possible to bring the injection flow into contact with the portion from the inner side to the outer side in the rotational flow. Therefore, the stirring efficiency can be increased.

[0017] Typically, the liquid introduced in the past exists on the inner side of the rotational flow, and the liquid introduced recently exists on the outer side of the rotational flow. When the temperature of the liquid introduced into the inlet changes over time, the temperature of the liquid introduced in the past and the temperature of the liquid introduced recently are not the same. That is, a temperature variation occurs from the inner side to the outer side in the rotational flow. The above configuration mixes the newly introduced injection flow with the portion having a temperature distribution in the rotational flow, thereby achieving temperature uniformity.

[0018] In an embodiment, the nozzle is a passage through which the liquid introduced through the inlet flows, and has a passage that spreads in the width direction. The central axis of the passage passes through a position shifted in the width direction from the central axis of the container. In an embodiment, the container has an inner side surface facing the first stirring chamber and surrounding the first stirring chamber. The nozzle has an opening facing the inner side surface. According to this configuration, on the premise that the inner surface of the container has a cylindrical, spherical, or ellipsoidal form, a rotational flow can be naturally formed.

[0019] In this embodiment, the second stirring chamber is located above the first stirring chamber. The container has a bottom surface facing the first stirring chamber. The partition wall has a bottom surface facing the first stirring chamber. The nozzle is separated from the bottom surface and the bottom surface. With this configuration, when the jet flow collides with the inner surface of the container, a flow other than the rotational flow (e.g., a secondary flow or tributary flow) is easily generated. Such a separate flow can further increase the stirring efficiency. The nozzle may be located at or near an intermediate position between the bottom surface and the bottom surface.

[0020] In this embodiment, the injection structure includes a flat, hollow member. The hollow member includes a nozzle protruding from the container into a first stirring chamber, and an outer end protruding from the container to the outside of the container and having an inlet. The hollow member extends in the direction of the rotating flow, and the area of ​​the portion of the hollow member that the rotating flow collides with is relatively small. Therefore, the motion of the rotating flow is not significantly impaired by the hollow member. The hollow case, which will be described later, corresponds to the hollow member.

[0021] In this embodiment, the hollow member includes a passage through which liquid introduced via an inlet flows, two opposing inner surfaces separated by the passage, and a reinforcing member positioned in the passage and connected to the two inner surfaces. If the hollow member penetrates a container, stress concentration is likely to occur in the hollow member. With this configuration, even if a force that expands the hollow member is applied, the reinforcing member can prevent damage to the hollow member. Multiple support columns, described later, correspond to the reinforcing member. In this embodiment, the two inner surfaces are the bottom surface and the top surface of the passage, extending in the central axis direction and the width direction of the passage.

[0022] In this embodiment, the rotating flow is sampled at multiple radial positions in the rotating flow through multiple through-holes. This configuration increases the diversity of temperature or concentration of the multiple sampled flows. This improves the degree of mixing or uniformity of the liquid in the second stirring chamber. Polar coordinates can be defined with respect to the central axis of the container. In this case, the central axis of the container corresponds to the origin of the polar coordinates. The above-mentioned multiple radial positions are multiple positions defined by multiple distances (radii) from the origin.

[0023] The charged particle beam apparatus according to this embodiment includes a cooling target, cooling equipment, and a mixer. The cooling target is equipment for irradiating a sample with a charged particle beam. The cooling equipment is equipment for cooling the refrigerant returning from the cooling target. The mixer is provided between the cooling equipment and the cooling target and suppresses temperature changes of the refrigerant sent from the cooling equipment toward the cooling target. The mixer includes a container, a partition wall, an inlet, an outlet, and an injection structure. The container is a hollow container with an internal space. The partition wall intersects the central axis of the container and divides the internal space into a first stirring chamber and a second stirring chamber. The partition wall has a plurality of through holes connecting the first stirring chamber and the second stirring chamber. The inlet is for introducing the refrigerant into the first stirring chamber. The outlet is for discharging the refrigerant from the second stirring chamber. The injection structure injects the refrigerant introduced through the inlet into the first stirring chamber, thereby generating a rotating flow that rotates around the central axis of the container in the first stirring chamber. Multiple sampling flows are generated by sampling the swirling flow through multiple through-holes. These multiple sampling flows flow into the second stirring chamber.

[0024] According to the above configuration, temperature changes of the refrigerant supplied to the charged particle beam apparatus can be suppressed, thereby eliminating or mitigating problems caused by changes in refrigerant temperature. For example, it is possible to suppress the shift in the irradiation position of the charged particle beam caused by changes in the temperature of the refrigerant. The refrigerant is, for example, cooling water.

[0025] (2) Details of the embodiment Figure 1 shows a charged particle beam apparatus 10 according to an embodiment. Specifically, the charged particle beam apparatus 10 is a transmission electron microscope, a scanning transmission electron microscope, an electron beam lithography apparatus, an ion beam processing apparatus, etc. The charged particle beam apparatus 10 has a cooling device 12 that is cooled. The cooling device 12 includes a charged particle source, various lenses, electronic circuits, etc. A temperature sensor is provided in the cooling device 12, but its illustration is omitted.

[0026] The charged particle beam apparatus 10 has a cooling system 14. The cooling system 14 cools the equipment to be cooled using cooling water as a refrigerant. The cooling system 14 includes a chiller 16, a mixer 18, and a main valve unit 20. The chiller 16 is a cooler that cools the cooling water. The mixer 18 equalizes the temperature of the cooling water. In the main valve unit 20, the supplied cooling water is divided into multiple branches, but this is not shown in the illustration.

[0027] The controller 32 controls the operation of the cooling equipment 14. Specifically, the controller 32 provides feedback control to the operation of the chiller 16 according to the temperature detected by the temperature sensor. Even with such feedback control, temperature changes occur in the cooling water discharged from the chiller 16 due to the response characteristics of the cooling water, etc. In other words, temperature fluctuations exceeding the upper limit of a specific frequency band cannot be suppressed by the above feedback control, so a mixer 18 is provided downstream of the chiller 16.

[0028] The mixer 18 may also be called an inline mixer or a static mixer. The mixer 18 has a container 34. The internal space of the container 34 is divided into a first stirring chamber 38 and a second stirring chamber 40 by a partition wall 36. The container 34 is provided with an inlet 42 into which cooling water is introduced and an outlet 44 for which cooling water is discharged. In the configuration example shown in Figure 1, the second stirring chamber 40 is located above the first stirring chamber 38.

[0029] A nozzle 70 is provided in the first stirring chamber 38. Cooling water is ejected from the nozzle 70, generating a jet flow 48. The jet flow 48 generates a swirling flow 50 in the first stirring chamber 38. The newly generated jet flow also comes into contact with the already existing swirling flow 50, resulting in heat exchange. When the jet flow 48 collides with the inner side surface of the container, multiple branched flows (multiple secondary flows) are generated. These branched flows also contribute to improving the degree of liquid mixing in the first stirring chamber 38.

[0030] The partition wall 36 has a group of through-holes consisting of multiple through-holes. The rotating flow 50 is sampled through these multiple through-holes, thereby generating multiple sampling flows 54. These multiple sampling flows 54 are mixed with the existing cooling water in the second stirring chamber 40, like a reverse shower, thereby causing heat exchange. An insulating material 56 is provided on the outside of the container 34. In other words, the insulating material 56 surrounds the container 34.

[0031] In the mixer 18, two-stage stirring is performed: stirring of the cooling water in the first stirring chamber 38 and stirring of the cooling water in the second stirring chamber 40. This increases the degree of mixing of the cooling water and significantly suppresses the temporal temperature change of the cooling water. To achieve such an effect, rotating members such as stirring blades are not required. In other words, high stirring results can be obtained with a simple static configuration.

[0032] A pipe 22 is provided between the cooled equipment 12 and the main valve unit 20, and a pipe 24 is provided between the main valve unit 20 and the chiller 16. A pipe 26 is provided between the chiller 16 and the mixer 18, a pipe 28 is provided between the mixer 18 and the main valve unit 20, and a pipe 30 is provided between the main valve unit 20 and the cooled equipment 12.

[0033] The mixer 18 will be described in detail below.

[0034] Figure 2 shows the external appearance of the mixer 18. The insulation material is not shown in Figure 2. This is also the case in Figures 3 and beyond. In Figure 2, the x-direction is the first horizontal direction, the y-direction is the second horizontal direction, and the z-direction is the vertical direction.

[0035] The container 34 has a rounded cylindrical shape, a spherical shape, or an ellipsoidal (elliptical shell) shape. The container 34 consists of a cylindrical middle section 34A, a hemispherical or semi-ellipsoidal lower section 34B, and a hemispherical or semi-ellipsoidal upper section 34C. A hollow case 60 having a horizontal orientation penetrates a specific part of the middle section 34A. The hollow case 60 is a hollow member that functions as an injection structure. The hollow case 60 has a nozzle located inside the container 34 (not shown in Figure 2) and an outer end 62 located outside the container 34.

[0036] An inlet 42 for introducing cooling water is provided at the outer end 62. Cooling water is introduced into the inlet 42 from below. This cooling water then flows through a passage in the hollow case 60 and is ejected into the container 34.

[0037] An outlet 44 is provided at the top of the upper part 34C. The outlet 44 is for discharging the cooling water that comes out of the container 34. The opening of the outlet 44 faces upward. In Figure 2, lines 58a, 58b, and 58c are weld lines.

[0038] Figure 3 shows the interior of the container 34. Inside the container 34, there is a disc-shaped partition wall 36 that extends in the x and y directions. The internal space of the container 34 is divided into two parts by the partition wall 36. Specifically, it is divided into a first stirring chamber 38 and a second stirring chamber 40.

[0039] As described above, the hollow case 60 penetrates the container 34. The hollow case 60 has a slit-shaped passage. The central axis of the passage is parallel to the y-direction. The rear end of the passage is closed, and the front end of the passage forms an opening 72. An inlet 42 is provided at the outer end 62 of the hollow case 60. The inside of the inlet 42 is connected to the passage inside the hollow case 60. Reinforcing members are placed inside the hollow case 60 to prevent damage to the hollow case 60. These will be explained later. Note that in Figure 3, the welded portion between the hollow case 60 and the container 34 is represented by multiple lines.

[0040] Reference numeral 64 indicates the central axis of the container 34. The partition wall 36 intersects (more precisely, perpendicular to) the central axis 64. The central axis 64 passes through the center of the partition wall 36. The partition wall 36 has a group of through-holes 66, which consists of multiple through-holes. In the example shown in Figure 3, the group of through-holes 66 is composed of multiple rows of through-holes 68. The multiple rows of through-holes 68 have a radial arrangement. Each row of through-holes 68 is composed of multiple through-holes 68a provided at multiple radial positions. Each radial position is a position on a polar coordinate system defined with the center of the partition wall 36 as the origin. In Figure 3, the cross section identified by line AA is shown in Figure 4.

[0041] In Figure 4, the hollow case 60 has a plate-like shape, and its internal space constitutes a passage. The passage is a thin space extending in the x and y directions. The central axis of the passage is parallel to the x direction. The y direction corresponds to the width direction.

[0042] As described above, stress concentration is likely to occur in the hollow case 60, and if the thickness of the hollow case 60 is reduced, the hollow case 60 becomes more susceptible to damage. Therefore, in this embodiment, reinforcing members are provided in the passage. Specifically, two support columns 78A and 78B are provided. The hollow case 60 has two inner surfaces (top and bottom) 74 and 76. The two support columns 78A and 78B are welded to the two inner surfaces 74 and 76, respectively. Such reinforcing members effectively prevent damage to the hollow case 60 even if the thickness of the hollow case 60 is reduced.

[0043] Since the thickness of the hollow case 60 in the z-direction is very small, the hollow case 60 does not significantly hinder the motion of the rotating flow described below. Specifically, the area of ​​the side surface 80 of the hollow case 60 is very small, and the rotating flow can easily bypass the hollow case 60 (see reference numeral 81).

[0044] Figure 5 illustrates the function of the hollow case 60. The portion of the hollow case 60 that is located inside the container 34 functions as a nozzle 70. The nozzle 70 protrudes from the inner surface of the container 34 into the first stirring chamber. Incidentally, the outer end of the hollow case 60 protrudes outward from the outer surface of the container 34.

[0045] The tip of the nozzle 70 forms a slit-shaped opening 72. Cooling water is ejected from the opening 72, that is, a jet stream 48 is generated. The jet stream 48 is a flow directed toward a specific portion 82A on the inner surface of the container 34. The central axis 84 of the passage within the nozzle 70 (which can also be called the central axis of the nozzle 70) is parallel to the y-direction. The central axis 84 is shifted in the +x direction from the center 64a through which the central axis of the container 34 passes.

[0046] In the illustrated example configuration, there is a certain gap between the hollow case 60 and another specific part 82B, but this gap can be made smaller or even eliminated. The other specific part 82B is the part located on the positive x-direction side when viewed from the center 64a.

[0047] The jet stream 48 strikes an inclined inner surface (specifically a particular part 82A) with respect to the central axis 84, resulting in the generation of a swirling flow 50. The swirling flow 50 corresponds to a vortex flow. A new jet stream 48 comes into contact with the existing swirling flow, causing mixing and heat exchange.

[0048] Figure 6 shows a longitudinal section of the container 34. The internal space of the container 34 is divided by a partition wall 36, which acts as a horizontal plate, thereby forming a first stirring chamber 38 and a second stirring chamber 40.

[0049] The first stirring chamber 38 is a space enclosed by the bottom surface 100 of the container 34, the lower surface 102 of the partition wall 36, and the inner side surface 104 of the container 34. The lower surface 102 can also be called the ceiling surface of the first stirring chamber 38. The bottom surface 100 has a hemispherical or semi-ellipsoidal shape, the lower surface 102 is flat, and the inner side surface 104 has a cylindrical shape.

[0050] The second stirring chamber 40 is a space enclosed by the upper surface 106 of the partition wall 36, the ceiling surface 108 of the container 34, and the inner side surface 110 of the container 34. The upper surface 106 is flat, the ceiling surface 108 has a hemispherical or semi-ellipsoidal shape, and the inner side surface 110 has a cylindrical shape.

[0051] The internal space of the container 34 is cylindrical, spherical, or ellipsoidal, or a combination of these shapes. The shape of the internal space is rounded to minimize stagnation of the cooling water.

[0052] A nozzle 70 is provided at an intermediate position in the z-direction within the first stirring chamber 38. The nozzle 70 protrudes from the container 34 into the first stirring chamber 38 (protruding towards the positive y-direction). The nozzle 70 is in a horizontal position. The passage within the nozzle 70 extends in the x-direction and the y-direction. The nozzle 70 (the central axis of the passage) is separated from the bottom surface 100 and the lower surface 102, and in practice, the opening 72 of the nozzle 70 is located at an intermediate height in the first stirring chamber 38.

[0053] Cooling water is continuously injected from the opening 72 at the tip of the nozzle 70 toward a specific portion 82A of the inner side surface 104. This generates a jet flow 48. When the jet flow 48 strikes the specific portion 82A, a swirling flow 50 is generated and maintained. The swirling flow 50 is a flow that rotates around the central axis of the container 34, and specifically corresponds to a vortex flow. The swirling flow 50 consists of a swirling flow 50A below the nozzle 70 and a swirling flow 50B above the nozzle 70. However, in the first stirring chamber 38, the entire amount of cooling water present there gradually moves toward the second stirring chamber 40.

[0054] A new injection flow 48 is mixed with the existing rotating flow 50, thereby agitating the cooling water in the first stirring chamber 38. A certain stirring effect can also be expected within the rotating flow 50. When the injection flow 48 hits a specific section 82A, branch flows (secondary flows) 48a and 48b are generated in addition to the rotating flow 50. Branch flows 48a are upward flows, and branch flows 48b are downward flows. Such branch flows 48a and 48b enhance the stirring effect.

[0055] The upper part of the rotating flow 50 is sampled through the group of through-holes 66 formed in the partition wall 36, thereby generating multiple sampling flows 54. These sampling flows 54 flow into the second stirring chamber 40. Thereupon, the multiple sampling flows 54 are mixed with the cooling water already present in the second stirring chamber, further increasing the degree of mixing.

[0056] In reality, the multiple sampling streams 54 have a rotational component. The inflow of the multiple sampling streams 54 into the second stirring chamber 40 creates a relatively slow rotational flow 86 in the second stirring chamber 40. This also contributes to improving the stirring efficiency. In the second stirring chamber 40, the cooling water present there gradually moves toward the outlet. Through this series of processes, the temperature of the cooling water is further homogenized.

[0057] According to the mixer of this embodiment, the cooling water, which has been sufficiently homogenized thermally through a two-stage stirring process, is discharged through the outlet.

[0058] If the period corresponding to the upper limit of the frequency band of the electrical feedback control (closed-loop control) is expressed as T1, and the flow rate of cooling water per unit time is expressed as L1, then preferably the internal volume of the container 34 is (T1 × L1) or more. For example, if the period T1 is 0.05 Hz and the flow rate L1 per unit time is 14.5 L / min, then the internal volume of the container 34 is set to 4.8 L or more. In that case, the internal volume of the container 34 may be, for example, 11.5 L. The volume of the second stirring chamber 40 is, for example, within the range of 1 / 5 to 1 / 2 of the volume of the container 34. If the area of ​​the inlet (and the area of ​​the outlet) is expressed as S1, and the total area of ​​the through-hole group is expressed as S2, then, for example, the total area S2 is set such that the condition S1 ≤ S2 ≤ (10 × S1) is satisfied.

[0059] In Figure 6, the container 34 is made of a metal such as stainless steel. The wall thickness of the container 34 is set to a range of, for example, 2 to 6 mm. Regarding the internal space of the container 34, the width (height) 88 in the z direction is set to a range of, for example, 240 to 280 mm. The width 90 of the middle section 90 in the z direction is set to a range of, for example, 110 to 140 mm. The widths 92 and 94 of the lower section 92 and upper section 94 are set to a range of, for example, 70 to 100 mm. The diameter 96 of the internal space of the container 34 is set to a range of, for example, 240 to 280 mm. The width in the x direction of the passage in the hollow case (nozzle 70) is set to a range of, for example, 60 to 80 mm. The width (height) of that passage in the z direction is set to a range of, for example, 2 to 6 mm. The wall thickness of the hollow case is set to a range of, for example, 1 to 4 mm. The inner diameter of the inlet and outlet is set to, for example, within the range of 15 to 30 mm. The height of the partition wall 36 from the bottom surface 100 is set to, for example, within the range of 240 to 270 mm. The height of the central axis of the passage from the bottom surface 100 is set to, for example, within the range of 70 to 100 mm. The diameter of each through hole is set to, for example, within the range of 2 to 10 mm. All values ​​described in this specification are for illustrative purposes only.

[0060] Figure 7 shows the experimental results for the mixer according to the embodiment. The horizontal axis is the time axis, and the vertical axis is the temperature axis. Waveform 112 shows the change in temperature of the cooling water introduced into the inlet. Waveform 114 shows the change in temperature of the cooling water discharged from the outlet. An offset 116 occurs between the two waveforms 112 and 114, but this is not due to the action of the mixer and is for convenience only. Incidentally, T1 above is 0.05 Hz.

[0061] Waveform 112 shows a fluctuation of approximately ±0.015°C, while waveform 114 shows a fluctuation of only approximately ±0.002°C. If the range of change of waveform 112 is set to 1, the range of change of waveform 114 is 1 / 8. Note that waveform 114 contains measurement noise and various frequency components.

[0062] Figure 8 shows another experimental result for the mixer according to the embodiment. The horizontal axis is the time axis, and the vertical axis is the temperature axis. Waveform 200 shows the change in temperature of the cooling water introduced into the inlet. Waveform 202 shows the change in temperature of the cooling water discharged from the outlet. Temperature axis 204 shows the temperature of the cooling water introduced into the inlet, and temperature axis 206 shows the temperature of the cooling water discharged from the outlet.

[0063] Waveform 200 corresponds to a sine wave of 0.005 Hz, and its amplitude 208 is 0.2°C. The flow rate is 14.5 L / min. On the other hand, in waveform 202, the amplitude 210 is 0.005°C. From these, a gain of 0.025 is calculated. That is, the water temperature fluctuation is suppressed to 1 / 40. As described above, a significant temperature fluctuation suppression effect can be obtained with the mixer according to this embodiment.

[0064] Figure 9 shows other arrangement examples of the hollow case 60. The hollow case 60 may be positioned closer to the inner side of the container 34. That is, the nozzle 70 may be shifted further towards the positive x-direction. Such a configuration can form a faster rotating flow.

[0065] Figure 10 shows a first modified example of the partition wall. In the partition wall 36A, the through-hole group 66A is composed of multiple through-holes arranged randomly.

[0066] Figure 11 shows a second modified example of the partition wall. The through-hole group 66B is composed of multiple rows of through-holes, each row of through-holes composed of multiple through-holes. Each through-hole has an elliptical shape that is elongated in the tangential direction. When such a configuration is adopted, each sampling flow becomes flattened, so the contact area between the cooling water present in the second stirring chamber and each sampling flow can be increased. In other words, heat exchange can be promoted. Shapes other than circular and elliptical (e.g., rectangular) may be adopted as the shape of the through-holes.

[0067] The mixer shown in Figure 2 can also be used in an inverted position. However, if such a configuration is adopted, air tends to remain near the ceiling of the container. To avoid such problems, it is preferable to adopt the configuration according to the embodiment.

[0068] In the multiple rows of through-holes shown in Figure 3, etc., a curved shape may be adopted for each row of through-holes. In the nozzle shown in Figure 3, etc., the opening at the tip may be made up of multiple holes. A curved opening may be used instead of a straight opening.

[0069] According to this embodiment, the equipment to be cooled in the charged particle beam apparatus can be cooled using cooling water with highly suppressed temperature changes, thereby improving the performance of the charged particle beam apparatus. In particular, problems such as charged particle beam drift can be eliminated or significantly reduced. The mixer according to this embodiment may also be used for concentration homogenization. The mixer according to this embodiment may also be applied to apparatus other than a charged particle beam apparatus. [Explanation of symbols]

[0070] 10 Charged particle beam apparatus, 12 Cooled equipment, 14 Cooling equipment, 16 Chiller, 28 Mixer, 20 Main valve section, 34 Container, 36 Partition, 38 First stirring chamber, 40 Second stirring chamber, 42 Inlet, 44 Outlet, 48 Jet stream, 50 Rotating stream, 54 Multiple sampling streams, 70 Nozzle.

Claims

1. A mixer provided between a cooling target, which is equipment for irradiating a sample with a charged particle beam, and a cooling equipment for cooling the refrigerant returned from the cooling target, wherein the mixer suppresses temperature changes of the refrigerant sent from the cooling equipment toward the cooling target, A container having an internal space, A partition wall intersects the central axis of the container and divides the internal space into a first stirring chamber and a second stirring chamber, the partition wall having a plurality of through holes connecting the first stirring chamber and the second stirring chamber, An inlet for introducing a liquid refrigerant into the first stirring chamber, An outlet for discharging liquid from the second stirring chamber, An injection structure that injects the liquid introduced through the inlet into the first stirring chamber, thereby generating a rotating flow in the first stirring chamber that rotates around the central axis of the container, Includes, Multiple sampling flows are generated by sampling the rotating flow through the multiple through holes, and these multiple sampling flows flow into the second stirring chamber. A mixer characterized by the following features.

2. In the mixer according to claim 1, The injection structure includes a nozzle that protrudes from the container into the first stirring chamber. A mixer characterized by the following features.

3. In the mixer according to claim 2, The nozzle generates a jet stream that spreads in the width direction intersecting the central axis of the container. A mixer characterized by the following features.

4. In the mixer according to claim 3, The nozzle has a passage through which the liquid introduced through the inlet flows, and the passage widens in the width direction. The central axis of the passage passes through a position shifted in the width direction from the central axis of the container. A mixer characterized by the following features.

5. In the mixer according to claim 4, The container has an inner side surface that faces and surrounds the first stirring chamber, The nozzle has an opening facing the inner side surface, A mixer characterized by the following features.

6. A container having an internal space, A partition wall intersects the central axis of the container and divides the internal space into a first stirring chamber and a second stirring chamber, the partition wall having a plurality of through holes connecting the first stirring chamber and the second stirring chamber, An inlet for introducing liquid into the first stirring chamber, An outlet for discharging liquid from the second stirring chamber, An injection structure that injects the liquid introduced through the inlet into the first stirring chamber, thereby generating a rotating flow in the first stirring chamber that rotates around the central axis of the container, Includes, The sampling of the rotating flow through the multiple through holes generates multiple sampling flows, which flow into the second stirring chamber. The injection structure includes a nozzle that protrudes from the container into the first stirring chamber. The second stirring chamber is located above the first stirring chamber. The container has a bottom surface facing the first stirring chamber, The partition wall has a lower surface facing the first stirring chamber, The nozzle is separated from the bottom surface and the lower surface, A mixer characterized by the following features.

7. In the mixer according to claim 1, The injection structure includes a flat, hollow member, The aforementioned hollow member is A nozzle protruding from the container into the first stirring chamber, An outer end portion that protrudes from the container to the outside of the container and has the inlet, A mixer characterized by including

8. A container having an internal space, A partition wall intersects the central axis of the container and divides the internal space into a first stirring chamber and a second stirring chamber, the partition wall having a plurality of through holes connecting the first stirring chamber and the second stirring chamber, An inlet for introducing liquid into the first stirring chamber, An outlet for discharging liquid from the second stirring chamber, An injection structure that injects the liquid introduced through the inlet into the first stirring chamber, thereby generating a rotating flow in the first stirring chamber that rotates around the central axis of the container, Includes, The sampling of the rotating flow through the multiple through holes generates multiple sampling flows, which flow into the second stirring chamber. The injection structure includes a flat, hollow member, The aforementioned hollow member is A nozzle protruding from the container into the first stirring chamber, An outer end portion that protrudes from the container to the outside of the container and has the inlet, Includes, The aforementioned hollow member is A passage through which the liquid introduced via the inlet flows, Two opposing inner surfaces separated by the aforementioned passage, A reinforcing member is arranged in the passage and connected to the two inner surfaces, A mixer characterized by including

9. In the mixer according to claim 1, The plurality of through holes allows the rotating flow to be sampled at multiple radial positions in the rotating flow. A mixer characterized by the following features.

10. A cooling device is a facility for irradiating a sample with charged particle beams, A cooling system for cooling the refrigerant returned from the object to be cooled, A mixer provided between the cooling equipment and the object to be cooled, which suppresses temperature changes of the refrigerant sent from the cooling equipment toward the object to be cooled, Includes, The aforementioned mixer is, A container having an internal space, A partition wall intersects the central axis of the container and divides the internal space into a first stirring chamber and a second stirring chamber, the partition wall having a plurality of through holes connecting the first stirring chamber and the second stirring chamber, An inlet for introducing refrigerant into the first stirring chamber, An outlet for discharging the refrigerant from the second stirring chamber, An injection structure that injects the refrigerant introduced through the inlet into the first stirring chamber, thereby generating a rotating flow in the first stirring chamber that rotates around the central axis of the container, Includes, Multiple sampling flows are generated by sampling the rotating flow through the multiple through holes, and these multiple sampling flows flow into the second stirring chamber. A charged particle beam apparatus characterized by the following features.

Images