Cloud chamber

Abstract

To provide a user-friendly cloud chamber for observing a radiation ray.SOLUTION: In a cloud chamber 100, a steam supply device 250 supplies steam 204 to an observation room 202, the supplied steam 204 in the observation room 202 is cooled to form a supersaturation steam layer 206, and a track of a radiation ray passing through the supersaturation steam layer 206 is observed. In the cloud chamber 100, a cooling box 310 that includes a cooling plate 312 having a plurality of cooling plates 330 for cooling the steam 204 in the observation room 202 is provided, a mixture of generated dry ice 304 generated from liquefied carbon dioxide 384 and gaseous carbon dioxide is introduced into the cooling box 310, the generated dry ice 304 is accumulated in a passage formed by the plurality of cooling plates 330, and the accumulated generated dry ice 304 cools the steam 204 in the observation room 202 via the cooling plate 312.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a cloud chamber for observing the tracks of radiation and the like. [Background technology]

[0002] Cloud chambers have the ability to observe the tracks of radiation and other substances. A commonly used cloud chamber works by evaporating a liquid such as ethanol to create an ethanol vapor layer within the observation chamber. One side of the created vapor layer is then cooled to create a supersaturated vapor layer within the observation chamber. When the radiation to be observed passes through the supersaturated vapor layer, it acts on the molecules present in the supersaturated vapor layer, ionizing them. The ionized molecules become nuclei, and the surrounding supersaturated vapor condenses. Molecules ionize one after another along the radiation track, causing the supersaturated vapor to condense, and fog is generated along the radiation track. By shining light into the chamber and observing the state of the fog, the track of the radiation to be observed can be observed.

[0003] Cloud chambers for observing the tracks of radiation, etc., are equipped with a vapor generator to generate vapor from a liquid such as ethanol (ethyl alcohol) to create a vapor layer in the observation chamber, and a cooling device to cool part of the vapor layer to create a supersaturated vapor layer.

[0004] As mentioned above, radiation tracks can be observed by passing the radiation to be observed through the supersaturated vapor layer. It is important to allow as much radiation as possible to pass through the supersaturated vapor layer, and to achieve this, it is important to widen the supersaturated vapor layer. To increase the thickness of the supersaturated vapor layer, it is important to improve the capacity of the cooling device used to generate the supersaturated vapor layer. However, simply trying to improve the capacity of the cooling device would make the cooling device itself larger and heavier. Ultimately, this would increase the size of the entire cloud chamber used to observe radiation tracks, which would create various obstacles in handling, including transportation. Therefore, it is preferable for the cooling device to be small and lightweight.

[0005] Some attempts have been made to use solid dry ice to cool the vapor in the observation chamber. Dry ice is a cryogenic solid, and there are various issues with cloud chambers that use dry ice, such as how to obtain the dry ice and set it in the cloud chamber, and what kind of structure should be used to efficiently cool the vapor in the observation chamber using the set dry ice. Patent Document 1 listed below discloses a cloud chamber that uses dry ice to cool the vapor in the observation chamber. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-317686 Summary of the Invention [Problem to be solved by the invention]

[0007] In the cloud chamber described in Patent Document 1, dry ice 15 is used to cool ethyl alcohol vapor, as described in paragraphs

[0018] to

[0021] of the specification. According to the description in these paragraphs, dry ice 15 is first placed on the inner bottom of the insulating layer 14 of the observation tank body storage box 13. Next, the observation tank body 12 is placed on top of the dry ice 15, and the tips of each heat-transfer male screw 23 are inserted into the dry ice 15. Next, ethyl alcohol 26 is stored in the storage groove 27, and then a lid member 20 is placed over the upper opening of the observation tank body 12 to seal the observation tank body 12. According to paragraph

[0034] of the specification, the above configuration improves the cooling efficiency of the bottom of the observation tank body 12.

[0008] In the cloud chamber described in Patent Document 1, it is necessary to first place dry ice 15 on the inner bottom of the insulating layer 14 of the observation chamber main body housing box 13, and then perform work such as digging the tips of each heat transfer male screw 23 into the dry ice 15. Dry ice 15 is a cryogenic solid, and placing the dry ice itself requires careful attention and is a difficult task. Furthermore, it is necessary to dig the many heat transfer male screws 23 into the placed dry ice, which is a significant burden. In other words, there is a major problem in that the cloud chamber, which is an observation device, is difficult to use.

[0009] The object of the present invention is to provide a cloud chamber that is easy to use. The following describes a number of embodiments in which various improvements and innovations have been implemented. The following embodiments not only improve usability, which is the solution to the problem that the present invention aims to solve, but also provide the effects of each individual embodiment. For example, one effect of the embodiments is that the time available for observation can be extended by adjusting the cooling device settings. Thus, the embodiments have many other effects in addition to this effect. These will be specifically explained as the effects of the embodiments in the explanation of each embodiment below. [Means for solving the problem]

[0010] [First invention] The first invention to solve the above problem is: 1. A cloud chamber for observing tracks of radiation passing through the supersaturated vapor layer in the observation chamber, comprising: an observation device including an observation chamber filled with vapor and a vapor supply device for supplying the vapor to the observation chamber; and a cooling device for cooling the vapor in the observation chamber to form a supersaturated vapor layer in the observation chamber, the cooling device comprises a cooling chamber, a cooling plate provided on an upper portion of the cooling chamber, a plurality of cooling plates mechanically connected to the cooling plate and extending downward and laterally of the cooling chamber, and a connection device for connecting to a liquefied carbon dioxide container that holds liquefied carbon dioxide; a cloud chamber configured to introduce a mixture of dry ice generated from the liquefied carbon dioxide and gaseous carbon dioxide from one side of the plurality of cooling plates in the horizontal direction, guide the introduced mixture of the generated dry ice and the gaseous carbon dioxide to another side in the horizontal direction by the plurality of cooling plates, store the generated dry ice contained in the mixture in a passage formed between the plurality of cooling plates, cool the cooling plates with the generated dry ice stored in the passage, and cool the vapor in the observation chamber with the cooled cooling plates to form the supersaturated vapor layer.

[0011] [Second Invention] The second invention for solving the above problem is the first invention, The cooling device is a cloud chamber characterized in that it has ice packs stored in sealed storage means under the plurality of cooling plates, and an elastic body is provided under the ice packs to press the ice packs toward the plurality of cooling plates.

[0012] [Third Invention] The third invention for solving the above problem is one of the first and second inventions, an exhaust port for discharging the gaseous carbon dioxide in the other direction in the lateral direction of the plurality of cooling plates is provided, and a filter for preventing the passage of the generated dry ice is provided between the exhaust port and the plurality of cooling plates; The cloud chamber is characterized in that the filter prevents the generated dry ice from passing through, and the generated dry ice is stored in the passage formed between the plurality of cooling plates.

[0013] [Fourth Invention] The fourth invention for solving the above problem is one of the first and second inventions, a filter for preventing the passage of the produced dry ice is provided below the plurality of cooling plates, and an outlet for discharging the gaseous carbon dioxide is provided below the filter; The cloud chamber is characterized in that the generated dry ice is stored in the passage formed between the plurality of cooling plates by preventing the passage of the generated dry ice by the filter.

[0014] [Fifth Invention] The fifth invention for solving the above problem is the fourth invention, This cloud chamber is characterized in that after a predetermined amount of produced dry ice is stored in the cooling chamber, the cross-sectional area of ​​the outlet for discharging the gaseous carbon dioxide from the cooling chamber is reduced, thereby reducing the amount of gaseous carbon dioxide discharged from the cooling chamber.

[0015] [Sixth Invention] The sixth invention for solving the above problem is the second invention, The ice pack is a material that becomes solid at a predetermined temperature or lower and changes phase at a temperature higher than the predetermined temperature, The sealed storage means is a bag-like container that stores the ice pack in a sealed state, The cloud chamber is characterized in that the ice pack is held in a state where it is pressed by the elastic body toward the plurality of cooling plates.

[0016] [Seventh Invention] The seventh invention to solve the above problem is one of the first and second inventions, the steam supply device that supplies the steam to the observation chamber includes a liquid supply tray that holds a liquid for generating the steam, a warming device that warms the liquid, and a liquid absorber that guides the liquid held in the liquid supply tray into the observation chamber; The cloud chamber is characterized in that the liquid supply tray has a liquid supply port that opens to the outside of the observation device. [Effects of the Invention]

[0017] According to the present invention, it is possible to create a cloud chamber that is easy to use. The following examples will also provide various other advantages. These advantages will be described in the explanation of each example. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a cross-sectional view illustrating an embodiment of a cloud chamber to which the present invention is applied. [Figure 2] 2 is a cross-sectional view taken along the line AA in FIG. 1; [Figure 3] 2 is a cross-sectional view of the embodiment shown in FIG. 1 BB. [Figure 4(a)] 4 is an explanatory diagram for explaining a method of supplying the produced dry ice to the cooling device, and is a cross-sectional view taken along CC in FIG. 3. FIG. [Figure 4(b)] 4 is an explanatory diagram for explaining the state in which the produced dry ice is stored in the cooling device, and is a cross-sectional view taken along CC in FIG. 3. FIG. [Figure 5(a)] 3. FIG. 4 is an explanatory diagram for explaining another method of supplying produced dry ice to the cooling device, and is a cross-sectional view taken along line CC in FIG. [Figure 5(b)] 5a。 FIG. 5a is a cross-sectional view taken along the line DD in FIG. 5a. [Figure 6(a)] 10 is an explanatory diagram for explaining the storage state of the produced dry ice in another method of supplying produced dry ice to the cooling device. FIG. [Figure 6(b)] 6a EE cross-sectional view. [Figure 7(a)] FIG. 10 is an explanatory diagram of the initial state of the cooling operation using dry ice produced by the cooling device. [Figure 7(b)] FIG. 10 is an explanatory diagram of the state after time has passed in the cooling operation state using dry ice produced in the cooling device. [Figure 8] FIG. 10 is an explanatory diagram illustrating the basic configuration of still another embodiment of a cooling device. [Figure 9] FIG. 9 is an explanatory diagram illustrating a specific example of the basic configuration shown in FIG. 8. [Figure 10(a)]10 is a view showing another embodiment of a cooling device for a cloud chamber to which the present invention is applied. [Figure 10(b)] 10 is a view showing yet another embodiment of a cooling device for a cloud chamber to which the present invention is applied. [Figure 11] 10 is another embodiment of the cloud chamber observation device to which the present invention is applied. DETAILED DESCRIPTION OF THE INVENTION

[0019] [Introduction] In the following embodiments, components with the same reference numerals have substantially the same structure and operation, perform substantially the same actions, and achieve the same effects. To avoid complication, descriptions of the structures, operations, and effects of components with the same reference numerals may be omitted. In particular, if the configuration in the following embodiments is partially changed, explaining the entire configuration would be extremely complication. Therefore, the description will be limited to the changed parts, and descriptions of the operations, operations, and effects of overlapping components will be omitted.

[0020] 1. Description of the basic configuration of one embodiment of a cloud chamber to which the present invention is applied 1 is a cross-sectional view of a cloud chamber 100 according to one embodiment of the present invention. The cloud chamber 100 for observing radiation tracks comprises an observation device 200 for observing radiation tracks and a cooling device 300 for generating a supersaturated vapor layer 206 in an observation chamber 202 of the observation device 200. The observation chamber 202 of the observation device 200 is filled with vapor 204 generated by evaporating a liquid. In this embodiment, ethanol vapor generated by evaporating ethanol is used as the vapor 204, so that the vapor 204 in the observation chamber 202 is composed of ethanol vapor in a near-saturated state, making it easy to ensure the thickness of the supersaturated vapor layer 206.

[0021] The vapor 204 in the observation chamber 202 is cooled by a cooling device 300 installed below the observation chamber 202, forming a supersaturated vapor layer 206 inside the observation chamber 202. When the radiation to be observed passes through this supersaturated vapor layer 206, molecules such as nitrogen and oxygen present in the supersaturated vapor layer 206 are ionized. This ionization occurs along the path of travel of the flying radiation. The generated ions act as nuclei, and the supersaturated vapor around the ions, i.e., supersaturated ethanol molecules, gather together and form a mist. By irradiating the supersaturated vapor layer 206 with light from a lighting device 220 composed of LED elements or the like, the mist generated along the path of travel of the radiation can be observed as a radiation track.

[0022] In order to capture more of the radiation to be observed, it is preferable to increase the thickness of the supersaturated vapor layer 206. Furthermore, if more supersaturated vapor can be collected relative to the ions generated by the passage of radiation, the growth of the mist is promoted, making it easier to observe the radiation tracks. From these perspectives, this embodiment uses ethanol (ethyl alcohol), which more easily creates a supersaturated state, as the liquid, and ethanol vapor as the vapor 204. Furthermore, in order to increase the thickness of the supersaturated vapor layer 206, the cooling capacity of the cooling device 300 that cools the observation chamber 202 is further improved. As will be explained below, the cooling device 300 of this embodiment uses dry ice 304 produced from liquefied carbon dioxide 384. As will be explained below, this improves usability and safety, significantly improves cooling capacity, improves observation capabilities, and enables a longer observation duration (the time during which continuous observations can be performed) compared to conventional devices.

[0023] 1.1 Description of the steam supply device 250 in the embodiment shown in FIG. 1 The configuration of the vapor supply device 250 shown in Fig. 1 will be described. The vapor supply device 250 includes a liquid supply tray 252 that stores ethanol 253, which is a liquid for generating vapor, and a liquid absorber 260 that supplies the ethanol 253 to the inside of the observation chamber 202. The ethanol 253 used to generate vapor 204 is supplied to and held in the liquid supply tray 252. In this embodiment, the liquid supply tray 252 and the heating device 254, which will be described next, are covered with a heat-insulating cover 257 to provide a heat-retaining effect, and therefore, in this embodiment, the heat-insulating cover 257 is removed before the ethanol 253 is supplied to the liquid supply tray 252.

[0024] The ethanol 253 stored in the liquid supply tray 252 is absorbed by the liquid absorber 260 and introduced into the observation chamber 202. The ethanol 253 absorbed by the liquid absorber 260 evaporates and becomes vapor, filling the observation chamber 202. A heating device 254 is provided to increase the amount of ethanol 253 evaporated and bring the vapor 204 closer to a saturated state. The heating device 254 may be one that uses electricity to increase the temperature of the ethanol 253, or one that increases the temperature of the ethanol 253 by pouring hot water over it. It may also be configured to blow hot air. It may also be a heating element such as a pocket warmer.

[0025] As will be explained below, compared to cooling devices used in conventional cloud chambers, the cooling device 300 described in the following embodiment has the significant advantage of significantly extending cooling duration. For example, it has the potential to continue cooling for more than 8 hours, or even 12 hours. This allows for continuous observations without maintenance for cooling the cooling device 300, a period unthinkable with conventional cloud chambers 100. Because the cooling device 300 can maintain its cooling function for such a long time, it is desirable to correspondingly extend the supply time of ethanol 253 vapor from the vapor supply device 250. The configuration of the vapor supply device 250 in Figure 1 allows for easy addition of ethanol 253 during observation. Furthermore, it is also configured to maintain heating by the heating device 254 for a long period of time. Furthermore, in this embodiment, the heating device 256, which can maintain heating for a long period of time, can be used as needed. Furthermore, the configuration in Figure 1 allows for the heat supply from the heating device 254 and the heating device 256 to be maintained for a long period of time because the heat supply from the heating device 254 and the heating device 256 is covered by a heat-insulating cover 257, which has the function of maintaining a high temperature of the ethanol 253 for a long period of time.

[0026] Heating device 256 contains metal powder stored in a breathable bag. When not in use, the breathable bag is further sealed with an airtight bag, and heat generation is stopped. The metal powder is, for example, iron powder, which is highly oxidizable. When oxygen is supplied from the surroundings of the breathable bag that contains the iron powder, the powder combines with the supplied oxygen and oxidizes. This oxidation is the basis for heat generation. Such heating device 256 may be, for example, a commonly used, commercially available heating pad. This type of product can maintain heat generation for half a day or a full day, is extremely easy to handle, and is highly safe.

[0027] By appropriately adjusting the temperature difference between the steam 204 in the upper part of the observation chamber 202 and the steam in the lower part of the observation chamber 202 cooled by the cooling device 300, it is possible to generate the supersaturated steam layer 206 required for observation. As will be described below, the cooling device 300 of this embodiment has excellent cooling capabilities and can maintain the temperature of the steam 204 in the lower part of the observation chamber 202 lower than conventional devices. As a result, even if the temperature of the steam in the upper part of the observation chamber 202 is set lower than in conventional devices, it is possible to adjust the temperature difference between the steam in the upper and lower parts of the observation chamber 202 to a sufficient level, and a supersaturated steam layer 206 with a height suitable for observation can be generated.

[0028] A liquid absorbent 264 capable of absorbing liquid by capillary action is provided, for example, on the periphery of the observation chamber 202 shown in FIG. 1 . In this embodiment, ethanol is used as the liquid that generates vapor, and the liquid absorbent 264 has the function of absorbing the ethanol liquid. The ethanol vapor in the supersaturated vapor layer 206 liquefies and accumulates at the bottom of the observation chamber 202. The ethanol liquid that accumulates at the bottom of the observation chamber 202 is absorbed by the liquid absorbent 264 and moves to the top of the liquid absorbent 264 by capillary action. As the ethanol liquid rises within the liquid absorbent 264, it is heated by the surrounding vapor 204 and air, and its temperature increases. As a result, it vaporizes again at a position higher than the supersaturated vapor layer 206, becoming ethanol vapor and acting as the vapor 204 shown in the figure. In this way, the ethanol changes from a vapor 204 state to a supersaturated vapor in the supersaturated vapor layer 206, contributing to the observation, and after liquefaction becomes an ethanol liquid, which moves to the upper part of the observation chamber 202 by the liquid absorbent 264 and turns back into vapor. By circulating and using ethanol in this way, it is possible to reduce the amount of ethanol consumed, which is supplied from outside the observation device 200 for observation. The configuration and concept of using the liquid absorbent 264 to reduce ethanol consumption described here can be applied to all of the embodiments described in this patent application specification.

[0029] 1.2 Effect of Steam Supply Device 250 As mentioned above, the cooling device 300 not only has better cooling efficiency than cooling devices based on conventional technology, but also has a longer cooling duration. For example, the cooling device 300 can be operated continuously for approximately 12 hours, starting in the morning and continuing until the evening. A new challenge for this new cooling device 300 is maintaining the vapor 204 in the observation chamber 202 at a stable, near-saturated state for an extended period of time. The liquid supply tray 252 is provided with a liquid supply port 262 that opens to the outside of the observation device 200. This makes it possible to supply ethanol 253 from the liquid supply port 262 very easily and as needed while maintaining the observation state, making it possible to continuously supply the vapor 204 of ethanol 253 for an extended period of time.

[0030] Furthermore, by using a heating element that generates heat by oxidizing metal powder such as iron as the heating device 256, heating can be performed for a long period of time and is easy to operate and handle. The heat-retaining cover 257 is made of a heat-insulating material with excellent thermal insulation properties, and the structure of covering the entire device with the heat-retaining cover 257 keeps the ethanol 253 at a high temperature, allowing it to be kept warm for a long period of time. Therefore, the vapor supply device 250 described herein is safe and can be made small and lightweight. When the cloud chamber 100 is used in an educational institution, it is safe, compact, extremely easy to operate, and provides excellent effects. Note that the vapor supply device 250 shown in FIG. 1 is only one example, and modified versions of the vapor supply device 250 are described below.

[0031] 1.3 Explanation of the configuration and operation of the observation device 200 In this embodiment, the observation device 200 is surrounded by a side observation window 212 for observing the radiation trajectory, and is made of a transparent material such as glass. The top observation window 214, which forms the top surface, is also made of a transparent material such as glass. By irradiating the supersaturated vapor layer 206 with light from the illumination device 220, the fog generated by radiation passing through the supersaturated vapor layer 206 can be observed through the side observation window 212 and the top observation window 214. In this embodiment, observation is possible through both the top observation window 214 and the side observation window 212, but only one of them may be used. In this case, by using an insulating wall on the side other than the observation window, cooling of the vapor 204 can be facilitated, thereby reducing the burden on the cooling device 300. In conventional cloud chambers 100, the cooling capacity of the cooling device 300 could not be increased, so the side observation window 212 was often omitted and this part was instead made of a wall made of insulating material. Of course, this may also be done in this embodiment. However, the cooling device 300 described below has a large cooling capacity, so it is possible to provide a side observation window 212, and in this embodiment, a cloud chamber 100 that is easier to observe can be obtained.

[0032] 2. Description of Cooling Device 300 2.1 Description of the basic configuration of the cooling device 300 The basic configuration of a cooling device 300 used in the embodiment of the present invention shown in Fig. 1 will be described. In order to cool the steam 204 supplied from the steam supply device 250 to the observation chamber 202 and form the supersaturated steam layer 206, a cooling plate 312 for cooling the steam 204 is provided with a plurality of cooling plates 330 extending downward from the cooling plate 312 and mechanically connected to the cooling plate 312.

[0033] Fig. 2 shows the AA cross section of the cooling device 300 shown in Fig. 1. In this embodiment, as an example, the cooling plate 312 has four cooling plates 330 that are integrally connected and extend downward. As shown in Fig. 2, the cooling plates 330 are cooling plates 3301, 3302, 3303, and 3304.

[0034] Fig. 3 shows a cross section taken along the line BB of cooling device 300 shown in Fig. 1. As shown in Figs. 2 and 3, the outer periphery of cooling device 300 is surrounded by an outer wall formed of heat insulating material 360, and cooling chamber 302 is formed inside. As described above, cooling chamber 302 has a plurality of cooling plates 330 extending downward and laterally from cooling plate 312. Passages 3321, 3322, 3323, 3324, and 3325 are formed between each of cooling plates 330.

[0035] Liquefied carbon dioxide 384 or a mixture of produced dry ice 304 generated from liquefied carbon dioxide 384 and gaseous carbon dioxide is introduced into cooling chamber 302 via inlet 320 and introduction passage 322. Liquefied carbon dioxide 384 remains in the form of the mixture at least within cooling chamber 302. The mixture flows along cooling plate 330 provided inside cooling chamber 302, splitting into passages 3321, 3322, 3323, 3324, and 3325, as shown by arrows 3401 to 3405 in FIG. 3 . Filter 324 allows gaseous carbon dioxide to pass through but not produced dry ice 304, so produced dry ice 304 constituting the mixture accumulates in passages 3321 to 3325, and eventually these passages are filled with produced dry ice 304. Passages 3321 to 3325 formed on both sides of cooling plates 3301 to 3304 provided in cooling chamber 302 are filled with generated dry ice 304, thereby cooling cooling plates 3301 to 3304, respectively, and further cooling integrated cooling plate 312, thereby cooling observation chamber 202. Steam 204 in observation chamber 202 is cooled, and the above-mentioned supersaturated steam layer 206 is formed.

[0036] 2.2 Explanation of the operation for storing the produced dry ice 304 4(a) and 4(b) are cross-sectional views taken along CC in FIG. 3. In FIGS. 1, 3, 4(a), and 4(b), liquefied carbon dioxide container 380 supported by support device 104 contains liquefied carbon dioxide 384 and vaporized carbon dioxide 382. Liquefied carbon dioxide 384 is introduced from liquefied carbon dioxide container 380 through connection device 390, inlet 320, and introduction passage 322 of cooling device 300. Liquefied carbon dioxide container 380 expands and vaporizes inside connection device 390, introduction passage 322, or its outlet. This rapidly cools the carbon dioxide, generating dry ice 304. Dry ice 304 may be generated at the connection between connection device 390, which is the outlet of liquefied carbon dioxide container 380, and liquefied carbon dioxide container 380. Alternatively, a structure that expands the passage system may be formed inside connection device 390, allowing dry ice 304 to be generated inside connection device 390. Furthermore, an expanded section of the passage cross section may be formed inside the introduction passage 322 or at the outlet of the introduction passage 322 to generate the dry ice 304. In this embodiment, the liquefied carbon dioxide container 380 is connected to the introduction passage 322 via a connecting device 390, but the introduction passage 322 or the inlet 320 may be used as the connecting device 390, and the liquefied carbon dioxide container 380 may be directly connected to the inlet 320.

[0037] As described above, the produced dry ice 304, together with gaseous carbon dioxide, flows from path 3321 to path 3325, as indicated by arrows 3401 to 3405. As described above, the flow of the produced dry ice 304 is blocked by filter 324, and as shown in FIG. 4(a), the path is filled from the filter 324 on the other side toward one side 344. While FIGS. 4(a) and 4(b) show the state of the produced dry ice 304 in a schematic manner, this is merely to avoid cluttering the drawings. In reality, the produced dry ice 304 also accumulates at the bottom of path 3323 formed along cooling plate 3302. The shape of one side of the produced dry ice 304 is not vertical; its lower portion gradually widens toward one side 344. Over time, the inclined surface moves toward one side 344, filling path 3323 with the produced dry ice 304.

[0038] 4(b) is a schematic diagram showing the state after further time has passed. As described above, in reality, the produced dry ice 304 has piled up on one side of the produced dry ice 304 so as to fill the bottom of the passage 3323. In this way, the passage 3323 is filled with the produced dry ice 304. At the same time, the other passages are also filled with the produced dry ice 304, and the entire cooling chamber 302 is filled with the produced dry ice 304. Once the cooling chamber 302 is filled with the produced dry ice 304, there is no longer any need to store the produced dry ice 304, so the exhaust ports 2361, 2362, and 2363 of the opening and closing device 238 are closed by the opening and closing device 238. As the cooling operation by the produced dry ice 304 progresses, the produced dry ice 304 turns into gaseous carbon dioxide, and a small opening is formed for venting the carbon dioxide gas, thereby maintaining the exhaust.

[0039] 2.3 Explanation of the Functions and Effects of the Cooling Device 300 Described in FIGS. 1 and 2 to 4 (1) Effects of using the liquefied carbon dioxide container 380 In this embodiment, cooling is performed using dry ice 304 generated from liquefied carbon dioxide, making it possible to use small, commercially available cartridges for the liquefied carbon dioxide container 380. This makes it extremely easy to handle and safe for even inexperienced personnel. A mixture of gaseous carbon dioxide and dry ice 304 can be produced very easily using commercially available cartridges. Furthermore, the resulting dry ice 304 exhibits cooling capabilities comparable to those of solid dry ice, allowing for the generation of a sufficiently wide supersaturated vapor layer 206. Furthermore, as described below, high cooling efficiency can be achieved, enabling observations to be continued for significantly longer periods of time than conventional cooling devices equipped with mechanical cooling mechanisms or cooling devices using solid dry ice.

[0040] (2) Explanation of the effects of using generated dry ice 304 A plurality of cooling plates 330 integrally connected to the cooling plate 312 are cooled by the produced dry ice 304, and the produced dry ice 304 is carried and accumulated by the gaseous carbon dioxide. The gaseous carbon dioxide tends to flow more in passages with larger cross-sectional areas, automatically avoiding passages filled with the produced dry ice 304 and automatically flowing in large amounts in passages that are not filled with the produced dry ice 304. As a result, most of the flows containing the produced dry ice 304 are automatically selected in areas where there is little accumulation, and the produced dry ice 304 is carried there. As a result, the cooling chamber 302 tends to become uniform overall, and the produced dry ice 304 is effectively accumulated in a manner that naturally leads to uniformity.

[0041] For example, in the initial state when a mixture containing produced dry ice 304 is introduced into cooling chamber 302, much of the produced dry ice 304 is directed to passage 3323, which is closest to introduction passage 322 in FIG. 3 , and much of the produced dry ice 304 accumulates in passage 3323. As a result, the accumulated produced dry ice 304 gradually clogs passage 3323, reducing the amount of mixture flowing through passage 3323 and causing more of the mixture to be directed to other passages 3322 and 3324. Due to this phenomenon, produced dry ice 304 naturally accumulates in each of passages 3321 to 3325, and the entire cooling chamber 302 is filled with produced dry ice 304. Of course, the shapes of passages 3321 to 3325 may also be changed to more uniformly distribute the amount of mixture flowing through each of passages 3321 to 3325. Even when utilizing this shape, the resulting dry ice 304 also acts to fill the space more uniformly overall. Conventional attempts to cool using solid, hard dry ice require manual manipulation of the shape and placement of the dry ice. Processing hard, low-temperature dry ice is a very difficult task. This embodiment allows even inexperienced people to use it very easily and safely.

[0042] 2 is an explanatory diagram that schematically illustrates the state of produced dry ice 304 during the cooling operation of cooling device 300. Cooling plate 3301 that constitutes cooling device 300 is cooled by produced dry ice 304 that has accumulated in paths 3321 and 3322 on both sides of it. Similarly, cooling plate 3302 is cooled by produced dry ice 304 that has accumulated in paths 3322 and 3323, cooling plate 3303 is cooled by produced dry ice 304 that has accumulated in paths 3323 and 3324, and cooling plate 3304 is cooled by produced dry ice 304 that has accumulated in paths 3324 and 3325.

[0043] The fluid dry ice 304 accumulated in the passages 3321 and 3322 in contact with the surface of the cooling plate 3301 vaporizes, creating gaps 3330 and 3331 between the surface of the cooling plate 3301 and the fluid dry ice 304. However, in this embodiment, the fluid dry ice 304 prevents gaps 3330 and 3331 from deepening. Furthermore, the width of these gaps is also prevented from widening. This is because the fluid dry ice 304 is not a solid, hard mass of dry ice, but has fluidity. For example, as gap 3330 deepens, the fluid dry ice 304 acts to fill gap 3330. Similarly, as gap 3330 widens, the fluid dry ice 304 forming gap 3330 moves, preventing gap 3330 from widening. This phenomenon is similar for gaps 3331 to 3338. Therefore, the decrease in cooling efficiency is suppressed, and high cooling efficiency is maintained for a long period of time.

[0044] On the other hand, conventional dry ice cooling devices use hard, solid dry ice. When a gap forms between the contact surfaces of the cooling mechanism, such as between the cooling plate 312 and the solid dry ice, the gap continues to widen and grow. This rapidly reduces the cooling capacity. Therefore, even if the hard dry ice is barely used and some dry ice remains inside the cooling device 300, the cooling function is insufficient. For example, in the past, after a short observation, it was necessary to remove the block of dry ice, reshape its surface uniformly, and then reinsert the dry ice. This makes it difficult to extend the continuous observation time, and even worse, it is extremely difficult to use, making it unsuitable for inexperienced users.

[0045] 2.4 Description of Other Embodiments of Cooling Device 300 (1) Description of the configuration and operation of another embodiment of the cooling device 300 The configuration and operation of another embodiment of the cooling device 300 will be described with reference to FIGS. 5(a) and 5(b). In the cooling device 300 in the embodiment shown in FIGS. 1 and 3, the exhaust port 236 consisting of the exhaust port 2361 and the exhaust port 2363 is provided on the other side of the cooling chamber 302 for exhausting gaseous carbon dioxide taken in from the inlet 320 on one side of the cooling chamber 302. However, the cooling device 300 in the embodiment shown in FIGS. 1 and 3 may be the embodiment shown in FIGS. 4 and 5 described below, or may be the embodiment shown in FIGS. 8 and 9 described thereafter. Of course, the configuration of the cooling device 300 described in the above embodiment may be changed, or a new configuration may be added to the configuration of the above embodiment.

[0046] In the embodiment shown in Figures 5(a) and 5(b), when liquid carbon dioxide or a mixture of gaseous carbon dioxide and produced dry ice 304 is introduced through inlet passage 322 provided laterally of cooling chamber 302, the liquid carbon dioxide becomes almost entirely a mixture of gaseous carbon dioxide and produced dry ice 304 when introduced into cooling chamber 302, and flows as shown by arrows 3401 to 3405 in Figure 5(a). The gaseous carbon dioxide that constitutes the mixture is discharged to the outside through filter 326 provided below cooling chamber 302. Meanwhile, produced dry ice 304 accumulates on the entire surface of filter 326 by falling or being blown in, and accumulates from the other side 346 opposite injection port 320. This is because the opening of exhaust port 237 is made large so that the mixture of produced dry ice 304 and gaseous carbon dioxide can flow in forcefully from introduction passage 322 provided on one side, and the openings of exhaust port 2351 and exhaust port 2352 are also made large.

[0047] To efficiently fill the cooling chamber 302 with produced dry ice 304, it is desirable to introduce the produced dry ice 304 through the introduction passage 322 with force. In other words, it is desirable to maintain the storage state of the produced dry ice 304 in a state that allows gaseous carbon dioxide to pass through the filter 326 as easily as possible, from the beginning to the end of the process of accumulating the produced dry ice 304. In this embodiment, the introduction passage 322 is provided on one side of the cooling chamber 302, and the mixture flows vigorously toward the other side of the cooling chamber 302, and the produced dry ice 304 tends to accumulate from the other side. Therefore, the ventilation on the other side of the filter 326 becomes poor, but the filter 326's function of allowing gaseous carbon dioxide to pass through is maintained on the one side. Even if the amount of stored produced dry ice 304 increases, the function of allowing gaseous carbon dioxide to pass through the filter 326 on the one side is maintained for a relatively long time, so the time required to accumulate the produced dry ice 304 in the cooling chamber 302 is shortened.

[0048] (2) Explanation of the Functions and Effects of Other Embodiments of the Cooling Device 300 Figures 5(a) and 5(b) show the initial stage of the operation of storing the produced dry ice 304 in the cooling chamber 302. Meanwhile, Figures 6(a) and 6(b) show the stage nearing the end of the operation of storing the produced dry ice 304 in the cooling chamber 302. Furthermore, Figures 7(a) and 7(b) are diagrams illustrating the operating state of the cooling device 300 after the operation of storing the produced dry ice 304 in the cooling chamber 302 has been completed, and the cooling device 300 is ready for the next radiation observation state.

[0049] By completing the accumulation of the produced dry ice 304 in the cooling chamber 302 in a short time, the preparation work for observing the target radiation can be completed quickly, and the observation can be started promptly. Furthermore, after the accumulation of the produced dry ice 304 in the cooling chamber 302 is completed, it becomes possible to stop using the liquefied carbon dioxide container 380 and to separate the liquefied carbon dioxide container 380. Since the cooling function can be maintained by the produced dry ice 304 accumulated in the cooling chamber 302, it is possible to prevent the waste of liquefied carbon dioxide in the liquefied carbon dioxide container 380. The liquefied carbon dioxide container 380 is also easier to handle, reducing the burden on the user.

[0050] As described above, by forcefully flowing the mixture of gaseous carbon dioxide and produced dry ice 304 introduced into cooling chamber 302 from inlet passage 322 through filter 326, the produced dry ice 304 is not accumulated uniformly on the surface of filter 326, but is instead sprayed unevenly, for example, onto the other side 346, so that more produced dry ice 304 accumulates on the other side in the initial stage. As a result, in the initial stage, the amount of accumulated produced dry ice 304 on the other side is much greater than that on the one side. Therefore, while the amount of gaseous carbon dioxide passing through the other side of filter 326 decreases, the amount of gaseous carbon dioxide passing through filter 326 on one side of filter 326 can be maintained at a high level, thereby suppressing a decrease in the rate at which produced dry ice 304 accumulates. This is as explained using the schematic diagrams of Figures 5(a) and 5(b).

[0051] The states shown in Figures 6(a) and 6(b) are schematic representations of the final accumulation of the produced dry ice 304 in the cooling chamber 302. The same effect can be achieved even in this state. In other words, the flow of the mixture indicated by arrows 3401 to 3405 in Figure 6(a) is maintained until the final state. Therefore, it is easy to maintain the flows indicated by arrows 2426 and 2424 in Figure 6(b). This effectively reduces the decline in the effect of storing the produced dry ice 304. Of course, Figure 6(b) is a schematic representation, and the produced dry ice 304 is actually accumulated on the upper surface of the filter 326 located on one side 344. However, the thickness of this accumulation, or in other words, the depth of the accumulation, is much less than on the other side 346. This maintains smooth accumulation of the produced dry ice 304 until near the end of the accumulation process, thereby shortening the overall accumulation time for the produced dry ice 304.

[0052] In FIGS. 5(a) and 5(b) and 6(a) and 6(b), gaseous carbon dioxide discharged into the exhaust passage 232 is exhausted from the side of the cooling device 300 via the exhaust port 2351 or the exhaust port 2352, as indicated by arrows 2421 and 2425. Exhausting gaseous carbon dioxide from the side of the cooling device 300 is an example; exhaust from the bottom is also possible. Here, the openings of the exhaust port 2351 or the exhaust port 2352 are made larger than the amount of gaseous carbon dioxide exhausted. This is to avoid a decrease in the introduction rate of the mixture of gaseous carbon dioxide and produced dry ice 304 supplied to the cooling chamber 302 from the aforementioned inlet 320. This prevents a decrease in the accumulation time of the produced dry ice 304 in the cooling chamber 302, as described above. The same applies when exhausting gaseous carbon dioxide from the bottom of the cooling device 300, for example.

[0053] As shown by exhaust port 2351 and exhaust port 2352, there are multiple exhaust ports for gaseous carbon dioxide. The exhausted gaseous carbon dioxide is at a very low temperature, and if it is exhausted from only one location, there is a risk that only a portion of it will be cooled suddenly. There is also a possibility of adverse effects on other devices placed in the vicinity. There is also a possibility of the influence of liquefaction of moisture in the atmosphere. In this embodiment, the exhausted gaseous carbon dioxide is dispersed.

[0054] 3. Description of the cloud chamber 100 in observation state 3.1 Description of the operation of the cooling device 300 in the observation state Figure 7(a) is a conceptual diagram showing the state of cooling device 300 at the start of observation. The spaces between cooling plates 330 fixed integrally to cooling plate 312 are filled with produced dry ice 304. Note that Figure 7(a) shows cooling plate 3302, which is one of cooling plates 330. In this state, produced dry ice 304 is in close contact with the surface of each of cooling plates 3301 to 3304 that make up cooling plate 330.

[0055] The produced dry ice 304 cools the steam 204 in the observation chamber 202 described in Fig. 1, forming a supersaturated steam layer 206. By irradiating the supersaturated steam layer 206 with light from the lighting device 220, it becomes possible to observe the radiation tracks that are the object of observation.

[0056] The cooling action causes the produced dry ice 304 to evaporate, generating gaseous carbon dioxide, but the amount is small, so in the observation state an exhaust port with a diameter like exhaust port 2351 or exhaust port 2352 is not necessary, and as shown by exhaust port 328, a cross-sectional area one order of magnitude or less than the cross-sectional area of ​​the exhaust ports created by exhaust port 2351 or exhaust port 2352 is sufficient. Gaseous carbon dioxide is exhausted from exhaust port 328 with this small cross-sectional area, as shown by arrow 329.

[0057] Figure 7(b) is a conceptual diagram showing the state in which the amount of produced dry ice 304 has decreased as a result of long-term observation of radiation tracks. The surface of cooling plate 3302, which is integrally fixed to cooling plate 312, is largely exposed, reducing the contact area with the produced dry ice 304. Cooling plate 3302 is shown as a representative example of cooling plates 3301 to 3304 that make up cooling plate 330. The contact state between cooling plate 3304 and produced dry ice 304 is as previously described with reference to Figure 2. Gaps form between cooling plate 3304 and produced dry ice 304, but as mentioned above, stacked, fluid produced dry ice 304 easily crumbles, constantly suppressing the expansion of these gaps. This is a major difference from using solid, sturdy dry ice.

[0058] 3.3 Explanation of the operation and effect of the cooling device 300 in observation state The state in which the fresh dry ice 304 is stored in the cooling chamber 302 has been described above using Figure 7(a). Even when the fresh dry ice 304 is stored, the weight of the cooling device 300 is very light compared to when, for example, solid, hard dry ice is stored. This reduces the weight of the entire cloud chamber 100, making it easy to handle. Furthermore, the small load on the filter 326 in this embodiment is structurally very advantageous.

[0059] Some people may think that the cooling capacity of the produced dry ice 304 will be reduced because it contains gaseous carbon dioxide. For example, one might think that the cooling capacity would be greater if solid, hard dry ice were used. However, when using hard dry ice, it is difficult to maintain good heat transfer between the hard dry ice and the cooling plate 312, and the embodiment shown in Figure 7 exhibits much better cooling capacity.

[0060] As explained using Figure 2, the produced dry ice 304 crumbles easily, which suppresses the growth of gaps between the produced dry ice 304 and the surfaces of each plate that makes up the cooling plate 330, and is highly effective in maintaining high cooling efficiency.

[0061] The produced dry ice 304 is lighter than hard blocks of dry ice and is easier to hold. For example, it places less strain on the filter 326 that holds the produced dry ice 304. The exhaust port 2373, exhaust port 2372, and exhaust port 2371 may be connected, given their functions. In this embodiment, they are divided into multiple parts. This division reduces the mechanical strain on the filter 326 and allows for a shape that is structurally easier to manufacture.

[0062] The opening area of ​​the exhaust port for gaseous carbon dioxide during cooling is smaller than that during the storage operation of the produced dry ice 304, making it easier to maintain a low temperature in the cooling chamber 302. In particular, in this embodiment, the injection port 320 is unnecessary during cooling, and the injection port 320 can be covered with the insulating wall 2442. Furthermore, the exhaust port 2373, the exhaust port 2372, and the exhaust port 2371 are blocked with insulating material so that the gaseous carbon dioxide flowing into the exhaust passage 232 through the filter 326 is blocked by the passage formation body 244 made of insulating material that forms the exhaust passage 232. Although the filter 326 does not have an insulating effect, this configuration ensures that the filter 326 is thermally insulated from the outside world. Furthermore, the exhaust ports 2351 and 2352, which have large opening areas, are thermally insulated by the insulating material 360. This structure maintains a high cooling efficiency using the produced dry ice 304.

[0063] 4. Description of the cloud chamber 100 with a new configuration 4.1 Description of the configuration and operation of the cooling device 300 equipped with the ice pack 350 In the configurations of the embodiments described above using FIGS. 5(a) and 5(b), 6(a) and 6(b), and 7(a) and 7(b), the embodiments shown in FIGS. 8 and 9 further include an ice pack 350 below the cooling plate 330. The ice pack 350 is also commonly referred to as a heat storage material. The ice pack 350 is contained in a sealed container, is solid at low temperatures, and undergoes a phase change as the temperature rises. While the phase change occurs, the temperature remains constant. The ice pack 350 used in this embodiment may be either a soft or hard type. While a soft type ice pack 350 provides better adhesion to other devices, since the produced dry ice 304 is used, the gap between the ice pack 350 and other devices is filled with the produced dry ice 304, so a hard type ice pack 350 can also be used.

[0064] In addition to the embodiments shown in Figures 8 and 9, ice pack 350 is also used in the embodiments shown in Figures 10(a) and 10(b). In this specification, the commonly used ice packs and heat storage materials are collectively referred to as ice pack 350. In some industries, ice packs are interpreted as meaning soft types and heat storage materials as meaning hard types. However, as mentioned above, in this specification, they are collectively referred to as ice pack 350. Furthermore, in this specification, ice packs that use hard containers made of plastic or the like are referred to as hard types, and those that use soft containers such as bags are referred to as soft types. While most ice packs are primarily composed of water with a polymer mixed in, this specification is not limited to this. Ice pack 350 refers to a material that changes phase based on temperature, becoming liquid at high temperatures and solid at low temperatures.

[0065] In the embodiment shown in Figure 8, the upper surface of ice pack 350 is in contact with the lower surface of cooling plate 330, but a metal plate, for example, which has good heat transfer properties, may be provided between the upper surface of ice pack 350 and the lower surface of cooling plate 330. In this case, consideration must be given to exhausting gaseous carbon dioxide. In this embodiment, a filter 326 is provided below ice pack 350 to prevent the passage of generated dry ice 304. The gaseous carbon dioxide that passes through filter 326 is exhausted to the outside through exhaust port 357 provided in cover 356, which is provided at the bottom of exhaust chamber 352 and made of a heat insulating material.

[0066] As described above, the produced dry ice 304 accumulated in the cooling chamber 302 is produced based on liquefied carbon dioxide sent from the liquefied carbon dioxide container 380 via the connection device 390. Where the produced dry ice 304 is produced based on liquefied carbon dioxide is determined by where the enlarged cross-section portion is formed on the transfer path. This embodiment of the present invention operates normally as long as at least a mixture of liquefied carbon dioxide and produced dry ice 304 is formed at the entrance to the observation chamber 202.

[0067] The ice pack 350 has a large surface area, covering most of the cooling chamber 302 shown in Figures 5(a) and 6(a). In this embodiment, one ice pack 350 is used, but multiple ice packs may be used. The resulting dry ice 304 accumulated in the cooling chamber 302 accumulates on the top surface of the ice pack 350, but where no ice pack 350 is present, it accumulates on the top surface of the filter 326. Because the resulting dry ice 304 accumulates regardless of the shape of the top surface of the ice pack 350, the gap between the ice pack 350 and the stacked resulting dry ice 304 is filled in well, maintaining high cooling efficiency. The ice pack 350 can efficiently suppress the temperature rise of the resulting dry ice 304.

[0068] Furthermore, when the top surface of the ice pack 350 is in contact with the cooling plate 330, the ice pack 350 can directly cool the cooling plate 330, and even if there is a gap, the gap between the ice pack 350 and the cooling plate 330 is filled with the stacked dry ice 304, making it possible to efficiently suppress the temperature rise of the cooling plate 330.

[0069] Cover 356 can be easily removed, and by removing cover 356, elastic body 354, and filter 326, ice pack 350 can be replaced. Ice pack 350 cooled in a cooling device such as a freezer can be easily replaced with used ice pack 350.

[0070] 4.2 Explanation of the configuration and operation of the cooling device 300 using the elastic body 354 In the embodiment shown in Fig. 8, to explain the concept, a spring-based elastic body 354 is used, and the filter 326 presses the ice pack 350 toward the cooling plate 330. In the cooling device 300 shown in Fig. 9, an insulating elastic body 355 is used instead of a spring as the elastic body 354, thereby suppressing heat transfer to the cooling chamber 302 through the cover 356. The insulating elastic body 355 is, for example, an elastic body made of resin or rubber, and can suppress heat transfer more effectively than a metal elastic body. For example, heat transfer can be suppressed more effectively when a large number of air bubbles are formed inside, like a sponge.

[0071] 4.3 Explanation of the effect of using the cooling device 300 with the ice pack 350 8 and 9, in order to cool the vapor 204 in the observation chamber 202, ice packs 350 are used in addition to the produced dry ice 304. The ice packs 350 are easy to handle, reducing the burden of preparatory work required for use. As described above, the use of the produced dry ice 304 makes it possible to significantly extend the continuous operating time of the cooling device 300 compared to conventional devices. In addition, the use of ice packs 350 in this embodiment makes it possible to significantly extend the continuous observation time.

[0072] In this embodiment, even if a gap occurs at the contact point between ice pack 350 and another device, such as cooling plate 330, produced dry ice 304 enters the gap, filling the gap and preventing the gap from expanding. As a result, not only soft type but also hard type ice packs 350 can be used as ice pack 350. Furthermore, even when soft type ice pack 350 is used, the cooling efficiency is significantly improved compared to when produced dry ice 304 is not used, as produced dry ice 304 fills the gap that is likely to occur at the contact point as described above.

[0073] In this embodiment, the filter 326 is pressed upward by the elastic body 354 or the insulating elastic body 355 to hold the produced dry ice 304 and the ice pack 350. The produced dry ice 304 is lighter than solid, hard dry ice. The ice pack 350 is also relatively light. Therefore, the produced dry ice 304 and the ice pack 350 can be held even with a small pressing force from the elastic body 354 or the insulating elastic body 355. If hard dry ice were used instead of the produced dry ice 304, the weight would increase. Furthermore, there would be a large difference in mass between when there is a large amount of hard dry ice and when there is a small amount left after consumption. The elastic body 354 or the insulating elastic body 355 is required to be able to press the hard dry ice upward even when it has a large mass. Therefore, when hard dry ice is used, a greater load is placed on the elastic body 354 or the insulating elastic body 355 than in this embodiment. Furthermore, the force applied to the filter 326 would also increase. For this reason, a greater pressing force is required of the insulating elastomer 355 and the insulating elastomer 355, and a more robust structure is required of the filter 326. In this embodiment, since the generated dry ice 304, which has a small mass, is used, the burden on the filter 326, the elastomer 354, and the insulating elastomer 355 can be reduced. This also leads to improved durability.

[0074] The same applies to cover 356. In this embodiment, the load applied to cover 356 is less than when hard dry ice is used. Cover 356 is removed when replacing ice packs 350, so it is required that it can be easily removed with little force. In addition, lightweight insulating elastomer 355 and filter 326 also lead to improved workability. An advantage of using recycled dry ice 304 in this embodiment is that it makes it easier to replace ice packs 350, which involves removing cover 356, insulating elastomer 355, and filter 326. Furthermore, it also leads to improved durability of the mechanism for attaching and removing cover 356.

[0075] 5. Description of an embodiment in which the cooling plate 312 is cooled by the ice pack 350 5.1 Description of structure and operation 10(a) and 10(b) show a configuration in which the cooling plate 312 is directly cooled by the ice pack 350, and the vapor 204 in the observation chamber 202 is cooled to form the supersaturated vapor layer 206. The difference between the embodiment shown in FIG. 10(a) and the embodiment shown in FIG. 10(b) is whether an elastic body 354 or an insulating elastic body 355 is used to press the ice pack 350 toward the cooling plate 312, but the basic configuration and effects are the same. The basic configuration and operation, including the embodiment shown in FIG. 10(b), will be explained using FIG. 10(a).

[0076] In the configuration of cloud chamber 100 described in the embodiment, the configuration and effects of observation device 200 have already been described above using Figures 1, 8, and 9. In this embodiment, cooling device 300 is configured to cool cooling plate 312 using ice pack 350 placed in cooling chamber 302, and cooling plate 312 cools vapor 204 in observation chamber 202 to form supersaturated vapor layer 206. Ice pack 350 is pressed upward by elastic body 354 via insulating plate 370 so that the upper surface of ice pack 350 contacts cooling plate 312. Multiple elastic bodies 354 may be provided, and the lower sides of elastic bodies 354 are supported by cover 356.

[0077] It is desirable for the front surface of the ice pack 350 to be in close contact with the underside of the cooling plate 312. For this reason, the ice pack 350 used in this embodiment is preferably soft. As mentioned above, the ice pack 350 has the property of undergoing a phase change as the temperature rises, and its temperature is maintained constant during the phase change. The phase change makes the ice pack 350 easily deformable, so when pressed by the elastic body 354, the top surface of the ice pack 350 is in close contact with the underside of the cooling plate 312. Even when the soft ice pack 350 undergoes a phase change and softens, the material itself does not move freely like pure water. Therefore, the softened material at the contact surface with the cooling plate 312 maintains close contact with the cooling plate 312, resulting in excellent heat transfer. This allows for significantly higher cooling efficiency than conventional devices using hard dry ice. Although the ice pack is primarily composed of water, it contains a polymer, which, as mentioned above, maintains viscosity even in its liquid form.

[0078] Since heat insulating plate 370 is provided on the underside of ice pack 350, even if a metallic elastic material is used as elastic body 354, heat transfer to ice pack 350 via cover 356 or elastic body 354 is suppressed. Unlike the above-described embodiment, ice pack 350 does not generate gas due to a phase change, so there is no need to provide an exhaust port.

[0079] 10(b) differs from the embodiment in Fig. 10(a) in that it uses an insulating elastomer 355 that also functions as an insulating plate 370 and an elastomer 354. However, the use of ice pack 350 improves adhesion between the cooling plate 312 and ice pack 350, and the effect of achieving high cooling efficiency remains the same. Observation can be started easily by removing cover 356 and replacing the used ice pack 350 with an ice pack 350 that has been kept at a low temperature.

[0080] 5.2 Explanation of the effects of the embodiment shown in Figures 10(a) and (b) The ice pack 350 used in this embodiment is as described in the embodiment of Figures 8 and 9. The ice pack 350 is easy to handle and highly safe. Furthermore, unlike dry ice, it can be used repeatedly by cooling it in a freezer.

[0081] 10(a) and 10(b), a single ice pack 350 is shown, but in actual use, multiple ice packs may be arranged side by side, and in some cases multiple ice packs may be stacked. Even when multiple ice packs are arranged side by side in this embodiment, the ice packs 350 can easily maintain close contact with the cooling plate 312 to be cooled, as will be explained below, and a good cooling effect can be obtained.

[0082] As mentioned in the operation description of the above embodiment, ice pack 350 undergoes a phase change when its temperature rises, changing from solid to liquid. This liquid has viscosity, and when ice pack 350 is pressed against cooling plate 312 by elastic body 354 and insulating elastic body 355, the top surface of ice pack 350 adheres to the bottom surface of cooling plate 312 over a wide area and maintains this adhesion. For example, if solid dry ice is used to cool the bottom surface of cooling plate 312, unlike ice pack 350, evaporation occurs on the top surface of the solid dry ice, resulting in an uneven top surface. Even if pressure is applied from below, it is difficult to ensure that the solid dry ice adheres to the bottom surface of cooling plate 312. For this reason, when using solid dry ice, it is necessary to reshape the contact surface of the solid dry ice into a uniform flat surface every short period of time. Because ice pack 350 maintains optimal adhesion as described above, it can be used continuously for a long period of time before losing its cooling function.

[0083] In this embodiment, it is extremely easy to remove and attach the cover 356 and the elastomer 354. Similarly, it is extremely easy to remove and attach the cover 356 and the insulating elastomer 355. Therefore, replacing used ice pack 350 with a new, cooled ice pack 350 is not only easy, but can be done in an extremely short time. For example, even if it becomes necessary to replace ice pack 350 during observation, the interruption time can be kept extremely short.

[0084] The ice pack 350 is very light compared to other cooling means. Therefore, the cooling device 300 is extremely light, and as a result, the entire cloud chamber 100 is light. It is easy to carry. It is also easy to set up for observation. This effect applies not only to this embodiment, but also to all of the above-mentioned embodiments.

[0085] The cloud chamber 100 is a device that is often carried around during use. When transporting the device, damage and breakdown of the device are major issues. The structure of the cooling device 300 is very simple, and precision that requires fine adjustments is not required. This is due to the flexibility of the ice pack 350. Therefore, even when transported or moved, breakdowns or deterioration that would affect observation characteristics are unlikely to occur. In the embodiments shown in Figures 1, 8, and 9, in addition to the flexibility of the ice pack 350, the generated dry ice 304 also has flexibility, thereby providing the effects described here.

[0086] 6. Explanation of the configuration and effects of the steam supply device 250 The operation of the steam supply device 250 has been described in the embodiment shown in Fig. 1, but the operation and effects of the steam supply device 250 will be described using Fig. 1 and Fig. 11. This description also applies to the embodiments shown in Fig. 8, Fig. 9, Fig. 10(a), and Fig. 10(b).

[0087] The above-described embodiment has the effect of enabling the cooling operation of the cooling device 300 to continue for a much longer period of time than conventional devices. As a result, a new issue that had been overlooked in conventional devices has become apparent: the need to be able to sustain the supply of steam 204 to the observation chamber 202 for a long period of time. In the above-described embodiment, the steam 204 used is made from liquid ethanol 253. Ethanol 253 for generating steam 204 is stored in the liquid supply tray 252 shown in FIG. 11, and the ethanol 253 is absorbed by the liquid absorber 260 through capillary action and introduced into the observation box 210. The ethanol 253 introduced into the observation box 210 evaporates in the observation chamber 202, becoming steam 204.

[0088] 11 , the liquid supply tray 252 opens to the outside of the insulating peripheral wall 216. Therefore, when it becomes necessary to supply ethanol 253, it is possible to supply ethanol 253 to the liquid supply tray 252 without stopping the monitoring operation of the cloud chamber 100. When the state of the vapor 204 in the observation chamber 202 becomes lower than the saturated state, the amount of ethanol vapor evaporating from the liquid absorber 260 automatically increases, and the amount of ethanol absorbed by the liquid absorber 260 from the liquid supply tray 252 increases. As a result, the liquid absorber 260 automatically supplies the ethanol 253 stored in the liquid supply tray 252 to the observation chamber 202 in an optimal state so that the concentration of the vapor 204 in the observation chamber 202 becomes appropriate.

[0089] In the embodiment shown in FIG. 11 , as described above, ethanol 253 can be supplied to the liquid supply tray 252 as needed while the cloud chamber 100 is operating. Furthermore, the liquid absorber 260 automatically guides the ethanol 253 required to maintain the operation of the cloud chamber 100 into the observation chamber 202. Therefore, there is no risk that the operating state of the cloud chamber 100 will be affected by the supply of ethanol 253 to the liquid supply tray 252. Of course, a lid or the like may be provided on the liquid supply tray 252. The concept and configuration shown in FIG. 11 can also be applied to other embodiments. As described above, the cooling device 300 to which the present invention is applied can maintain cooling capacity for much longer than conventional devices, thereby meeting the need for continuous long-term operation of the cloud chamber 100. The configuration and concept shown in FIG. 11 play a major role in achieving this need.

[0090] 1, an upper observation window 214 is provided on the top of the observation chamber 202 to enable observation from above, and the observation chamber 202 is covered with a transparent side observation window 212 to enable observation of the periphery of the observation chamber 202. In the embodiment of FIG. 11, an upper observation window 214 is provided on the top of the observation chamber 202 to enable observation from above, and the periphery of the observation chamber 202 is covered with a heat-insulating outer peripheral wall 216. A liquid absorber 260 is provided to penetrate the upper observation window 214 and the heat-insulating outer peripheral wall 216, and ethanol 253 is introduced into the observation chamber 202 through the penetrated liquid absorber 260. In the apparatus of FIG. 1, ethanol 253 is heated by the heating device 254, so that a large amount of vapor 204 that is close to a saturated state is supplied into the observation chamber 202. Although not shown in FIG. 11, the ethanol 253 is heated, and the ethanol 253 absorbed by the liquid absorber 260 in the observation chamber 202 is heated, and vapor 204 that is close to a saturated state is supplied into the observation chamber 202.

[0091] In the vapor supply device 250 shown in Fig. 1, by opening the heat-retaining cover 257 as needed, it is possible to supply additional ethanol 253 to the liquid supply port 262. Although not shown, the liquid supply tray 252 shown in Fig. 11 is provided with a heat-retaining cover, and by opening the heat-retaining cover, it is possible to add ethanol 253. With this structure, in the above-mentioned embodiment in which the cooling effect can be maintained for an extremely long time, it is possible to easily add ethanol 253 as the observation time passes, and it is possible to continue operating the observation device 200 for a long time.

[0092] 7. Features and effects of the above-mentioned embodiment 7.1 Features of the above-mentioned embodiment [First feature] The first feature is, A cloud chamber (100) for observing the tracks of radiation passing through the supersaturated vapor layer (206) in the observation chamber (202), the cloud chamber (100) comprising an observation device (200) having an observation chamber (202) filled with vapor (204) and a vapor supply device (250) for supplying the vapor (204) to the observation chamber (202), and a cooling device (300) for cooling the vapor (204) in the observation chamber (202) to form a supersaturated vapor layer (206) in the observation chamber (202), The cooling device 300 includes a cooling chamber 302, a cooling plate 312 provided on an upper portion of the cooling chamber 302, a plurality of cooling plates 330 mechanically connected to the cooling plate 312 and extending downward and laterally of the cooling chamber 302, and a connection device 290 for connecting to a liquefied carbon dioxide container 380 that holds liquefied carbon dioxide 384; A mixture of produced dry ice 304 generated from liquefied carbon dioxide 384 and gaseous carbon dioxide is introduced from one side 344 in the horizontal direction of a plurality of cooling plates 330, the introduced mixture of produced dry ice 304 and gaseous carbon dioxide is guided to the other side 346 in the horizontal direction by the plurality of cooling plates 330, the produced dry ice 304 constituting the mixture guided to a passage 332 formed between the plurality of cooling plates 330 is stored, the produced dry ice 304 stored in the passage cools the cooling plate 312, and the cooled cooling plate 312 cools the steam 204 in the observation chamber 202 to form a supersaturated steam layer 206.

[0093] [Second feature] The second feature is the same as the first feature regarding the cloud chamber 100, but in addition to the first feature, The cooling device 300 is characterized in that ice packs 350 stored in sealed storage means are provided under a plurality of cooling plates 330, and an elastic body is provided under the ice packs 350 to press the ice packs 350 toward the cooling plates (330).

[0094] [Third feature] The third feature is that in the cloud chamber 100 which can be one of the first feature or the second feature, An exhaust port 236 for discharging the gaseous carbon dioxide is provided on the other side 346 of the plurality of cooling plates 330 in the lateral direction, and a filter 324 for preventing the passage of the generated dry ice 304 is provided between the exhaust port 236 and the plurality of cooling plates 330; The filter 324 prevents the generated dry ice 304 from passing through, and the generated dry ice 304 can be stored in the passages 332 formed between the plurality of cooling plates 330.

[0095] [Fourth feature] A fourth feature for solving the above problem is a cloud chamber 100 having one of the first and second features, A filter 324 for preventing the passage of the produced dry ice 304 is provided below the plurality of cooling plates 330, and an exhaust port 236 for discharging the gaseous carbon dioxide is further provided below the filter 324. The filter 324 prevents the passage of the produced dry ice 304, thereby storing the produced dry ice 304 in the passages 332 formed between the plurality of cooling plates 330.

[0096] [Fifth feature] The fifth feature is that in the cloud chamber 100 having the fourth feature, After a predetermined amount of produced dry ice 304 is stored in the cooling chamber 302, the cross-sectional area of ​​the exhaust port 328 for discharging the gaseous carbon dioxide from the cooling chamber 302 is reduced, thereby reducing the amount of gaseous carbon dioxide discharged from the cooling chamber 302.

[0097] [Sixth feature] The sixth feature is that in the cloud chamber 100 having the second feature, The ice pack 350 is a material that becomes solid at a predetermined temperature or below and changes phase at a temperature higher than the predetermined temperature, The sealed storage means is a bag-like structure that stores the ice pack 350 in a sealed state. The cooling agent 350 is held in a state in which it is pressed by the elastic body 354 toward the plurality of cooling plates 330 .

[0098] [7th feature] A seventh feature is a cloud chamber 100 having one of the first and second features, The steam supply device 250 that supplies the steam 204 to the observation chamber 202 includes a liquid supply tray 252 that holds a liquid for generating the steam 204, a heating device 254 that heats the liquid held in the liquid supply tray 252, and a liquid absorber 260 that guides the liquid held in the liquid supply tray 252 into the observation chamber 202; The liquid supply tray 252 is characterized by having a liquid supply port 262 that opens to the outside of the observation device 200 .

[0099] 7.2 Effects of the above features The effects of the first feature are as described in the section on effects of the present invention. Furthermore, specific effects of specific embodiments are described in, for example, the section on the effects of the cooling device 300 shown in Figures 1 and 2 to 4 in section 2.3 above.

[0100] The effects of the second feature are described, for example, in the above-mentioned section 4.3, "Explanation of Effects When Using Cooling Device 300 Having Ice Pack 350," and also in the above-mentioned section 5.2, "Explanation of Effects of the Example Depicted in Figures 10(a) and 10(b)."

[0101] The effects achieved by the third feature are described in, for example, the section in Item 2.3 above, which explains the effects of the cooling device 300 shown in FIGS. 1 and 2 to 4.

[0102] The effects of the fourth feature are described in, for example, the section (2) Explanation of the effects of other embodiments of the cooling device 300 in the section 2.4 Explanation of other embodiments of the cooling device 300 mentioned above.

[0103] The effects of the fifth feature are described in, for example, the section in Item 3.3, "Explanation of the Function and Effect of the Cooling Device 300 in the Observation State," above.

[0104] The effect of the sixth feature is described in, for example, the section of item 4.3, "Explanation of the effect when using the cooling device 300 having the ice pack 350," above.

[0105] The effects of the seventh feature are described in, for example, the above-mentioned section 1.2 Effects of the steam supply device 250 and section 6. Explanation of the configuration and effects of the steam supply device 250. [Explanation of symbols]

[0106] 100 cloud chamber, 104 support device, 200 observation device, 202 observation chamber, 204 vapor, 206 supersaturated vapor layer, 208 liquid, 210 observation box, 212 side observation window, 214 upper observation window, 220 lighting device, 232 exhaust passage, 234 exhaust passage, 2351 exhaust port, 2352 exhaust port, 236 exhaust port, 2361 exhaust port, 2362 exhaust port, 2363 exhaust port, 237 exhaust port, 2371 ·Exhaust port, 2372···Exhaust port, 2373···Exhaust port, 238···Opening and closing device, 2421···Arrow, arrow, 2424···Arrow, 2425···Arrow, 2426···Arrow, 244···Passage former, 2441···Insulating wall, 2442···Insulating wall, 250···Steam supply device, 252···Liquid supply tray, 253···Ethanol, 254···Heating device, 256···Heating device, 257···Insulating cover, 260···Liquid absorber, 262···Liquid supply port, 300···Cooling Apparatus, 302... cooling chamber, 304... generated dry ice, 312... cooling plate, 320... inlet, 322... introduction passage, 324... filter, 326... filter, 328... exhaust port, 329... arrow, 330... cooling plate, 3301... cooling plate, 3302... cooling plate, 3303... cooling plate, 3304... cooling plate, 332... passage, 3321... passage, 3322... passage, 3323... passage, 3324... passage , 3325···passageway, 3330···gap, 3331···gap, 3338···gap, 3401···arrow, 3405···arrow, 344···one side, 346···other side, 350···ice pack, 352···exhaust chamber, 354···elastic body, 355···insulating elastomer, 356···cover, 357···exhaust port, 360···insulating material, 370···insulating board, 380···liquefied carbon dioxide container, 382···vaporized carbon dioxide, 384···liquefied carbon dioxide, 390···connecting device.

Claims

1. 1. A cloud chamber for observing tracks of radiation passing through the supersaturated vapor layer in the observation chamber, comprising: an observation device including an observation chamber filled with vapor and a vapor supply device for supplying the vapor to the observation chamber; and a cooling device for cooling the vapor in the observation chamber to form a supersaturated vapor layer in the observation chamber, the cooling device comprises a cooling chamber, a cooling plate provided on an upper portion of the cooling chamber, a plurality of cooling plates mechanically connected to the cooling plate and extending downward and laterally of the cooling chamber, and a connection device for connecting to a liquefied carbon dioxide container that holds liquefied carbon dioxide; a cloud chamber including: a first cooling plate having a first opening; a second cooling plate having a second opening; a second cooling plate having a second opening; a third cooling plate having a second opening; a fourth cooling plate having a second opening; a fourth cooling plate having a second opening; a fourth cooling plate having a second opening; a fourth cooling plate having a second opening; a fourth cooling plate having a second opening; a fourth cooling plate having a second opening; a fifth cooling plate having a second opening; a fifth cooling plate having a second opening; a fifth cooling plate having a second opening; a fifth cooling plate having a second opening; a fifth cooling plate having a second opening; a fifth cooling plate having a second opening; a fifth cooling plate having a second opening; a fifth cooling plate having a second opening; a sixth ...

2. 2. The cloud chamber according to claim 1, The cloud chamber is characterized in that the cooling device has ice packs stored in a sealed storage means under the plurality of cooling plates, and an elastic body is provided under the ice packs to press the ice packs toward the plurality of cooling plates.

3. The cloud chamber according to claim 1 or claim 2, an exhaust port for discharging the gaseous carbon dioxide in the other direction in the lateral direction of the plurality of cooling plates is provided, and a filter for preventing the passage of the generated dry ice is provided between the exhaust port and the plurality of cooling plates; A cloud chamber characterized in that the filter prevents the generated dry ice from passing through, and the generated dry ice is stored in the passage formed between the plurality of cooling plates.

4. 3. The cloud chamber according to claim 1 or claim 2, a filter for preventing the passage of the produced dry ice is provided below the plurality of cooling plates, and an outlet for discharging the gaseous carbon dioxide is provided below the filter; a filter that prevents the generated dry ice from passing through, thereby storing the generated dry ice in the passage formed between the plurality of cooling plates;

5. The cloud chamber according to claim 4, a cross-sectional area of ​​the outlet for discharging the gaseous carbon dioxide from the cooling chamber is reduced after a predetermined amount of produced dry ice has been stored in the cooling chamber, thereby reducing the amount of gaseous carbon dioxide discharged from the cooling chamber.

6. 3. The cloud chamber according to claim 2, The ice pack is a material that becomes solid at a predetermined temperature or lower and changes phase at a temperature higher than the predetermined temperature, The sealed storage means is a bag-like bag that stores the ice pack in a sealed state, 10. A cloud chamber according to claim 9, wherein the cooling agent is held in a state pressed by the elastic body toward the plurality of cooling plates.

7. 3. The cloud chamber according to claim 1 or claim 2, the vapor supply device that supplies the vapor to the observation chamber includes a liquid supply tray that holds a liquid for generating the vapor, a warming device that warms the liquid, and a liquid absorber that guides the liquid held in the liquid supply tray into the observation chamber; 10. A cloud chamber according to claim 9, wherein the liquid supply tray is provided with a liquid supply port that opens to the outside of the observation device.

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