Abstract:
A camera ( 10 ) according to the present invention includes: a sensor module ( 1 ) which measures radiation data; heat radiation parts ( 14 - 1, 14 - 2 ) which radiate heat generated as the sensor module ( 1 ) is cooled; an electrical apparatus ( 20 ); and fans ( 15 - 1, 15 - 2 ) which generate a flow of a first fluid for cooling the heat radiation parts ( 14 - 1, 14 - 2 ). The camera further has a first passage ( 41 ) through which the first fluid flows, a second passage ( 43 ) through which a second fluid for cooling the electrical apparatus ( 20 ) flows, and a merging part ( 44 ) which suctions the second fluid from the second passage ( 43 ) into the first passage ( 41 ) by means of the flow of the first fluid. Such a camera ( 10 ) can be made more compact than other cameras which further include a fan for circulating the second fluid through the second passage ( 43 ).

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a camera, and more particularly to a camera which is used for visualizing states of distribution of radioactive substances. 
       BACKGROUND ART 
       [0002]    “Radioactive substance visualization cameras” are known which visualize states of distribution of radioactive substances. The radioactive substance visualization camera is equipped with a cooling device and a sensor module. The cooling device cools the sensor module. While being cooled at a predetermined temperature or lower, the sensor module measures radiation data which shows a state of distribution of radioactive substances. 
         [0003]    PTL 1 discloses a radiation detector which measures radiation including X-rays and gamma rays. This radiation detector achieves an improved signal-noise ratio by cooling a semiconductor radiation detecting element by means of an electronic cooling element. 
       CITATION LIST 
     Patent literature 
       [0000]    
       
         {PTL 1} 
       
     
         [0005]    The Publication of Japanese Patent No. 4138107 
       SUMMARY OF INVENTION 
     Technical Problem 
       [0006]    Some radioactive substance visualization cameras include a heat generation part, which generates heat, separately from the sensor module. It is desired that the heat generation part of such a radioactive substance visualization camera be cooled and at the same time as the camera is made compact. 
         [0007]    An object of the present invention is to provide a compact camera. 
       Solution to Problem 
       [0008]    A camera according to the present invention includes: a sensor module which, on exposure to radiation, measures radiation data for visualizing a state of distribution of radioactive substances; a heat radiation part which radiates heat generated as the sensor module is cooled; a heat generation part which is different from the sensor module; a fan which generates a flow of a first fluid for cooling the heat radiation part; and a case. In this camera, the case forms a first passage through which the first fluid flows, a second passage through which a second fluid for cooling the heat generation part flows, and a merging part which sucks the second fluid from the second passage into the first passage by means of the flow of the first fluid. 
         [0009]    Such a camera can adequately cool both of the sensor module and the heat generation part by means of the first fluid and the second fluid, and can adequately measure the radiation data. Moreover, such a camera can be made more lightweight than other cameras which further include a fan for circulating the second fluid through the second passage. 
         [0010]    The heat generation part may be an electrical apparatus which controls the sensor module. Such a camera can make the sensor module work more properly by adequately cooling the electronic apparatus. 
         [0011]    The camera according to the present invention may further include a heat conducting member which comes into thermal contact with the sensor module. In this camera, the electrical apparatus is disposed further on a vertically upper side than the heat conducting member. In such a camera, water droplets formed by condensation on the heat conducting member are unlikely to come into contact with the electrical apparatus, and negative effects of the water droplets on the electrical apparatus can be reduced. 
         [0012]    The case may further have an air intake opening for supplying the first fluid to the second fluid. The air intake opening is disposed further on a vertically lower side than the electrical apparatus. In such a camera, water droplets entering through the air intake opening are unlikely to come into contact with the electrical apparatus, and negative effects of the water droplets on the electrical apparatus can be reduced. 
         [0013]    The second passage may be formed such that the second fluid flows through a periphery of the sensor module. In such a camera, conduction of heat from outside to the sensor module is reduced, so that the sensor module can be cooled adequately. 
       Advantageous Effects of Invention 
       [0014]    The camera according to the present invention can adequately cool both of the sensor module and the heat generation part, and at the same time can be made more lightweight than other cameras which further include a fan for cooling the heat generation part. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0015]      FIG. 1  is a sectional view showing an embodiment of a radioactive substance visualization camera. 
           [0016]      FIG. 2  is a transverse sectional view showing the embodiment of the radioactive substance visualization camera. 
           [0017]      FIG. 3  is a back view showing the embodiment of the radioactive substance visualization camera. 
           [0018]      FIG. 4  is a bottom view showing the embodiment of the radioactive substance visualization camera. 
           [0019]      FIG. 5  is a view through an upper surface showing the embodiment of the radioactive substance visualization camera. 
           [0020]      FIG. 6  is a view through a side surface showing the embodiment of the radioactive substance visualization camera. 
           [0021]      FIG. 7  is a top view showing another embodiment of the radioactive substance visualization camera. 
           [0022]      FIG. 8  is a transverse sectional view showing the another embodiment of the radioactive substance visualization camera. 
           [0023]      FIG. 9  is a sectional view showing the another embodiment of the radioactive substance visualization camera. 
           [0024]      FIG. 10  is a vertical sectional view showing the another embodiment of the radioactive substance visualization camera. 
           [0025]      FIG. 11  is a vertical sectional view showing the another embodiment of the radioactive substance visualization camera. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0026]    Embodiments of a camera will be described below with reference to the drawings. As shown in  FIG. 1 , a radioactive substance visualization camera  10  includes a sensor module  1 , a cooling device  2 , and a case  3 . The sensor module  1  includes a sensor case  5 , an imaging sensor  6 , and a heat insulation material  7 . 
         [0027]    The sensor case  5  is formed as a case which seals the inside. The imaging sensor  6  is disposed inside the sensor case  5 . While being exposed to radiation emitted from radioactive substances, the imaging sensor  6  is controlled by an electrical apparatus, to be described later, so as to measure radiation data for visualizing the state of distribution of the radioactive substances. The radiation data shows a plurality of directions and a plurality of pieces of radioactivity data corresponding to the plurality of directions. Of the plurality of pieces of radioactivity data, a piece of radioactivity data corresponding to a certain direction shows the nuclide of the radioactive substance disposed in that direction from the radioactive substance visualization camera  10 , and shows the amount of substance of the nuclide. 
         [0028]    The heat insulation material  7  is formed of a material having a heat conductivity lower than the heat conductivity of a material forming the sensor case  5 . The heat insulation material  7  covers the sensor case  5 . 
         [0029]    The sensor module  1  has the imaging sensor  6  disposed in a closed space sealed by the sensor case  5  and thereby prevents dew condensation on the imaging sensor  6 . The sensor module  1  has the sensor case  5  covered with the heat insulation material  7  and thereby prevents heat from the outside of the radioactive substance visualization camera  10  from being conducted to the imaging sensor  6 . 
         [0030]    The cooling device  2  includes an aluminum plug  11 , first Peltier cooler  12 - 1 , a first radiator  14 - 1 , and a first fan  15 - 1 . The aluminum plug  11  is formed of metal aluminum. The aluminum plug  11  is formed of an inner portion and an outer portion, and the inner portion and the outer portion are in thermal contact with each other. The inner portion is disposed inside the sensor case  5 , and is in thermal contact with the sensor module  1 . The outer portion is disposed outside the sensor case  5 . 
         [0031]    The first Peltier cooler  12 - 1  includes a Peltier element. The first Peltier cooler  12 - 1  is disposed between the aluminum plug  11  and the first radiator  14 - 1 , and is disposed so as to intersect a first straight line  16 - 1  connecting the aluminum plug  11  and the first radiator  14 - 1 . The first Peltier cooler  12 - 1  is in thermal contact with the aluminum plug  11 . The first Peltier cooler  12 - 1  is controlled by the electrical apparatus, to be described later, so as to transfer heat from the first aluminum plug  11  to the first radiator  14 - 1  by means of the Peltier element. That is, the first Peltier cooler  12 - 1  heats the first radiator  14 - 1  and cools the aluminum plug  11 . 
         [0032]    The first radiator  14 - 1  is disposed so as to intersect the first straight line  16 - 1  and such that the first Peltier cooler  12 - 1  is disposed between the aluminum plug  11  and the first radiator  14 - 1 . The first radiator  14 - 1  is in thermal contact with the first Peltier cooler  12 - 1 . The first radiator  14 - 1  has a plurality of fins formed on the side opposite to the side in contact with the first Peltier cooler  12 - 1 . 
         [0033]    The first fan  15 - 1  is disposed so as to intersect the first straight line  16 - 1  and such that the first radiator  14 - 1  is disposed between the first fan  15 - 1  and the first Peltier cooler  12 - 1 . The first fan  15 - 1  is controlled by the electrical apparatus, to be described later, so as to send outside air toward the plurality of fins formed on the first radiator  14 - 1 . 
         [0034]    The cooling device  2  further includes a second Peltier cooler  12 - 2 , a second radiator  14 - 2 , and a second fan  15 - 2 . 
         [0035]    The second Peltier cooler  12 - 2  includes a Peltier element. The second Peltier cooler  12 - 2  is disposed between the aluminum plug  11  and the second radiator  14 - 2 , and is disposed so as to intersect a second straight line  16 - 2  connecting the aluminum plug  11  and the second radiator  14 - 2 . The second Peltier cooler  12 - 2  is further in thermal contact with the aluminum plug  11 . The second Peltier cooler  12 - 2  is controlled by the electrical apparatus, to be described later, so as to transfer heat from the aluminum plug  11  to the second radiator  14 - 2  by means of the Peltier element. That is, the second Peltier cooler  12 - 2  heats the second radiator  14 - 2  and cools the aluminum plug  11 . 
         [0036]    The second radiator  14 - 2  is disposed so as to intersect the second straight line  16 - 2  and such that the second Peltier cooler  12 - 2  is disposed between the aluminum plug  11  and the second radiator  14 - 2 . The second radiator  14 - 2  is in thermal contact with the second Peltier cooler  12 - 2 . The second radiator  14 - 2  has a plurality of fins formed on the side opposite to the side in contact with the second Peltier cooler  12 - 2 . 
         [0037]    The second fan  15 - 2  is disposed so as to intersect the second straight line  16 - 2  and such that the second radiator  14 - 2  is disposed between the second fan  15 - 2  and the second Peltier cooler  12 - 2 . The second fan  15 - 2  is controlled by the electrical apparatus, to be described later, so as to send outside air toward the plurality of fins formed on the second radiator  14 - 2 . 
         [0038]    The cooling device  2  is further formed such that the first straight line  16 - 1  and the second straight line  16 - 2  intersect with each other, and that the point at which the first straight line  16 - 1  and the second straight line  16 - 2  intersect with each other lies in the aluminum plug  11 . That is, the distance from the center of the first radiator  14 - 1  to the center of the second radiator  14 - 2  is longer than the distance from the center of the first Peltier cooler  12 - 1  to the center of the second Peltier cooler  12 - 2 . In this case, the first radiator  14 - 1  and the second radiator  14 - 2  can be made relatively large, and the area of their surfaces in contact with air can be made relatively large. 
         [0039]    The case  3  forms an outer shell of the radioactive substance visualization camera  10 . That is, the sensor module  1  and the cooling device  2  are disposed inside the case  3 . 
         [0040]    As shown in  FIG. 2 , the radioactive substance visualization camera  10  further includes an electrical apparatus  20 . The electrical apparatus  20  is disposed on the vertically upper side than the cooling device  2 . The electrical apparatus  20  is electrically connected with the imaging sensor  6 , and is connected so as to be able to transmit information. The electrical apparatus  20  supplies power to the imaging sensor  6 , and controls the imaging sensor  6  such that radiation data for visualizing a state of distribution of radioactive substances is measured. The electrical apparatus  20  further supplies power to the first Peltier cooler  12 - 1  and the second Peltier cooler  12 - 2 , and controls the first Peltier cooler  12 - 1  and the second Peltier cooler  12 - 2  such that the imaging sensor  6  is cooled. The electrical apparatus  20  further supplies power to the first fan  15 - 1  and the second fan  15 - 2 , and controls the first fan  15 - 1  and the second fan  15 - 2  such that the first radiator  14 - 1  and the second radiator  14 - 2  are subjected to air. 
         [0041]    As shown in  FIG. 3 , the case  3  has a first air intake opening  21 - 1 , a second air intake opening  21 - 2 , and a back-side air discharge opening  22  formed in the back surface. As shown in  FIG. 4 , the case  3  further has a bottom-side air intake opening  23 , a first bottom-side air discharge opening  24 - 1 , and a second bottom-side air discharge opening  24 - 2  formed in the bottom surface. 
         [0042]    As shown in  FIG. 1 , the first air intake opening  21 - 1  is formed so as to lie on the first straight line  16 - 1  and such that the first fan  15 - 1  is disposed between the first air intake opening  21 - 1  and the first radiator  14 - 1 . The second air intake opening  21 - 2  is formed so as to lie on the second straight line  16 - 2  and such that the second fan  15 - 2  is disposed between the second air intake opening  21 - 2  and the second radiator  14 - 2 . The first fan  15 - 1  suctions air from outside the case  3  through the first air intake opening  21 - 1  and sends the air to the first radiator  14 - 1 . The second fan  15 - 2  suctions air from outside the case  3  through the second air intake opening  21 - 2  and sends the air to the second radiator  14 - 2 . 
         [0043]    As shown in  FIG. 5 , the radioactive substance visualization camera  10  further includes a partition plate  35 . The partition plate  35  is formed as a plate. The partition plate  35  is disposed inside the case  3 , and is disposed between the electrical apparatus  20  and the cooling device  2 . As shown in  FIG. 6 , the radioactive substance visualization camera  10  further includes a partition plate  36 . The partition plate  36  is formed as a plate. The partition plate  36  is disposed inside the case  3 . 
         [0044]    The partition plate  35  and the partition plate  36 , with the case  3 , form a rear Peltier cooling passage  41  and a second lower Peltier cooling passage  42 - 2 . The rear Peltier cooling passage  41  discharges air having come into contact with the first radiator  14 - 1  and air having come into contact with the second radiator  14 - 2  from the back-side air discharge opening  22 . The second lower Peltier cooling passage  42 - 2  discharges air having come into contact with the second radiator  14 - 2  from the second bottom-side air discharge opening  24 - 2 . 
         [0045]    As shown in  FIG. 1 , the partition plate  35  and the partition plate  36 , with the case  3 , form a first lower Peltier cooling passage  42 - 1 . The first lower Peltier cooling passage  42 - 1  discharges air having come into contact with the first radiator  14 - 1  from the first bottom-side air discharge opening  24 - 1 . 
         [0046]    As shown in  FIG. 6 , the partition plate  35  and the partition plate  36 , with the case  3 , further form a casing internal cooling passage  43  and a merging part  44 . The merging part  44  is formed on the midstream side of the rear Peltier cooling passage  41 , and is formed from the first radiator  14 - 1  and the second radiator  14 - 2  to the back-side air discharge opening  22 . The casing internal cooling passage  43  is formed between the sensor module  1  and the case  3 , and is formed between the electrical apparatus  20  and the case  3 . The casing internal cooling passage  43  is connected with the bottom-side air intake opening  23  and is connected with the merging part  44 . As air flows through the rear Peltier cooling passage  41 , the merging part  44  suctions air from the casing internal cooling passage  43  into the rear Peltier cooling passage  41 . That is, while air is flowing through the rear Peltier cooling passage  41 , the merging part  44  suctions air from the casing internal cooling passage  43  into the rear Peltier cooling passage  41  by means of the flow of the air flowing through the rear Peltier cooling passage  41 . 
         [0047]    The aluminum plug  11  of such a radioactive substance visualization camera  10  can be made more compact, so that the camera can be made more compact, than other cameras of which the first straight line  16 - 1  and the second straight line  16 - 2  are parallel to each other. 
         [0048]    Actions of the radioactive substance visualization camera  10  include a cooling action and an imaging action. The cooling action is performed by the electrical apparatus  20 . First, the electrical apparatus  20  controls the first fan  15 - 1  to thereby send air suctioned through the first air intake opening  21 - 1  toward the first radiator  14 - 1 , and controls the second fan  15 - 2  to thereby send air suctioned through the second air intake opening  21 - 2  toward the second radiator  14 - 2 . The electrical apparatus  20  further controls the first Peltier cooler  12 - 1  to thereby transfer heat from the aluminum plug  11  to the first radiator  14 - 1 , and controls the second Peltier cooler  12 - 2  to thereby transfer heat from the aluminum plug  11  to the second radiator  14 - 2 . 
         [0049]    In the radioactive substance visualization camera  10 , as the cooling action is performed, the aluminum plug  11  is cooled by the first Peltier cooler  12 - 1  and the second Peltier cooler  12 - 2 . As the aluminum plug  11  is cooled, the imaging sensor  6  is cooled. 
         [0050]    When the cooling action is performed, the first radiator  14 - 1  is heated by the first Peltier cooler  12 - 1 . When the temperature of the first radiator  14 - 1  is higher than the outside air temperature, the first radiator  14 - 1  is cooled on contact with air sent by the first fan  15 - 1 . The second radiator  14 - 2  is cooled by the first fan  15 - 1  in the same manner as the first radiator  14 - 1 . As the first radiator  14 - 1  and the second radiator  14 - 2  are cooled, the first Peltier cooler  12 - 1  and the second Peltier cooler  12 - 2  can cool the imaging sensor  6  with high efficiency. 
         [0051]    While the air sent by the first fan  15 - 1  and the second fan  15 - 2  is flowing through the rear Peltier cooling passage  41 , the merging part  44  suctions air from the casing internal cooling passage  43  into the rear Peltier cooling passage  41  by means of the flow of the air flowing through the rear Peltier cooling passage  41 . As the air is suctioned by the merging part  44 , the casing internal cooling passage  43  suctions air through the bottom-side air intake opening  23 , and circulates the air between the sensor module  1  and the case  3  and through the periphery of the electrical apparatus  20 . 
         [0052]    The imaging action is performed while the cooling action is being performed. The electrical apparatus  20  supplies power to the imaging sensor  6  and controls the imaging sensor  6  to thereby measure radiation data. The radiation data shows a plurality of directions and a plurality of pieces of radioactivity data corresponding to the plurality of directions. Of the plurality of pieces of radioactivity data, a piece of radioactivity data corresponding to a certain direction shows the nuclide of the radioactive substance disposed in that direction from the radioactive substance visualization camera  10 , and shows the amount of substance of the nuclide. The electrical apparatus  20  outputs the radiation data to an external apparatus. 
         [0053]    The radiation data is analyzed and thereby processed into a radioactive substance visualization image. The radioactive substance visualization image is formed of a plurality of regions corresponding to the plurality of directions. In a region corresponding to a certain direction of the plurality of regions, an image of an object disposed in that direction is projected, and a piece of radioactivity data of the plurality of pieces of radioactivity data corresponding to that direction is shown over the image of the object. Such a radioactive substance visualization image can display a state of distribution of radioactive substances in a manner that makes it more easily understandable. 
         [0054]    According to such a radioactive substance visualization camera  10 , the electrical apparatus  20  is cooled and prevented from overheating as air flows through the casing internal cooling passage  43 . Since overheating of the electrical apparatus  20  is prevented, the radioactive substance visualization camera  10  can adequately control the imaging sensor  6 , the first Peltier cooler  12 - 1 , the second Peltier cooler  12 - 2 , the first fan  15 - 1 , and the second fan  15 - 2 . As the first Peltier cooler  12 - 1 , the second Peltier cooler  12 - 2 , the first fan  15 - 1 , and the second fan  15 - 2  are adequately controlled, the radioactive substance visualization camera  10  can adequately cool the imaging sensor  6 . As the imaging sensor  6  is adequately controlled, the radioactive substance visualization camera  10  can adequately measure radiation data. 
         [0055]    While the radioactive substance visualization camera  10  is being used outdoors, the case  3  may reach a high temperature due to exposure to sunlight. According to such a radioactive substance visualization camera  10 , as air flows through the casing internal cooling passage  43 , the amount of heat conducted from the case  3  is reduced, so that the sensor module  1  is prevented from being heated by sunlight. As the amount of heat conducted from the case  3  is reduced, the sensor module  1  can adequately cool the imaging sensor  6  and adequately measure radiation data. 
         [0056]    Since the radioactive substance visualization camera  10  uses the flow of air flowing through the rear Peltier cooling passage  41  to circulate air through the casing internal cooling passage  43 , it can circulate air through the casing internal cooling passage  43  without using a fan for sending air to the casing internal cooling passage  43 . Therefore, the radioactive substance visualization camera  10  can be made more lightweight and more compact than other radioactive substance visualization cameras which include a fan for sending air to the casing internal cooling passage  43 . 
         [0057]    In the radioactive substance visualization camera  10 , as the aluminum plug  11  is cooled, dew condensation occurs in the periphery of the aluminum plug  11  and water droplets formed by the dew condensation may fall. In the radioactive substance visualization camera  10 , since the electrical apparatus  20  is disposed further on the vertically upper side than the aluminum plug  11 , water droplets formed by dew condensation are unlikely to come into contact with the electrical apparatus  20 . Thus, the radioactive substance visualization camera  10  can reduce the negative effects of the water droplets on the electrical apparatus  20 . 
         [0058]    While the radioactive substance visualization camera  10  is being used outdoors, raindrops may enter through the holes formed in the case  3 . The radioactive substance visualization camera  10  has the first air intake opening  21 - 1 , the second air intake opening  21 - 2 , the back-side air discharge opening  22 , the bottom-side air intake opening  23 , the first bottom-side air discharge opening  24 - 1 , and the second bottom-side air discharge opening  24 - 2  formed in a region of the case  3  further on the vertically lower side than the electrical apparatus  20 . Therefore, the radioactive substance visualization camera  10  can reduce the negative effects of raindrops entering through the holes formed in the case  3  on the electrical apparatus  20 . 
         [0059]    The aluminum plug  11  can be substituted with a heat conducting member which is formed of a material other than metal aluminum. The material has a heat conductivity higher than the heat conductivity of the material forming the sensor case  5 . The radioactive substance visualization camera including such a heat conducting member can also be made compact as with the radioactive substance visualization camera of the already-described embodiment. 
         [0060]      FIG. 7  shows another embodiment of the radioactive substance visualization camera. In a radioactive substance visualization camera  50 , the case  3  of the radioactive substance visualization camera  10  of the already-described embodiment is substituted with another case  55 . As with the case  3 , the case  55  has the first air intake opening  21 - 1 , the second air intake opening  21 - 2 , the back-side air discharge opening  22 , the bottom-side air intake opening  23 , the first bottom-side air discharge opening  24 - 1 , and the second bottom-side air discharge opening  24 - 2 . The case  55  further has a first top-side air discharge opening  56 - 1  and a second top-side air discharge opening  56 - 2 . 
         [0061]    As shown in  FIG. 8 , the radioactive substance visualization camera  50  further includes an electrical apparatus  51 . The electrical apparatus  51  is disposed on the vertically lower side of the cooling device  2 . The electrical apparatus  51  is provided with waterproofing measures so as to work properly even on contact with water droplets. The electrical apparatus  51  controls, with the electrical apparatus  20 , the imaging sensor  6 , the first Peltier cooler  12 - 1 , the second Peltier cooler  12 - 2 , the first fan  15 - 1 , and the second fan  15 - 2 . As with the electrical apparatus  51 , the electrical apparatus  20  is provided with waterproofing measures so as to work properly even on contact with water droplets. 
         [0062]    In the radioactive substance visualization camera  50 , the partition plate  35  and the partition plate  36  of the radioactive substance visualization camera  10  of the already-described embodiment are also substituted with other partition plates  52 ,  53 . The partition plate  52  is formed as a bent plate. The partition plate  52  is disposed inside the case  3  and is disposed between the electrical apparatus  20  and the cooling device  2 . The partition plate  53  is formed as a bent plate. The partition plate  53  is disposed inside the case  3  and is disposed between the electrical apparatus  51  and the cooling device  2 . 
         [0063]    As shown in  FIG. 9 , the partition plate  52 , with the case  55 , forms a first upper Peltier cooling passage  61 - 1 , a second upper Peltier cooling passage  61 - 2 , a first upper merging part  62 - 1 , a second upper merging part  62 - 2 , and an upper casing internal cooling passage  63 . The first upper Peltier cooling passage  61 - 1  discharges air having come into contact with the first radiator  14 - 1  from the first top-side air discharge opening  56 - 1 . The second upper Peltier cooling passage  61 - 2  discharges air having come into contact with the second radiator  14 - 2  from the second top-side air discharge opening  56 - 2 . 
         [0064]    The first upper merging part  62 - 1  is formed on the midstream side of the first upper Peltier cooling passage  61 - 1  and is formed from the first radiator  14 - 1  to the first top-side air discharge opening  56 - 1 . The second upper merging part  62 - 2  is formed on the midstream side of the second upper Peltier cooling passage  61 - 2  and is formed from the second radiator  14 - 2  to the second top-side air discharge opening  56 - 2 . 
         [0065]    The upper casing internal cooling passage  63  is formed between the sensor module  1  and the case  55  and is formed between the electrical apparatus  20  and the case  55 . The upper casing internal cooling passage  63  is connected with the bottom-side air intake opening  23  and is connected with the first upper merging part  62 - 1  and the second upper merging part  62 - 2 . 
         [0066]    As air flows through the first upper Peltier cooling passage  61 - 1 , the first upper merging part  62 - 1  suctions air from the upper casing internal cooling passage  63  into the first upper Peltier cooling passage  61 - 1 . That is, when air is flowing through the first upper Peltier cooling passage  61 - 1 , the first upper merging part  62 - 1  suctions air from the upper casing internal cooling passage  63  into the first upper Peltier cooling passage  61 - 1  by means of the flow of the air flowing through the first upper Peltier cooling passage  61 - 1 . As air flows through the second upper Peltier cooling passage  61 - 2 , the second upper merging part  62 - 2  suctions air from the upper casing internal cooling passage  63  into the second upper Peltier cooling passage  61 - 2 . That is, when air is flowing through the second upper Peltier cooling passage  61 - 2 , the second upper merging part  62 - 2  suctions air from the upper casing internal cooling passage  63  into the second upper Peltier cooling passage  61 - 2  by means of the flow of the air flowing through the second upper Peltier cooling passage  61 - 2 . 
         [0067]    As shown in  FIG. 10 , the partition plate  53 , with the case  55 , forms a lower casing internal cooling passage  64 , and as with the partition plate  52 , forms the first lower Peltier cooling passage, the second lower Peltier cooling passage, a first lower merging part, and a second lower merging part (all not shown). The first lower Peltier cooling passage discharges air having come into contact with the first radiator  14 - 1  from the first bottom-side air discharge opening  24 - 1 . The second lower Peltier cooling passage discharges air having come into contact with the second radiator  14 - 2  from the second bottom-side air discharge opening  24 - 2 . 
         [0068]    The first lower merging part is formed on the midstream side of the first lower Peltier cooling passage and is formed from the first radiator  14 - 1  to the first bottom-side air discharge opening  24 - 1 . The second lower merging part is formed on the midstream side of the second lower Peltier cooling passage and is formed from the second radiator  14 - 2  to the second bottom-side air discharge opening  24 - 2 . 
         [0069]    The lower casing internal cooling passage  64  is formed between the sensor module  1  and the case  55  and is formed between the electrical apparatus  51  and the case  55 . The lower casing internal cooling passage  64  is connected with the bottom-side air intake opening  23  and is connected with the first lower merging part and the second lower merging part. 
         [0070]    As air flows through the first lower Peltier cooling passage, the first lower merging part suctions air from the lower casing internal cooling passage  64  into the first lower Peltier cooling passage. That is, when air is flowing through the first lower Peltier cooling passage, the first lower merging part suctions air from the lower casing internal cooling passage  64  into the first lower Peltier cooling passage by means of the flow of the air flowing through the first lower Peltier cooling passage. As air flows through the second lower Peltier cooling passage, the second lower merging part suctions air from the lower casing internal cooling passage  64  into the second lower Peltier cooling passage. That is, when air is flowing through the second lower Peltier cooling passage, the second lower merging part suctions air from the lower casing internal cooling passage  64  into the second lower Peltier cooling passage by means of the flow of the air flowing through the second lower Peltier cooling passage. 
         [0071]    As shown in  FIG. 11 , the partition plate  52  and the partition plate  53 , with the case  55 , form a rear Peltier cooling passage  65 . As with the rear Peltier cooling passage  41  of the already-described embodiment, the rear Peltier cooling passage  65  discharges air having come into contact with the first radiator  14 - 1  and air having come into contact with the second radiator  14 - 2  from the back-side air discharge opening  22 . 
         [0072]    The partition plate  52 , with the case  55 , further forms an upper merging part  66 . The upper merging part  66  is formed on the midstream side of the rear Peltier cooling passage  65  and is formed from the first radiator  14 - 1  and the second radiator  14 - 2  to the back-side air discharge opening  22 . The upper merging part  66  is connected with the upper casing internal cooling passage  63 . As air flows through the rear Peltier cooling passage  65 , the upper merging part  66  suctions air from the upper casing internal cooling passage  63  into the rear Peltier cooling passage  65 . That is, when air is flowing through the rear Peltier cooling passage  65 , the upper merging part  66  suctions air from the upper casing internal cooling passage  63  into the rear Peltier cooling passage  65  by means of the flow of the air flowing through the rear Peltier cooling passage  65 . 
         [0073]    The partition plate  52 , with the case  55 , further forms a lower merging part  67 . The lower merging part  67  is formed on the midstream side of the rear Peltier cooling passage  65  and is formed from the first radiator  14 - 1  and the second radiator  14 - 2  to the back-side air discharge opening  22 . The lower merging part  67  is connected with the upper casing internal cooling passage  63 . As air flows through the rear Peltier cooling passage  65 , the lower merging part  67  suctions air from the upper casing internal cooling passage  63  into the rear Peltier cooling passage  65 . That is, when air is flowing through the rear Peltier cooling passage  65 , the lower merging part  67  suctions air from the upper casing internal cooling passage  63  into the rear Peltier cooling passage  65  by means of the flow of the air flowing through the rear Peltier cooling passage  65 . 
         [0074]    The radioactive substance visualization camera  50  works almost in the same manner as the radioactive substance visualization camera  10  of the already-described embodiment. That is, the electrical apparatus  20  and the electrical apparatus  51  control the first fan  15 - 1  to thereby send air, suctioned through the first air intake opening  21 - 1 , toward the first radiator  14 - 1 , and control the second fan  15 - 2  to thereby send air, suctioned through the second air intake opening  21 - 2 , toward the second radiator  14 - 2 . As air is sent by the first fan  15 - 1  to the first radiator  14 - 1 , the first radiator  14 - 1  is cooled. As air is sent by the second fan  15 - 2  to the second radiator  14 - 2 , the second radiator  14 - 2  is cooled. 
         [0075]    The electrical apparatus  20  and the electrical apparatus  51  further control the first Peltier cooler  12 - 1  to thereby transfer heat from the aluminum plug  11  to the first radiator  14 - 1 , and control the second Peltier cooler  12 - 2  to thereby transfer heat from the aluminum plug  11  to the second radiator  14 - 2 . The aluminum plug  11  is cooled through these actions. As the aluminum plug  11  is cooled, the imaging sensor  6  is cooled. 
         [0076]    As the first fan  15 - 1  and the second fan  15 - 2  send air, the first upper merging part  62 - 1 , the second upper merging part  62 - 2 , and the upper merging part  66  suction air from the upper casing internal cooling passage  63  into the first upper Peltier cooling passage  61 - 1 , the second upper Peltier cooling passage  61 - 2 , and the rear Peltier cooling passage  65 . As air is suctioned by the first upper merging part  62 - 1 , the second upper merging part  62 - 2 , and the upper merging part  66 , air flows through the upper casing internal cooling passage  63 . As air flows through the upper casing internal cooling passage  63 , the radioactive substance visualization camera  50  cools the electrical apparatus  20  and reduces the amount of heat conducted from the case  55  to the sensor module  1 . 
         [0077]    As the first fan  15 - 1  and the second fan  15 - 2  send air, the first lower merging part, the second lower merging part, and the lower merging part  67  suction air from the lower casing internal cooling passage  64  into the first lower Peltier cooling passage  42 - 1 , the second lower Peltier cooling passage  42 - 2 , and the rear Peltier cooling passage  65 . As air is suctioned by the first lower merging part, the second lower merging part, and the lower merging part  67 , air flows through the lower casing internal cooling passage  64 . As air flows through the lower casing internal cooling passage  64 , the radioactive substance visualization camera  50  cools the electrical apparatus  51  and reduces the amount of heat conducted from the case  55  to the sensor module  1 . 
         [0078]    While the imaging sensor  6  is being cooled, the electrical apparatus  20  and the electrical apparatus  51  control the imaging sensor  6  in the same manner as the electrical apparatus  20  of the radioactive substance visualization camera  10  of the already-described embodiment, to thereby measure radiation data. 
         [0079]    In such a radioactive substance visualization camera  50 , as with the radioactive substance visualization camera  10  of the already-described embodiment, overheating of the electrical apparatus  20  and the electrical apparatus  51  is prevented, and the amount of heat conducted from the case  3  to the sensor module  1  is reduced, so that radiation data can be measured adequately. 
         [0080]    Moreover, the radioactive substance visualization camera  50  can circulate air through the upper casing internal cooling passage  63  and the lower casing internal cooling passage  64  by means of the flow of air generated by the first fan  15 - 1  and the second fan  15 - 2 . Therefore, the radioactive substance visualization camera  50  can be made more lightweight and more compact than other radioactive substance visualization cameras which include a fan for sending air to the upper casing internal cooling passage  63  and the lower casing internal cooling passage  64 . 
         [0081]    In the radioactive substance visualization camera  50 , as the aluminum plug  11  is cooled, dew condensation occurs in the periphery of the aluminum plug  11  and water droplets formed by the dew condensation may fall. Since the electrical apparatus  51  is provided with the waterproofing measures, it works properly even on contact with water droplets formed by dew condensation. While the radioactive substance visualization camera  50  is being used outdoors, raindrops may enter through the holes formed in the case  3 . Since the electrical apparatus  20  is provided with the waterproofing measures, it works properly even on contact with entering raindrops. 
         [0082]    In the radioactive substance visualization camera  10  of the already-described embodiment, since the electrical apparatus  20  is disposed on the vertically upper side of the aluminum plug  11 , water droplets formed by dew condensation in the periphery of the aluminum plug  11  are unlikely to come, into contact with the electrical apparatus  20 , so that the level of waterproofing measures for the electrical apparatus  20  can be lowered. Since the level of waterproofing measures for the electrical apparatus  20  is lowered, the electrical apparatus  20  of the radioactive substance visualization camera  10  of the already-described embodiment can be produced more easily than the electrical apparatus  51 . 
         [0083]    Moreover, since the radioactive substance visualization camera  10  of the already-described embodiment has no hole formed in the top surface of the case  3 , water droplets are unlikely to enter the case  3 , so that the level of waterproofing measures for the electrical apparatus  20  can be lowered. Since the level of waterproofing measures for the electrical apparatus  20  is lowered, the radioactive substance visualization camera  10  of the already-described embodiment can be produced more easily than the radioactive substance visualization camera  50 . 
       REFERENCE SIGNS LIST 
       [0000]    
       
           1  sensor module 
           2  cooling device 
           3  case 
           10  radioactive substance visualization camera 
           11  aluminum plug 
           12 - 1  first Peltier cooler 
           12 - 2  second Peltier cooler 
           14 - 1  first radiator 
           14 - 2  second radiator 
           15 - 1  first fan 
           15 - 2  second fan 
           20  electrical apparatus 
           21 - 1  first air intake opening 
           21 - 2  second air intake opening 
         back-side air discharge opening 
           23  bottom-side air intake opening 
           24 - 1  first bottom-side air discharge opening 
           24 - 2  second bottom-side air discharge opening 
           35  partition plate 
           36  partition plate 
           41  rear Peltier cooling passage 
           42 - 1  first lower Peltier cooling passage 
           42 - 2  second lower Peltier cooling passage 
           43  casing internal cooling passage 
           44  merging part 
           50  radioactive substance visualization camera 
           51  electrical apparatus 
           52  partition plate 
           53  partition plate 
           55  case 
           56 - 1  first top-side air discharge opening 
           56 - 2  second top-side air discharge opening 
           61 - 1  first upper Peltier cooling passage 
           61 - 2  second upper Peltier cooling passage 
           62 - 1  first upper merging part 
           62 - 2  second upper merging part 
           63  upper casing internal cooling passage 
           64  lower casing internal cooling passage 
           65  rear Peltier cooling passage 
           66  upper merging part 
           67  lower merging part