JPH0358138B2 - - Google Patents

Description

[Detailed Description of the Invention] In radiation detectors such as proportional counters or Geiger-Muller counters, gas-sealed types have good air-tightness in the housing, and moreover, the occluded gas in the housing is discharged during exhaust. This requires heating it to a high temperature of several hundred degrees. For this reason, conventionally, the housing was assembled by welding or silver brazing, which can withstand high temperatures and has good airtightness. However, these methods are not easy to work with, and it is difficult to obtain a housing with a complicated structure. Therefore, the present invention provides a seal that allows easy assembly of the casing, allows its shape to be arbitrarily designed, and does not have the drawbacks of occluded gas being released from the casing during use or deterioration of characteristics due to leakage of outside air. This paper relates to a method for manufacturing a type radiation detector.

The manufacturing method of the present invention involves first assembling a casing using an inorganic adhesive that is difficult to maintain airtightness over a long period of time but can withstand high temperatures; It is attached to an exhaust device to evacuate the air and is heated to a high temperature of several hundred degrees to exhaust the gas stored in the housing. Next, reduce the above heating temperature to room temperature or a temperature close to this, apply an organic material-based paint that cannot withstand high temperatures but has high airtightness on top of the above-mentioned inorganic material-based adhesive, and continue evacuation. By doing so, the interior of the housing is made into a high vacuum, and then an appropriate gas is introduced to achieve the desired pressure, the exhaust pipe is cut, and the housing is sealed to complete a sealed radiation detector.

FIG. 1 is a longitudinal cross-sectional view showing an example of a proportional counter during the manufacturing process according to the method of the present invention as described above. That is, a cylindrical main body 1 made of stainless steel or the like is provided with an entrance window 2 for radiation to be detected in the center thereof. In addition, hermetic seals 5 and 6 are attached to the centers of the two circular thin plate-shaped cover plates 3 and 4, respectively, and a mounting hole for an exhaust pipe 7 is provided at an appropriate position in the cover plate 3. be. FIG. 2 is an enlarged view of portions A, B, and C of FIG. 1 in a state in which the above-described parts have been assembled. In this way, the inorganic adhesive 8, which is mainly composed of alumina or silica and has a high heat resistance temperature of over 1000°, is first applied to both ends of the main body 1, and the cover plates 3 and 4 are fitted together to form a casing.
Also, apply the same adhesive 8 to one end of the exhaust pipe 7 and fit it into the hole in the cover plate 3. In this state, insert the core wire 9 through the window 2 and seal both ends with hermetic seals 5 and 6. Weld to the lead-in wire. Next, for example, window 2
The adhesive 8 is applied to the edge of the window plate 10 made of beryllium or the like and the window plate 10 is attached to complete the assembly.

If the above-mentioned alumina or silica is the main component, an example of the inorganic material adhesive 8 is an aqueous one-component paste containing silica as the main component,
It can be cured in 20 hours at room temperature and in about 1 hour at 150°C, and has a heat resistance temperature of about 1200°C.

After completing the assembly as described above, install the exhaust pipe 7.
is connected to an exhaust device, and the main body 1 and cover plates 3 and 4 are
By evacuating the inside of the housing to as high a vacuum as possible and heating it to several hundred degrees by covering it with a furnace, the gases stored in the main body 1, cover plates 3, 4, etc. are discharged. let In this case, the adhesive 8 and the like can be degassed more quickly by evacuating the outside of the housing to a low vacuum. Next, the casing consisting of the main body 1 etc. is heated to room temperature to 150℃.
While cooling to a low temperature of about ℃, continue to exhaust the air.
For example, a paint 11 made of an appropriate organic material such as an epoxy resin is applied to the exposed outer surface of the inorganic adhesive 8 and its surroundings over a sufficiently wide area and as thickly as possible. FIG. 3 is an enlarged view of portions A, B, and C of FIG. 1 in this state. After carrying out the above treatment, a desired ionized gas is sent from the exhaust device through the exhaust pipe 7 to create an appropriate pressure inside the housing, and the exhaust pipe 7 is crushed and cut at a desired position.
Complete the proportional counter.

An example of the epoxy resin-based paint 11 is a paste-like modified epoxy resin, such as
It can be cured at 110°C for 90 minutes or at 150°C for 5 to 10 minutes, and has a heat resistance temperature of 180°C.

As described above with respect to the embodiments, the present invention uses an inorganic material adhesive 8 that can withstand high temperatures of 1000° C. or more, but does not have sufficient airtightness because it is essentially a porous material. The main body 1
The necessary parts such as the lid plates 3 and 4 and the window plate 10 are assembled to form a casing, and in this state, the casing is first connected to an exhaust system to evacuate the air, and at the same time, it is heated to a high temperature of several hundred degrees to perform degassing treatment. . Next, the above-mentioned housing is cooled to room temperature or a temperature close to this, and an organic material-based paint 11 having sufficient airtightness but a heat-resistant temperature of, for example, about 100-odd degrees Celsius or less is applied to the outer surface of the inorganic material-based adhesive 8. By coating the exposed parts, the airtightness is improved, the desired gas is injected, and the exhaust pipe is cut to complete a sealed radiation detector. As described above, the present invention can be easily assembled using an adhesive without requiring difficult operations such as welding, silver soldering, or soldering. Therefore, the manufacturing efficiency of the detector is significantly improved, and special equipment such as welding is not required. Moreover, it is possible to easily manufacture a detector having a complicated shape and structure. In addition, in the exhaust process, after heating to a high temperature to completely exhaust the occluded gas, a highly airtight organic paint is applied on top of the inorganic adhesive. There is no fear that the pressure or components of the ionized gas will change due to release of gas or intrusion of the atmosphere, and a long-life detector with stable characteristics can be obtained.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of a closed proportional counter manufactured by the method of the present invention, FIG. 2 is an enlarged view of each part of A, B, and C in the assembled state of the counter in FIG. FIG. 3 is an enlarged view of each part of A, B, and C of the counter tube shown in FIG. 1 when it is completed. In the figure, 1 is the main body, 2 is the radiation entrance window, 3 and 4 are the cover plates,
5 and 6 are hermetic seals, 7 is an exhaust pipe, 8 is an inorganic adhesive, 9 is a core wire, 10 is a window plate, 11
is an organic material-based paint.

Claims (1)

[Claims] 1 Assemble a metal airtight casing using an inorganic adhesive that can withstand high temperatures, stretch an anode core wire inside the casing, evacuate the casing, and heat it to several hundred degrees to discharge the occluded gas on the casing wall. Next, lower the heating temperature, apply a highly airtight organic material-based paint on the inorganic material-based adhesive, evacuate the inside of the housing to a high vacuum, fill it with the desired gas, and then open the exhaust port. A method for manufacturing a sealed radiation detector, characterized in that the radiation detector is sealed and separated from the exhaust device.