JPH0589821A - Ionization chamber and its manufacture - Google Patents

Abstract

PURPOSE:To facilitate manufacture and construct in small and thin form by affixing a charge collecting electrode to a spacer, performing sealing, affixing an oversurface plate to it, and affixing it to an undersurface plate in a sensing gas atmosphere inside a chamber. CONSTITUTION:A spacer 36 and a charge collecting electrode 30 are affixed together, and to the resultant an oversurface plate 24 is affixed. An electric insulative resin is poured into an opening 36a, which is sealed. The bonded object is placed in a chamber, and at the same time, an adhesive is applied to an undersurface plate 26 followed by placing of the resultant in the chamber. The sensing gas is introduced into the chamber, and the inside is set to a specified pressure. An elevating mechanism 50 is operated, and the undersurface plate 26 is coupled with the bonded object, and the adhesive is solidified while the obtained condition is held for a certain period of time. An ionization chamber thus formed is taken out of the chamber, and an electroconductive resin is applied to the side face and left for solidifying.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ionization chamber for detecting radiation by the ionization action of gas and a method for manufacturing the same.

[0002]

2. Description of the Related Art An ionization chamber is known as a radiation detector. This ionization chamber is used, for example, as a pocket dosimeter for radiation exposure management.

FIG. 7 shows a conventional general ionization chamber. In FIG. 7, a disk-shaped upper plate 14 also made of a metal member is joined to the electrode container 12 made of a cylindrical metal member by, for example, welding. An opening is formed in the center of the upper surface plate 14, and a spacer 16 holding the charge collecting electrode 18 and having an insulating function is inserted and arranged in the opening.

The electrode container 12 formed as described above is filled with the detection gas 100 from the outside. Specifically, the detection gas 100 is introduced into the electrode container 12 through the gas introduction tube 20 formed to project from the container 12, and when the detection gas is filled to a predetermined pressure, the tube 20 is filled with the detection gas 100, for example. Sealing is performed by crushing.

In such an ionization chamber, a high DC voltage V is applied between the charge collecting electrode 18 and the electrode container 12. Therefore, when the radiation enters from the outside, the detection gas 100 is ionized by the energy of the radiation, and the charged particles are collected on the charge collecting electrode 18 by the electric field action by the high voltage. Therefore, the charge collected in this way,
That is, the radiation can be detected as a result by measuring the current.

[0006]

However, the above-mentioned conventional ionization chamber has a problem that it is difficult to make it compact and thin. That is, since the shape of the ionization chamber is cylindrical, when applied to, for example, a pocket dosimeter,
It was difficult to reduce the thickness of the pocket dosimeter.
Therefore, since such a dosimeter is bulky, there is a large restriction on the mounting place on the clothes.

Further, in the conventional method for manufacturing an ionization chamber, it is necessary to connect a gas introduction pipe to the tube 20 for each ionization chamber to carry out gas filling, which is an obstacle to simplifying the manufacturing process. .. In addition, the electrode container is sealed by the tube 2
Although it was carried out by crushing 0, the process was complicated and there was a problem that the residual tube left in the ionization chamber after completion was an obstacle.

The present invention has been made in view of the above conventional problems, and an object of the present invention is to reduce the size and thickness of an ionization chamber.

Another object of the present invention is to provide a simple method for manufacturing an ionization chamber suitable for mass production.

[0010]

In order to achieve the above object, the present invention comprises an upper surface plate and a lower surface plate made of a flat metal member, and a metal material connecting the outer peripheral edges of the upper surface plate and the lower surface plate. A side peripheral wall, a top plate, the bottom plate, and a flat plate-shaped charge collecting portion arranged in parallel with the surfaces of the top plate and the bottom plate in an electrode container composed of the side walls. And a terminal portion connected to the charge collecting portion and protruding from a part of the side peripheral wall, a spacer arranged in the electrode container for insulatingly holding the charge collecting electrode, and the electrode container And a detection gas enclosed therein.

Further, the present invention relates to a container forming an outer periphery of an ionization chamber, which is an electrode container composed of at least two element members, and a collector which is disposed in the electrode container and has one end protruding to the outside as a terminal portion. At least one element in a method for producing an ionization chamber, which includes a charge electrode and a spacer arranged in the electrode container to insulate and hold the collection electrode, and in which a predetermined detection gas is sealed in the electrode container. After disposing the spacer and the charge collecting electrode on the member, the element member and another element member are hermetically bonded in the predetermined detection gas atmosphere.

[0012]

According to the invention described in claim 1, the entire ionization chamber is formed in a flat plate shape, and the thickness thereof can be remarkably reduced as compared with the conventional case. Therefore, there is an advantage that, for example, a pocket dosimeter, which is not bulky even if it is put in a pocket or the like, can be configured.

According to the second aspect of the present invention, the joining of the specific element member forming the electrode container and the other element member and the encapsulation of the detection gas into the electrode container are performed simultaneously. Therefore, it is possible to reduce the number of steps as compared with the related art. In addition, since the production can be performed without connecting a gas introduction pipe or the like to the ionization chamber itself, it is possible to easily manufacture a plurality of ionization chambers collectively, which is advantageous in mass production.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the appearance of the ionization chamber according to the present invention. As shown, this ionization chamber has a flat plate shape as a whole. First, each member will be described with reference to FIG.

The electrode container 22 connects the upper surface ground electrode (hereinafter referred to as the upper surface plate) 24, the lower surface ground electrode (hereinafter referred to as the lower surface plate) 26 facing the upper surface plate 24, and the outer peripheral edges of both of them. And a side surface ground electrode (hereinafter, referred to as a side peripheral wall) 28. The upper plate 24 and the lower plate 26 are made of metal members, and in this embodiment, they are made of stainless steel. Further, the side peripheral wall 28 is made of a solidified conductive resin.

Inside the electrode container 22, a charge collecting electrode 30 is provided.
Are arranged. Specifically, this charge collecting electrode is composed of a charge collecting portion 32 existing in the electrode container 22 and a terminal portion 34 connected to this charge collecting portion. Here, the terminal portion 34 projects to the outside.

The collector electrode 30 is made of a metal member, and in this embodiment, it is made of stainless steel, copper, or the like. This charge collecting electrode 30 is formed in a flat plate shape in the present embodiment, and the surface thereof is the upper plate 24 and the lower plate 2.
It is parallel to 6. A spacer 36 is arranged inside the electrode container 22 to insulate and hold the charge collection electrode 30. The spacer 36 is made of an insulating material such as alumina or ceramic, and forms a side peripheral frame of the electrode container.

As is apparent from FIGS. 1 and 2, the spacer 36 has an opening 36a through which the terminal portion 34 of the charge collecting electrode is projected. And that opening 3
A sealing member 38 for sealing the inside of the electrode container 22 is arranged inside 6a. The sealing member 38 is made of an insulating material, and is formed by pouring an insulating resin into the opening 36a, for example.

A detection gas for detecting radiation is enclosed in the ionization chamber constructed as described above, and in this embodiment, it is enclosed at, for example, 7 atmospheres. This is to increase the detection sensitivity. For reference, the size of the ionization chamber is 15 mm in length, 10 mm in width, and 4 mm in thickness. As described above, the side peripheral wall 28 is
It is formed by coating a conductive resin on the side peripheral surface of the spacer 36 and further solidifying it. Of course, a metal frame may be used as the side peripheral wall 28. However, by using a conductive resin or the like as described above, the upper plate 24 and the lower plate 26 can be electrically joined to each other without special joining, and the manufacturing process can be simplified. is there.

Next, a method of manufacturing this ionization chamber will be described.

First, the spacer 36 and the charge collection electrode 30 are attached to each other with, for example, an adhesive.

Next, with respect to the bonded members,
Further, the upper surface plate 24 is bonded in the air with an adhesive or the like.

After that, an insulating resin is poured into the opening 36a to form a sealing member, that is, the opening 36a is sealed. If the adhesive or the like used in the above step simultaneously functions as a sealing member, that is, if the excess adhesive seals the opening 36a, this step is omitted. After each of the above steps, the bonded product bonded in each of the above steps is put into the chamber, and at the same time, the adhesive is applied to the lower surface plate 26 and put into the chamber. FIG. 3 shows the concept of the chamber. The chamber 40 is in an airtight state, and a gas supplier 42 is connected to the chamber 40. A mounting table 44 and a descending table 46 are provided inside the chamber 40, and the descending table 46 is supported by an elevating mechanism 50.

The above-mentioned combined object is placed on the mounting table 44, while the lower plate 26 is held on the elevating table 46.
Specifically, the lower surface plate 26 is held by a holder (not shown) provided on the lift table 46. At this time, the two are accurately aligned. Next, chamber 4
The inside of 0 is evacuated to evacuate the adhesive. Then, the detection gas is introduced into the chamber, and the inside thereof is brought to a predetermined pressure (for example, 7 atm).

In this state, the elevating mechanism 50 is operated to join the lower surface plate 26 to the above-mentioned combined object. Then, the state is maintained for a predetermined time (for example, 12 hours), and the adhesive is completely solidified.

After a lapse of a predetermined time, the ionization chamber formed as described above is taken out of the chamber, a side face thereof is coated with a conductive resin, and the resin is solidified. The ionization chamber thus formed is shown in FIG.

Therefore, according to the above manufacturing process,
The detection gas can be enclosed and the members can be joined at the same time, the number of steps can be reduced, and the manufacturing cost can be reduced. In addition, 40 in the chamber
The detection gas introduced in the above can be reused, and according to this, the expensive detection gas can be used without waste.

Here, it has been proved by the experiments of the present inventors that the joining with the adhesive can sufficiently withstand the pressure of the enclosed gas. An epoxy adhesive is used in this embodiment.

Next, a method of manufacturing a plurality of ionization chambers will be described. FIG. 4 shows an upper surface plate array 60 in which a plurality of upper surface plates 24 are connected. Further, FIG. 5 shows a charge collection electrode array 62 in which a plurality of charge collection electrodes 30 are connected, and FIG. 6 shows a spacer array 64 in which a plurality of spacers 36 are connected. The bottom plate array (not shown) has the same shape as the top plate array 60.

Such an array structure is formed by a corrosive method using an exposure technique or machining. In this embodiment, the corrosion method of processing by etching is used, and a large number of members can be simultaneously formed in a series of etching steps.

The simultaneous production of a plurality of ionization chambers will be specifically described.

First, the spacer array 64 and the collecting charge electrode array 62 are bonded to each other, while the top plate array 60 is joined thereto.
Are joined.

In this state, the above-described sealing (arrangement of the sealing member 38) is performed, and the spacer array is cut into individual elements. In this state, the collector electrode array 62, the upper plate array 60, or both are not individually separated but are integrally combined. Then, it is placed in the chamber and the above-mentioned gas filling and bonding of the lower surface plate array are performed.

Then, the ionization chamber array, which is a connected body of the ionization chambers formed as described above, is taken out from the chamber,
Each ionization chamber is separated into individual units, and the above-mentioned conductive resin is coated on the side peripheral surface of each ionization chamber.

Therefore, according to the above manufacturing method,
Since a large number of ionization chambers can be formed simultaneously in a series of steps, the manufacturing cost can be remarkably reduced and the accuracy can be made uniform. Note that FIG.
And as shown in FIG. 6, a top plate (bottom plate) array 6
0 and the spacer array 64 include a protrusion 66 for positioning.
By forming a and the recess 66b, it is possible to prevent the positional displacement between the two members at the time of bonding.

[0037]

As described above, according to the present invention,
It is possible to provide a small and thin ionization chamber, and there is an advantage that the pocket dosimeter can be made thin when applied to, for example, a pocket dosimeter.

Further, according to the manufacturing method of the present invention, since the detection gas can be enclosed and the members can be bonded at the same time,
The manufacturing process can be simplified and the manufacturing cost can be reduced. Further, according to the present invention, it is possible to easily manufacture a large number of ionization chambers at the same time, and it is possible to provide a manufacturing method suitable for mass production.

[Brief description of drawings]

FIG. 1 is an external view showing the external appearance of an ionization chamber.

FIG. 2 is a partially cutaway sectional view showing a configuration of an ionization chamber.

FIG. 3 is a conceptual diagram showing a configuration of a chamber.

FIG. 4 is a plan view showing the structure of a top plate (bottom plate) array.

FIG. 5 is a plan view showing the structure of a charge collection electrode array.

FIG. 6 is a plan view showing the structure of a spacer array.

FIG. 7 is an exploded perspective view showing a configuration of a conventional ionization chamber.

[Explanation of symbols]

 24 upper surface plate 26 lower surface plate 28 side peripheral wall (conductive resin coating) 30 current collecting electrode 36 spacer 40 chamber

Claims (2)

[Claims] 1. An upper surface plate and a lower surface plate made of a flat metal member, a side peripheral wall made of a metal material connecting outer peripheral edges of the upper surface plate and the lower surface plate, the upper surface plate, the lower surface plate and the side periphery. A flat plate-shaped charge collecting portion arranged in parallel with the surfaces of the upper surface plate and the lower surface plate in an electrode container formed of a wall, and connected to the charge collecting portion and protruding from a part of the side peripheral wall. An ionization chamber comprising: a charge collecting electrode composed of a terminal portion; a spacer arranged in the electrode container for insulating and holding the charge collecting electrode; and a detection gas sealed in the electrode container. .. 2. A container forming an outer periphery of an ionization chamber, comprising an electrode container composed of at least two element members, a charge collecting electrode disposed in the electrode container and having one end protruding to the outside as a terminal portion. A spacer arranged in the electrode container and insulatingly holding the collecting electrode; and a spacer for at least one element member in the method of manufacturing an ionization chamber, wherein a predetermined detection gas is sealed in the electrode container. And a method for manufacturing an ionization chamber, characterized in that, after disposing the charge collecting electrode, the element member and another element member are hermetically bonded in the predetermined detection gas atmosphere.