JPH03144395A - Method of manufacturing multi-channel ion chamber radiation detector - Google Patents

Abstract

PURPOSE:To make a simple and inexpensive production possible by processing electrode support grooves in one side of the insulating board formed in a specific size by integrating a plurality of small insulating plates to make an insulating boards of a specific size. CONSTITUTION:After small insulating plates 11' are connected to integrate, electrode support grooves are processed. In addition, the small insulating plates 11' are connected before the grooves are processed and the other grooves provided in the connected parts are also processed simultaneously. Accordingly, the error of the position and the direction of local and discontinuous grooves at the connected part produced in the case where they are processed by a conventional method do not occur. Furthermore, because the work for matching the position and the direction of the grooves 12 to connect them is needed, the error in the process does not occur. Accordingly, electrode plates can be arranged at regular pitches and a multi-channel ion chamber radiation detector of a uniform space resolution can be obtained.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for manufacturing a multi-channel connection μ ionization chamber radiation detector used in third generation O [Prior Art] A multi-channel ionization chamber type radiation detector (hereinafter referred to as a single radiation detector) is a metal or glass container filled with Xs gas having a large radiation absorption coefficient. A number of high voltage electrode plates and a number of transducer plates are held alternately.

In particular, in a radiation detector for a CT apparatus, the container and the insulating plate are formed in an arc shape, and the electrode plates are arranged in a fin-up manner toward the focal point of the X-ray tube between the opposing insulating plates.

Figures 5 and 6 are schematic diagrams showing the configuration of the genus ray detector, in which (1) is an insulating plate that supports the electrodes, and - in terms of radiation, it has an effective field of view sufficient to photograph the human body. to ensure about 8
It has an arc length of 000.

On each opposing surface of the insulating plate (1), a large number of electrode support grooves are cut radially at an equal angular pitch of a certain angle 9, for example 0.05, intersecting at one point (Xm focal point) about 1 m away, In this groove of a large number (for example, 1000 sheets) of ttiii
In the radiation detector with the above configuration in which the plate (2) is inserted and fixed, each electric wire must be insulated from each other with a resistance of about 1014Ω or more, and the pitch between adjacent electric wires must be It is also narrow, about Q, 5 m - 1,5 m. Electricity must be firmly fixed to prevent it from being vibrated and deformed by external forces, so ceramics or glass with superior insulation, rigidity, and precision machinability are used as insulating plates to support electricity. Materials such as and engineering differential snacks are used.

On the other hand, the detector of an X-ray CT device is made long enough to ensure a sufficient field of view for tomography of the human body.

It is necessary to continuously arrange the above-mentioned electric tower sheet metal in a length of about 800H, and the insulating plate that holds it has a similar long arc shape. However, it is technically and economically difficult to manufacture the above-mentioned materials such as ceramics into the length 1 having sufficient characteristics to be used as an insulating plate.

Therefore, a detector unit (3) in which an electrode plate is attached between a pair of small insulating plates having an arc length e that have been cut at is installed, and these detector units (3) are joined together as shown in Figure 1. Thus, a long arc-shaped radiation S having a predetermined arc length Li was obtained.

[The invention attempts to solve the problem. 1!1 Problem] This kind of radiation S
In the detector, tW is held by inserting it into a groove in the insulating plate, so the error in the IR processing position is zero compared to the error in the arrangement of electric values!
Connect.

The electrode support grooves on the insulating plate are generally machined using a processing machine such as a diamond saw or a tweezersaw, but the position where the grooves are machined depends on mechanical play and deflection of the processing machine, changes in ambient air temperature in the installation environment, and processing heat. 9. Due to thermal expansion of the processing machine and workpiece due to reaction heat, etc., there is a slight deviation from the design value.

Therefore, in the conventional method, a detector unit is formed by supporting an electric element between a pair of small insulating plates, and several to ten units are connected to form a radiation detection gg of a predetermined size.
The machining accuracy varies slightly for each small insulating plate that forms each detection unit, and when these are finally connected, especially at the connecting part.

A large error exceeding the allowable error occurs in the position of the groove produced for each of the above-mentioned small insulating plates.

As a detector for X-ray CT, the detection center /I/(signal wt, air gap between opposing high voltage electrodes sandwiching FIjAt) tl needs to be provided continuously even in the connecting part of the small insulating plate. The detection cell in particular has characteristics that are significantly different from other parts, and ring artifacts are likely to occur.

The positions and directions of the grooves on the small insulating plates that have been individually grooved have their own specific deviations from the design values. If you try to match the pitch of the grooves on the connecting part, the #l direction will no longer intersect at one point.

Alternatively, if they are made to intersect at the tW1 point, the pitches will no longer match.

The work of connecting several of these small insulating plates by matching the positions and directions of the grooves as well as their external shapes is a time-consuming and difficult work.

It was a cabinet. Even if grooves are precisely machined in the small insulating plate of each detector unit according to the design value, and the electrode plates are arranged at equal pitches, when connecting each detector unit, each unit metal is placed in the best arrangement and position. It may not always be possible to arrange them, and there is a risk that they may be arranged or connected in the wrong position, causing even larger errors.

This invention was made in order to solve the problems of the conventional method. Electrodes can be arranged at equal pitches, especially at the joints of small connecting plates, and can be used for multichannel without variations in spatial resolution. An object of the present invention is to provide an ionization chamber type radiation detection at-a manufacturing method that can be easily manufactured.

[Means for solving Section M]

The method of manufacturing a multi-channel ionization chamber radiation detector according to the present invention involves connecting and integrating a plurality of small insulating plates to form an insulating substrate of a predetermined size, and then processing a metal support groove on one side of the insulating plate. It is characterized in that the electrode plates are successively fitted and supported in the grooves of the insulating plate which have been grooved in the ninth order.

[Effect]

After the small insulating plates are connected and integrated, the electrode support grooves are machined.

Among the causes of errors in groove machining, most of them do not change in the short time it takes to process a single groove, but rather change slowly over a long period of time while machining a large number of grooves. . The small insulating plates are already connected together before the grooves are formed, and the grooves provided in the connected parts are also formed at the same time. Therefore, errors in the position and direction of local and discontinuous grooves applied to the connecting portion, which occur when processing using conventional methods, do not occur.

Furthermore, since there is no need to align the grooves and connect them, errors do not occur in this process.

Therefore, the electrical plates can be arranged at equal pitches, and a multichannel ionization chamber radiation detector with uniform spatial resolution can be obtained.

〔Example〕

Embodiments of the present invention will be explained below with reference to the drawings.

Figures 1 to 3 show the insulating substrate of the radiation detector of the present invention! 〇 Figure 1 is a perspective view of the entire manufacturing process. The small insulating plate (lit') that constitutes a conventional detector unit is generally machined into an arc shape with a large diameter (for example, 1 m radius) and has a length of 1 arc and a width of 11. For example, it is a ceramic plate with W and thickness -.

As a first step, the small insulating plates α' are assembled by connecting and fixing the end faces of a plurality of pieces (three pieces in the drawing) according to a predetermined arc length (size), and fixing the insulating substrate (Ill to f'!).
There is. FIG. 2 shows the insulating substrate Qll created in this ts1 step.

The method of fixing each small insulating plate a1)' is to connect the end faces of each small insulating plate to be joined with adhesive or the like, or to use a metal plate such as stainless steel as a base and glue, braze, or screw it. - A plurality of grooves Q2 for supporting the power supply board are cut on one surface of the insulating substrate αD created in the first step. (Second step) Grooves may be formed by cutting the small insulating plate by dicing, or by etching using a photomask, or by adding another insulator onto the small insulating plate. Good too.

Figure 3 shows the insulating substrates a made in the @2 process.As the next process, the two insulating clothing boards made in the @2 process are placed so that the groove surfaces face each other w['V'2E,
- Place the small insulating plates facing parallel to each other at a distance corresponding to the length of the sides, and insert the IHf'i into the opposing grooves of the pair and hold them one after another. (Third step) The end face of (2) was cut in the same radial direction as the groove, but as described in JP-A-57-203982, a small insulating plate with the end face cut diagonally across the groove was used. Good too.

FIG. 4 shows an insulating substrate αl1t- in which the small insulating plates a11' thus formed are connected and fixed together, and grooves are cut out.

In addition, in the embodiment, a small insulating plate having a circular arc shape was prepared.

Several small insulating plates were connected together to form an arc-shaped insulating substrate with a predetermined arc length, but several small insulating plates were connected and integrated into one loincloth, and then processed into an arc shape or by cutting a groove. It may be processed into a predetermined shape and size, such as a nine-arc shape. moreover,
In the embodiment, the insulating substrate is formed into an arc shape, but it can also be formed into a rectangular shape and machined with grooves parallel to each other on the - plane, or radial lWt cutting that converges to the - point. good.

Furthermore, when connecting multiple small insulating sheet metal pedestals, especially with screws, it is necessary to release the fixed small insulating plates after the groove processing in the second step. Disassemble it into small insulating plates, make a detector unit by holding two power supply plates facing the grooved wheel insulating plates 1 of HA,
A detector unit may be constructed by connecting a plurality of these detector units and fixing them on a pedestal. [Effects] According to the present invention, the positional accuracy of the grooves is improved, and the pitch between adjacent electrode plates and their directional accuracy are improved. A highly sensitive, uniform, and highly accurate multichannel ionization chamber radiation detector can be easily and inexpensively manufactured.

Furthermore, if the multi-channel ionization chamber type radiation detector manufactured according to the present invention is used in an X1iCT device.

A high-quality reconstructed image without ring artifacts can be obtained.

[Brief explanation of the drawing]

1 to ts3 are perspective views showing a schematic configuration of a single-fold example of the present invention, and FIG. 6 is a partially enlarged view of FIG. 5.

Claims (1)

[Claims] (1) In a radiation detector in which a plurality of electrode plates are attached to a pair of parallel insulating plates, a process of connecting and integrating a plurality of small insulating plates to create an insulating substrate, and A method for manufacturing a multi-channel ionization box radiation detector, comprising the steps of forming a groove for supporting the electrode plate, and sequentially inserting the ends of the electrode plate into the groove and mounting the electrode plate on an insulating substrate.