JPH08101277A - Ionization chamber type x-ray detector - Google Patents

Abstract

PURPOSE: To obtain an ionization chamber type X-ray detector for measuring X-rays accurately using a both-sided electrode plate in which the workability is enhanced when a signal is taken out from the both-sided electrode. CONSTITUTION: High voltage electrodes 2A and signal electrodes 2B are arranged alternately in a detector case 8. Xenon gas is ionized by incident X-rays to produce an electric signal and a multilayer both-sided signal electrode plate, comprising a central metal plate of molybdenum applied with an insulation layer on the opposite sides thereof and electrode planes are formed thereon, is employed as a signal electrode 2B. A signal take-out terminal 3 is formed at the upper end of the both-sided signal electrode plate 2B while avoiding the X-ray path. The terminal 3 is inserted into an H-shaped inserting part 56 formed at a part of a flexible board 5 on which a U-shaped conductive metal pattern 52 is formed and then the terminal is secured in place by soldering. Under a state where the terminal part 3 is inserted into the inserting part 56, the flexible board 5 clamps the terminal part resiliently from the opposite sides and secures the terminal part in place while inclining, thus ensuring a sufficient soldering area.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ionization box type X-ray detector effective for an X-ray CT apparatus which requires a highly accurate X-ray detection ability, and more particularly to an ionization box using a double-sided signal electrode plate. The present invention relates to an improvement in the connection structure of terminals of a type X-ray detector.

[0002]

2. Description of the Related Art In an X-ray CT apparatus, the incident X
As a detector for detecting lines with high accuracy,
A so-called ionization chamber type X-ray detector is used. The structure of the ionization box type X-ray detector for such an X cotton CT apparatus is, for example, as shown in Japanese Patent Publication No. 58-3350.
A signal output terminal was provided on the side opposite to the line incident direction, and lead wires were wound around the signal output terminal sections between this terminal and the connector terminal of the printed circuit board for extracting the detection signal to the outside of the detector. After that, it was general that they were connected by soldering work.

Further, in order to improve the space utilization efficiency and to realize a highly accurate X-ray detecting ability, which was a defect in the conventional detector using the electrode plate made of a single metal plate, a metal plate such as molybdenum is used. The ionization chamber type X-ray detector adopting a double-sided signal electrode plate having a so-called five-layer structure in which an insulating layer is arranged on both sides of the electrode, and a surface electrode layer made of a metal layer is sequentially formed on the insulating layer. Is, for example, JP-A-58-l
It is already known from Japanese Patent No. 66282.

[0004]

In the above-mentioned prior art, there is a problem in the connection work of the signal takeout terminals, especially in the case where such a double-sided signal electrode plate is adopted. That is, in such a double-sided signal electrode plate, due to its multi-layer structure (five-layer structure), even in the part of the electrode plate forming the signal extraction terminal, both surfaces are connected to different surface electrode layers, so that separate signal extraction is performed. Since the surfaces are independent, the connection processing by winding the lead wire as described above cannot be performed. Therefore, when soldering lead wires, etc., the soldering iron is applied from both right and left sides while fixing the wire material to each surface, which greatly deteriorates the terminal connection work by soldering. There is a problem that it ends up. From this, for example, use a flexible board with a rectangular hole that matches the cross-sectional shape of the signal output terminal, insert the signal output terminal part of the double-sided signal electrode plate into this hole, and then perform the soldering work for double-sided signal output. Is considered to do.

However, in such a signal extraction connection structure, even if the signal extraction terminal of the double-sided signal electrode plate is inserted into the terminal insertion hole formed in the flexible substrate, the electrode surface to be fixed by soldering and the flexible substrate surface are perpendicular to each other. Becomes
Alternatively, depending on the dimensional accuracy of the insertion hole, these may be separated from each other, making it impossible to secure a sufficient solder bonding area for soldering the two together. It is necessary to firmly fix the flexible substrate to the surface of the signal extraction terminal of the double-sided signal electrode plate even during the soldering work until it is fixed. This is not easy to work with, and the reliability of the soldering work is low. There was a problem. Further, in order to ensure high detection accuracy of the detector, the solder connection work between the signal takeout terminal of the double-sided signal electrode plate and the flexible board has a bad influence on the electric field in the channel formed by the high voltage electrode. Must be considered so as not to affect.

Further, in the above-mentioned prior art, particularly in the case of employing a double-sided signal electrode plate having a multilayer structure, it is necessary to ground the central metal plate for high precision X-ray detection. Also in this case, since the insulating layer and the metal layer are further laminated on both sides of the central metal plate, a connection structure for surely grounding them is required.

Therefore, in the present invention, in view of the above problems in the prior art, a signal suitable for a detector capable of detecting incident X-rays with high accuracy by using a double-sided signal electrode plate composed of a multilayer electrode plate. It is an object of the present invention to provide an ionization chamber type X-ray detector having an improved structure for connecting terminals.

[0008]

In order to achieve the above object, according to the present invention, high voltage electrodes and signal electrodes are alternately arranged, and the signal electrodes are applied to the signal electrodes by ionizing action of gas around the electrodes by incident X-rays. An ionization box type X-ray detector for obtaining an electric signal, wherein the signal electrodes are provided on both sides of a conductive metal plate.
At least, consisting of a double-sided signal electrode plate of a multilayer structure in which an insulating layer and a metal layer forming an electrode surface on the insulating layer are formed,
Furthermore, by using a flexible substrate having an insertion portion formed in part and an electrode pattern formed on the surface thereof, different electrode surfaces formed on both side surfaces of the signal extraction terminal portion formed on a part of the double-sided signal electrode plate can be formed. In the ionization box type X-ray detector which is electrically taken out and connected to the outside, the insertion part formed in a part of the flexible substrate is a signal extraction terminal part of the double-sided signal electrode plate of the double-sided signal electrode plate. Ionization box type X-ray detection formed in such a shape that the signal take-out terminal portion is sandwiched by its elasticity from the both side surfaces in the inserted state and is in contact with both the side surfaces of the signal take-out terminal portion while being inclined. Vessels are suggested.

As one embodiment of the present invention, a double-sided signal electrode plate having a multi-layer structure adopted in the ionization chamber type X-ray detector according to the present invention, wherein both side surfaces of the central metal plate are In addition to the region for forming the electrode surface, a center metal plate grounding region for grounding the center metal plate is provided at the upper and lower ends thereof.

[0010]

That is, in the ionization box type X-ray detector according to the present invention, when performing the connecting work for taking out the signal electrode plates formed on both surfaces of the multi-layered double-sided signal electrode plate to the outside, In a state in which the signal extraction terminal portion of the double-sided signal electrode plate is inserted into the insertion portion formed in a part of the flexible substrate, the insertion portion sandwiches the signal extraction terminal portion from its both side surfaces due to its elasticity, and Since it comes in contact with both side surfaces while inclining, the contact and fixation between them can be surely maintained, and the area for solder connection between them can be sufficiently secured. The work efficiency of the soldering work for connecting the electrodes, which is necessary for assembling, is significantly improved. At the same time, according to the connection structure as described above, the solder connection portion also has a fixed shape, and a part of the solder connection portion is formed to project due to the soldering work, and the solder connection portion is formed by the high voltage electrode. It is also possible to surely prevent the influence of the electric field in the channel in question, which adversely affects the detection performance of the device.

Further, according to the ionization chamber type X-ray detector adopting the double-sided signal electrode plate according to the embodiment of the present invention,
By making a solder connection for grounding using the central metal plate ground area, the solder connection work also becomes easier,
The central metal plate of the double-sided signal electrode plate can be reliably grounded, and the connection structure for grounding ensures the detection accuracy of the detection device without adversely affecting the electric field in the channel from that position. Can be improved.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of one embodiment according to the present invention will be described below with reference to the accompanying drawings. First, referring to the attached FIG. 4, an X-ray CT in which the present invention is adopted.
The ionization chamber type X-ray detector for the apparatus and its electrode block structure will be described. FIG. 4A shows a plurality (3 in this embodiment).
1) electrode blocks are connected and arranged inside the case of the detector. These electrode blocks are held by a pair of substantially fan-shaped insulating plates 1A and 1B which are arranged in parallel vertically facing each other. The insulating plates 1A and 1B are made of an insulating material such as a ceramic material, and a plurality of grooves are formed on the opposing surfaces thereof, though not clearly shown in these figures. A plurality of electrode plates, that is, the high voltage electrode plate 2A and the signal electrode plate 2B are inserted between the insulating plates 1A and 1B while being inserted into the groove.
Are alternately arranged substantially parallel to the direction of an X-ray tube (not shown) which is an X-ray generation source (so-called focal point position), and are further fixed to each other with an adhesive.

As shown in the sectional view of FIG. 4 (b), a plurality of electrode blocks having such a structure are provided inside the detector case 4 in which an ionized gas such as xenon gas is sealed. It is located in. Of these electrode plates 2A and 2B, one high voltage electrode plate 2A is made of one conductive metal plate, and the other signal electrode plate 2B is
It consists of a so-called double-sided signal electrode plate that can be electrically insulated on the front and back sides and assigned to different channels.

In such an ionization chamber type X-ray detector, a high voltage bias is applied to the high voltage electrode plate 2A,
On the other hand, the signal electrode plate 2B has a role of collecting electrons ionized by the X-rays incident on the channel. That is, when X-rays are incident on the inter-electrode gap (channel), the incident X-rays ionize the xenon gas in the detector case 4, and are separated into positive ions and negative ions, so that the high voltage of the high voltage electrode plate 2A is high. Depending on the polarity of the signal, either one of the ions moves to the signal electrode surface 2B, and the generated electrons are collected in the double-sided signal electrode 2B, so that the current signal is detected.

By adopting the above-mentioned double-sided signal electrode plate 2B in such an ionization chamber type X-ray detector, only one electrode plate can fit in one channel width. Therefore, as compared with the conventional structure of a detector that uses a signal electrode plate made of a single metal plate, its space utilization efficiency is improved and highly accurate X-ray detection becomes possible. As will be described later in detail, the double-sided signal electrode plate 2B is usually made of a metal having a high X-ray absorption coefficient as the material of the center electrode plate thereof and having a plate thickness that sufficiently reduces crosstalk due to the X-rays. It is used, and an insulating layer is laminated on both side surfaces thereof, and a metal electrode layer is further laminated on the surface thereof to form a so-called five-layer structure.

The double-sided signal electrode 2B is also formed by the above principle.
The signal detected by the X-ray detector is a part of the multi-sided double-sided signal electrode plate, specifically, the X-ray in the ionization chamber X-ray detector.
In order to avoid the line passage, a signal take-out line 5 composed of a flexible substrate is connected to the signal take-out terminal 3 formed on the insulating plate 1A side (upper side) and projecting to the side opposite to the X-ray incident side. Through the detector motherboard 6
It is connected to the electrode pattern formed above, is drawn out of the detector case 4 from this electrode pattern, and is further electrically connected to each channel terminal of the connector 7 of the detector. In addition, from the high voltage electrode plate 2A, the insulating plate 1B
The connection terminal 4 is formed on the side (lower side) and on the side opposite to the X-ray incident side. In these figures, reference numeral 8 is a double-sided signal electrode grounding line for grounding the center electrode plate of the double-sided signal electrode 2B, and reference numeral 9 is
The high voltage signal connection lines connected to them for supplying high voltage high voltage signals to the high voltage electrode plate 2A are shown.

Next, FIG. 5 shows the double-sided signal electrode plate 2 described above.
The detailed structure of B is shown. 5A shows the shape of one side of the double-sided signal electrode plate 2B, and FIG. 5B shows the AA cross section in FIG. 6A. First, FIG.
The structure of the double-sided signal electrode plate 2B in the thickness direction will be described with reference to the cross-sectional view of (b). The double-sided signal electrode plate 2B has a central conductive metal plate such as molybdenum or tungsten having a high X-ray absorption coefficient at its center. Insulating layers 22 and 22 made of polyimide, for example, are formed on both surfaces of the insulating layer 21 and conductive metal electrode layers 23 and 23 made of copper foil or the like are formed on the outer surfaces thereof.
Is a double-sided signal electrode plate having a so-called multi-layer structure, which is formed by stacking 5 layers in total. These layers are firmly connected by a very thin adhesive layer or heat fusion treatment such as high-pressure and high-temperature treatment, thus constituting one electrode plate. Therefore, the insulating layer 22 allows the electrode layers 23,
Are completely insulated, and each of them functions as a signal electrode element by extracting a signal from each surface to the outside by a signal extraction connection structure independent of each other. Further, the double-sided signal electrode 2B has the insulating plates 1A, 1B as is apparent from FIG. 4 (a) or FIG. 4 (b).
Since it is fixed on top with an insulating adhesive, it is electrically unstable and extremely unstable. for that reason,
Actually, it is necessary to keep the potential of the molybdenum plate, which is the central electrode plate 21, at zero through the ground line.

Next, the shape of the central electrode plate 21 of the double-sided signal electrode plate 2B and the pattern shape of the electrode layer 23 on the surface will be described with reference to FIG. As described above, as the shape of the electrode 2B, X-rays are incident from the left side in the drawing, and the vertical end portions thereof are fixed to the insulating plates 1A and 1B. Therefore, the electrode signal extraction terminal 3
Is formed so as to project to the side opposite to the X-ray incident side (that is, the back side as a detector) for the purpose of ensuring the connection workability. Further, in order to avoid the X-ray passage, an insulating plate is used in this example. It is formed at the upper end near 1A.

The center electrode plate 2 of the double-sided signal electrode plate 2B is also used.
The insulating layers 22 formed on both side faces of the first electrode 1 are formed to have the same size up to the end portions so as to cover the entire side faces of the center electrode plate 21. Further, the pattern of the electrode layer 23 formed on the surface of the insulating layer 22 is the same as that of the central metal plate 21.
The insulating band is formed with a certain distance from the outer peripheral edge of the electrode layer 23. That is, by forming the insulating band into a shape slightly smaller than the central metal plate 21, the electrode layers 23 formed on both sides,
23 is able to ensure the insulation. In FIG. 5A, this insulating band is indicated by reference numeral 25.
Further, in this figure, narrow conductive layers (guard electrodes) 26, 26 are formed at the upper and lower ends of the double-sided signal electrode plate 2B, but one (upper) conductive layer 26 is used for centering. The structure for grounding the metal plate 21 will be described in detail later.

FIG. 6 is an enlarged view of the signal extraction terminal 3 of the double-sided signal electrode plate 2B. In this figure, the shape indicated by the thick line L indicates the outer peripheral shape of the center electrode plate 21, the electrode layer 23 which is the outermost metal foil layer is deleted along the outer circumference, and the inner insulating layer 22 is exposed. The exposed insulating band 25 is indicated by the shaded area. As shown in this figure, the place where the electrode layer area on the right side of the signal extraction terminal 3 is large is a portion which is inserted into a flexible substrate for signal extraction described later and is connected by soldering.

Further, a fixing projection 27 is formed at the signal extraction terminal 3 portion of the double-sided signal electrode plate 2B so as to prevent the flexible substrate from going further. Alternatively, as the shape of this portion, as shown in FIG. 7, the same action can be achieved by making the tip end portion narrow. Basically, the flexible substrate need only have a shape that does not go deeper, and the shape is not limited to the above-described embodiment as long as this shape is satisfied.

Further, in FIG. 6 and FIG. 7 described above, the shape indicated by the thick line L is a region surrounded by the outer peripheral shape of the center electrode plate 21 and the insulating band 25, that is, the upper side of the center electrode plate 21. A narrow layer 26 formed along the side is a ground region 26 provided to ground the molybdenum plate that is the center electrode plate 21 to the ground potential. Further, reference numeral 29 in these drawings, which will be described later, shows the center electrode plate 21.
Is a protrusion for soldering, which is used when is grounded by soldering.

Here, the reason why the ground region 28 and the center electrode plate 21 are electrically connected is understood by explaining the manufacturing process of the double-sided signal electrode plate 2B having the multi-layer structure described below. To be done. The double-sided signal electrode plate 2B having the five-layer structure is produced by applying the existing process for producing an electronic circuit board, and is usually replaced with a printed circuit board material such as a glass epoxy material used in the production of the electronic circuit board. It is created by using a metal plate such as molybdenum, which will be the center electrode plate 21. Therefore, the shape of the electrode layer 23 is
It is created by etching the existing printed circuit board. The outline process of the production is as follows. (1) A five-layer material having a size capable of taking out a plurality of electrodes is prepared. (2) The insulating band 25 of FIG. 5, that is, only the hatched area in FIGS. 6 and 7, is subjected to so-called misaligned etching treatment from both side surfaces of the material so as to correspond to each other. The electrode layer 23 of the metal foil is removed. (3) Finally, a press punching die that matches the outer peripheral shape of the center electrode plate 21 in FIGS. 6 and 7 is punched in accordance with the center position of the outer peripheral shape of the band-shaped region that has been subjected to the above etching treatment.

As described above, in the above-described manufacturing process, the electrode layer 23 is punched at a certain distance from the punched cross section, so that between the central metal plate 21 and the electrode layers on both side surfaces thereof, there is a space between them. Electrical insulation is maintained. However, as is clear from FIG. 5, FIG. 6 or FIG. 7, since the outer peripheral portions of the ground area 28 arranged at the upper and lower ends of the double-sided signal electrode plate 2B are not subjected to the above etching treatment, the material is press-molded. When punching with, the electrode layer 23 made of a very soft material (copper, aluminum, etc.) exceeds the insulating layer cross-sectional distance and is electrically connected to the central metal plate 22 in a state like a very thin foil film. Will be connected to. This is as if the cross section of the central metal plate had been copper-plated, so this part is also very good for soldering work.

As can be understood from the above description, in the double-sided signal electrode plate 2B used in the embodiment of the present invention, electrode surfaces (layers) as independent detection elements are formed on both side surfaces of the double-sided signal electrode board 2B. ) 23, a signal take-out terminal 3 for taking out the signal, and a ground region 28 electrically connected to the central metal plate, which makes it clear that the structure is divided into three regions.

Next, referring to FIG. 8, electrode surfaces (layers) 2 independently formed as detection elements on both side surfaces of the signal extraction terminal 3 of the double-sided signal electrode plate 2B described above.
A signal extraction flexible board for extracting the signals from 3 and 23 to the outside will be described.

FIG. 8A shows the shape of the signal extracting flexible substrate 5 in which a plurality of substrates are continuously formed in the lateral direction. Further, FIG. 8B shows the shape of the signal extracting flexible substrate 5 which is made of only one sheet. The flexible substrate 5 used here is a bendable structure in which a conductive metal pattern 52 such as copper or aluminum is provided on an insulating substrate 51 made of polyimide or the like which is used for connecting an ordinary electric circuit or the like. Basically, it is the same as other electrical parts. In this configuration, the signal extraction flexible substrate 5 has a minimum configuration of 2 channels, which is a unit of the electrode connection structure employing the above-mentioned double-sided signal electrode, and particularly, connection of signal extraction terminals in a detector having a structure of 500 channels or more. Considering the work, the signal extraction flexible substrate 5 having a structure of a plurality of sheets as shown in FIG. (A) is convenient, and the reference numeral 53 in this figure indicates
The cuts are formed in the upper and lower directions of the flexible board to allow the individual flexible boards to be aligned and to improve the solder workability. Further, the soldering terminals 54 of the signal extraction flexible substrate 5 shown on the upper side of these figures are formed in, for example, a rod shape, which is a detector motherboard 6 for sending out a detection electric signal from the inside of the detector case 8 to the outside. The shape is such that it can be directly inserted into the hole for soldering, and thus the structure is convenient for connection by soldering work.

The portion of the soldering terminal 54 of the signal extracting flexible substrate 5 is shown in FIG.
Alternatively, as shown in FIG. 10B, a shape in which an insulating substrate 51 such as polyimide is extended to the tip portion of the metal pattern 52 may be used. The tip portion 55 has an insulating film formed on the surface thereof so that the metal pattern 52 is exposed.

Further, FIG. 9 (a) shows an enlarged structure of the lower end portion of the signal extracting flexible substrate 5 as described above. As is apparent from the figure, this lower end portion is An insertion portion 56 for inserting and soldering the signal extraction terminal 3 of the double-sided signal electrode plate 2B is formed. That is, the insertion portion 56 is formed in the shape of "D" or "H" across the lower end of the metal pattern 52 formed in a substantially "U" shape on the insulating substrate 51 such as polyimide. It is a notch. In addition, B in FIG.
As is clear from the -B cross section, at the lower end portion of the insulating substrate 51 such as polyimide, the insulating film 5 formed on the surface of the insulating substrate 51 is formed.
7 is cut away, and its “U” -shaped metal pattern 5
2 is exposed. In addition, according to the embodiment of the present invention described above, the insertion portion 5 formed in a part of the flexible substrate.
The shape of 6 is specifically a notch (cut) formed in an “D” or “H” shape, however, the present invention is not limited to this, and the same effect as the above-mentioned insertion portion can be obtained. Other shapes may be used as long as the shape can be achieved.

The flexible board 5 for signal extraction described above.
By using each of the electrode surfaces 2 of the double-sided signal electrode plate 2B.
FIG. 2 attached herewith shows a connection structure of terminals for extracting signals from the signal extraction terminals 3 and 23 to the outside through the signal extraction terminal 3 and further grounding the central metal plate 22 thereof. As is clear from this figure, the signal extraction terminal 3 of the double-sided signal electrode plate 2B is inserted into the insertion portion 56 of the signal extraction flexible board 5 and then electrically connected and fixed by soldering. ing. In the figure, reference numeral 1
0 indicates a soldered portion.

As described above, the double-sided signal electrode plate 2 is
By inserting the signal extraction terminal 3 of B into the insertion portion 56 of the signal extraction flexible substrate 5, as shown in FIG.
As shown in FIG. 5, the flexible substrate 5 has its insertion portion 56 elastically sandwiching the signal output terminal 3 of the double-sided signal electrode plate 2B from both side surfaces thereof and contacting the both side surfaces while inclining. Becomes Therefore, the contact and fixation between them can be surely maintained, and the area for solder connection between them can be secured sufficiently, and the soldering work for electrode connection necessary for assembling the detector can be performed. Work efficiency will be greatly improved.

In the solder connection portion of the signal extraction flexible substrate 5, the conductive metal pattern 52 is bent in a U shape as described above, and the solder connection portion of this portion is formed. In the vicinity area, this metal pattern 5
Since the second surface is exposed, the solder workability is good. Further, in order to improve the workability of the soldering work, conductive metal patterns may be formed on both the front and back surfaces of the flexible substrate 5, and the soldering portion may be preliminarily subjected to a treatment such as solder plating or gold plating. good. Further, an "D" or "H" -shaped notch is formed as an insertion portion 56 in this portion, and the size of this notch is equal to that of the signal extraction terminal 3 of the double-sided signal electrode plate 2B. Naturally, the tip is sized so that it can be inserted. At this time, it is preferable that the width of the metal pattern 52 on the flexible substrate 5 and the width of the electrode layer (surface) at the tip of the signal output terminal 3 are designed to be approximately the same width. .

Actually, as shown in FIG. 1, when the signal take-out terminal 3 of the double-sided signal electrode plate 2B is inserted, the U-shaped conductive metal pattern 52 formed on the surface of the flexible substrate 5 is inserted. Since the notch of the portion 56 is widened and bent on both sides, a disconnection occurs. Therefore, the cut conductive metal patterns 52, 52 are electrically connected to the electrode layers (surfaces) 3 formed on both side surfaces of the double-sided signal electrode plate 2B independently by the subsequent soldering. Connected. At this time, the cut-out portions of the flexible substrate 5 which are widened to both sides sandwich the plated conductive metal pattern portion of the double-sided signal electrode plate 2B from both sides. Therefore, the position of the flexible substrate 5 does not fluctuate and become unstable as in the conventional case, and is stabilized at a place to be soldered. Further, as is clear from the drawing, the cutout portions of the flexible substrate 5 which are spread out on both sides are fixed in a state of being in contact with both side surfaces of the double-sided signal electrode plate 2B while being inclined. Therefore, since the solder portion is stable and the attaching work surface is large, the workability of the solder is improved and the assembling work can be improved.

At the same time, according to the connection structure as described above, the solder connection portion also has a constant shape. for that reason,
As in the past, a part of the solder may be formed to protrude due to the soldering work, and the solder connection part may affect the electric field in the channel formed by the high-voltage electrode and adversely affect the detection performance of the device. Can be surely prevented.

In FIG. 2 again, reference numeral 30 is a grounding metal plate, and this grounding metal plate is a small protrusion 29 formed on the upper end of the double-sided signal electrode plate 2B, as shown in FIG. Is a metal plate such as a copper plate having a plurality of holes 31 that meet the above condition and are formed at the same intervals as the intervals at which the double-sided signal electrode plates 2B are arranged. Such a grounding metal plate 3
0, and the ground area 26 of the double-sided signal electrode plate in its hole 31.
After inserting the protrusions 29 provided in the above, soldering them together, and also by easy solder connection work, the center metal plates 21 of the plurality of double-sided signal electrode plates are surely grounded to improve the detection accuracy. , At the same time, adjacent double-sided signal electrode plates 2B
Can be made extremely strong against vibrations by alternately fixing the signal extraction terminals 3 to each other.

As shown in FIG. 3, the shape of the end face of one insulating plate 1A holding the electrode plate therebetween is changed so that a gap between the insulating plate 1A and the ground area 26 of the double-sided signal electrode plate 2B is formed. 2 shows a ground connection structure of the center electrode plate into which, for example, the conductive rubber 30 'is inserted. With such a structure, the same effect as in FIG. 2 can be obtained. In the other embodiment, after the work of inserting the conductive rubber 30 'is completed, the signal extraction terminal 3 is inserted into the insertion portion 56 of the flexible substrate 5 and soldered.

As described above, according to the above-described embodiment of the present invention, the signal take-out terminal 3 is formed on the double-sided signal electrode plate 2B on the side of the insulating plate 1A outside the passage of X-rays, and its center is formed. By forming the grounded region of the metal plate, the factor that disturbs the electric field on the X-ray passage is eliminated, and the electrode end face is maintained with the electrode accuracy, so that the deterioration of the characteristics is reduced and the high-precision X-ray Measurement is possible. Furthermore, the flexible substrate 5
Since the length of the flexible board itself is minimized, vibration of the flexible board itself is reduced, and the depth direction of the elongated signal output terminal 3 is used as a ground area, and the end face in the longitudinal direction is formed of a large number of metal plates 30 or the like. Since it is connected to the ground terminal portion of 2B, its rigidity is increased, and it becomes stronger against vibrations, and the generation of noise due to vibrations of the terminal itself is reduced. Also in terms of workability, since the tip of the signal output terminal 3 serves as a signal connecting portion, and the width of the tip is narrow and the width of the root region thereof is wide, a signal is input to the insertion portion 56 of the flexible substrate 5. Even if the take-out terminal 3 is inserted, it does not go deeper than a predetermined position and the insertion hole has an "D" or "H" -shaped notch, so that the flexible board 5 is removed from both sides of the signal take-out terminal 3. Since it is sandwiched, the solder fixing area is increased, the reliability of soldering is improved, and
Since the signal extraction terminal 3 is firmly fixed only by inserting it into the cutout hole, the work of fixing the flexible substrate 5 is unnecessary, and the solder workability is greatly improved.

[0038]

As is clear from the above detailed description of the present invention, the ionization chamber type X-ray detector of the present invention has a signal extraction structure for extracting a detection signal to the outside of the detector case. By simply inserting the signal output terminal formed on a part of the double-sided signal electrode plate into the insertion part of the flexible board, the flexible board is securely fixed, and at the same time, the soldering area becomes large. Channel formed by the high voltage electrode with improved solderability and improved soldering reliability, no signal extraction structure in the X-ray passage part due to the connection structure, and the solder connection part has a constant shape. The electric field distribution is improved without disturbing the internal electric field, and it is possible to provide an ionization chamber type X-ray detector capable of highly accurate measurement, which is extremely technically effective. .

[Brief description of drawings]

FIG. 1 is a partially enlarged perspective view of a double-sided electrode signal extraction terminal portion of an ionization chamber type X-ray detector according to an embodiment of the present invention.

FIG. 2 includes the above-mentioned double-sided electrode signal extraction terminal portion,
It is a side view which shows the signal extraction structure of the double-sided electrode signal extraction terminal of an ionization chamber type X-ray detector.

FIG. 3 is a side view showing a signal extraction structure of a double-sided electrode signal extraction terminal of an ionization chamber type X-ray detector according to another embodiment of the present invention.

FIG. 4 is a perspective view and a sectional view showing an electrode block of an ionization chamber type X-ray detector according to an embodiment of the present invention and a sectional structure thereof.

FIG. 5 is a side view and a cross-sectional view showing the structure of a double-sided signal electrode plate that constitutes an electrode block of the ionization chamber type X-ray detector according to the embodiment of the present invention.

6 is a partially enlarged side view showing a detailed shape of a signal output terminal of the double-sided signal electrode plate of FIG.

FIG. 7 is a partially enlarged side view showing a detailed shape of a signal output terminal which is another modification of the double-sided signal electrode plate.

FIG. 8 is a plan view showing an example of a flexible substrate for connecting signal extraction terminals of the double-sided signal electrode plate.

9A and 9B are a partially enlarged plan view and a cross-sectional view showing a detailed structure of the flexible substrate.

FIG. 10 is a plan view showing an example of a flexible substrate according to another modification.

11 is a plan view showing the structure of a grounding metal plate used in the signal extraction structure of the double-sided electrode signal extraction terminal of FIG.

[Explanation of symbols]

 1A, 1B Insulation plate 2A High-voltage electrode plate 2B Double-sided signal electrode plate 21 Central metal plate 22 Insulation layer 23 Electrode layer 25 Insulation area 26 Grounding area 3 Signal extraction terminal 4 Detector case 5 Flexible board 52 Conductive metal pattern 56 Insert section 10 Soldering

Claims (1)

[Claims] 1. A high voltage electrode and a signal electrode are alternately arranged,
An ionization box type X-ray detector that obtains an electric signal to the signal electrode by an ionization action of gas around the electrode by an incident X-ray, wherein the signal electrode is provided on at least both surfaces of a conductive metal plate and an insulating layer and A double-sided signal electrode plate having a multi-layer structure in which a metal layer forming an electrode surface is formed on the insulating layer, and further, a flexible substrate having an insertion portion formed on a part thereof and an electrode pattern formed on the surface thereof, An ionization box type X-ray detector in which different electrode surfaces formed on both side surfaces of a signal extraction terminal portion formed on a part of a signal electrode plate are electrically taken out and connected to each other, and a part of the flexible substrate is provided. The insertion portion formed in the state that the signal extraction terminal portion of the double-sided signal electrode plate of the double-sided signal electrode plate is inserted, and the signal extraction terminal portion is formed on both side surfaces by its elasticity. Et pinching ionization chamber type X-ray detector, characterized in that said formed into a shape contacting with the inclined with respect to both side surfaces of the signal takeout lead terminal portion.