JPH06111758A - Ionization chamber type x-ray sensor - Google Patents
Ionization chamber type x-ray sensorInfo
- Publication number
- JPH06111758A JPH06111758A JP4284021A JP28402192A JPH06111758A JP H06111758 A JPH06111758 A JP H06111758A JP 4284021 A JP4284021 A JP 4284021A JP 28402192 A JP28402192 A JP 28402192A JP H06111758 A JPH06111758 A JP H06111758A
- Authority
- JP
- Japan
- Prior art keywords
- ray
- groove
- window
- stress
- plate
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 229920002430 Fibre-reinforced plastic Polymers 0.000 claims description 34
- 230000002093 peripheral effect Effects 0.000 claims description 14
- 239000013306 transparent fiber Substances 0.000 claims description 2
- 239000000835 fiber Substances 0.000 abstract description 5
- 239000012783 reinforcing fiber Substances 0.000 abstract description 3
- 230000003247 decreasing effect Effects 0.000 abstract 1
- 239000011151 fibre-reinforced plastic Substances 0.000 description 32
- 239000007789 gas Substances 0.000 description 11
- 230000035945 sensitivity Effects 0.000 description 7
- 238000001514 detection method Methods 0.000 description 6
- 229910052799 carbon Inorganic materials 0.000 description 5
- 238000010586 diagram Methods 0.000 description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 229910052786 argon Inorganic materials 0.000 description 3
- 238000006073 displacement reaction Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- 230000002238 attenuated effect Effects 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 230000003014 reinforcing effect Effects 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 229920006231 aramid fiber Polymers 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
- 238000005549 size reduction Methods 0.000 description 1
- 238000003325 tomography Methods 0.000 description 1
- 239000013585 weight reducing agent Substances 0.000 description 1
- 229910052724 xenon Inorganic materials 0.000 description 1
- FHNFHKCVQCLJFQ-UHFFFAOYSA-N xenon atom Chemical compound [Xe] FHNFHKCVQCLJFQ-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Measurement Of Radiation (AREA)
- Apparatus For Radiation Diagnosis (AREA)
- Electron Tubes For Measurement (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】この発明は、例えば、医療用Ｘ線
断層撮影装置（Ｘ線ＣＴ装置）等において、被検体に曝
射したＸ線を検出するためのＸ線検出器に係り、特に、
平行平板状電極を内装するとともに、Ｘ線を吸収して電
離するガス（例えば、Ｘｅ等）を高圧で封入した電離箱
型Ｘ線検出器に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray detector for detecting X-rays exposed to a subject, for example, in a medical X-ray tomography apparatus (X-ray CT apparatus) and the like. ,
The present invention relates to an ionization box type X-ray detector in which parallel plate electrodes are provided and a gas (for example, Xe) that absorbs X-rays and ionizes is enclosed at high pressure.
【０００２】[0002]
【従来の技術】従来のこの種の電離箱型Ｘ線検出器の構
成を図６、図７を参照して以下に説明する。図はＸ線Ｃ
Ｔに用いられる多チャンネル電離箱型Ｘ線検出器を示し
ている。図中、符号１は例えばアルミニウム（Ａｌ）合
金等で形成され、湾曲した形状を有する容器を示し、こ
の容器１内には、複数枚のバイアス電極板２と信号電極
板３とが絶縁体サポート７により支持されて交互に配列
されており、信号電極３を挟んで対向する２枚のバイア
ス電極板２の間に単位チャンネルが形成されている。ま
た、各チャンネルでの感度を均一にするために、これら
のバイアス電極板２、信号電極板３は円弧状に配列され
ている。このように平行平板状電極を内装した容器１内
には、キセノン（Ｘｅ）ガスが１５〜３０〔Kgf/cm2G〕
で封入されており、そのＸｅガスの圧力に耐えるため
に、容器１の外周壁４は１５〜２５mmの肉厚に形成され
ている。また、容器１の外周壁４の内、Ｘ線入射側の外
周壁には凹断面を形成するための溝６が設けられ、その
溝６の底面には、肉厚３mmのＸ線入射窓５が形成されて
いる。2. Description of the Related Art The structure of a conventional ionization chamber type X-ray detector of this type will be described below with reference to FIGS. The figure shows X-ray C
2 shows a multi-channel ionization chamber type X-ray detector used for T. In the figure, reference numeral 1 indicates a container having a curved shape, which is formed of, for example, an aluminum (Al) alloy or the like, and in this container 1, a plurality of bias electrode plates 2 and signal electrode plates 3 are insulator supports. 7, the unit channels are formed alternately between two bias electrode plates 2 facing each other with the signal electrode 3 interposed therebetween. Further, the bias electrode plate 2 and the signal electrode plate 3 are arranged in an arc shape in order to make the sensitivity uniform in each channel. In the container 1 in which the parallel plate electrodes are thus installed, xenon (Xe) gas is contained in an amount of 15 to 30 [Kgf / cm 2 G].
The outer peripheral wall 4 of the container 1 is formed to have a wall thickness of 15 to 25 mm in order to withstand the pressure of the Xe gas. Further, among the outer peripheral wall 4 of the container 1, a groove 6 for forming a concave cross section is provided on the outer peripheral wall on the X-ray incident side, and the bottom surface of the groove 6 has an X-ray incident window 5 having a thickness of 3 mm. Are formed.
【０００３】図示しないＸ線発生装置から照射され、被
検体を透過したＸ線ＸＲは、Ｘ線入射窓５から容器１内
に入射し、入射したＸ線の強度は各チャンネルごとに電
流値として検出される。X-rays XR, which are emitted from an X-ray generator (not shown) and have passed through the subject, enter the container 1 through the X-ray entrance window 5, and the intensity of the incident X-rays is a current value for each channel. To be detected.
【０００４】[0004]
【発明が解決しようとする課題】しかしながら、このよ
うな構成を有する従来例の場合には、次のような問題が
ある。すなわち、Ｘ線入射窓５の肉厚（３mm）はＸ線の
減衰を少なくしＸ線検出感度を良くするために、他の外
周壁４の肉厚（１５〜２５mm）に比べて薄くなっている
が、容器１内には高圧でＸｅガスが封入されているの
で、Ｘ線入射窓５には、図８に示すように応力による歪
みが発生する。これは、容器１内に高圧でＸｅガスを封
入したことにより、容器１の外周壁を外側に押し広げよ
うとする力が働いているが、Ｘ線入射窓５部分の肉厚が
薄いので、応力が集中し歪みも大きくなるからである。
また、そのような歪みが発生すると、Ｘ線入射窓５部分
での変形によるＸ線検出感度の低下や、Ｘ線検出器自体
の破壊が起こり得るという問題がある。However, the conventional example having such a structure has the following problems. That is, the thickness of the X-ray entrance window 5 (3 mm) is smaller than that of the other outer peripheral wall 4 (15 to 25 mm) in order to reduce X-ray attenuation and improve X-ray detection sensitivity. However, since the container 1 is filled with Xe gas at high pressure, the X-ray entrance window 5 is distorted by stress as shown in FIG. This is because by enclosing Xe gas in the container 1 at a high pressure, a force to push the outer peripheral wall of the container 1 outward is exerted, but since the thickness of the X-ray entrance window 5 portion is thin, This is because stress concentrates and strain also increases.
Further, when such distortion occurs, there is a problem that the X-ray detection sensitivity may be reduced due to deformation in the X-ray entrance window 5 portion, or the X-ray detector itself may be destroyed.
【０００５】また、最近の傾向として、小型、軽量、コ
ストダウンを目的としてＸ線検出器の小型化が望まれて
いるが、そのためには平行平板状電極を小型化しなけれ
ばならず、平行平板状電極の小型化によるＸ線吸収能力
低下を補うためにはＸｅガスの封入圧力を上げる必要が
ある。そのように、Ｘｅガスの封入圧力を上げれば、Ｘ
線入射窓５で発生する歪みによる変形や、応力が許容値
をこえ破壊が一層起こり易くなるという問題もある。Further, as a recent trend, there is a demand for miniaturization of an X-ray detector for the purpose of size reduction, weight reduction, and cost reduction. For that purpose, the parallel plate electrodes must be miniaturized. In order to compensate for the decrease in the X-ray absorption capacity due to the miniaturization of the cylindrical electrode, it is necessary to increase the filling pressure of Xe gas. In this way, if the filling pressure of Xe gas is increased, X
There is also a problem that deformation due to strain generated in the line incident window 5 or stress exceeds an allowable value and fracture is more likely to occur.
【０００６】この発明は、このような事情に鑑みてなさ
れたものであって、Ｘ線入射窓部分での応力と歪みを減
少させる電離箱型Ｘ線検出器を提供することを目的とす
る。The present invention has been made in view of the above circumstances, and an object thereof is to provide an ionization chamber type X-ray detector which reduces stress and strain in the X-ray entrance window portion.
【０００７】[0007]
【課題を解決するための手段】この発明は、このような
目的を達成するために、次のような構成をとる。すなわ
ち、この発明は、平行平板状電極を内装するとともに、
Ｘ線を吸収して電離するガスを高圧で封入した容器のＸ
線入射側外周壁を凹断面に形成して、Ｘ線を取り込むた
めのＸ線入射窓を設けた電離箱型Ｘ線検出器において、
前記容器のＸ線入射側外周壁に形成した凹断面を塞ぐよ
うにＸ線透過性の繊維強化プラスチック板を架設して前
記Ｘ線入射窓を補強したものである。The present invention has the following constitution in order to achieve such an object. That is, the present invention is provided with a parallel plate electrode,
X in a container in which a gas that absorbs X-rays and ionizes is enclosed at high pressure
An ionization box type X-ray detector having an X-ray incidence window for capturing X-rays, the outer peripheral wall of the radiation incidence side having a concave cross section,
The X-ray entrance window is reinforced by arranging an X-ray transparent fiber reinforced plastic plate so as to close the concave cross section formed on the X-ray entrance side outer peripheral wall of the container.
【０００８】[0008]
【作用】この発明の作用は次のとおりである。容器のＸ
線入射側外周壁に形成した凹断面を塞ぐようにＸ線透過
性の繊維強化プラスチック板を架設することにより、前
記凹断面の側壁を押し広げる方向に働く応力を減少させ
ることができるので、Ｘ線入射窓の歪みを減少させるこ
とができる。The operation of the present invention is as follows. X in the container
Since the X-ray permeable fiber reinforced plastic plate is installed so as to close the concave cross section formed on the outer peripheral wall of the ray incident side, the stress acting in the direction of expanding the side wall of the concave cross section can be reduced. The distortion of the line entrance window can be reduced.
【０００９】なお、Ｘ線透過性の繊維強化プラスチック
板は、少なくともＸ線入射窓を形成する物質の原子番号
よりも小さい原子番号の元素により構成された繊維強化
プラスチックにより形成する。Ｘ線はＸ線入射窓に入射
する前にＸ線透過性の繊維強化プラスチック板を透過す
るが、このようなＸ線透過性の繊維強化プラスチックを
用いれば、Ｘ線透過性の繊維強化プラスチック板でのＸ
線の著しい減衰は防止できる。The X-ray permeable fiber reinforced plastic plate is made of a fiber reinforced plastic composed of at least an element having an atomic number smaller than that of the substance forming the X-ray entrance window. X-rays are transmitted through the X-ray transmissive fiber-reinforced plastic plate before entering the X-ray entrance window. If such an X-ray transmissive fiber-reinforced plastic is used, the X-ray transmissive fiber-reinforced plastic plate is used. X at
Significant attenuation of the line can be prevented.
【００１０】[0010]
【実施例】以下、図面を参照してこの発明の一実施例を
説明する。この実施例では、従来例で説明したＸ線ＣＴ
に用いられる多チャンネル電離箱型Ｘ線検出器を例に採
り説明する。なお、図中、従来例で用いた符号と同じ符
号は、従来例と同じ構成であるので、ここでの説明は省
略する。図１は、この発明の一実施例に係る電離箱型Ｘ
線検出器の全体構成を示す斜視図であり、図２は図１の
Ａ−Ａ矢視断面図である。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In this embodiment, the X-ray CT described in the conventional example is used.
A multi-channel ionization chamber type X-ray detector used in the above will be described as an example. In the figure, the same reference numerals as those used in the conventional example have the same configurations as those in the conventional example, and thus the description thereof is omitted here. FIG. 1 shows an ionization chamber type X according to an embodiment of the present invention.
It is a perspective view which shows the whole structure of a line detector, and FIG. 2 is a sectional view taken along the line AA of FIG.
【００１１】この実施例では、図に示すように、容器１
のＸ線入射側外周壁に凹断面を形成するために設けた溝
６を覆うように、Ｘ線透過性ＦＲＰ（繊維強化プラスチ
ック）板１０を架設し、Ｘ線入射窓５部分を補強してい
る。このＸ線透過性ＦＲＰ板１０としては、例えば、強
化繊維としてカーボン（Ｃ）を用いたＣ−ＦＲＰが好ま
しい。これは、Ｘ線入射窓５から入射するＸ線ＸＲがＸ
線透過性ＦＲＰ板１０によって著しく減衰されるのを防
止し、Ｘ線透過性ＦＲＰ板１０によるＸ線検出感度の低
下を防止するためである。すなわち、一般にＸ線を減衰
させる要因である光電効果やコンプトン効果は、Ｘ線が
透過する物質を構成する元素の原子番号に比例してお
り、原子番号が小さい元素で構成された物質は、原子番
号が大きい元素で構成された物質よりもＸ線の減衰が少
ない。従って、Ｘ線透過性ＦＲＰ板１０はＸ線入射窓５
を構成するアルミニウム（Ａｌ：原子番号１３）よりも
原子番号が小さい元素で構成されていることが好まし
く、Ｃ−ＦＲＰは、水素（Ｈ：原子番号１）、炭素
（Ｃ：原子番号６）、酸素（Ｏ：原子番号８）によって
構成されており、ＡｌよりもＸ線の減衰が少ないので、
Ｘ線透過性ＦＲＰ板１０として好ましい。ちなみに、Ｘ
線透過性ＦＲＰ板１０（Ｃ−ＦＲＰで形成）の厚みを１
mmとした場合、肉厚３mmのＸ線入射窓５に比べて、密度
が半分以下になり、Ｘ線透過性ＦＲＰ板１０でのＸ線の
減衰量は、Ｘ線入射窓５のおよそ１０分の１以下とな
る。In this embodiment, as shown in FIG.
The X-ray transparent FRP (fiber reinforced plastic) plate 10 is installed so as to cover the groove 6 provided to form the concave cross section on the outer peripheral wall of the X-ray incident side, and the X-ray incident window 5 portion is reinforced. There is. As the X-ray transparent FRP plate 10, for example, C-FRP using carbon (C) as a reinforcing fiber is preferable. This is because the X-ray XR entering from the X-ray entrance window 5 is X
This is to prevent the X-ray transparent FRP plate 10 from being significantly attenuated and to prevent the X-ray transparent FRP plate 10 from deteriorating the X-ray detection sensitivity. That is, the photoelectric effect or Compton effect, which is a factor that generally attenuates X-rays, is proportional to the atomic number of the element that constitutes the substance through which X-rays pass, and a substance composed of an element with a small atomic number is X-rays are less attenuated than substances composed of higher numbered elements. Therefore, the X-ray transparent FRP plate 10 has the X-ray entrance window 5
Is preferably composed of an element having an atomic number smaller than that of aluminum (Al: atomic number 13) constituting C, and C-FRP is hydrogen (H: atomic number 1), carbon (C: atomic number 6), Since it is composed of oxygen (O: atomic number 8) and has less X-ray attenuation than Al,
It is preferable as the X-ray transparent FRP plate 10. By the way, X
The thickness of the linearly transparent FRP plate 10 (formed by C-FRP) is 1
When the thickness is set to mm, the density is less than half that of the X-ray entrance window 5 having a thickness of 3 mm, and the X-ray attenuation amount of the X-ray transparent FRP plate 10 is about 10 minutes of the X-ray entrance window 5. Of 1 or less.
【００１２】また、このＸ線透過性ＦＲＰ板１０は、厚
みを１mmで形成し、図１に示すように、溝６を全て覆う
ように設けられている。これは、Ｘ線を検出する各チャ
ンネルごとでＸ線検出感度のバラツキが起きないように
するためである。Ｘ線透過性ＦＲＰ板１０は、容器１に
ネジ１１によってネジ止めされている。また、Ｘ線透過
性ＦＲＰ板１０の繊維方向を図３に示すように、溝６を
跨ぐ方向（図中、矢印で示す方向）に合わせて取り付け
ることが好ましい。これは、溝６を押し広げようとする
応力に対抗し、Ｘ線透過性ＦＲＰ板１０の切断等を防止
するためである。すなわち、溝６を押し広げようとする
応力は、Ｘ線透過性ＦＲＰ板１０の繊維を引っ張る方向
にかかることになり、溝６を押し広げようとする応力に
対してＸ線透過性ＦＲＰ板１０の強度が最も強い状態で
対抗することになるので、Ｘ線透過性ＦＲＰ板１０の切
断等は防止される。The X-ray transparent FRP plate 10 is formed to have a thickness of 1 mm and is provided so as to cover all the grooves 6 as shown in FIG. This is to prevent variations in the X-ray detection sensitivity among the channels that detect X-rays. The X-ray transparent FRP plate 10 is screwed to the container 1 with screws 11. Further, as shown in FIG. 3, the fiber direction of the X-ray transparent FRP plate 10 is preferably attached so as to be aligned with the direction straddling the groove 6 (the direction indicated by the arrow in the figure). This is to counter the stress that tends to widen the groove 6 and prevent the X-ray transparent FRP plate 10 from being cut. That is, the stress for expanding the groove 6 is applied in the direction of pulling the fibers of the X-ray transparent FRP plate 10, and the X-ray transparent FRP plate 10 is applied against the stress for expanding the groove 6. Therefore, the X-ray transparent FRP plate 10 is prevented from being cut or the like.
【００１３】上述のような構成により、Ｘ線入射窓５を
補強した場合のＸ線入射窓５部分にかかる応力を、従来
例と比較して以下に説明する。Ｘ線検出器の各寸法等の
計算条件は図４に示す通りである。The stress applied to the portion of the X-ray entrance window 5 when the X-ray entrance window 5 is reinforced by the above-mentioned structure will be described below in comparison with the conventional example. Calculation conditions such as respective dimensions of the X-ray detector are as shown in FIG.
【００１４】すなわち、 （１）容器１の外径（Ｈ、Ｔ）は７０mm（Ｈ）×８２mm
（Ｔ）である。 （２）容器１の３方の外周壁４の肉厚（Ｄ１、Ｄ２、Ｄ
３）は、それぞれ１７mm（Ｄ１）、１６mm（Ｄ２）、１
８mm（Ｄ３）である。 （３）Ｘ線入射窓５の肉厚（ＤＭ）は３mmであり、溝６
の幅（Ｗ）は２５mmである。 （４）容器１内には、Ｘｅガスが２６〔Kgf/cm2 G 〕で
封入されている。 （５）Ｘ線透過性ＦＲＰ板１０の厚み（Ｕ）は１mmで、
ヤング率を３０GPa とした。 （６）容器１の材料はＡｌ合金で、ヤング率を７１．７
GPa 、ポアソン比０．３３と考えた。(1) The outer diameter (H, T) of the container 1 is 70 mm (H) x 82 mm
(T). (2) Wall thickness (D1, D2, D) of the outer peripheral wall 4 on three sides of the container 1
3) is 17 mm (D1), 16 mm (D2), 1
It is 8 mm (D3). (3) The thickness (DM) of the X-ray entrance window 5 is 3 mm, and the groove 6
Has a width (W) of 25 mm. (4) The container 1 is filled with Xe gas at 26 [Kgf / cm 2 G]. (5) The thickness (U) of the X-ray transparent FRP plate 10 is 1 mm,
Young's modulus was set to 30 GPa. (6) The material of the container 1 is an Al alloy, and the Young's modulus is 71.7.
The GPa and Poisson's ratio were considered to be 0.33.
【００１５】このような条件における、Ｘ線入射窓５部
分にかかる応力を有限要素法で計算すると、図５に示す
ようになる。図中、最大主応力は、Ｘ線入射窓５部分に
かかった応力の最大値であり、変位は、Ｘ線入射窓５部
分に起こった最大変位量を示す。The stress applied to the X-ray entrance window 5 portion under such conditions is calculated by the finite element method as shown in FIG. In the figure, the maximum principal stress is the maximum value of the stress applied to the X-ray incident window 5 portion, and the displacement indicates the maximum amount of displacement that occurred in the X-ray incident window 5 portion.
【００１６】このように、溝６を覆うようにＸ線透過性
ＦＲＰ板１０を架設することにより、Ｘ線入射窓５部分
にかかる応力を約２４MPa も減少させ、変位を１７μｍ
も減少させることができた。これは、溝６により形成さ
れる凹断面の側壁を押し広げる方向に働く応力が、Ｘ線
透過性ＦＲＰ板１０によって抑えられるからである。As described above, by constructing the X-ray transparent FRP plate 10 so as to cover the groove 6, the stress applied to the X-ray entrance window 5 portion is reduced by about 24 MPa, and the displacement is 17 μm.
Could also be reduced. This is because the X-ray transparent FRP plate 10 suppresses the stress acting in the direction of expanding the side wall of the concave cross section formed by the groove 6.
【００１７】また、Ｘ線透過性ＦＲＰ板１０によるＸ線
の減衰も上述したように、大きな影響を与えることはな
い。Further, the attenuation of X-rays by the X-ray transparent FRP plate 10 does not have a great influence as described above.
【００１８】ところで、Ｘ線透過性ＦＲＰ板１０によっ
てＸ線入射窓５を補強することにより、Ｘ線入射窓５に
かかる最大主応力を約２４MPa （約、３割）減少させる
ことができたが、Ｘ線入射窓５にかかる最大主応力が従
来のままで良いとすれば、Ｘ線入射窓５の肉厚を従来よ
り薄く（およそ３mmの肉厚を２．５mmに）することがで
きる。これは、Ｘ線入射窓５でのＸ線の減衰を減少させ
ることになり、Ｘ線検出の感度を向上させることができ
る。By reinforcing the X-ray entrance window 5 with the X-ray transparent FRP plate 10, the maximum principal stress applied to the X-ray entrance window 5 can be reduced by about 24 MPa (about 30%). Assuming that the maximum principal stress applied to the X-ray incident window 5 is the same as the conventional one, the thickness of the X-ray incident window 5 can be made thinner than the conventional one (about 3 mm in wall thickness is 2.5 mm). This means that the attenuation of X-rays at the X-ray entrance window 5 is reduced, and the sensitivity of X-ray detection can be improved.
【００１９】なお、上述の実施例では、Ｘ線透過性ＦＲ
Ｐ板１０としてＣ−ＦＲＰを用いた場合について説明し
たが、強化繊維としては、カーボンに限らず、例えば、
ボロン添加カーボンやアラミド繊維、アルミナ等であっ
てもよい。In the above embodiment, the X-ray transparency FR
The case where C-FRP is used as the P plate 10 has been described, but the reinforcing fiber is not limited to carbon, and for example,
It may be boron-added carbon, aramid fiber, alumina or the like.
【００２０】また、上述の実施例では、Ｘ線透過性ＦＲ
Ｐ板１０の厚みを１mmとして説明したが、Ｘ線透過性Ｆ
ＲＰ板１０の厚みを１mm以上にしてもよく、Ｘ線透過性
ＦＲＰ板１０の厚みを厚くすれば、Ｘ線入射窓５にかか
る応力を一層減少させることができる。このときのＸ線
の減衰は、Ｘ線入射窓５を厚くすることにより同程度に
補強するよりも、少なくすることができる。Further, in the above-mentioned embodiment, the X-ray transmission FR
Although the thickness of the P plate 10 has been described as 1 mm, the X-ray transparency F
The thickness of the RP plate 10 may be 1 mm or more, and the stress applied to the X-ray entrance window 5 can be further reduced by increasing the thickness of the X-ray transparent FRP plate 10. The attenuation of the X-rays at this time can be reduced as compared with the case where the X-ray entrance window 5 is made thick to reinforce it to the same degree.
【００２１】さらに、上述の実施例では、Ｘ線ＣＴに用
いられる多チャンネル電離箱型Ｘ線検出器を例に採り説
明したが、この発明はこれに限らず、平行平板状電極を
内装するとともに、Ｘ線を吸収して電離するガスを高圧
で封入した電離箱型Ｘ線検出器であれば適用することが
でき、また、内部に封入するガスもＸｅに限らず、例え
ば、Ｋｒ（クリンプトン）やＡｒ（アルゴン）等であっ
ても同様の効果を得ることができる。Further, in the above-mentioned embodiment, the multi-channel ionization chamber type X-ray detector used for the X-ray CT has been described as an example, but the present invention is not limited to this, and the parallel plate electrodes are incorporated. , An ionization box type X-ray detector in which a gas that absorbs X-rays and ionizes is enclosed at a high pressure can be applied, and the gas enclosed inside is not limited to Xe, and for example, Kr (crimpton) The same effect can be obtained with Ar, Ar (argon), or the like.
【００２２】[0022]
【発明の効果】以上の説明から明らかなように、この発
明によれば、容器のＸ線入射側外周壁に形成した凹断面
を塞ぐようにＸ線透過性の繊維強化プラスチック板を架
設することにより、前記凹断面の側壁を押し広げる方向
に働く応力と、Ｘ線入射窓の歪みを減少させることがで
きる。また、Ｘ線入射窓の補強にＸ線透過性の繊維強化
プラスチック板を用いているので、補強のための著しい
Ｘ線の減衰を防止することができ、Ｘ線検出感度の低下
を防止することができる。As is apparent from the above description, according to the present invention, the X-ray permeable fiber reinforced plastic plate is installed so as to close the concave cross section formed on the X-ray incident side outer peripheral wall of the container. As a result, it is possible to reduce the stress acting in the direction of expanding the side wall of the concave section and the distortion of the X-ray entrance window. Further, since the X-ray transmitting fiber reinforcing plastic plate is used to reinforce the X-ray entrance window, it is possible to prevent a significant attenuation of X-rays for reinforcement and prevent a decrease in X-ray detection sensitivity. You can
【図１】この発明の一実施例に係る電離箱型Ｘ線検出器
の全体構成を示す斜視図である。FIG. 1 is a perspective view showing an overall configuration of an ionization chamber type X-ray detector according to an embodiment of the present invention.
【図２】図１のＡ−Ａ矢視断面図である。FIG. 2 is a sectional view taken along the line AA of FIG.
【図３】Ｘ線透過性ＦＲＰ板を容器に取り付ける際の繊
維方向を示す図である。FIG. 3 is a diagram showing fiber directions when an X-ray transparent FRP plate is attached to a container.
【図４】従来例との比較を行う計算モデルを示す図であ
る。FIG. 4 is a diagram showing a calculation model for comparison with a conventional example.
【図５】従来例との比較を行った結果を示す図である。FIG. 5 is a diagram showing a result of comparison with a conventional example.
【図６】従来例に係る電離箱型Ｘ線検出器の全体構成を
示す斜視図である。FIG. 6 is a perspective view showing the overall configuration of an ionization chamber type X-ray detector according to a conventional example.
【図７】従来例の内部構成を示す図である。FIG. 7 is a diagram showing an internal configuration of a conventional example.
【図８】従来例の問題を説明するための図である。FIG. 8 is a diagram for explaining a problem of a conventional example.
１ … 容器 ２ … バイアス電極板 ３ … 信号電極板 ４ … 外周壁 ５ … Ｘ線入射窓 ６ … 溝 １０ … Ｘ線透過性ＦＲＰ（繊維強化プラスチック）
板DESCRIPTION OF SYMBOLS 1 ... Container 2 ... Bias electrode plate 3 ... Signal electrode plate 4 ... Outer peripheral wall 5 ... X-ray entrance window 6 ... Groove 10 ... X-ray transparent FRP (fiber reinforced plastic)
Board
Claims (1)
線を吸収して電離するガスを高圧で封入した容器のＸ線
入射側外周壁を凹断面に形成して、Ｘ線を取り込むため
のＸ線入射窓を設けた電離箱型Ｘ線検出器において、 前記容器のＸ線入射側外周壁に形成した凹断面を塞ぐよ
うにＸ線透過性の繊維強化プラスチック板を架設して前
記Ｘ線入射窓を補強したことを特徴とする電離箱型Ｘ線
検出器。1. A parallel plate electrode is provided inside and X
An ionization box type X-ray detector having an X-ray incidence side outer peripheral wall of a container in which a gas absorbing and ionizing rays is enclosed at a high pressure and having an X-ray incidence window for capturing X-rays. An ionization box type X-ray, wherein an X-ray transparent fiber reinforced plastic plate is installed so as to close a concave cross section formed on an X-ray incidence side outer peripheral wall of the container to reinforce the X-ray incidence window. Detector.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4284021A JPH06111758A (en) | 1992-09-28 | 1992-09-28 | Ionization chamber type x-ray sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4284021A JPH06111758A (en) | 1992-09-28 | 1992-09-28 | Ionization chamber type x-ray sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH06111758A true JPH06111758A (en) | 1994-04-22 |
Family
ID=17673280
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4284021A Pending JPH06111758A (en) | 1992-09-28 | 1992-09-28 | Ionization chamber type x-ray sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH06111758A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5406023A (en) * | 1992-02-25 | 1995-04-11 | Yamaha Corporation | Electronic musical instrument using simplified registration selection |
| JP2016081877A (en) * | 2014-10-22 | 2016-05-16 | アズビル株式会社 | Ultraviolet light sensor |
-
1992
- 1992-09-28 JP JP4284021A patent/JPH06111758A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5406023A (en) * | 1992-02-25 | 1995-04-11 | Yamaha Corporation | Electronic musical instrument using simplified registration selection |
| JP2016081877A (en) * | 2014-10-22 | 2016-05-16 | アズビル株式会社 | Ultraviolet light sensor |
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