JPH01172791A - Radiation detecting element - Google Patents
Radiation detecting elementInfo
- Publication number
- JPH01172791A JPH01172791A JP62332333A JP33233387A JPH01172791A JP H01172791 A JPH01172791 A JP H01172791A JP 62332333 A JP62332333 A JP 62332333A JP 33233387 A JP33233387 A JP 33233387A JP H01172791 A JPH01172791 A JP H01172791A
- Authority
- JP
- Japan
- Prior art keywords
- scintillator
- light
- radiation
- efficiency
- photodiode
- 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
- 230000005855 radiation Effects 0.000 title claims abstract description 32
- 238000001514 detection method Methods 0.000 claims description 32
- 230000035945 sensitivity Effects 0.000 claims description 22
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 abstract description 7
- 229910021417 amorphous silicon Inorganic materials 0.000 abstract description 3
- 238000005498 polishing Methods 0.000 abstract description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 abstract 2
- 229910052681 coesite Inorganic materials 0.000 abstract 1
- 229910052906 cristobalite Inorganic materials 0.000 abstract 1
- 229910052738 indium Inorganic materials 0.000 abstract 1
- APFVFJFRJDLVQX-UHFFFAOYSA-N indium atom Chemical compound [In] APFVFJFRJDLVQX-UHFFFAOYSA-N 0.000 abstract 1
- 230000002285 radioactive effect Effects 0.000 abstract 1
- 239000000377 silicon dioxide Substances 0.000 abstract 1
- 235000012239 silicon dioxide Nutrition 0.000 abstract 1
- 229910052682 stishovite Inorganic materials 0.000 abstract 1
- 229910052905 tridymite Inorganic materials 0.000 abstract 1
- 238000002591 computed tomography Methods 0.000 description 9
- 238000000034 method Methods 0.000 description 7
- 206010034972 Photosensitivity reaction Diseases 0.000 description 3
- 229910052782 aluminium Inorganic materials 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 230000036211 photosensitivity Effects 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000004907 flux Effects 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 238000000059 patterning Methods 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910003437 indium oxide Inorganic materials 0.000 description 1
- PJXISJQVUVHSOJ-UHFFFAOYSA-N indium(iii) oxide Chemical compound [O-2].[O-2].[O-2].[In+3].[In+3] PJXISJQVUVHSOJ-UHFFFAOYSA-N 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000001020 plasma etching Methods 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- FDNAPBUWERUEDA-UHFFFAOYSA-N silicon tetrachloride Chemical compound Cl[Si](Cl)(Cl)Cl FDNAPBUWERUEDA-UHFFFAOYSA-N 0.000 description 1
- 229910001887 tin oxide Inorganic materials 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1337—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers
- G02F1/13378—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers by treatment of the surface, e.g. embossing, rubbing or light irradiation
- G02F1/133788—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers by treatment of the surface, e.g. embossing, rubbing or light irradiation by light irradiation, e.g. linearly polarised light photo-polymerisation
Landscapes
- Physics & Mathematics (AREA)
- Nonlinear Science (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Mathematical Physics (AREA)
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Measurement Of Radiation (AREA)
- Light Receiving Elements (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、Ｘ線ＣＴ（コンピュータ断層撮影）装置等に
利用される放射線検出器に関し、特に放射線入射位置に
よる検出感度のバラツキが少なく。DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a radiation detector used in an X-ray CT (computed tomography) device, etc., and in particular has little variation in detection sensitivity depending on the radiation incident position.
高いＳ／Ｎ比で検出感度が高く、実装を容易にした放射
線検出素子に関する。The present invention relates to a radiation detection element that has a high S/N ratio, high detection sensitivity, and is easy to implement.
ＣＴ用固体検出素子の代表的なものとして、シンチレー
タとフォトダイオードを組合せたものがある。近年、非
晶質材料の応用研究の進歩により上記フォトダイオード
として、非晶質シリコンフオドダイオードを用いること
が可能になりつつある。このような研究例として醜等の
報告（応用物理学会誌、 １９８６年、８２４頁）があ
る。また、関連する文献として、特開昭６２−７１８８
１号公報、同６２−４３５８５号公報を挙げることがで
きる。A typical solid-state detection element for CT is one that combines a scintillator and a photodiode. In recent years, advances in applied research on amorphous materials have made it possible to use amorphous silicon photodiodes as the photodiodes. An example of such research is the report by Ugami et al. (Journal of Applied Physics, 1986, p. 824). In addition, as a related document, JP-A-62-7188
Publications No. 1 and No. 62-43585 can be mentioned.
上記従来技術は、放射線の入射位置により検出感度が異
なるという問題があった。以下、これを説明する。The above conventional technology has a problem in that the detection sensitivity varies depending on the radiation incident position. This will be explained below.
検出素子の構造の一例を第２図（ａ）に示す。シンチレ
ータ素子１０ａの大きさは、例えば、２０ｍｍ Ｘ１ｍ
＋＋＋Ｘ１ｍｍである。検出器のＸ線入射面と対向する
面１３ａには、フォトダイオードが形成されている。ま
た、他の面１１ａ、１２ａには、光反射層が形成されて
いる。この検出素子の動作原理を、第２図（ｂ）を用い
て説明する。An example of the structure of the detection element is shown in FIG. 2(a). The size of the scintillator element 10a is, for example, 20 mm x 1 m.
+++X1mm. A photodiode is formed on the surface 13a of the detector facing the X-ray incident surface. Further, a light reflecting layer is formed on the other surfaces 11a and 12a. The operating principle of this detection element will be explained using FIG. 2(b).
入射したＸｗ＆量子は、シンチレータ内のごく微小領域
（通常数１０μｍの範囲）で光に変換される。The incident Xw & quantum is converted into light in a very small area (usually in the range of several tens of μm) within the scintillator.
１Ｘ線量子は通常光子１０００個程度に変換される。One X-ray quantum is usually converted into about 1000 photons.
これらの光子は等方的に放出され、適当な条件下ではシ
ンチレータ下面（フォトダイオード形成面）に略ローレ
ンツ型分布で示される光束として伝播する（図の゛′Ｘ
線量子（Ａ）”）。これがフォトダイオードで面積分さ
れ、入射Ｘ、ｌ信号として検出されるわけである。These photons are emitted isotropically and, under appropriate conditions, propagate to the bottom surface of the scintillator (photodiode formation surface) as a light flux with an approximately Lorentzian distribution ('X' in the figure).
line quantum (A)"). This is area-integrated by a photodiode and detected as incident X, l signals.
さて、検出器の端面に近いところに入射したＸ線（図の
゛′Ｘ線量子（Ｂ）”）により放出された光は、通常、
シンチレータ端面に形成された光反射層により光反射さ
れた後に、シンチレータ下面に到達する。端面における
光反射率は、通常１００％になることはない。その結果
、端面近傍に入射したＸ線に対する光出力は、端面での
光損失分だけ減少する。すなわち、Ｘ線入射位置により
、検出信号量が変化してしまうわけである。Now, the light emitted by X-rays incident near the end face of the detector ("X-ray quantum (B)" in the figure) is usually
After the light is reflected by the light reflecting layer formed on the end face of the scintillator, it reaches the lower surface of the scintillator. The light reflectance at the end face is usually never 100%. As a result, the optical output for X-rays incident near the end face is reduced by the amount of optical loss at the end face. That is, the detected signal amount changes depending on the X-ray incident position.
このようなＸ線入射位置による感度むら、特に長手方向
（ＣＴ用検出器ではスライス方向に当る）の感度むらは
、ｘｇｃＴ装置用検出器では、ＣＴ画像のアーチファク
トの原因となるので問題である。第２図（ｂ）中の最下
段に、従来構造の素子の感度むらの測定結果の一例を示
しである。図から端面近傍での感度が減少していること
がわかる。Such sensitivity unevenness due to the X-ray incident position, especially sensitivity unevenness in the longitudinal direction (which corresponds to the slice direction in a CT detector) is a problem in a detector for an xgcT device because it causes artifacts in CT images. The bottom row of FIG. 2(b) shows an example of measurement results of sensitivity unevenness of an element with a conventional structure. The figure shows that the sensitivity decreases near the end face.
本発明は上記事情に鑑みてなされたもので、その目的と
するところは、従来の放射線検出素子における上述の如
き問題を解消し、検出感度の放射線入射位置依存性のな
い、ＣＴ用検出器として好適な放射線検出素子を堤供す
ることにある。The present invention has been made in view of the above circumstances, and its purpose is to solve the above-mentioned problems with conventional radiation detection elements, and to provide a CT detector with no dependence of detection sensitivity on the radiation incident position. An object of the present invention is to provide a suitable radiation detection element.
本発明の上記目的は、放射線を可視光に変換するシンチ
レータと、該シンチレータの放射線入射面と対向する面
上に形成された光検出素子とを有する放射線検出素子に
おいて、前記シンチレータの放射線入射面上の点（ｘ、
ｙ）に入射した放射線の生成する光が、前記光検出素子
が形成されたシンチレータ面（ｘ’＋ｙ’）に到達する
光到達効率をｆ（ｘ、ｙ）とした場合に、前記光検出素
子の光検出効率ｇ（ｘ’＋ ｙ’）が、
ｇ（ｘ’＋ｙ’）＝ｆ−１（ｘ＋ｙ：ｘ＝ｘ’＋ｙ＝ｙ
’）となる如く、前記光検出素子の形状を決定すること
を特徴とする放射線検出素子によって達成される。The above object of the present invention is to provide a radiation detection element having a scintillator that converts radiation into visible light and a photodetection element formed on a surface facing the radiation incidence surface of the scintillator. The point (x,
y), where f(x, y) is the light arrival efficiency at which the light generated by the radiation incident on the photodetector element reaches the scintillator surface (x'+y') on which the photodetector element is formed. The photodetection efficiency g(x'+y') is g(x'+y')=f-1(x+y:x=x'+y=y
') is achieved by a radiation detection element characterized by determining the shape of the photodetection element.
本発明に係わる放射線検出素子においては、シンチレー
タからフォトダイオードへの光到達効率ｆが、Ｘ線入射
位置依存性を持っていても、フォトダイオードの光検出
効率ｇの光入射位置依存性を、当該シンチレータから当
該フォトダイオードへの光到達効率のＸ線入射位置依存
性と相殺するようにしているので、検出素子全体として
の信号出力は、Ｘ線入射位置に依存しない。なお、ここ
で、Ｘ線がシンチレータへ入射する位置、即ちＸ線入射
位置は、近似的には、光がシンチレータからフォ１−ダ
イオード面へ出射する位買、即ち光出射位置に、はぼ等
しいものと考えて良い。In the radiation detection element according to the present invention, even if the light arrival efficiency f from the scintillator to the photodiode has an X-ray incident position dependence, the light detection efficiency g of the photodiode has a light incident position dependence. Since the dependence of the light arrival efficiency from the scintillator to the photodiode on the X-ray incident position is offset, the signal output of the detection element as a whole does not depend on the X-ray incident position. Note that here, the position where the X-rays enter the scintillator, that is, the X-ray incident position, is approximately equal to the position where the light exits from the scintillator to the photodiode surface, that is, the light exit position. It can be considered a thing.
以下、本発明の実施例を図面に基づいて詳細に説明する
。Embodiments of the present invention will be described in detail below with reference to the drawings.
第１図は、本発明の一実施例を示すＸ線検出素子の斜視
図である。本実施例に示すシンチレータ１０は、ＣｄＷ
Ｏ，結晶シンチレータ、Ｇｄ２Ｏ２Ｓ系セラミックシン
チレータ等で、例えば、３０ｍｍ Ｘ ３ ｍｍＸ１ｍ
ｍの大きさである。シンチレータＩＯのＸ線入射面およ
び側面１１．端面１２には、例えば、アルミによる光反
射膜が形成されている。FIG. 1 is a perspective view of an X-ray detection element showing one embodiment of the present invention. The scintillator 10 shown in this example is CdW
O, crystal scintillator, Gd2O2S ceramic scintillator, etc., for example, 30 mm x 3 mm x 1 m
The size is m. X-ray entrance surface and side surface of scintillator IO 11. A light reflecting film made of, for example, aluminum is formed on the end face 12.
また、シンチレータ１０のＸ線入射面と対向する面１３
には、例えば、非晶質Ｓ １−ｐｉｎフ第１−ダイオー
ドを、シンチレータ上に直接形成する。フォトダイオー
ドの出力は、ＩＶ変換回路により電圧信号に変換し、検
出する。In addition, a surface 13 of the scintillator 10 facing the X-ray incident surface
For example, an amorphous S1-pin diode is formed directly on the scintillator. The output of the photodiode is converted into a voltage signal by an IV conversion circuit and detected.
Ｘ線ＣＴ用の検出素子の場合、素子の長平方向（これを
Ｘ方向とする）がスライス方向に相当し、この方向の素
子感度分布が一様であることが大切である。この分布が
不均一だと、例えば１頭頂部撮影の如きスライス方向に
急激にＸ線吸収量が異なる被写体を撮影した場合、デー
タキャリプレーン９ンが十分行えず、ＣＴ両画像リング
状アーチファクトが生ずるからである。In the case of a detection element for X-ray CT, the longitudinal direction of the element (this is referred to as the X direction) corresponds to the slice direction, and it is important that the element sensitivity distribution in this direction be uniform. If this distribution is non-uniform, for example, when photographing a subject with sharply different X-ray absorption amounts in the slice direction, such as when photographing the top of the head, data calibration cannot be performed sufficiently, resulting in ring-shaped artifacts in both CT images. It is from.
短手方向（ｘ方向）に関しては、Ｘ方向はど、−様性に
対する要求は強くない。そこで、この素子のＸ方向につ
いてのみ、検出感度を一様にする。Regarding the lateral direction (x direction), there is no strong requirement for -likeness in the X direction. Therefore, the detection sensitivity of this element is made uniform only in the X direction.
その方法として、フォトダイオードのＸ方向の長さ（幅
：ｄとする）を変化させる。すなわち、シンチレータか
らフォトダイオードへの光伝達効率ｆ（ｘ）＝ｆ（ｘ、
ｙＪ
ここで、ｙｏはＸ方向の中心位置
に対してフォトダイオード幅ｄを、
ｄ （ｘ）ｃｃ ｆ−”（ｘ）
となるように設定する。これにより、ｄが一定のときの
光感度分布ｆ（ｘ）が、第３図（ａ）に示したものから
、第３図（ｂ）に示すような光感度分布に改善すること
ができた。第３図（ｂ）において、光感度が完全に一様
にならないのは、シンチレータ内で光が拡がるため、Ｘ
線入射位置（ｘ、ｙ）と光出射位置（ｘ’＋ｙ’）が必
ずしも一致しないためである。As a method, the length (width: d) of the photodiode in the X direction is changed. That is, the light transfer efficiency from the scintillator to the photodiode f(x) = f(x,
yJ Here, yo is the photodiode width d with respect to the center position in the f(x) could be improved from the one shown in Figure 3(a) to the photosensitivity distribution shown in Figure 3(b).In Figure 3(b), the photosensitivity distribution was The reason why the light is not completely uniform is that the light spreads within the scintillator, so
This is because the line incident position (x, y) and the light exit position (x'+y') do not necessarily match.
必要に応じてこのバラツキを更に補正することも可能で
ある。すなわち、上記補正後のＸ線感度分布をｇ ’
（ｘ ＋ ｙ ）とすれば、ｄ（ｘ）αｆ−’（ｘ）・
ｇ’−’（ｘ）とすれば良く、これにより、検出感度分
布をより一様にできる。It is also possible to further correct this variation if necessary. In other words, the X-ray sensitivity distribution after the above correction is g'
(x + y), then d(x)αf-'(x)・
g'-'(x), thereby making the detection sensitivity distribution more uniform.
以下、第４図に基づいて、フォトダイオードの形成方法
を説明する。シンチレータのフォトダイオード形成面は
、鏡面研磨等により平滑にする。Hereinafter, a method for forming a photodiode will be explained based on FIG. 4. The photodiode forming surface of the scintillator is made smooth by mirror polishing or the like.
その上に、必要に応じて、保護膜として、例えばＳｉＯ
２を形成する。更に、その上に透明電極として、例えば
、ＩＴＯ（酸化スズ・インジウム）、Ｓｎ○２．ＳｎＯ
，／ＩＴＯＺ層膜等を形成し、次に、ｎ型、ｉ型、ｎ型
の順に非晶質シリコン膜を、フォトダイオード面全面に
形成する。On top of that, if necessary, as a protective film, for example, SiO
form 2. Further, as a transparent electrode, for example, ITO (tin oxide/indium oxide), Sn○2. SnO
, /ITOZ layers, etc. are formed, and then n-type, i-type, and n-type amorphous silicon films are formed on the entire surface of the photodiode in this order.
ｎ型は例えば、膜厚０，０１ μｍのａ−８ＩＣ：Ｈ膜
、ｉ型は例えば、膜厚１μｍのａ−Ｓ工■イ膜、ｎ型は
、例えば膜厚０．０３μｍの微結晶水素化シリコン（μ
Ｃ−３、Ｃ：Ｈ）膜である。ｎ層上に、アルミ電極を形
成する。アルミ電極は、電極形成用マスクを用いて、先
に説明した素子形状に形成する。For example, the n-type is a 0.01 μm thick a-8IC:H film, the i-type is a 1 μm thick a-S technology film, and the n-type is a 0.03 μm thick microcrystalline hydrogen film. silicon chloride (μ
C-3, C:H) film. An aluminum electrode is formed on the n-layer. The aluminum electrode is formed into the element shape described above using an electrode formation mask.
電極形成後、プラズマエツチングにより、電極形成部以
外の非晶質膜を除去する。これにより、シンチレータの
光伝達効率の変動を相殺するフォトダイオードの形成が
でき、Ｘ方向について検出感度が一様な検出器が実現で
きる。After forming the electrodes, the amorphous film other than the electrode forming portions is removed by plasma etching. As a result, it is possible to form a photodiode that cancels out fluctuations in the light transmission efficiency of the scintillator, and it is possible to realize a detector with uniform detection sensitivity in the X direction.
本発明に係わるフォトダイオードの他の形成方法として
は、シンチレータ上に矩形のフ第１・ダイオードを前述
の方法により形成した後、Ｘ方向のＸ線感度分布を測定
して、この結果に基づき、例えば、レーザパターンユン
グ法により、第５図に示す如く、上記矩形のフォトダイ
オードに溝１４を切り、フォトダイオードを部分的に除
去することにより感度を調整する方法がある。ここで、
レーザパターンニングのビーム幅は、例えば１００〜５
００μｍ程度としシンチレータ内での光束の拡がりに比
べ小さいことが必要である。また、端面近傍ではパター
ンピッチは荒くし、中心部では細かくして、全体の感度
が一様になるようにしている。なお１本実施例における
パターンは、点状等、他の形状であっても良い。Another method for forming a photodiode according to the present invention is to form a rectangular first diode on a scintillator by the method described above, then measure the X-ray sensitivity distribution in the X direction, and based on this result, For example, there is a method of adjusting the sensitivity by cutting a groove 14 in the rectangular photodiode and partially removing the photodiode, as shown in FIG. 5, using the laser pattern Jung method. here,
The beam width of laser patterning is, for example, 100 to 5
It is necessary that the diameter is approximately 0.00 μm, which is smaller than the spread of the light flux within the scintillator. In addition, the pattern pitch is made rougher near the end face and finer in the center to make the overall sensitivity uniform. Note that the pattern in this embodiment may have other shapes such as dots.
この方法によれば、シンチレータの光伝達効率以外にフ
ォトダイオード感度にコントロール不可能な位置依存性
がある場合にも、フォトダイオードの幅を調整すること
により、Ｘ線検出素子の感度分布を一様にすることがで
きる。According to this method, even if the photodiode sensitivity has uncontrollable position dependence other than the light transmission efficiency of the scintillator, the sensitivity distribution of the X-ray detection element can be made uniform by adjusting the width of the photodiode. It can be done.
第６図は本発明の更に他の実施例を示すものであり、こ
の実施例では、上述の如きレーザパターンニングにより
、二次元面上でのＸ線検出感度を一定にしたものである
。FIG. 6 shows still another embodiment of the present invention, in which the X-ray detection sensitivity on a two-dimensional surface is made constant by laser patterning as described above.
上記各実施例においては、光検出素子として、フォトダ
イオードを用いた例を示したが、本発明は他の光検出素
子の使用を妨げるものではない。In each of the above embodiments, a photodiode is used as the photodetection element, but the present invention does not preclude the use of other photodetection elements.
以上述べた如く、本発明によれば、放射線を可視光に変
換するシンチレータと、該シンチレータの放射線入射面
と対向する面上に形成された光検出素子とを有する放射
線検出素子において、前記シンチレータの放射線入射面
上の点（ｘ、ｙ）に入射した放射線の生成する光が、前
記光検出素子が形成されたシンチレータ面（ｘ’＋ｙ’
）に到達する光到達効率をｆ（ｘ、ｙ）とした場合に、
前記光検出素子の光検出効率ｇ （” ’ ＋ ｙ ’
）が、ｇ（”＋ ｙ’）＝ｆ−１（ｘ、ｙ：ｘ＝ｘ’
＋ｙ＝ｙ’）となる如く、前記光検出素子の形状を決定
するようにしたので、検出感度の放射線入射位置依存性
のない、ＣＴ用検出器として好適な放射線検出素子を実
現できるという顕著な効果を奏するものである。As described above, according to the present invention, there is provided a radiation detection element including a scintillator that converts radiation into visible light and a photodetection element formed on the surface of the scintillator that faces the radiation incident surface. The light generated by the radiation incident on the point (x, y) on the radiation entrance surface is transmitted to the scintillator surface (x'+y'
) is f(x, y), then
The photodetection efficiency g of the photodetection element ("' + y '
) is g("+y')=f-1(x,y:x=x'
Since the shape of the photodetecting element is determined so that the detection sensitivity is not dependent on the radiation incident position, it is possible to realize a radiation detecting element suitable for use as a CT detector. It is effective.
第１図は本発明の一実施例を示すＸ線検出素子の斜視図
、第２図（ａ）は従来のＸ線検出素子の購造の一例を示
す斜視図、同（ｂ）はその動作特性を示す図、第３図は
実施例と従来技術における光感度分布の比較を示すグラ
フ、第４図は実施例のＸ線検出素子の断面図、第５図は
他の実施例を示すフォトダイオードの平面図、第６図（
ａ）は他の実施例を示す放射線検出素子の側面図、同（
ｂ）は同下面図である。
１０：シンチレータ、１１：側面、１２：端面、１３：
Ｘ線入射面と対向する面、１４：溝。
特許出願人 株式会社 日立製作所
゛パノ
第 １ 図
第 ２ 図
ゝ１３ａ
第 ２ 図
（ｂ）
Ｘ＠入射位置
第 ３ 図
（ａ）
１５ １０ ５ ０ （中
心）Ｘ方向Ｘ線入射位置（ｍｍ ）
中心からの距離
第 ４ 図FIG. 1 is a perspective view of an X-ray detection element showing an embodiment of the present invention, FIG. 2(a) is a perspective view showing an example of purchasing a conventional X-ray detection element, and FIG. Figure 3 is a graph showing a comparison of photosensitivity distribution between the example and the conventional technology, Figure 4 is a cross-sectional view of the X-ray detection element of the example, and Figure 5 is a photo showing another example. Top view of the diode, Figure 6 (
a) is a side view of a radiation detection element showing another embodiment;
b) is a bottom view of the same. 10: scintillator, 11: side surface, 12: end surface, 13:
Surface facing the X-ray incident surface, 14: Groove. Patent applicant: Hitachi, Ltd. Panorama Figure 1 Figure 2 Figure 2 13a Figure 2 (b) X @ incident position Figure 3 (a) 15 10 5 0 (center) Distance from Figure 4
Claims (1)
チレータの放射線入射面と対向する面上に形成された光
検出素子とを有する放射線検出素子において、前記シン
チレータの放射線入射面上の点（ｘ、ｙ）に入射した放
射線の生成する光が、前記光検出素子が形成されたシン
チレータ面（ｘ’、ｙ’）に到達する光到達効率をｆ（
ｘ、ｙ）とした場合に、前記光検出素子の光検出効率ｇ
（ｘ’、ｙ’）が、 ｇ（ｘ’、ｙ’）＝ｆ＾−＾１（ｘ、ｙ：ｘ＝ｘ’、ｙ
＝ｙ’）となる如く、前記光検出素子の形状を決定する
ことを特徴とする放射線検出素子。 ２、前記光検出素子の光検出効率ｇ（ｘ’、ｙ’）をそ
の感度分布が一様であることが要求される方向に走る溝
状の切欠部により、前記光検出素子の形状を調整するこ
とを特徴とする特許請求の範囲第１項記載の放射線検出
素子。 ３、前記光検出素子の光検出効率ｇ（ｘ’、ｙ’）をそ
の感度分布が一様であることが要求される方向と直交す
る方向の寸法のみを変化させることにより、前記光検出
素子の形状を調整することを特徴とする特許請求の範囲
第１項記載の放射線検出素子。[Claims] 1. A radiation detection element comprising a scintillator that converts radiation into visible light and a photodetection element formed on a surface opposite to the radiation incidence surface of the scintillator, wherein the radiation incidence surface of the scintillator The light arrival efficiency with which the light generated by the radiation incident on the upper point (x, y) reaches the scintillator surface (x', y') on which the photodetection element is formed is expressed as f(
x, y), the photodetection efficiency g of the photodetection element
(x', y') is g(x', y')=f^-^1(x, y: x=x', y
= y'). 2. The shape of the photodetecting element is adjusted by a groove-like notch running in a direction that requires uniform sensitivity distribution of the photodetecting efficiency g(x', y') of the photodetecting element. A radiation detection element according to claim 1, characterized in that: 3. By changing only the dimension of the photodetection efficiency g(x', y') of the photodetection element in the direction orthogonal to the direction in which the sensitivity distribution is required to be uniform, the photodetection element can be improved. The radiation detection element according to claim 1, wherein the shape of the radiation detection element is adjusted.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62332333A JPH01172791A (en) | 1987-12-28 | 1987-12-28 | Radiation detecting element |
| US07/261,420 US5041729A (en) | 1987-10-28 | 1988-10-24 | Radiation detector and manufacturing process thereof |
| DE3836835A DE3836835A1 (en) | 1987-10-28 | 1988-10-28 | RADIATION DETECTOR AND PRODUCTION METHOD DAFUER |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62332333A JPH01172791A (en) | 1987-12-28 | 1987-12-28 | Radiation detecting element |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01172791A true JPH01172791A (en) | 1989-07-07 |
Family
ID=18253789
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62332333A Pending JPH01172791A (en) | 1987-10-28 | 1987-12-28 | Radiation detecting element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01172791A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4868151A (en) * | 1986-06-25 | 1989-09-19 | Jujo Paper Co., Ltd. | Heat-sensitive recording material |
| US4982096A (en) * | 1988-01-06 | 1991-01-01 | Hitachi Medical Corporation | Multi-element radiation detector |
| JP2008286550A (en) * | 2007-05-15 | 2008-11-27 | Toshiba Corp | Detection element, detector, and manufacturing method for the detection element |
| KR100882537B1 (en) * | 2007-04-25 | 2009-02-18 | 라드텍주식회사 | A detector module with pixelated scintillators for radiation imaging and the manufacturing method thereof |
-
1987
- 1987-12-28 JP JP62332333A patent/JPH01172791A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4868151A (en) * | 1986-06-25 | 1989-09-19 | Jujo Paper Co., Ltd. | Heat-sensitive recording material |
| US4982096A (en) * | 1988-01-06 | 1991-01-01 | Hitachi Medical Corporation | Multi-element radiation detector |
| KR100882537B1 (en) * | 2007-04-25 | 2009-02-18 | 라드텍주식회사 | A detector module with pixelated scintillators for radiation imaging and the manufacturing method thereof |
| JP2008286550A (en) * | 2007-05-15 | 2008-11-27 | Toshiba Corp | Detection element, detector, and manufacturing method for the detection element |
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