JPH0554078B2 - - Google Patents
Info
- Publication number
- JPH0554078B2 JPH0554078B2 JP58006955A JP695583A JPH0554078B2 JP H0554078 B2 JPH0554078 B2 JP H0554078B2 JP 58006955 A JP58006955 A JP 58006955A JP 695583 A JP695583 A JP 695583A JP H0554078 B2 JPH0554078 B2 JP H0554078B2
- Authority
- JP
- Japan
- Prior art keywords
- single crystal
- thin film
- crystal substrate
- cdte single
- type cdte
- 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.)
- Expired - Lifetime
Links
- 239000000758 substrate Substances 0.000 claims description 24
- 239000013078 crystal Substances 0.000 claims description 22
- 230000005855 radiation Effects 0.000 claims description 22
- 239000010409 thin film Substances 0.000 claims description 22
- 229910004613 CdTe Inorganic materials 0.000 claims description 19
- 229910052738 indium Inorganic materials 0.000 claims description 4
- 238000010586 diagram Methods 0.000 description 8
- 239000000969 carrier Substances 0.000 description 5
- 239000012212 insulator Substances 0.000 description 3
- 238000005520 cutting process Methods 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 230000005684 electric field Effects 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 239000003708 ampul Substances 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
- G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
- G01T1/16—Measuring radiation intensity
- G01T1/24—Measuring radiation intensity with semiconductor detectors
Landscapes
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Physics & Mathematics (AREA)
- High Energy & Nuclear Physics (AREA)
- Molecular Biology (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Light Receiving Elements (AREA)
- Measurement Of Radiation (AREA)
Description
【発明の詳細な説明】
本発明は、Ｘ線CT等に用いられる多チヤンネ
ル形放射線検出器に関するものである。更に詳し
くは、本発明はＰ形CdTe単結晶基板を用いた位
置分解能の高い多チヤンネル形放射線検出器に関
するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multichannel radiation detector used in X-ray CT and the like. More specifically, the present invention relates to a multichannel radiation detector with high positional resolution using a P-type CdTe single crystal substrate.
第１図は従来公知のＸ線CTに用いられている
Xeガス電離箱の一例を示す構成斜視図である。
この電離箱は、絶縁体サポート１の間に高圧電極
２１と信号電極３１とを交互に例えば0.5mm〜1.0
mmの間隔で配列し、これらをXeガス25Kg／cm2に
加圧された耐圧容器４内に収容して構成されてい
る。ここで、Xeガス加圧を行なうのは、Ｘ線CT
センサとしての高感度を得るためである。各電極
板は、電極間ギヤツプを1.0mm程度以下と小さく
する必要があることから、0.1mm程度の薄いしか
も放射線が透過しにくいタングステン材料が用い
られている。 Figure 1 is used in conventionally known X-ray CT.
FIG. 2 is a perspective view of the configuration of an example of a Xe gas ionization chamber.
In this ionization chamber, high voltage electrodes 21 and signal electrodes 31 are arranged alternately between insulator supports 1, for example, by 0.5 mm to 1.0 mm.
They are arranged at intervals of mm and housed in a pressure-resistant container 4 pressurized to 25 kg/cm 2 of Xe gas. Here, Xe gas pressurization is performed using X-ray CT.
This is to obtain high sensitivity as a sensor. Since each electrode plate needs to have a small interelectrode gap of about 1.0 mm or less, it is made of tungsten material that is thin, about 0.1 mm, and difficult for radiation to pass through.
このように構成される従来のXeガス電離箱に
おいては、耐圧容器が必要で全体構成が大型かつ
重量も大きくなる欠点がある。また、薄い電極を
用いることから、これら各電極板の振動防止がノ
イズ対策上必要であり、また、絶縁体サポータの
絶縁物表面リークによるノイズ電流も考慮しなく
てはならない欠点がある。 The conventional Xe gas ionization chamber configured in this manner has the disadvantage that a pressure-resistant container is required, resulting in a large and heavy overall configuration. Furthermore, since thin electrodes are used, it is necessary to prevent vibration of each of these electrode plates as a noise countermeasure, and there is also the drawback that noise current due to leakage from the surface of the insulator of the insulator supporter must be taken into consideration.
ここにおいて、本発明は従来のXeガス電離箱
の欠点に鑑みてなされたもので、各チヤンネル間
ピツチを小さくでき、全体が小形で製作が容易、
かつ動作の安定な多チヤンネル形放射線検出器を
実現しようとするものである。 Here, the present invention was made in view of the drawbacks of the conventional Xe gas ionization chamber, and the pitch between each channel can be reduced, the whole is small and easy to manufacture.
The aim is to realize a multi-channel radiation detector with stable operation.
第２図は本発明に係る多チヤンネル放射線検出
器の一例を示す構成斜視図である。この図におい
て、５は厚さが１〜２mmのＰ形CdTe単結晶基板
である。このCdTe単結晶基板は、CdとTeとを
化学当量混合し、これを石英ガラスアンプルに真
空封入した後、ブリツジマン炉等で加熱し、結晶
化し、得られた単結晶インゴツトを切断、加工し
て作られる。６はCdTe単結晶基板５の一方の面
（背面側）に設けた共通電極で、単結晶基板５と
はオーミツク接合し、本発明においては、これ
が、Agペースト層によつて形成されている。７
１，７２，７３，…７ｎは、CdTe単結晶基板５
の他方の面に所定ピツチで配列するように設けた
Al又はInの薄膜電極で、例えば蒸着法又はスパ
ツタ法によつて付着形成される。これらの各薄膜
電極７１，７２，７３，…７ｎは、CdTe単結晶
基板５との間でシヨツトキーバリヤ接合し、有感
電極として作用する。８は単結晶基板５の支持ホ
ールダで、基板５は、共通電極６を構成するAg
ペーストの接着力によつてこの支持ホールダに固
着されている。 FIG. 2 is a perspective view showing an example of a multichannel radiation detector according to the present invention. In this figure, 5 is a P-type CdTe single crystal substrate with a thickness of 1 to 2 mm. This CdTe single-crystal substrate is produced by mixing Cd and Te in chemical equivalents, vacuum-sealing the mixture in a quartz glass ampoule, heating it in a Bridgeman furnace, etc. to crystallize it, and cutting and processing the resulting single-crystal ingot. Made. Reference numeral 6 denotes a common electrode provided on one surface (back side) of the CdTe single crystal substrate 5, which is in ohmic contact with the single crystal substrate 5, and in the present invention is formed of an Ag paste layer. 7
1, 72, 73,...7n are CdTe single crystal substrates 5
arranged at a predetermined pitch on the other side of the
Thin film electrodes of Al or In, deposited, for example, by vapor deposition or sputtering. Each of these thin film electrodes 71, 72, 73, . 8 is a support holder for the single crystal substrate 5, and the substrate 5 is an Ag constituting the common electrode 6.
It is fixed to this support holder by the adhesive force of the paste.
このように構成された多チヤンネル放射線検出
器において、測定すべき放射線は、薄膜電極７
１，７２，７３，…７ｎ側から入射する。 In the multi-channel radiation detector configured in this way, the radiation to be measured is transmitted through the thin film electrode 7.
The light is incident from the 1, 72, 73, . . . 7n side.
第３図は、本発明に係る放射線検出器の動作を
説明するための説明図で、イは断面図、ロはイに
対応する結晶基板内部の電位分布図である。 FIG. 3 is an explanatory diagram for explaining the operation of the radiation detector according to the present invention, in which A is a sectional view and B is a potential distribution diagram inside the crystal substrate corresponding to A.
CdTe単結晶基板５と、Al又はInで形成した薄
膜電極７１とが、シヨツトキーバリア接合を形成
すると、第３図ロに示すように薄膜電極７１側か
ら電位分布が生じ、これによつて薄膜電極７１付
近に幅Weffの空乏層５０が生じる。ここに、薄
膜電極７１側から放射線が入射すると、その中で
エネルギーを失い、自由キヤリアが発生する。基
板５はＰ形CdTeであつて、正孔が多数キヤリア
となる。このキヤリアは、空乏層５０内で発生し
たものが、薄膜電極７１に集められ、電離電流I1
として外部に取り出される。この電離電流I1の大
きさは、薄膜電極７１が形成されている面に入射
する放射線エネルギに対応している。なお、空乏
層５０内で発生した自由キヤリアは、この空乏層
内の電界で加速され、薄膜電極７１に到達し、電
離電流となるが、これ以外で発生したキヤリア
は、電界が存在しないので加速されず、直ちに再
結合して消滅するので、電離電流には寄与しな
い。 When the CdTe single crystal substrate 5 and the thin film electrode 71 made of Al or In form a shot key barrier junction, a potential distribution is generated from the thin film electrode 71 side as shown in FIG. A depletion layer 50 having a width Weff is generated near the thin film electrode 71. When radiation enters here from the thin film electrode 71 side, energy is lost therein and free carriers are generated. The substrate 5 is P-type CdTe, and many holes serve as carriers. These carriers are generated within the depletion layer 50 and are collected on the thin film electrode 71, resulting in an ionization current I 1
It is taken out to the outside as. The magnitude of this ionization current I 1 corresponds to the radiation energy incident on the surface on which the thin film electrode 71 is formed. Note that free carriers generated within the depletion layer 50 are accelerated by the electric field within this depletion layer, reach the thin film electrode 71, and become an ionization current, but carriers generated elsewhere are accelerated because no electric field exists. Since it immediately recombines and disappears, it does not contribute to the ionization current.
このような動作は、第２図において、各薄膜電
極７１，７２，７３…が形成された各部分につい
てそれぞれ適用されるものであつて、各空乏層で
それぞれ放射線感度をもつ複数チヤンネルの放射
線検出器が実現できる。 Such an operation is applied to each portion where the thin film electrodes 71, 72, 73, etc. are formed in FIG. The device can be realized.
このように構成された本発明に係る放射線検出
器は、放射線のエネルギー吸収効率が高いこと、
無バイアスで放射線検出が行なえる等の特長があ
る。また、各薄膜電極相互間の相互干渉もなく、
信号を分離できる。それ故に、薄膜電極の配列ピ
ツチを小さくすることが可能で、位置分解能の高
い多チヤンネル形放射線検出器が実現できる。 The radiation detector according to the present invention configured as described above has high radiation energy absorption efficiency;
It has the advantage of being able to detect radiation without bias. In addition, there is no mutual interference between each thin film electrode,
Can separate signals. Therefore, the arrangement pitch of the thin film electrodes can be reduced, and a multichannel radiation detector with high positional resolution can be realized.
第４図は、本発明に係る放射線検出器における
放射線（Ｘ線）ビーム位置と薄膜電極７１，７２
からの出力の関係を示す線図である。 FIG. 4 shows the radiation (X-ray) beam position and thin film electrodes 71 and 72 in the radiation detector according to the present invention.
2 is a diagram showing the relationship between the outputs from the
第５図は、第４図線図を得るための実験システ
ム説明図である。ここでは、Ｐ形CdTe単結晶基
板５上に、薄膜電極を、電極ピツチ１mm、電極幅
0.5mmでAlを蒸着して形成させた場合である。Ｘ
線管８１より発生したCWX線をチヨツパ８２に
よつて断続し、これをスリツトコリメータ８３を
介して、放射線CdTe検出器に照射する。この検
出器は、図示してないが、1/400mm単位で動く移
動ステージに乗つており、これを移動させつつ、
各薄膜電極７１，７２からの信号電圧V71′V72の
感度比をプロツトしたものである。 FIG. 5 is an explanatory diagram of an experimental system for obtaining the diagram shown in FIG. Here, thin film electrodes are placed on a P-type CdTe single crystal substrate 5 with an electrode pitch of 1 mm and an electrode width of 1 mm.
This is the case where Al is deposited to a thickness of 0.5 mm. X
The CW X-rays generated from the ray tube 81 are interrupted by a chopper 82, and are irradiated to a radiation CdTe detector via a slit collimator 83. This detector is mounted on a moving stage that moves in 1/400 mm units, although it is not shown.
The sensitivity ratio of the signal voltages V 71 'V 72 from the respective thin film electrodes 71 and 72 is plotted.
第４図に示した実験結果から、隣接チヤンネル
からの信号リークは非常に小さく、チヤンネル分
離特性が良好であることが認められる。 From the experimental results shown in FIG. 4, it is recognized that signal leakage from adjacent channels is very small and the channel separation characteristics are good.
なお、上記の実験例では、CdTe単結晶基板５
上に線状の薄膜電極を所定ピツチで一列に配列し
たものについて例示したが、点状の薄膜電極を格
子状に配列し、二次元的に配列する多チヤンネル
放射線検出器を構成してもよい。 In addition, in the above experimental example, the CdTe single crystal substrate 5
Although the example shown above is one in which linear thin film electrodes are arranged in a line at a predetermined pitch, a multi-channel radiation detector in which dotted thin film electrodes are arranged in a grid pattern and arranged two-dimensionally may also be constructed. .
以上詳細に説明したように、本発明によれば、
Ｐ形CdTe単結晶基板、Agペースト層による共通
電極、複数個のAlまたはInの線状薄膜電極の組
み合わせで構成したもので、各チヤンネル間に切
り込み溝などを設けなくとも隣のチヤンネルとの
間での信号分離が可能となり、チヤンネル間ピツ
チを小さくすることができる上に、全体を小形に
構成できる。 As explained in detail above, according to the present invention,
It is composed of a P-type CdTe single crystal substrate, a common electrode made of an Ag paste layer, and multiple linear thin film electrodes of Al or In, so that each channel can be connected to the adjacent channel without the need for cutting grooves or the like. This makes it possible to separate signals at each channel, reduce the pitch between channels, and also make the entire structure compact.
また、本発明においては、Ｐ形CdTe単結晶基
板の連続する他方の表面にAgペースト層によつ
て共通電極を形成し、このAgペースト層の接着
力によつて、Ｐ形CdTe単結晶基板をホールダに
固着保持するように構成した結果、１mm程度の薄
いＰ形CdTe単結晶基板を、電気的に影響しない
形態で、しかも機械的な強度を維持しながら、長
期間にわたつて安定して保持することができ、動
作の安定な多チヤンネル形放射線検出器が実現で
きる。 Furthermore, in the present invention, a common electrode is formed on the other continuous surface of the P-type CdTe single-crystal substrate using an Ag paste layer, and the P-type CdTe single-crystal substrate is As a result of being configured to be firmly held in the holder, a thin P-type CdTe single crystal substrate of approximately 1 mm can be stably held for a long period of time without being affected electrically, while maintaining mechanical strength. A multi-channel radiation detector with stable operation can be realized.
第１図は従来公知のＸ線CTに用いられている
Xeガス電離箱の一例を示す構成斜視図、第２図
は本発明に係る放射線検出器の一例を示す構成斜
視図、第３図は動作説明図、第４図は特性の一例
を示す線図、第５図は第４図の特性を得るための
実験システム説明図である。
５……CdTe単結晶基板、６……共通電極、７
１，７２，７３……薄膜電極。
Figure 1 is used in conventionally known X-ray CT.
FIG. 2 is a perspective view of the structure of an example of the Xe gas ionization chamber, FIG. 2 is a perspective view of the structure of an example of the radiation detector according to the present invention, FIG. 3 is an explanatory diagram of operation, and FIG. 4 is a diagram showing an example of characteristics. , FIG. 5 is an explanatory diagram of an experimental system for obtaining the characteristics shown in FIG. 4. 5... CdTe single crystal substrate, 6... Common electrode, 7
1, 72, 73...Thin film electrode.
Claims (1)
と、 Ｐ形CdTe単結晶基板の連続する一方の表面に
所定ピツチで配列するように形成した複数個の
AlまたはInの薄膜電極と、 このＰ形CdTe単結晶基板の連続する他方の表
面にAgペースト層によつて形成した共通電極と、 Agペースト層の接着力によつて前記Ｐ形CdTe
単結晶基板を固着保持する支持ホールダとを備
え、 前記薄膜電極側から被測定放射線を入射させる
ようにした多チヤンネル形放射線検出器。[Claims] 1. A flat substrate made of a P-type CdTe single crystal, and a plurality of substrates arranged at a predetermined pitch on one continuous surface of the P-type CdTe single crystal substrate.
A thin film electrode of Al or In, a common electrode formed by an Ag paste layer on the other continuous surface of this P-type CdTe single crystal substrate, and a common electrode formed by an Ag paste layer on the other continuous surface of this P-type CdTe single crystal substrate, and
A multi-channel radiation detector, comprising a support holder that firmly holds a single crystal substrate, and in which radiation to be measured is incident from the thin film electrode side.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58006955A JPS59132382A (en) | 1983-01-19 | 1983-01-19 | Multichannel type radiation detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58006955A JPS59132382A (en) | 1983-01-19 | 1983-01-19 | Multichannel type radiation detector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59132382A JPS59132382A (en) | 1984-07-30 |
| JPH0554078B2 true JPH0554078B2 (en) | 1993-08-11 |
Family
ID=11652645
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58006955A Granted JPS59132382A (en) | 1983-01-19 | 1983-01-19 | Multichannel type radiation detector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59132382A (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0734480B2 (en) * | 1986-07-07 | 1995-04-12 | 株式会社ジャパンエナジー | CdTe radiation detection element |
| US6331705B1 (en) | 1997-05-08 | 2001-12-18 | State Of Israel, Atomic Energy Commission | Room temperature solid state gamma or X-ray detectors |
| IL120807A (en) * | 1997-05-08 | 2001-03-19 | Israel Atomic Energy Comm | Method for compensating for the effects of incomplete charge collection and for improving spectroscopic characteristics of room temperature solid state gamma or x-ray detectors |
| US6621084B1 (en) * | 1998-09-24 | 2003-09-16 | Elgems Ltd. | Pixelated photon detector |
| EP1674887A3 (en) * | 1998-09-24 | 2006-11-08 | Elgems Ltd. | Pixelated photon detector |
| US7122804B2 (en) * | 2002-02-15 | 2006-10-17 | Varian Medical Systems Technologies, Inc. | X-ray imaging device |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4929070A (en) * | 1972-07-12 | 1974-03-15 | ||
| JPS57149981A (en) * | 1981-03-12 | 1982-09-16 | Yokogawa Hokushin Electric Corp | Multichannel type radiation detector |
-
1983
- 1983-01-19 JP JP58006955A patent/JPS59132382A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4929070A (en) * | 1972-07-12 | 1974-03-15 | ||
| JPS57149981A (en) * | 1981-03-12 | 1982-09-16 | Yokogawa Hokushin Electric Corp | Multichannel type radiation detector |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS59132382A (en) | 1984-07-30 |
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