JPH0627852B2 - Radiation detector - Google Patents
Radiation detectorInfo
- Publication number
- JPH0627852B2 JPH0627852B2 JP2229867A JP22986790A JPH0627852B2 JP H0627852 B2 JPH0627852 B2 JP H0627852B2 JP 2229867 A JP2229867 A JP 2229867A JP 22986790 A JP22986790 A JP 22986790A JP H0627852 B2 JPH0627852 B2 JP H0627852B2
- Authority
- JP
- Japan
- Prior art keywords
- radiation detector
- radiation
- raising device
- temperature raising
- present
- 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 - Fee Related
Links
Landscapes
- Measurement Of Radiation (AREA)
- Light Receiving Elements (AREA)
Description
【発明の詳細な説明】 ［産業上の利用分野］ 本発明は、例えば、医療分野、工業分野、原子力分野等
の高線量率な放射線を計測する分野で使用する放射線検
出器に関する。DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a radiation detector used in the field of measuring radiation with a high dose rate, such as the medical field, industrial field, and nuclear field.
［従来技術］ 室温使用、高感度を目的とした放射線検出器としては、
広いバンドギャップを有し、高原子番号の元素から構成
される、ＧａＡｓ、ＣｄＴｅ、ＨｇＩ２等の化合物半導
体を用いたものが一般的である。[Prior Art] As a radiation detector for room temperature use and high sensitivity,
It is common to use a compound semiconductor such as GaAs, CdTe, or HgI 2 having a wide band gap and composed of a high atomic number element.
［発明が解決しようとする課題］ 上記のような化合物半導体は、放射線検出素子として用
いるための高抵抗結晶の育成が難しく、多数の欠陥を有
する結晶しか得られていない。[Problems to be Solved by the Invention] In the compound semiconductor as described above, it is difficult to grow a high resistance crystal for use as a radiation detection element, and only a crystal having many defects is obtained.
これらの欠陥は、検出素子中で放射線の入射によって生
じたキャリアの捕獲中心として働き、捕獲状態で存在す
る時間（デトラッピングタイム）τＤが長いものは、式
１に示すように実効的なキャリアの移動度μｒを低下さ
せ、第７図の（ａ）のように高線量入射時の出力低下現
象を引き起こしていた。These defects act as a trapping center for carriers generated by the incidence of radiation in the detection element, and those having a long trap time (detrapping time) τ D are effective carriers as shown in Equation 1. The mobility μ r of γ was decreased, causing the output decrease phenomenon at the time of high dose incidence as shown in FIG. 7 (a).
〔μ０：キャリアの真の移動度、τ＋：自由キャリアが
捕獲されるまでの時間（トラッピングタイム）〕 なお、第７図の（ｂ）は２重計数を無視した理論直線で
あり、（ｃ）は出力低下が無い場合の実験データであ
る。 [Μ 0 : true carrier mobility, τ + : time until free carriers are captured (trapping time)] Note that (b) in FIG. 7 is a theoretical straight line ignoring double counting, c) is experimental data when there is no output reduction.
また、このような欠陥は結晶内に局所的に分布するため
に、放射線透過画像撮影用のアレイ型放射線検出素子に
は特に大きな影響を与え、得られた画像に補正不可能な
ムラを生じさせていた。Further, since such defects are locally distributed in the crystal, they have a particularly large influence on the array type radiation detection element for radiographic image capturing, causing uncorrectable unevenness in the obtained image. Was there.
本発明は上記のような従来技術の欠点を解消するために
創案されたものであり、欠陥が多数存在する化合物半導
体を用いても、高線量入射時に出力低下現象が起こらな
い良好な放射線検出器を提供することを目的とする。The present invention was devised in order to solve the above-mentioned drawbacks of the prior art. Even if a compound semiconductor having a large number of defects is used, a good radiation detector that does not cause an output reduction phenomenon at high dose incidence. The purpose is to provide.
［課題を解決するための手段］ 上記目的を達成するために、本発明の放射線検出器は、
放射線検出器の近傍に昇温装置を配置し、この昇温装置
によって検出素子を加熱することにより、実効的なキャ
リア移動度を増加させ、高線量入射時に生じる出力低下
現象を抑制する。[Means for Solving the Problems] In order to achieve the above object, the radiation detector of the present invention comprises:
By disposing a temperature raising device near the radiation detector and heating the detection element by this temperature raising device, the effective carrier mobility is increased and the output reduction phenomenon occurring at the time of high dose incidence is suppressed.
［作用］ 捕獲されていない自由キャリアの密度Ｎと、捕獲状態に
あるキャリアの密度ＮＴとの比Ｎ／ＮＴは、詳細平衡の
原理より、 と表され、これはまた、半導体のバンド理論より、 〔Ｎｃ：伝導帯の状態密度、ＮＤ：トラップレベルの状
態密度、ＥＤ：トラップレベルの位置エネルギー〕 とも表せる。よって、式２＝式３より、 として、捕獲状態で存在する時間を表現できる。[Operation] The ratio N / N T of the density N T of uncaptured free carriers to the density N T of carriers in the trapped state is Which is also based on the semiconductor band theory, [N c : conduction band density of states, N D : trap level density of states, E D : trap level potential energy]. Therefore, from Equation 2 = Equation 3, As, the time existing in the capture state can be expressed.
ここで、τ＋の値は常温付近でτＤに比べて殆ど変化し
ないことが実験的に確かめられているため、τＤの値は
温度Ｔの逆数の指数関数で変化する。すなわち、温度Ｔ
が上昇すると急激に捕獲状態で存在する時間τＤが減少
し、それに伴ってキャリアの実効的な移動度μｒも増加
する。Here, it has been experimentally confirmed that the value of τ + hardly changes as compared with τ D at around room temperature, so the value of τ D changes as an exponential function of the reciprocal of the temperature T. That is, the temperature T
When rises, the time τ D existing in the trapped state decreases rapidly, and the effective mobility μ r of carriers also increases accordingly.
本発明はこの原理を利用したものであり、放射線検出素
子の近傍に設けた昇温装置によって放射線検出素子を加
熱して、実効的なキャリア移動度を増加させることによ
り、高線量入射時にも出力低下を引き起こさないように
することができる。The present invention utilizes this principle, and the radiation detecting element is heated by the temperature raising device provided in the vicinity of the radiation detecting element to increase the effective carrier mobility. It can be prevented from causing a decline.
［実施例］ 本発明の実施例を以下図面に基づいて説明する。[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.
第１図は本発明の放射線検出器の一実施例であり、１は
放射線検出素子、２は信号処理回路、３は昇温装置、４
はプリント基板であり、プリント基板４上に放射線検出
素子１と信号処理回路２とが載っており、放射線検出素
子１と反対側に、プリント基板４を挟んで昇温装置３が
取り付けられている。この昇温装置３によって放射線検
出素子１は適切な温度に加熱され保持される。FIG. 1 shows an embodiment of a radiation detector of the present invention, in which 1 is a radiation detection element, 2 is a signal processing circuit, 3 is a temperature raising device, and 4 is a temperature raising device.
Is a printed circuit board, the radiation detection element 1 and the signal processing circuit 2 are mounted on the printed circuit board 4, and the temperature raising device 3 is attached on the opposite side of the radiation detection element 1 with the printed circuit board 4 interposed therebetween. . The radiation detecting element 1 is heated and held at an appropriate temperature by the temperature raising device 3.
次に、この放射線検出器をアレイ型放射線検出器に用い
た場合の使用方法を説明する。Next, a method of using this radiation detector when used as an array type radiation detector will be described.
第１図に示した放射線検出器を第２図のように放射線検
出素子１が平面状に一列に並ぶように配置するととも
に、各列の素子を各列ごとに第３図に示すように相互に
ずらせて集合させて階段状に配置することにより、アレ
イ型放射線検出器を構成する。そして、各放射線検出器
の昇温装置３に信号を加えない状態で放射線入射量を変
化させながら、各放射線検出器のカウント数を測定す
る。The radiation detectors shown in FIG. 1 are arranged so that the radiation detection elements 1 are arranged in a line in a plane as shown in FIG. 2, and the elements of each row are arranged in each row as shown in FIG. An array type radiation detector is constructed by staggering and arranging them in a stepwise manner. Then, the count number of each radiation detector is measured while changing the amount of radiation incident without applying a signal to the temperature raising device 3 of each radiation detector.
この測定の結果、例えば、第４図のように、※印の画素
で出力低下が起こっているとすると、この各画素ごとの
欠陥分布に従い、各放射線検出器の昇温装置３に任意な
温度分布を持たせることにより、第５図のように出力低
下が生じていた※印の画素も他の画素と同程度の出力を
得ることができ、アレイ型放射線検出器の感度ムラを低
減することができる。As a result of this measurement, if, for example, as shown in FIG. 4, the output is reduced in the pixel marked with *, according to the defect distribution of each pixel, the temperature of the temperature raising device 3 of each radiation detector is set to an arbitrary temperature. By giving the distribution, the output of the pixel marked with * as shown in Fig. 5 can be obtained at the same level as other pixels, and the sensitivity unevenness of the array type radiation detector can be reduced. You can
なお、上記実施例では昇温装置をプリント基板を挟んで
放射線検出素子と反対側に設けた場合を説明したが、こ
の設置場所はこれに限らず、放射線検出素子を加熱でき
る場所であれば任意の位置に設けることができる。In the above embodiment, the case where the temperature raising device is provided on the side opposite to the radiation detecting element with the printed circuit board interposed therebetween is not limited to this, and any location may be used as long as the radiation detecting element can be heated. Can be provided at the position.
第６図は本発明の他の実施例であり、一枚のプリント基
板４の片面に放射線検出素子１…１を２次元的に配列
し、その裏面に信号処理回路２を実装した複数枚のプリ
ント基板５を検出側の基板４にそれぞれ垂直に実装した
３次元実装構造のアレイ型放射線検出器である。このア
レイ型放射線検出器の場合にも、各放射線検出素子１の
近傍に昇温装置を設け、各画素ごとの欠陥分布に従い、
昇温装置に任意な温度分布を持たせることにより、感度
ムラを低減することができる。FIG. 6 shows another embodiment of the present invention. A plurality of radiation detection elements 1 ... 1 are two-dimensionally arranged on one surface of one printed circuit board 4 and a signal processing circuit 2 is mounted on the back surface thereof. This is an array type radiation detector having a three-dimensional mounting structure in which a printed circuit board 5 is vertically mounted on each of the detection side substrates 4. Also in the case of this array type radiation detector, a temperature raising device is provided in the vicinity of each radiation detection element 1, and according to the defect distribution for each pixel,
By giving the temperature raising device an arbitrary temperature distribution, sensitivity unevenness can be reduced.
さらに、第６図のような３次元実装構造のアレイ型放射
線検出器をマトリックス状に配置した大規模放射線検出
器にも本発明を適用することができる。Furthermore, the present invention can be applied to a large-scale radiation detector in which array-type radiation detectors having a three-dimensional mounting structure as shown in FIG. 6 are arranged in a matrix.
昇温装置の種類としては、抵抗加熱、赤外線加熱、電磁
加熱等いかなるものでも使用可能である。Any type of heating device such as resistance heating, infrared heating, electromagnetic heating, etc. can be used.
［発明の効果］ 本発明の放射線検出器は以上のように構成されているの
で、欠陥が多数存在する化合物半導体結晶を用いても、
高線量入射時に出力低下現象が起こらない良好な特性を
得ることができる。EFFECT OF THE INVENTION Since the radiation detector of the present invention is configured as described above, even if a compound semiconductor crystal having many defects is used,
It is possible to obtain good characteristics in which the output reduction phenomenon does not occur at high dose incidence.
また、その結果、アレイ型放射線検出器の感度ムラを大
幅に低減でき、アレイ面積の拡大化と、材料コストの低
減化が可能となる。Further, as a result, the sensitivity unevenness of the array type radiation detector can be significantly reduced, and the array area can be expanded and the material cost can be reduced.
第１図は本発明の放射線検出器の実施例を示す図、第２
図、第３図は第１図に示した放射線検出器をマトリック
ス状に配置したアレイ型放射線検出器を示す図、第４図
は従来のアレイ型放射線検出器の各画素の出力特性を示
す図、第５図は本発明を適用した場合のアレイ型放射線
検出器の各画素の出力特性を示す図、第６図は本発明の
他の実施例を示す図、第７図は高線量入射時の出力低下
現象を説明するための図である。 １……放射線検出素子、２……信号処理回路、 ３……昇温装置、４……プリント基板FIG. 1 is a diagram showing an embodiment of the radiation detector of the present invention, and FIG.
3 and FIG. 3 are diagrams showing an array type radiation detector in which the radiation detectors shown in FIG. 1 are arranged in a matrix, and FIG. 4 is a diagram showing output characteristics of each pixel of a conventional array type radiation detector. FIG. 5 is a diagram showing the output characteristics of each pixel of the array type radiation detector when the present invention is applied, FIG. 6 is a diagram showing another embodiment of the present invention, and FIG. FIG. 6 is a diagram for explaining the output reduction phenomenon of FIG. 1 ... Radiation detecting element, 2 ... Signal processing circuit, 3 ... Temperature raising device, 4 ... Printed circuit board
Claims (1)
この放射線検出素子の近傍に配置された昇温装置とを有
することを特徴とする放射線検出器。1. A radiation detecting element comprising a compound semiconductor,
A radiation detector, comprising: a temperature raising device arranged near the radiation detection element.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2229867A JPH0627852B2 (en) | 1990-08-30 | 1990-08-30 | Radiation detector |
| EP91114396A EP0473125B1 (en) | 1990-08-30 | 1991-08-28 | Radiation detector |
| DE69116770T DE69116770T2 (en) | 1990-08-30 | 1991-08-28 | Radiation detector |
| US07/751,888 US5248885A (en) | 1990-08-30 | 1991-08-29 | Radiation detector having means for exciting trapped carriers |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2229867A JPH0627852B2 (en) | 1990-08-30 | 1990-08-30 | Radiation detector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04110691A JPH04110691A (en) | 1992-04-13 |
| JPH0627852B2 true JPH0627852B2 (en) | 1994-04-13 |
Family
ID=16898946
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2229867A Expired - Fee Related JPH0627852B2 (en) | 1990-08-30 | 1990-08-30 | Radiation detector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0627852B2 (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002202377A (en) * | 2001-01-05 | 2002-07-19 | Shimadzu Corp | Radiation detector |
| JP2003130961A (en) * | 2001-07-19 | 2003-05-08 | Siemens Ag | Detector module, detector for X-ray computed tomography, and method for creating tomographic image by X-ray computed tomography |
| US7514692B2 (en) * | 2005-06-22 | 2009-04-07 | Ge Medical Systems Israel, Ltd. | Method and apparatus for reducing polarization within an imaging device |
| US7312458B2 (en) * | 2005-06-22 | 2007-12-25 | General Electric Company | Method and apparatus for reducing polarization within an imaging device |
| US7781741B2 (en) * | 2005-10-27 | 2010-08-24 | General Electric Company | Methods and systems for controlling data acquisition system noise |
| JP2014519026A (en) * | 2011-05-11 | 2014-08-07 | コーニンクレッカ フィリップス エヌ ヴェ | Detection of ionizing radiation |
| JP2014145705A (en) * | 2013-01-30 | 2014-08-14 | Japan Atomic Energy Agency | Characteristic recovery method of silicon carbide radiation detector and operational method thereof |
| US9360564B2 (en) * | 2013-08-30 | 2016-06-07 | Semiconductor Energy Laboratory Co., Ltd. | Imaging device |
| EP4392766A1 (en) * | 2021-08-23 | 2024-07-03 | Kromek Group, Plc | Device performance prediction using material properties |
-
1990
- 1990-08-30 JP JP2229867A patent/JPH0627852B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04110691A (en) | 1992-04-13 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5248885A (en) | Radiation detector having means for exciting trapped carriers | |
| US6333504B1 (en) | Semiconductor radiation detector with enhanced charge collection | |
| EP1116047B1 (en) | Pixelated photon detector | |
| US6069360A (en) | Method and apparatus for electron-only radiation detectors from semiconductor materials | |
| JPH06505800A (en) | Digital gamma ray imaging device | |
| DE102007036821A1 (en) | Image detecting device controlling method, e.g. for use in gamma camera, involves applying heat to image detecting device having ohmic contact, and controlling heat to adjust temperature level of image detecting device | |
| JP2009534671A (en) | Radiation detector and polarization-reduced detection method | |
| JPH0627852B2 (en) | Radiation detector | |
| JPH08211199A (en) | X-ray image pickup device | |
| CN1023063C (en) | Radiography device | |
| US20220350038A1 (en) | Imaging system | |
| Owens et al. | Single carrier sensing techniques in compound semiconductor detectors | |
| CN100449765C (en) | x-ray inspection equipment | |
| US20100102844A1 (en) | Proximity charge sensing for semiconductor detectors | |
| Patt et al. | Mercuric iodide X-ray camera | |
| US20220365231A1 (en) | Imaging systems and methods of operating the same | |
| US20210263171A1 (en) | Radiation detector | |
| JPS6276478A (en) | two-dimensional radiation detector | |
| JP2733930B2 (en) | Semiconductor radiation detector | |
| US20230402486A1 (en) | Imaging methods using radiation detectors | |
| TWI842206B (en) | Imaging systems with image sensors for side radiation incidence during imaging and method of using the same | |
| JP2000046951A (en) | Radiation detection element | |
| Manolopoulos et al. | X-ray imaging with photon counting hybrid semiconductor pixel detectors | |
| WO2024044925A1 (en) | Side incidence image sensors with protruding integrated circuit chips | |
| Kurz et al. | Position-sensitive semiconductor detector for gamma rays |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20080413 Year of fee payment: 14 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090413 Year of fee payment: 15 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100413 Year of fee payment: 16 |
|
| LAPS | Cancellation because of no payment of annual fees |