JP3369681B2 - X-ray detector phosphor and X-ray detector using the same - Google Patents
X-ray detector phosphor and X-ray detector using the sameInfo
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- JP3369681B2 JP3369681B2 JP31672493A JP31672493A JP3369681B2 JP 3369681 B2 JP3369681 B2 JP 3369681B2 JP 31672493 A JP31672493 A JP 31672493A JP 31672493 A JP31672493 A JP 31672493A JP 3369681 B2 JP3369681 B2 JP 3369681B2
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- ray detector
- phosphor
- ray
- sintered body
- output
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Description
【０００１】[0001]
【産業上の利用分野】本発明は、Ｘ線診断等に用いられ
るＸ線ＣＴ装置等に好適なＸ線検出器用蛍光体とそれを
用いた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 phosphor suitable for an X-ray CT apparatus used for X-ray diagnosis and the like, and an X-ray detector using the same.
【０００２】[0002]
【従来の技術】近年、医療診断等の分野において、Ｘ線
ＣＴ装置が用いられている。従来のＸ線ＣＴ装置等にお
けるＸ線検出器には、高圧のキセノンガスを封入した電
離箱が一般的に用いられてきたが、この電離箱型の検出
器は、検出器自体が大きくて重い、電離電流（信号）が
十分に大きくない、Ｘ線吸収が小さい、残留イオン電流
がある等の問題を有していた。これらの問題点によっ
て、電離箱型Ｘ線検出器では信号／ノイズ比に優れ、診
断能、空間分解能、時間分解能（高速スキャン性）が大
きい等の特性を有する、高性能のＸ線ＣＴ装置の開発に
は限度があった。2. Description of the Related Art In recent years, X-ray CT apparatuses have been used in the fields of medical diagnosis and the like. An ionization chamber filled with high-pressure xenon gas has been generally used as an X-ray detector in a conventional X-ray CT apparatus or the like. However, in this ionization chamber type detector, the detector itself is large and heavy. However, there are problems that the ionization current (signal) is not sufficiently large, X-ray absorption is small, and there is a residual ion current. Due to these problems, the ionization chamber type X-ray detector has a high signal / noise ratio, a high diagnostic ability, a high spatial resolution, and a large time resolution (high-speed scanability). There was a limit to development.
【０００３】そこで、単結晶のCdWO4 蛍光体等を用いた
固体Ｘ線検出器が開発され、一部実用に供されている。
しかし、CdWO4 蛍光体を用いた固体Ｘ線検出器では、信
号がキセノンガス検出器よりも小さく、十分に満足でき
る信号／ノイズ比が得られない。これは、CdWO4 蛍光体
の固有の発光効率からくる限界である。Therefore, a solid-state X-ray detector using a single crystal CdWO 4 phosphor or the like has been developed and partially put into practical use.
However, in the solid-state X-ray detector using the CdWO 4 phosphor, the signal is smaller than that of the xenon gas detector, and a sufficiently satisfactory signal / noise ratio cannot be obtained. This is a limit due to the intrinsic luminous efficiency of the CdWO 4 phosphor.
【０００４】一方、上述したCdWO4 蛍光体固有の問題点
を解決するために、本発明者らは先に、Gd2 O 2 S:Prに
代表される希土類酸硫化物系蛍光体を用いることを提案
している。このようなGd2 O 2 S:Pr蛍光体等の半透明焼
結体を用いることにより、CdWO4 単結晶の約 2倍の光出
力（信号）を得ることが可能となる。しかし、上記希土
類酸硫化物系の焼結蛍光体は、実用されるＸ線条件であ
る 120kVp(20mmAlフィルタで濾過）で500R程度のＸ線を
照射すると、光出力が例えば約2%程度低下してしまうと
いう問題を有していた。On the other hand, in order to solve the above-mentioned problems peculiar to the CdWO 4 phosphor, the present inventors have previously used a rare earth oxysulfide phosphor represented by Gd 2 O 2 S: Pr. Is proposed. By using such a translucent sintered body such as a Gd 2 O 2 S: Pr phosphor, it is possible to obtain an optical output (signal) about twice that of a CdWO 4 single crystal. However, when the above rare earth oxysulfide-based sintered phosphor is irradiated with X-rays of about 500R under 120kVp (filtering with a 20mmAl filter) which is a practical X-ray condition, the light output is reduced by, for example, about 2%. It had a problem of being lost.
【０００５】[0005]
【発明が解決しようとする課題】上述したように、Gd2
O 2 S:Pr等の希土類酸硫化物系蛍光体を用いたＸ線検出
器は、CdWO4 蛍光体を用いた固体Ｘ線検出器に比べて約
2倍の光出力（信号）を得ることができるが、実用的な
条件下で大量のＸ線を照射すると、光出力が低下してし
まうという問題を有していた。As described above, Gd 2
X-ray detectors using rare earth oxysulfide phosphors such as O 2 S: Pr are about the same as solid-state X-ray detectors using CdWO 4 phosphor.
Although it is possible to obtain twice the light output (signal), there is a problem that the light output is reduced when a large amount of X-rays are irradiated under practical conditions.
【０００６】このように、Ｘ線検出器用蛍光体の光出力
が低下すると、Ｘ線ＣＴ装置等に適用した場合、Ｘ線Ｃ
Ｔ装置では基本的には初期のブランク値と測定値との差
に基いて画像形成を行っているため、光出力の低下が測
定誤差となり、画像の形成精度を低下させる等して、診
断能を不満足なものとしてしまう。よって、初期発光出
力に優れると共に、大量のＸ線曝射による光出力の低下
が少ないＸ線検出器用蛍光体の出現が強く望まれてい
た。As described above, when the light output of the phosphor for the X-ray detector is lowered, when applied to an X-ray CT apparatus or the like, the X-ray C
Since the T device basically forms an image based on the difference between the initial blank value and the measured value, the decrease in the light output causes a measurement error, which lowers the image forming accuracy and the diagnostic ability. To be unsatisfactory. Therefore, it has been strongly desired to develop a phosphor for an X-ray detector, which is excellent in the initial light emission output and has a small decrease in the light output due to a large amount of X-ray irradiation.
【０００７】本発明は、このような課題に対処するため
になされたもので、希土類酸硫化物系蛍光体の高発光出
力という特徴を阻害することなく、大量のＸ線曝射によ
る光出力の低下を防止したＸ線検出器用蛍光体を提供す
ることを目的としており、またそのような蛍光体の焼結
体を用いることによって、安定して高出力が得られるＸ
線検出器を提供するこを目的としている。The present invention has been made in order to address such a problem, and it does not impede the feature of the rare earth oxysulfide-based phosphors having a high light emission output, and the light output by a large amount of X-ray irradiation is It is an object of the present invention to provide a phosphor for an X-ray detector in which deterioration is prevented, and by using a sintered body of such a phosphor, stable high output can be obtained.
The purpose is to provide a line detector.
【０００８】[0008]
【課題を解決するための手段と作用】本発明者らは、上
記目的を達成するために研究を進めたところ、Gd2 O 2
S:Pr等の希土類酸硫化物系蛍光体の大量のＸ線曝射に伴
う光出力の低下要因が、Pr3+からPr4+への転換にあるこ
とを見出した。[Means and Actions for Solving the Problems] The present inventors have conducted research to achieve the above-mentioned object, and found that Gd 2 O 2
It was found that the factor of reducing the light output due to the large amount of X-ray irradiation of rare earth oxysulfide phosphors such as S: Pr is the conversion from Pr 3+ to Pr 4+ .
【０００９】本発明は、上記したような知見に基くもの
であって、本発明のＸ線検出器用蛍光体は、
化学式：Ａ2(1-x-y-z)Ｐｒ2xＤ2yＣｅ2zＯ2 Ｓ……（１）
（式中、ＡはＧｄおよびＹから選ばれる少なくとも１種
の元素を、ＤはＴｍ、ＹｂおよびＬｕから選ばれる少な
くとも１種の元素を示し、ｘ、ｙ、ｚはそれぞれ１×１
０-5≦ｘ≦１×１０-2、１×１０-6≦ｙ≦２×１０-3、
１×１０ -7 ≦ｚ≦１×１０-4を満足する数を示す）で実
質的に表される希土類酸硫化物蛍光体の焼結体を具備す
ることを特徴としている。The present invention is based on the above findings, and the phosphor for an X-ray detector of the present invention has the chemical formula: A 2 (1-xyz) Pr 2x D 2y Ce 2z O 2 S. (1) (In the formula, A represents at least one element selected from Gd and Y, D represents at least one element selected from Tm, Yb, and Lu, and x, y, and z are each 1 × 1.
0 -5 ≤ x ≤ 1 x 10 -2 , 1 x 10 -6 ≤ y ≤ 2 x 10 -3 ,
It is characterized by including a sintered body of a rare earth oxysulfide phosphor substantially represented by ( 1 × 10 −7 ≦ z ≦ 1 × 10 −4 ).
【００１０】[0010]
【００１１】さらに、本発明のＸ線検出器は、Ｘ線によ
り発光する蛍光発生手段と、前記蛍光発生手段からの光
を受けて、前記発光出力を電気的出力に変換する光検出
手段とを具備するＸ線検出器において、前記蛍光発生手
段として、上記した本発明のＸ線検出器用蛍光体（希土
類酸硫化物蛍光体の焼結体）を用いたことを特徴として
いる。Further, the X-ray detector of the present invention comprises a fluorescence generating means for emitting X-rays and a light detecting means for receiving the light from the fluorescence generating means and converting the light emission output into an electrical output. In the X-ray detector provided, the fluorescent substance for the X-ray detector of the present invention (rare earth) is used as the fluorescence generating means.
It is characterized by using a sintered body of phosphoric acid sulfide phosphor ) .
【００１２】本発明によるＸ線検出器用蛍光体は、Prと
共にTm、YbおよびLuから選ばれる少なくとも1種の元素
（D元素）を含有させることにより、Pr3+からPr4+への
転換を抑制したものである。The phosphor for an X-ray detector according to the present invention contains Pr and at least one element (D element) selected from Tm, Yb and Lu to convert Pr 3+ into Pr 4+ . it is obtained by suppression.
【００１３】上述したように、大量のＸ線曝射による光
出力の低下は、Pr3+がPr4+に転換することに起因する。
これは、例えば母体を構成する 3価イオンがGd3+である
場合を考えると、このGd3+のイオン半径が0.97オングス
トローム（以下、 Aと記載する）であるのに対し、Pr3+
のイオン半径は 1.06Aで、Pr4+のイオン半径は 0.92Aで
あるため、近くに S2-の欠損部のような電子トラップが
存在していると、Ｘ線の照射により、Pr3+が電子をトラ
ップに放出してPr4+として安定化されやすいためと考え
られる。母体を構成する 3価イオンが Y3+である場合
も、 Y3+のイオン半径が 0.92Aであるため、同様な現象
が生じる。このように、安定なPr4+が生成されると、こ
のPr4+による着色が生じて、その色に基く光吸収が起
き、光出力の低下を招くことになる。As described above, the decrease in light output due to a large amount of X-ray irradiation is due to the conversion of Pr 3+ into Pr 4+ .
Considering, for example, that the trivalent ion constituting the matrix is Gd 3+ , the ionic radius of this Gd 3+ is 0.97 angstrom (hereinafter referred to as A), while Pr 3+
Has an ion radius of 1.06A and Pr 4+ has an ion radius of 0.92A. Therefore, if an electron trap such as a S 2− defect is present nearby, X-ray irradiation causes Pr 3+ Is likely to be released as an electron into the trap and stabilized as Pr 4+ . The same phenomenon occurs when the trivalent ion forming the matrix is Y 3+ , because the ionic radius of Y 3+ is 0.92A. As described above, when stable Pr 4+ is generated, coloring by the Pr 4+ occurs, light absorption occurs based on the color, and the light output is reduced.
【００１４】そこで、本発明による蛍光体では、Pr3+の
近傍に、Yb3+（イオン半径:0.86A)、Tm3+（イオン半径:
0.87A）、Lu3+（イオン半径:0.83A）等の、母体を構成
するGd3+（イオン半径:0.97A）やY3+（イオン半径:0.92
A）よりイオン半径が小さいイオン（D元素イオン）を導
入することにより、イオン半径の不均衡を緩和してい
る。 Therefore, in the phosphor according to the present invention, in the vicinity of Pr 3+ , Yb 3+ (ionic radius: 0.86A) and Tm 3+ (ionic radius:
0.87A), Lu 3+ (ionic radius: 0.83A ), etc. that make up the matrix, such as Gd 3+ (ionic radius: 0.97A) and Y 3+ (ionic radius: 0.92)
The ion radius imbalance is alleviated by introducing an ion (D element ion) having a smaller ion radius than A) .
【００１５】本発明においては、結晶格子内における母
体構成イオンとPr3+とのイオン半径の不均衡を緩和する
ことによって、Pr3+を安定化させることができる。これ
により、Pr3+からPr4+への変換比率を低減させることが
でき、ひいては着色の結果生ずる発光の吸収による出力
低下を抑制することが可能となる。[0015] The onset Oite the Ming, by relaxing the ionic radius of the imbalance of the matrix constituent ions and Pr 3+ in the crystal lattice, it is possible to stabilize the Pr 3+. As a result, the conversion ratio of Pr 3+ to Pr 4+ can be reduced, and in turn, it is possible to suppress a decrease in output due to absorption of light emission resulting from coloring.
【００１６】上記(1)式におけるPrは、酸硫化物系蛍光
体の発光出力を増大させるための付活剤であり、その添
加量が上記(1)式のx値として1×10-2を超えると、逆に
発光出力の低下を招くこととなる。また、1×10-5未満
では十分な効果を得ることができない。より好ましいPr
の添加量は、x値として1×10-4〜3×10-3の範囲であ
る。[0016] Pr which definitive in equation (1) is an activator for increasing the light output of the oxysulfide phosphor, 1 × 10 the added amount is as x value of the (1) - On the other hand , when it exceeds 2 , the emission output is lowered. Further, if it is less than 1 × 10 −5 , a sufficient effect cannot be obtained. More preferable Pr
The addition amount of is in the range of 1 × 10 −4 to 3 × 10 −3 as the x value.
【００１７】また、本発明の酸硫化物系蛍光体は、微量
のCeを含むものであってもよい。すなわち、Gd2O2S:Pr
等の希土類酸硫化物系蛍光体は、残光（アフターグロ
ー）が比較的大きいため、例えば1000チャネルのＸ線検
出器を2秒で走査するような高速スキャン型のＸ線ＣＴ
装置（1チャネル当りの検出時間は約2msec）に使用した
場合、2msec以後も発光が継続すると、次のチャネルで
の信号（発光）と重なってノイズとなり、信号／ノイズ
比が低下して、十分に診断能が得られなくなる。酸硫化
物系蛍光体の残光は、微量のCeを添加することで小さく
することができる。ただし、(1)式のz値が1×10-4を超
えると、蛍光体本来の発光出力が低下し、Ｘ線検出器と
して用いた場合に、高信号／ノイズ比が得られなくな
る。Ceのより好ましい添加量は1×10-7〜1×10-6の範囲
である。Further, the oxysulfide phosphor of the present invention may contain a trace amount of Ce. That is, Gd 2 O 2 S: Pr
Since the rare earth oxysulfide phosphors such as the above have relatively large afterglow (afterglow), for example, a high-speed scan type X-ray CT that scans an X-ray detector of 1000 channels in 2 seconds.
When used in a device (detection time per channel is about 2 msec), if light emission continues for more than 2 msec, it will overlap with the signal (light emission) on the next channel, resulting in noise, and the signal / noise ratio will decrease The diagnostic ability cannot be obtained. The afterglow of the oxysulfide-based phosphor can be reduced by adding a trace amount of Ce. However, if the z value in the equation (1) exceeds 1 × 10 −4 , the original emission output of the phosphor decreases, and when used as an X-ray detector, a high signal / noise ratio cannot be obtained. The more preferable addition amount of Ce is in the range of 1 × 10 −7 to 1 × 10 −6 .
【００１８】上記 (1)式における D元素は、上述したよ
うに光出力の低下を防止する元素であり、その添加量が
(1)式中の y値が 2×10-3を超えると、逆に発光出力の
低下を招くこととなる。また、 1×10-6未満では十分な
効果を得ることができない。より好ましい y値は 1×10
-6〜 2×10-3の範囲である。The D element in the above formula (1) is an element which prevents the reduction of the light output as described above, and its addition amount is
If the y value in the equation (1) exceeds 2 × 10 -3 , on the contrary, the emission output will be reduced. Further, if it is less than 1 × 10 −6 , a sufficient effect cannot be obtained. More preferable y value is 1 × 10
It is in the range of -6 to 2 x 10 -3 .
【００１９】[0019]
【００２０】本発明のＸ線検出器は、上述した(1)式で
組成が実質的に表される蛍光体の焼結体を蛍光発生手段
として用いたものである。なお、光検出手段としては、
通常の光電変換素子を用いることができる。The X-ray detector of the present invention uses the sintered body of the phosphor whose composition is substantially represented by the above-mentioned formula (1) as the fluorescence generating means. As the light detecting means,
A usual photoelectric conversion element can be used.
【００２１】本発明による蛍光体の焼結体は、十分な発
光出力を有すると共に、大量のＸ線曝射による光出力の
低下が少なく、よってＸ線検出器の蛍光発生手段として
極めて有用である。また、このようなＸ線検出器を用い
たＸ線ＣＴ装置においては、光出力の低下による測定誤
差の発生を抑制することができるため、高診断能を得る
ことが可能となる。The sintered body of the phosphor according to the present invention has a sufficient light emission output, and the decrease in the light output due to a large amount of X-ray irradiation is small, and therefore it is extremely useful as a fluorescence generating means of an X-ray detector. . Further, in the X-ray CT apparatus using such an X-ray detector, it is possible to suppress the occurrence of a measurement error due to the decrease in the optical output, so that it is possible to obtain high diagnostic ability.
【００２２】Ｘ線検出器の蛍光発生手段等として用いる
本発明の蛍光体の焼結体は、例えば以下のようにして作
製される。The sintered body of the phosphor of the present invention used as the fluorescence generating means of the X-ray detector is produced, for example, as follows.
【００２３】まず、Gd、Pr、Tm、Ce等の各構成金属元素
を所定量秤量し、混合する。この際、各出発原料として
はそれぞれの酸化物が用いられる。次いで、これら金属
酸化物の混合物を例えば焼成して、構成金属元素を所定
量含む複合酸化物を作製する。あるいは、金属酸化物の
混合物を例えば塩酸で溶解し、各構成金属元素を所定量
含む塩化物を作製した後、この塩化物を例えばシュウ酸
で処理してシュウ酸塩とし、それを加熱して構成金属元
素を所定量含む複合酸化物を作製する。First, respective constituent metal elements such as Gd , Pr, Tm and Ce are weighed in predetermined amounts and mixed. At this time, each oxide is used as each starting material. Next, a mixture of these metal oxides is fired, for example, to prepare a composite oxide containing a predetermined amount of constituent metal elements. Alternatively, for example, a mixture of metal oxides is dissolved with hydrochloric acid to prepare a chloride containing a predetermined amount of each constituent metal element, and then the chloride is treated with, for example, oxalic acid to form an oxalate, which is heated. A composite oxide containing a predetermined amount of constituent metal elements is produced.
【００２４】Ceを添加する場合には、Ceを例えば十分に
溶解した状態で添加する等によって、添加量に見合った
Ceの付活効果を十分に引き出すことが好ましい。具体的
には、例えば上記塩化物を作製する時点で、Ceの酸化物
を十分に溶解させ、生成した塩化物中に均一に取り込ま
せる。そのために、例えば過酸化水素水(H2 O 2 ）を添
加し、Ce酸化物の溶解を促進させることが好ましい。In the case of adding Ce, the amount of Ce should be adjusted according to the amount to be added, for example, by adding Ce in a sufficiently dissolved state.
It is preferable to fully bring out the activation effect of Ce. Specifically, for example, at the time of producing the chloride, the oxide of Ce is sufficiently dissolved and uniformly incorporated in the produced chloride. Therefore, for example, hydrogen peroxide solution (H 2 O 2 ) is preferably added to accelerate the dissolution of Ce oxide.
【００２５】次に、上記複合酸化物の粉末を、硫化水素
気流中にて1000℃〜1100℃の温度で数時間処理し、目的
とする金属酸硫化物の合成粉末を作製する。次いで、得
られた金属酸硫化物の合成粉末を加圧成形する。この加
圧成形については、ラバープレス等を適用することによ
って、成形体密度を十分に高めることが好ましい。Next, the powder of the composite oxide is treated in a hydrogen sulfide gas stream at a temperature of 1000 ° C. to 1100 ° C. for several hours to prepare a synthetic powder of the target metal oxysulfide. Next, the obtained synthetic powder of metal oxysulfide is pressure-molded. For this pressure molding, it is preferable to sufficiently increase the density of the molded body by applying a rubber press or the like.
【００２６】この後、上記加圧成形体をMo、Ta、Nb、
W、Pt等の高融点金属からなる密閉可能な容器（カプセ
ル）内に脱気封入した後、この封入体に対してＨＩＰ処
理を施して焼結体とする。ＨＩＰ処理は、例えば1000〜
2000kgf/cm2 程度の圧力を印加しつつ、1100〜1800℃程
度の温度で 1〜10時間処理することが好ましい。Thereafter, the above pressure-molded body was subjected to Mo, Ta, Nb,
After deaeration and encapsulation in a sealable container (capsule) made of a high melting point metal such as W or Pt, the encapsulation body is subjected to HIP treatment to obtain a sintered body. HIP processing is, for example, 1000-
It is preferable to perform the treatment at a temperature of about 1100 to 1800 ° C. for 1 to 10 hours while applying a pressure of about 2000 kgf / cm 2 .
【００２７】[0027]
【実施例】以下、本発明の実施例について説明する。EXAMPLES Examples of the present invention will be described below.
【００２８】実施例１
まず、Gd2 O 3 粉末、Pr2 O 3 粉末、Yb2 O 3 粉末およ
び CeO2 粉末を、Gd2(1-x-y-z)Pr2xYb2yCe2z O2 S の x
値が 1×10-3、 y値が 1×10-3、および z値が 1×10-6
となるように所定量秤量し、これらを十分に混合した
後、所定量より若干過剰の塩酸中に溶解させて、複合塩
化物溶液を作製した。この際に、塩酸と同量位までの過
酸化水素水を添加することにより、難溶解性の酸化セリ
ウム(CeO2 ）を完全に溶解させた。Example 1 First, Gd 2 O 3 powder, Pr 2 O 3 powder, Yb 2 O 3 powder and CeO 2 powder were mixed with x of Gd 2 (1-xyz) Pr 2x Yb 2y Ce 2z O 2 S.
Values are 1 × 10 -3 , y values are 1 × 10 -3 , and z values are 1 × 10 -6.
A predetermined amount was weighed so as to obtain the following, and these were sufficiently mixed, and then dissolved in hydrochloric acid slightly in excess of the predetermined amount to prepare a complex chloride solution. At this time, the hardly soluble cerium oxide (CeO 2 ) was completely dissolved by adding a hydrogen peroxide solution up to about the same amount as hydrochloric acid.
【００２９】次に、上記複合塩化物溶液中に所定量のシ
ュウ酸溶液を投入し、十分に撹拌するとシュウ酸塩沈殿
が生成し、これを濾過、洗浄、乾燥した後、1000℃で 1
時間加熱して酸化し、複合酸化物を作製した。Next, a predetermined amount of oxalic acid solution was added to the above complex chloride solution and stirred sufficiently to form an oxalate salt precipitate, which was filtered, washed and dried, and then at 1000 ° C.
It was heated and oxidized for a period of time to prepare a composite oxide.
【００３０】この後、上記複合酸化物粉末を硫化水素気
流中にて1000℃〜1100℃の温度で数時間処理して、上記
組成の希土類酸硫化物の合成粉末を得た。これをラバー
プレスにより加圧成形し、Ta製のカプセル中に脱気、封
入した後、Ar雰囲気中にて圧力1000kgf/cm2 で、温度15
50℃で 5時間ＨＩＰ処理を施すことによって、目的とす
る半透明の焼結体を得た。After that, the composite oxide powder was treated in a hydrogen sulfide gas stream at a temperature of 1000 ° C. to 1100 ° C. for several hours to obtain a synthetic powder of a rare earth oxysulfide having the above composition. This is pressure-molded with a rubber press, deaerated and sealed in a Ta capsule, and then pressure is 1000 kgf / cm 2 in Ar atmosphere at a temperature of 15
By subjecting to HIP treatment at 50 ° C. for 5 hours, a target semitransparent sintered body was obtained.
【００３１】また、本発明との比較として、Ybを添加し
ない（上記組成式中の y値=0）以外は、上記実施例と同
一条件で、蛍光体の焼結体（比較例１）を作製した。Further, as a comparison with the present invention, a phosphor sintered body (Comparative Example 1) was prepared under the same conditions as in the above Example except that Yb was not added (y value in the above composition formula = 0). It was made.
【００３２】このようにして得た各希土類付活酸硫化ガ
ドリニウム蛍光体の焼結体から10×10× 5mmのチップを
それぞれ切り出し、これらの焼結体チップの発光出力を
測定した。発光出力は、比較試料としてCdWO4 単結晶シ
ンチレータと共に120kVp（20mmAlフィルタ使用）のＸ線
を上記焼結体チップに照射し、相対発光量として求め
た。次に、上記した各焼結体チップに同一条件で500Rの
Ｘ線を照射した後、同様に相対発光量を求めた。Chips of 10 × 10 × 5 mm were cut out from each of the rare earth-activated gadolinium oxysulfide phosphor sintered bodies thus obtained, and the emission output of each of these sintered body chips was measured. The luminescence output was obtained as a relative luminescence amount by irradiating the above sintered body chip with X-ray of 120 kVp (using a 20 mm Al filter) together with a CdWO 4 single crystal scintillator as a comparative sample. Next, after irradiating each of the above-mentioned sintered body chips with X-ray of 500R under the same condition, the relative amount of light emission was similarly obtained.
【００３３】その結果、500RのＸ線曝射前の値に対する
曝射後の値の比、すなわち出力低下は、Ybを添加してい
ない焼結体チップ（比較例１:y=0）では2.3%であったの
に対し、実施例１によるYbを添加した焼結体チップ(y=1
×10-3）では0.7%と、約 1/3とすることができた。As a result, the ratio of the value before the X-ray exposure of 500R to the value after the exposure, that is, the output reduction was 2.3 in the sintered body chip to which Yb was not added (Comparative Example 1: y = 0). %, While the Yb-added sintered body chip of Example 1 (y = 1
× 10 -3 ) was 0.7%, which was about 1/3.
【００３４】また、上記実施例１による蛍光体の焼結体
のアフターグローは、Ceを添加せずに作製した焼結体の
値を 100とすると、約 1/3であった。The afterglow of the sintered body of the phosphor of Example 1 was about 1/3 when the value of the sintered body produced without adding Ce was 100.
【００３５】実施例２〜５
組成式が実施例１と同一で、表１に示す各組成比の蛍光
体の焼結体を、それぞれ実施例１と同様にして作製し
た。これら各蛍光体の焼結体からそれぞれ実施例１と同
一形状のチップを切り出し、実施例１と同様にして、50
0RのＸ線曝射後の出力低下率を求めた。その結果を併せ
て表１に示す。Examples 2 to 5 Sintered phosphors having the same composition formula as in Example 1 and having the composition ratios shown in Table 1 were prepared in the same manner as in Example 1. From the sintered body of each of these phosphors, a chip having the same shape as that of Example 1 was cut out, and the same procedure as in Example 1 was performed.
The output reduction rate after X-ray exposure of 0R was obtained. The results are also shown in Table 1.
【００３６】[0036]
【表１】 [Table 1]
【００３７】[0037]
【００３８】[0038]
【００３９】[0039]
【００４０】[0040]
【００４１】[0041]
【発明の効果】以上説明したように本発明によれば、Gd
2 O 2 S:Pr等の希土類酸硫化物系蛍光体の特徴である高
発光出力を維持しつつ、大量のＸ線曝照射後において
も、発光出力の低下が小さいＸ線検出器用蛍光体を提供
することができる。よって、このような蛍光体の焼結体
を用いてＸ線検出器を構成することにより、安定して高
出力を得ることが可能となる。As described above, according to the present invention, Gd
A phosphor for an X-ray detector that maintains a high emission output, which is a characteristic of rare earth oxysulfide phosphors such as 2 O 2 S: Pr, and has a small decrease in emission output even after irradiation with a large amount of X-rays. Can be provided. Therefore, by constructing an X-ray detector using such a phosphor sintered body, it is possible to stably obtain a high output.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 平５−100037（ＪＰ，Ａ) 特開 昭56−151376（ＪＰ，Ａ) 特開 平２−6590（ＪＰ，Ａ) 特開 平２−173088（ＪＰ，Ａ) 特開 平５−209969（ＪＰ，Ａ) 特開 昭60−262885（ＪＰ，Ａ) 特開 昭60−170687（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) C09K 11/84 G01T 1/202 ─────────────────────────────────────────────────── --- Continuation of the front page (56) Reference JP-A-5-100037 (JP, A) JP-A-56-151376 (JP, A) JP-A-2-6590 (JP, A) JP-A-2- 173088 (JP, A) JP 5-209969 (JP, A) JP 60-262885 (JP, A) JP 60-170687 (JP, A) (58) Fields investigated (Int.Cl. 7 , DB name) C09K 11/84 G01T 1/202
Claims (3)
Ｏ2 Ｓ （式中、ＡはＧｄおよびＹから選ばれる少なくとも１種
の元素を、ＤはＴｍ、ＹｂおよびＬｕから選ばれる少な
くとも１種の元素を示し、ｘ、ｙ、ｚはそれぞれ１×１
０-5≦ｘ≦１×１０-2、１×１０-6≦ｙ≦２×１０-3、
１×１０ -7 ≦ｚ≦１×１０-4を満足する数を示す）で実
質的に表される希土類酸硫化物蛍光体の焼結体を具備す
ることを特徴とするＸ線検出器用蛍光体。1. The chemical formula: A 2 (1-xyz) Pr 2x D 2y Ce 2z
O 2 S (In the formula, A represents at least one element selected from Gd and Y, D represents at least one element selected from Tm, Yb, and Lu, and x, y, and z are each 1 × 1.
0 -5 ≤ x ≤ 1 x 10 -2 , 1 x 10 -6 ≤ y ≤ 2 x 10 -3 ,
A fluorescent substance for an X-ray detector, comprising a sintered body of a rare earth oxysulfide phosphor substantially represented by ( 1 × 10 −7 ≦ z ≦ 1 × 10 −4 ) body.
記蛍光発生手段からの光を受けて、前記発光出力を電気
的出力に変換する光検出手段とを具備するＸ線検出器に
おいて、 前記蛍光発生手段として、請求項１記載のＸ線検出器用
蛍光体を用いたことを特徴とするＸ線検出器。2. An X-ray detector comprising fluorescence generating means for emitting light by X-rays, and light detecting means for receiving the light from the fluorescence generating means and converting the light emission output into an electrical output. An X-ray detector using the phosphor for an X-ray detector according to claim 1 as the fluorescence generating means.
特徴とする請求項２記載のＸ線検出器。The X-ray detector according to claim 2, which is characterized in that.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP31672493A JP3369681B2 (en) | 1993-12-16 | 1993-12-16 | X-ray detector phosphor and X-ray detector using the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP31672493A JP3369681B2 (en) | 1993-12-16 | 1993-12-16 | X-ray detector phosphor and X-ray detector using the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07166162A JPH07166162A (en) | 1995-06-27 |
| JP3369681B2 true JP3369681B2 (en) | 2003-01-20 |
Family
ID=18080202
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP31672493A Expired - Fee Related JP3369681B2 (en) | 1993-12-16 | 1993-12-16 | X-ray detector phosphor and X-ray detector using the same |
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| Country | Link |
|---|---|
| JP (1) | JP3369681B2 (en) |
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1993
- 1993-12-16 JP JP31672493A patent/JP3369681B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH07166162A (en) | 1995-06-27 |
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