JPH03192187A - Phosphor - Google Patents
PhosphorInfo
- Publication number
- JPH03192187A JPH03192187A JP1331127A JP33112789A JPH03192187A JP H03192187 A JPH03192187 A JP H03192187A JP 1331127 A JP1331127 A JP 1331127A JP 33112789 A JP33112789 A JP 33112789A JP H03192187 A JPH03192187 A JP H03192187A
- Authority
- JP
- Japan
- Prior art keywords
- phosphor
- afterglow
- radiation
- pure water
- washed
- 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.)
- Granted
Links
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 title abstract description 22
- 239000012535 impurity Substances 0.000 claims abstract description 9
- 229910052727 yttrium Inorganic materials 0.000 claims abstract description 5
- 229910052765 Lutetium Inorganic materials 0.000 claims abstract description 4
- 229910052688 Gadolinium Inorganic materials 0.000 claims abstract 3
- 229910052746 lanthanum Inorganic materials 0.000 claims abstract 3
- 230000005284 excitation Effects 0.000 claims description 5
- 229910052693 Europium Inorganic materials 0.000 claims description 4
- 229910052777 Praseodymium Inorganic materials 0.000 claims description 4
- 230000005855 radiation Effects 0.000 abstract description 24
- 230000000638 stimulation Effects 0.000 abstract description 21
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 9
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 abstract description 8
- 239000000843 powder Substances 0.000 abstract description 7
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 abstract description 4
- 239000002994 raw material Substances 0.000 abstract description 3
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 abstract description 2
- 229910017604 nitric acid Inorganic materials 0.000 abstract description 2
- 235000006408 oxalic acid Nutrition 0.000 abstract description 2
- 239000002244 precipitate Substances 0.000 abstract description 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 abstract 2
- 229910002637 Pr6O11 Inorganic materials 0.000 abstract 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 abstract 1
- 150000001875 compounds Chemical class 0.000 abstract 1
- CMIHHWBVHJVIGI-UHFFFAOYSA-N gadolinium(III) oxide Inorganic materials [O-2].[O-2].[O-2].[Gd+3].[Gd+3] CMIHHWBVHJVIGI-UHFFFAOYSA-N 0.000 abstract 1
- 238000004020 luminiscence type Methods 0.000 abstract 1
- 229910000029 sodium carbonate Inorganic materials 0.000 abstract 1
- 235000017550 sodium carbonate Nutrition 0.000 abstract 1
- 229910052717 sulfur Inorganic materials 0.000 abstract 1
- 239000011593 sulfur Substances 0.000 abstract 1
- 235000001508 sulfur Nutrition 0.000 abstract 1
- LWIHDJKSTIGBAC-UHFFFAOYSA-K tripotassium phosphate Chemical compound [K+].[K+].[K+].[O-]P([O-])([O-])=O LWIHDJKSTIGBAC-UHFFFAOYSA-K 0.000 abstract 1
- 229910000404 tripotassium phosphate Inorganic materials 0.000 abstract 1
- 235000019798 tripotassium phosphate Nutrition 0.000 abstract 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 9
- 230000003287 optical effect Effects 0.000 description 5
- -1 rare earth oxysulfide Chemical class 0.000 description 5
- 238000005406 washing Methods 0.000 description 5
- 238000010908 decantation Methods 0.000 description 4
- UAHZTKVCYHJBJQ-UHFFFAOYSA-N [P].S=O Chemical compound [P].S=O UAHZTKVCYHJBJQ-UHFFFAOYSA-N 0.000 description 3
- 239000000919 ceramic Substances 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 150000002910 rare earth metals Chemical class 0.000 description 3
- 238000010521 absorption reaction Methods 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
- 230000007423 decrease Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 241000894007 species Species 0.000 description 2
- 229910004829 CaWO4 Inorganic materials 0.000 description 1
- 241000254158 Lampyridae Species 0.000 description 1
- 239000004677 Nylon 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
- 239000007864 aqueous solution Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000000921 elemental analysis Methods 0.000 description 1
- 230000005251 gamma ray Effects 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 229920001778 nylon Polymers 0.000 description 1
- 239000011224 oxide ceramic Substances 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 229910001404 rare earth metal oxide Inorganic materials 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000003325 tomography Methods 0.000 description 1
Landscapes
- Measurement Of Radiation (AREA)
- Luminescent Compositions (AREA)
Abstract
Description
【発明の詳細な説明】
［発明の目的］
（産業上の利用分野）
本発明は螢光体に関し、特にＸ線やγ線などの放射線検
出器に好適な螢光体に係る。[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a phosphor, and particularly to a phosphor suitable for a radiation detector such as an X-ray or a γ-ray.
（従来の技術）
シンチレータは、Ｘ線などの放射線の刺激によって可視
光又は可視光に近い波長の電磁波を放出する材料であり
、例えばＸ線ＣＴＣＸ線断層撮影装置）の検出器に用い
られている。かかるシンチレータの材料としては、Ｎａ
Ｉ、Ｃｓ Ｉ。(Prior Art) A scintillator is a material that emits visible light or electromagnetic waves with wavelengths close to visible light when stimulated by radiation such as X-rays, and is used in detectors of, for example, X-ray CTC (X-ray tomography equipment). . Materials for such scintillators include Na
I, Cs I.
ＣｄＷＯ，等の物質の単結晶や特公昭５９−４５０２２
号公報に開示されているＢ ａ Ｆ Ｃ９： Ｅ ｕｓ
ＬａＯＢｒ：Ｔｂ、Ｃｓｌ：Ｔｊｌ、ＣａＷＯ４のセラ
ミックス、特開昭５９−２７２８３号公報に開示されて
いる立方晶系希土類酸化物セラミックス、あるいは特開
昭５８−２０４０８８号公報に開示されているＧｄ２０
□Ｓ：ＰｒなどのＰｒ付活希土類オキシ硫化物螢光体か
らなるセラミックスが知られている。Single crystals of substances such as CdWO, etc.
B a F C9 disclosed in the publication No. E us
Ceramics of LaOBr:Tb, Csl:Tjl, CaWO4, cubic rare earth oxide ceramics disclosed in JP-A-59-27283, or Gd20 disclosed in JP-A-58-204088.
Ceramics made of Pr-activated rare earth oxysulfide phosphors such as □S:Pr are known.
上述したシンチレータは、■放射線吸収率が大きいこと
、■吸収した放射線を光に変換する効率が大きいこと、
及び■放射線刺激停止後の光の減衰が早いことが望まれ
る。ここで、放射線刺激停止後の光の減衰としては、数
マイクロ秒間から数ミリ秒間持続する発光中心種による
光が減衰する“本質的な減衰”と、数秒間から数十秒間
持続する格子欠陥などによると考えられる残光が減衰す
る“二次的な減衰”とに分類される。The above-mentioned scintillator has the following characteristics: ■High radiation absorption rate;■High efficiency in converting absorbed radiation into light;
and (2) It is desired that the light attenuates quickly after the radiation stimulation stops. Here, the attenuation of light after radiation stimulation has stopped includes "intrinsic attenuation" in which light is attenuated by luminescent species that lasts from several microseconds to several milliseconds, and lattice defects that last from several seconds to several tens of seconds. This is classified as "secondary attenuation" in which the afterglow is attenuated.
従来、Ｐｒ付活希土類オキシ硫化物螢光体は、放射線の
吸収率が大きく、かつ吸収した放射線を光に変換する効
率が大きいため、放射線刺激により大きな光出力が得ら
れるという利点を有し、前記■及び■の点でシンチレー
タとして好適である。Conventionally, Pr-activated rare earth oxysulfide phosphors have a high absorption rate of radiation and a high efficiency of converting the absorbed radiation into light, so they have the advantage of being able to obtain a large optical output by radiation stimulation. In terms of (1) and (2) above, it is suitable as a scintillator.
一方、前記螢光体は、放射線刺激停止により発光中心種
による光が速かに減衰し“本質的な減衰”については満
足できるものの、残光が大きく “二次的な減衰”につ
いては満足できず、前記■の点でシンチレータとしては
不十分であるという問題を有する。前記■の点に関して
より具体的に言えば、例えばＸＩＩＣＴ用のシンチレー
タとしては、Ｘ線刺激停止後の光出力が１ミリ秒後で初
期光出力の０．１％以下になるという基準、及び３０秒
後に１５ｐｐｍ以下になるという基準を満足することが
望まれている。前、記螢光体は、Ｘ線の刺激停止後の光
出力が０．１％以下になるのがｌＯマイクロ秒程度であ
り、“本質的な減衰“に係る前者の基準については十分
に満足するが、“二次的な減衰”に係る後者の基準につ
いては残光が大きいため満足することができない。On the other hand, in the case of the above-mentioned phosphor, although the light emitted by the luminescent center species rapidly attenuates when radiation stimulation is stopped, and the "essential attenuation" is satisfied, the afterglow is large and the "secondary attenuation" is unsatisfactory. First, it has the problem that it is insufficient as a scintillator in terms of point (2) above. To be more specific with regard to the above point (■), for example, for a scintillator for XIICT, the standard is that the light output after stopping X-ray stimulation is 0.1% or less of the initial light output 1 millisecond later, and 30 It is desired to satisfy the standard that the concentration becomes 15 ppm or less after seconds. As mentioned earlier, the optical output of the above-mentioned phosphor decreases to 0.1% or less after the X-ray stimulation stops, which is sufficient to satisfy the former criterion regarding "essential attenuation". However, the latter criterion regarding "secondary attenuation" cannot be satisfied because of the large afterglow.
そこで、Ｐｒ付活希土類オキシ硫化物螢光体に微量のＣ
ｅを共付活することにより、残光の低減を図ったものが
提案されている（特開昭５６−１５１３７６号）。Therefore, a trace amount of C is added to the Pr-activated rare earth oxysulfide phosphor.
A method has been proposed in which afterglow is reduced by coactivating e (Japanese Patent Application Laid-Open No. 151376/1983).
しかしながら、上述した微量のＣｅを共付活した螢光体
は、放射線刺激停止後の残光は低減できるものの、放射
線刺激による光出力が大きく低下し、Ｐｒ付活希土類オ
キシ硫化物螢光体の利点が失われてしまうという問題が
あった。However, although the above-mentioned phosphor co-activated with a small amount of Ce can reduce the afterglow after radiation stimulation stops, the light output due to radiation stimulation is greatly reduced, and the Pr-activated rare earth oxysulfide phosphor is The problem was that the advantages were lost.
（発明が解決しようとする課題）
本発明は従来の課題を解決するためになされたもので、
放射線刺激による光出力が十分に大きく、しかも放射線
刺激停止後の残光が十分に低減されたＸ線ＣＴのシンチ
レータなどに好適な螢光体を提供しようとするものであ
る。(Problems to be solved by the invention) The present invention has been made to solve the conventional problems.
The present invention aims to provide a phosphor suitable for scintillators of X-ray CT, etc., which has a sufficiently large light output due to radiation stimulation and has sufficiently reduced afterglow after the radiation stimulation has stopped.
［発明の構成コ
（課題を解決するための手段）
本発明に係る螢光体は、一般式
％式％（１）
［ただし、ＬｎはＬａ５Ｇｄ、Ｙ及びＬｕから選択され
る少なくとも１種、Ｘは０．０００２〜０．００３を示
す］で表わされると共に、Ｅｕ不純物濃度を２５４ｎｍ
紫外線励起による発光線強度比［４６，８ｎｍ（Ｅｕ）
／ ５１２ｎｍ（Ｐｒ） ］で０．００２以下としたこ
とを特徴とする螢光体であり、
また、本発明に係る別の発明は、前記一般式（１）で表
わされると共に、ＥｕとＰ「との含有重量比（Ｅ ｕ
／ Ｐ ｒ ）を０．００２以下としたことを特徴とす
る螢光体である。[Configuration of the Invention (Means for Solving the Problems) The phosphor according to the present invention has the general formula % (1) [However, Ln is at least one selected from La5Gd, Y and Lu, X is 0.0002 to 0.003], and the Eu impurity concentration is 254 nm.
Emission line intensity ratio due to ultraviolet excitation [46.8 nm (Eu)
/512nm(Pr)] is 0.002 or less, and another invention according to the present invention is represented by the general formula (1), and Eu and P' The content weight ratio (E u
/P r ) is 0.002 or less.
前記一般式（１）中のＸの値を限定した理由は、その値
が０．０００２〜０．００３の範囲を逸脱すると放射線
刺激による光出力が低下し、十分な前記光出力が得られ
ないことによる。The reason why the value of It depends.
前記発光線強度比［４８８ｎｍ（Ｅｕ）／ ５１２ｎｍ
（Ｐｒ） ］を限定した理由は、その発光線強度比が０
．００２を越えると放射線刺激停止後の残光を十分に低
減できなくなるからである。The emission line intensity ratio [488 nm (Eu)/512 nm
(Pr) ] is limited because its emission line intensity ratio is 0.
．． This is because if it exceeds 002, it will not be possible to sufficiently reduce the afterglow after the radiation stimulation has stopped.
前記含有重量比（Ｅｕ／Ｐｒ）を規定した理由は、その
含有重量比が０．００２を越えると放射線刺激停止後の
残光を十分に低減できなくなるか°らである。The reason for specifying the content weight ratio (Eu/Pr) is that if the content weight ratio exceeds 0.002, it will not be possible to sufficiently reduce the afterglow after radiation stimulation has stopped.
本発明に係る螢光体において、放射線刺激停止後の残光
をより低減させる観点から、Ｌａ５Ｇｄ、Ｙ、Ｌｕ及び
Ｐｒ以外の希土類元素の各々の含有量を１０ｐｐ■、以
下にすることが望ましい。In the phosphor according to the present invention, the content of each rare earth element other than La5Gd, Y, Lu, and Pr is desirably 10 pp or less, from the viewpoint of further reducing afterglow after radiation stimulation stops.
また、本発明に係る螢光体をＸ線やγ線などの放射線の
検出器用に適用する場合には、通常、螢光体の真密度に
対して９９％以上の密度を有するセラミックスの形態で
使用する。Further, when the phosphor according to the present invention is applied to a detector for radiation such as X-rays and γ-rays, it is usually in the form of a ceramic having a density of 99% or more of the true density of the phosphor. use.
（作用）
本発明によれば、前述した一般式（Ｉ）で表わされる組
成にすることによって放射線刺激による大きな光出力を
持つ螢光体を得ることができる。(Function) According to the present invention, a phosphor having a large optical output due to radiation stimulation can be obtained by using the composition represented by the above-mentioned general formula (I).
本発明者らはＰｒ付活希土類オキシ硫化物螢光体の残光
について種々検討したところ、（１） Ｐ ｒ濃度を増
加させると残光が減少すること、及び（２）微量不純物
、特にＥｕが存在すると残光が増加することを見出した
。これにより残光はＰｒ濃度あるいはＥｕ不純物濃度の
どちらか一方で決まるものではなく、同じＰｒ濃度なら
Ｅｕの少ない方が残光が少なく、同じＥ、ｕ濃度ならＰ
ｒ′ａ度の高い方が残光が少ないことが判明した。ここ
で微量のＥｕ不純物が残光に大きく影響する理由として
は、ＥｕとＰｒの相互作用が考えられる。即ち、螢光体
中のＥｕはＥｕ３″″として存在し、螢光体中のＰｒは
Ｐｒ”として存在する。前記Ｅ ｕ ”は三価から二価
になり易く、一方前記Ｐｒ３＋は三価から四価になり易
いため、前記Ｅｕと前記Ｐｒとの間で電子の移動が生じ
てトラップを形成し、これが残光の主原因となるのであ
る。The present inventors conducted various studies on the afterglow of Pr-activated rare earth oxysulfide phosphors and found that (1) the afterglow decreases as the Pr concentration increases, and (2) trace impurities, especially Eu It was found that the presence of afterglow increases. As a result, the afterglow is not determined by either the Pr concentration or the Eu impurity concentration; for the same Pr concentration, the less Eu the less the afterglow, and for the same E and U concentrations, the afterglow will be less.
It was found that the higher the r'a degree, the less afterglow. The reason why a small amount of Eu impurity greatly affects the afterglow is considered to be the interaction between Eu and Pr. That is, Eu in the phosphor exists as Eu3'''', and Pr in the phosphor exists as Pr''.Eu'' tends to change from trivalent to divalent, while Pr3+ changes from trivalent to divalent. Since it tends to become tetravalent, electrons move between the Eu and the Pr to form a trap, which is the main cause of afterglow.
そこで、本発明者らはＥｕの不純物濃度を前記Ｐｒとの
関係において、２５４ｎｍ紫外線励起による発光線強度
比［４６８ｎａ＋（Ｅｕ）／ ５１２ｎａ＋（Ｐｒ）
］で０．００２以下、又はＥｕとＰｒとの含有ｔｉｔ比
（Ｅ ｕ／Ｐ ｒ）が０．００２以下となるように設定
することによって、放射線刺激停止後の残光を十分に低
減した螢光体を得ることを見出した。Therefore, the present inventors set the impurity concentration of Eu in relation to the above-mentioned Pr, and calculated the emission line intensity ratio [468na+(Eu)/512na+(Pr)] by 254nm ultraviolet excitation.
] is set to 0.002 or less, or the content tit ratio of Eu and Pr (E u / Pr) is set to 0.002 or less, thereby producing a firefly with sufficiently reduced afterglow after radiation stimulation has stopped. I discovered that I could obtain a luminous body.
事実、Ｐｒ付活希土類オキシ硫化物螢光体を２５４ｎｓ
紫外線で励起したときの発光線は、第１図に示すように
Ｐｒ’＋の発光線の他にＥｕ”Ｔｂ”、Ｓｍ’＋などの
発光線が認められる。そして、同一の希土類酸化物原料
から作製した螢光体についてのＥｕ３＋の発光線強度と
Ｐｒ’＋の発光線強度との比である前記発光線強度比［
４６８ｎｍ（Ｅｕ）１５１２ ｎ５（Ｐｒ）］は、第２
図に示すように残光強度（Ｘ線刺激停止３０秒後の光出
力の初期光出力に対する相対値）とほぼ比例する。従っ
て、Ｅｕの不純物濃度を前記発光線強度比で０．００２
以下とすることにより、残光を十分に低減できる。In fact, the Pr-activated rare earth oxysulfide phosphor was
As shown in FIG. 1, when excited with ultraviolet light, emission lines such as Eu"Tb" and Sm'+ are recognized in addition to the Pr'+ emission line. Then, the emission line intensity ratio [
468 nm (Eu) 1512 n5 (Pr)] is the second
As shown in the figure, it is approximately proportional to the afterglow intensity (the relative value of the light output 30 seconds after the X-ray stimulation stops with respect to the initial light output). Therefore, the impurity concentration of Eu is 0.002 based on the emission line intensity ratio.
Afterglow can be sufficiently reduced by setting the following.
（実施例） 以下、本発明の実施例を詳細に説明する。(Example) Examples of the present invention will be described in detail below.
実施例１
純度９９．９９９％のＧｄ２０Ｂ２．０モルとＰｒ６０
１□３．３Ｘ １０−’モルとを硝酸水溶液に溶解し、
蓚酸０．３６モルを加えて、蓚酸塩を共沈させた。Example 1 2.0 mol of Gd20B with a purity of 99.999% and Pr60
1□3.3X 10-' mole is dissolved in an aqueous nitric acid solution,
0.36 mol of oxalic acid was added to coprecipitate oxalate.
得られた沈殿物を５回の純水デカンテーション洗浄によ
り吸引濾過した後、約１５０℃で一夜乾燥した。次いで
、これを２８０ ｍ（１石英るつぼに入れ、１０００℃
で１時間空気中で焼成して、酸化物粉体を得た。この酸
化物粉体に、Ｎ ａ ２ ＣＯ３２３ｇ ％５２３ｇ
ＳＫ３ ＰＯ４Ｂｇを加え、ボールミルにより十分に混
合して原料粉末を得た。この原料粉末をアルミするつぼ
に詰め、アルミナの蓋をした後、空気中１１００℃で４
時間焼成した。冷却後、前記アルミするつぼに純水を加
え、１時間静置して固形物をほぐし、これを１ｇビーカ
ーに移し、更にこの残りを数回の純水デカンテーション
洗浄により１ｇビーカーに移した。この１ｇビーカーの
内容物を ２００メツシユナイロン網に通過させた後、
１／２０塩酸水溶液を１０ｔｇ（ｌ加え、更に前記純水
デカンテーション洗浄をｐＨ６，５になるまで繰返した
。The obtained precipitate was suction-filtered by washing with pure water by decantation five times, and then dried at about 150° C. overnight. Next, this was placed in a 280 m (1) quartz crucible and heated to 1000°C.
The mixture was calcined in air for 1 hour to obtain an oxide powder. To this oxide powder, 523g of Na 2 CO323g%
SK3PO4Bg was added and thoroughly mixed using a ball mill to obtain a raw material powder. This raw material powder was packed into an aluminum pot, covered with an alumina lid, and heated to 1100℃ in air for 4 hours.
Baked for an hour. After cooling, pure water was added to the aluminum crucible, left to stand for 1 hour to loosen the solid matter, and this was transferred to a 1 g beaker, and the remainder was further transferred to a 1 g beaker by decantation washing with pure water several times. After passing the contents of this 1g beaker through a 200 mesh nylon screen,
10 tg (l) of 1/20 hydrochloric acid aqueous solution was added, and the above-mentioned pure water decantation washing was repeated until the pH reached 6.5.
次いで、これを６０℃の純水デカンテーション洗浄と室
温の純水デカンテーション洗浄とを交互に行ないながら
吸引濾過し、１２０℃で一夜乾燥し、（Ｌ ｎ １−
Ｐ ｒｘ ） ２０２ Ｓ ［Ｘ−０，０００５コで
示され、かつ２５４ｎｍ紫外線励起による発光線強度比
［４６８ｎｍ（Ｅｕ）／ ５１２ｎｍ（Ｐｒ） ］が０
．００１以下である螢光体を製造した。また、この螢光
体はＩＣＰ質量元素分析法によるＥｕとＰｒとの含有重
量比（Ｅ ｕ ／ Ｐ ｒ ）が０．０００４であった
。Next, this was suction-filtered while alternately performing decantation washing with pure water at 60°C and decanting washing with pure water at room temperature, and dried at 120°C overnight to obtain (L n 1-
P rx ) 202 S [X-0,0005], and the emission line intensity ratio [468 nm (Eu) / 512 nm (Pr)] due to 254 nm ultraviolet excitation is 0
．． A phosphor having a molecular weight of 0.001 or less was produced. Further, this phosphor had a content weight ratio of Eu to Pr (E u /P r ) of 0.0004 as determined by ICP mass elemental analysis.
実施例２〜１３及び比較例１〜７
前述した一般式（１）中のＸ、前記発光線強度比及び前
記含有重量比が下記第１表に示す値の螢光体を製造した
。なお、比較例７の螢光体についてのみＣａを付活した
。Examples 2 to 13 and Comparative Examples 1 to 7 Phosphors were produced in which X in the general formula (1), the emission line intensity ratio, and the content weight ratio were as shown in Table 1 below. Note that only the phosphor of Comparative Example 7 was activated with Ca.
得られた実施例１〜１３及び比較例１〜７の螢光体につ
いて、Ｘ線刺激による光出力を相対値として求め、Ｘ線
刺激停止３０秒後の初期光出力に対して残っている光出
力を残光強度として求めた。その結果を同第１表に併記
した。For the obtained phosphors of Examples 1 to 13 and Comparative Examples 1 to 7, the light output due to X-ray stimulation was determined as a relative value, and the remaining light was calculated based on the initial light output 30 seconds after the X-ray stimulation stopped. The output was determined as afterglow intensity. The results are also listed in Table 1.
第１表より明らかなように、Ｘ値が０．０００２〜０．
００３の範囲内で、かつ２５４ｎａ＋紫外線励起による
発光線強度比［４６８ｎｍ（Ｅｕ）／ ５１２ｎｆｆｌ
（Ｐｒ） ］が０．００２以下であるか、ＥｕとＰｒと
の含有重量比（Ｅ ｕ ／ Ｐ ｒ ）が０．００２以
下である実施例１〜１３の螢光体は、比較例１〜７の螢
光体に比べて光出力が１００程度と十分な光出力を有し
、かつ残光が１５Ｘ Ｉｎ’−’（１５ｐｐｍ）以下と
十分に低減されており、Ｘ線ＣＴのシンチレータとして
望まれている基準を十分に満足していることがわかる。As is clear from Table 1, the X value is between 0.0002 and 0.0002.
Within the range of 003, and the emission line intensity ratio due to 254na + ultraviolet excitation [468nm (Eu) / 512nffl
(Pr)] is 0.002 or less, or the weight ratio of Eu to Pr (Eu/Pr) is 0.002 or less. Compared to the phosphor No. 7, it has a sufficient optical output of about 100, and the afterglow is sufficiently reduced to 15X In'-' (15 ppm) or less, making it desirable as a scintillator for X-ray CT. It can be seen that the specified standards are fully satisfied.
［発明の効果コ
以上詳述した如く、本発明によればＰｒ付活希土類オキ
シ硫化物の利点である放射線刺激による大きな光出力が
十分に得られ、しかも放射線刺激停止後の残光が十分に
低減されたＸ線ＣＴのシンチレータなどに好適な螢光体
を提供することができる。[Effects of the Invention] As detailed above, according to the present invention, a large optical output due to radiation stimulation, which is an advantage of Pr-activated rare earth oxysulfide, can be sufficiently obtained, and the afterglow after the radiation stimulation has stopped is sufficiently reduced. It is possible to provide a phosphor suitable for scintillators of reduced X-ray CT.
第１図はＰｒ付活希土類オキシ硫化物からなる螢光体を
２５４ｎ１１紫外線で励起したときの発光線を示す特性
図、第２図は発光線強度比［４６８ｎｍ（Ｅｕ）／ ５
１２ ｎｍ（Ｐｒ）］に対する残光強度の変化を示す特
性図である。Figure 1 is a characteristic diagram showing the emission line when a phosphor made of Pr-activated rare earth oxysulfide is excited with 254n11 ultraviolet light, and Figure 2 is a characteristic diagram showing the emission line intensity ratio [468nm (Eu)/5
12 nm (Pr)] is a characteristic diagram showing changes in afterglow intensity.
Claims (2)
）［ただし、ＬｎはＬａ、Ｇｄ、Ｙ及びＬｕから選択さ
れる少なくとも１種、ｘは０．０００２〜０．００３を
示す］で表わされると共に、Ｅｕ不純物濃度を２５４ｎ
ｍ紫外線励起による発光線強度比［４６８ｎｍ（Ｅｕ）
／５１２ｎｍ（Ｐｒ）］で０．００２以下としたことを
特徴とする螢光体。(1) General formula (Ln_1_−_xPr_2)_2O_2S...(I
) [where Ln is at least one selected from La, Gd, Y, and Lu, and x represents 0.0002 to 0.003], and the Eu impurity concentration is 254n
Emission line intensity ratio by ultraviolet excitation [468 nm (Eu)
/512 nm (Pr)] of 0.002 or less.
）［ただし、ＬｎはＬａ、Ｇｄ、Ｙ及びＬｕから選択さ
れる少なくとも１種、ｘは０．０００２〜０．００３を
示す］で表わされると共に、ＥｕとＰｒとの含有重量比
（Ｅｕ／Ｐｒ）を０．００２以下としたことを特徴とす
る螢光体。(2) General formula (Ln_1_-_xPr_x)_2O_2S...(I
) [wherein Ln is at least one selected from La, Gd, Y, and Lu, and x represents 0.0002 to 0.003], and the content weight ratio of Eu and Pr (Eu/Pr ) is 0.002 or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33112789A JP2747068B2 (en) | 1989-12-22 | 1989-12-22 | Phosphor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33112789A JP2747068B2 (en) | 1989-12-22 | 1989-12-22 | Phosphor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03192187A true JPH03192187A (en) | 1991-08-22 |
| JP2747068B2 JP2747068B2 (en) | 1998-05-06 |
Family
ID=18240174
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP33112789A Expired - Lifetime JP2747068B2 (en) | 1989-12-22 | 1989-12-22 | Phosphor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2747068B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19506368C2 (en) * | 1994-02-25 | 2001-03-01 | Toshiba Kawasaki Kk | Scintillator and method for its manufacture, as well as X-ray detector and X-ray computed tomography scanner |
-
1989
- 1989-12-22 JP JP33112789A patent/JP2747068B2/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19506368C2 (en) * | 1994-02-25 | 2001-03-01 | Toshiba Kawasaki Kk | Scintillator and method for its manufacture, as well as X-ray detector and X-ray computed tomography scanner |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2747068B2 (en) | 1998-05-06 |
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