CN1042218C - 采用氢氧化物共沉淀法制备氧化钇－氧化钆陶瓷闪烁体的方法 - Google Patents

采用氢氧化物共沉淀法制备氧化钇－氧化钆陶瓷闪烁体的方法 Download PDF

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CN1042218C
CN1042218C CN92101172A CN92101172A CN1042218C CN 1042218 C CN1042218 C CN 1042218C CN 92101172 A CN92101172 A CN 92101172A CN 92101172 A CN92101172 A CN 92101172A CN 1042218 C CN1042218 C CN 1042218C
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yttrium oxide
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S·L·多尔
S·文卡塔拉曼尼
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Abstract

一种制备半透明至透明的多晶型氧化钇-氧化钆闪烁体的简化方法包括：制备含氧化钇-氧化钆组分的氢氧化物共沉淀水相悬浮液，然后将氢氧化物转化成草酸盐；草酸盐经洗涤中和、干燥和粉碎、以形成草酸盐细粉末；草酸盐细粉末经煅烧、冷压成块，并且在还原气氛或真空中烧结成半透明至透明的多晶型氧化钇-氧化钆闪烁体。

Description

采用氢氧化物共沉淀法制备氧化钇-氧化钆陶瓷闪烁体的方法
本发明涉及用于计算机X-射线断层照相术(CT)及其它X-射线、γ辐射和核辐射探测应用中的希土氧化物陶瓷闪烁体的制备方法，更确切地说，此方法涉及制备半透明至透明的多晶型氧化钇-氧化钆闪烁体。
计算机X-射线断层照相术扫描仪属医学诊断设备，受检体由平面光束或X-射线束照射，其强度变化与受检体中复杂光程的能量吸收有直接关系。从各种不同角度或视野来测量沿这些光程的X-射线强度(即X-射线吸收)，即可计算出辐射穿过受检体任一平面上各区域的X-射线吸收系数。这些区域通常由面积约为1毫米×1毫米的小方块组成。吸收系数用以产生影象，如由X-射线来贯穿的人体器官或工业设备结构件的影象。
扫描仪的主体和重要部件是X-射线探测器，用以接受穿过特定受检体后的X-射线。通常，X-射线探测器含有闪烁体材料，它在X-射线激发时发射光频辐射。在典型的医学或工业应用中，来自闪烁体材料的光辐射再照射到光电响应材料上，以产生电信号输出，电信号的幅度与所照射的X-射线的强度成正比。电信号经数字化，以供数字计算机处理，由此产生适合在阴极射线屏或其它永久性介质上形成影象的吸收系数。
由于计算机X-射线断层照相术的特殊要求，并非所有在X-射线或γ射线激发下能发射光辐射的闪烁体材料均适用于计算机X-射线断层照相术。适用的闪烁体必须是一种X-射线的高效转换体，能将X-射线转换成能为光电信增管或光二极管之类的光敏器件有效探测的电磁谱区(可见区和近可见区)的光辐射。同时也希望闪烁体具有高的光学清晰度，即能高效地透过光辐射，以避免光截留。这样，闪烁体深处的光辐射能够逸出，并为外设的光探测器所探测。此特点在医学诊断应用上特别重要，因为要尽量减少病人的受照，就要求X-射线的剂量尽可能低，同时又要能保持足够高的光子探测效率及高的信噪比。
适用的闪烁体材料的其它特性是：短余辉效应、低滞后现象、高X-射线阻止性能及光谱线性度。余辉效应是X-射线激发停止后，闪烁体继续发射光辐射的趋势，它引起信载信号随时间而模糊。在要求快速连续扫描的应用中，如动体器官成象时，短余辉效应特别重要。滞后现象是闪烁体材料特性，在相同X-射线激发下，它造成光辐射随闪烁体的辐射历程而变化。由于在计算机X-射线断层照相术中，要对来自每一个闪烁体元的光辐射作重复的精密测量，并且要求打到闪烁体上的相同的X-射线产生基本相同的光辐射，所以滞后现象是不利的。当以较高速率进行一些连续测量时，其典型的探测准确度约为千分之一数量级。高X-射线阻止性能对X-射线的高效探测是有利的，未被闪烁体吸收的X-射线将探测不到。光谱线性度是闪烁体材料的又一重要特性，因为打到闪烁体上的X-射线有不同的频率，要求闪烁体对X-射线的所有频率有基本相同的响应。
具有高的光学清晰度、密度、均匀度、立方晶系结构特性，并适用于计算机X-射线断层照相术的多晶型希土氧化物陶瓷闪烁体的组合物及其制备方法已由美国专利4421671、4518545、4525682、4466929、4466930和4747973所公开，在此并入本发明作为参考。简言之，多晶型陶瓷闪烁体是由能形成立方晶系结构的、选自Gd2O3、Y2O3、La2O3、Lu2O3及其混合物的希土氧化物制成。希土氧化物中掺入活性剂元素如铕、钕、镱、镝、铽和镨，以形成能在预定的波长下闪烁的立方晶系结构。根据需要加入足够量的透光促进剂如ThO2、ZrO2和Ta2O5，以改进陶瓷闪烁体的透明度。还可加入足够量的光辐射促进剂如CaO或SrO，以产生高的光辐射。
制备希土氧化物陶瓷闪烁体的重要工序是配制含有所需闪烁体材料成分的适用的粉末。适用的粉末粒度为亚微米至微米，并且其纯度为99.99％至99.9999％。亚微米至微米的粉末粒度可提供高的光学清晰度，当以这种粉末烧结来制备闪烁体时，较大的颗粒会造成孔隙率增高，进而会降低其光学清晰度。制备所期粉末原料的已知方法是湿法草酸盐化学沉淀工艺。将选定的摩尔百分数的硝酸钇、硝酸钆、硝酸铕、硝酸铌、硝酸镱、硝酸镝、硝酸铽和硝酸镨溶解于水。含所需闪烁体材料成分的硝酸盐水溶液与室温下饱和度为80％的草酸溶液混合。所得之草酸盐共沉淀经洗涤、中和、过滤，并在空气中于100℃下干燥8小时左右，然后使草酸盐在空气中于约700-900℃下煅烧热分解1至4小时，以形成相应的氧化物。通常在800℃下加热1小时已足够。最好将草酸盐或制成的氧化物用某种方法研磨，如采用球磨、胶体磨或流体能研磨，以提高粉末经烧结形成的闪烁体的光学清晰度。
将选取一定量的粉末组合物用模压或模压加均衡热压处理，以压制成粉末块，从而进一步提高其坯密度。压块经烧结法、烧结加均衡热压法或陶瓷热压法而密实。在上述已知的制备稀土陶瓷闪烁体材料的方法中，如用研磨过的草酸盐或氧化物制备烧结闪烁体，则其光学清晰度会有很大的改善。
本发明的目的是提供一种无需草酸盐或氧化物的研磨步骤而制备具有高光学清晰度的氧化钇-氧化钆陶瓷闪烁体的简化方法。
本发明的另一目的是用湿化学法制备氧化钇-氧化钆陶瓷闪烁体的细粉末，其方法为先形成氢氧化物共沉淀，接着将氢氧化物转化成草酸盐。
本文使用的术语“透明度”或“半透明度”意指闪烁体材料的不同光学清晰度。本发明方法制备的闪烁体材料的光学衰减系数通常小于100厘米-1，它是用相应离子的发光波长在抛光闪烁体材料片上作标准光波透射率试验(即“窄”角发射)测定的。适用的闪烁体材料有较低的衰减系数，因此有较高的光学清晰度，即较高的透明度。
我们发现了一种制备具有高光学清晰度的氧化钇-氧化钆陶瓷闪烁体的简化方法。采用不包括草酸盐粉末研磨步骤的本发明方法所制备的闪烁体与采用包括草酸盐粉末研磨步骤的已知方法制备的闪烁体比较，同样具有高的光学清晰度。
制备半透明至透明的多晶型氧化钇-氧化钆闪烁体的本发明方法是采用湿法氢氧化铵工艺制取含氧化钇-氧化钆组合物的氢氧化物共沉淀水相悬浮液。此氢氧化物悬浮液在搅拌时加入足够量的草酸，以将氢氧化物转化成草酸盐而形成草酸盐水相悬浮液。草酸盐经水洗中和、干燥和粉碎而成草酸盐细粉末。草酸盐粉末在空气中煅烧及热分解，使草酸盐完全氧化成含氧化钇-氧化钆组分的氧化物细粉末。氧化物粉末经冷压成块，并在还原气氛或真空中烧结，而形成半透明至透明的多晶型氧化钇-氧化钆闪烁体。
我们发现与由已知的方法制得的草酸盐共沉淀物相比，采用先制取含氧化钇-氧化钆组合物的氢氧化物共沉淀，接着将该氢氧化物转化成草酸盐，能制备出更细的共沉淀的草酸盐。结果，由于草酸盐的粒度减小，从而得到更细的氧化物粉末，并可烧结成具有较高光学清晰度的闪烁体。事实上，用本发明的方法所制备的氧化钇-氧化钆闪烁体的光学清晰度与在先前已知的方法中，用研磨过的草酸盐或氧化物粉末所制备的氧化钇-氧化钆闪烁体的光学清晰度相同。因此，无需在煅烧或烧结之前研磨草酸盐或氧化物粉末，同样能制备具有较高光学清晰度的氧化钇-氧化钆闪烁体。
本发明的氧化钇-氧化钆组合物闪烁体含有氧化钇和氧化钆以及三价稀土氧化物活化剂。具体地说，含氧化钇-氧化钆组合物闪烁体，以摩尔百分比计，含有约5-50％Gd2O3；约0.02-12％希土活化剂如铕、铌、镱、镝、铽和镨；其余组分为Y2O3。当材料中Gd2O3的含量低于5％摩尔时，对大多数实用的探测器设计而言，其X-射线的阻止性能太低；而当其含量高于50％摩尔时，却增加了非立方晶系，从而造成不良的光学清晰度。在氧化钇-氧化钆基体中，加入作为活化剂的三价希土元素氧化物如铕、铌、镱、镝、铽和镨氧化物，可提高闪烁体效率。尽管下列的例子不完全，但含氧化钇-氧化钆组合物闪烁体的优选组合物的实例为：约25-30％摩尔Gd2O3、约1-6％摩尔Eu2O3、其余为Y2O3；约30％摩尔Gd2O3、约0.25％摩尔Nb2O3、其余为Y2O3；约40％摩尔Gd2O3、约0.15％摩尔Tb2O3、其余为Y2O3 ；约40％摩尔Gd2O3、约0.2％摩尔Dy2O3、其余为Y2O3。
上述的氧化钇-氧化钆组合物提供了一种立方晶相，后者的特征是具有高度的闪烁体材料结构对称性。此种结构的材料特别适用于计算机X-射线断层照相术。闪烁体制料中非立方晶相(如单斜晶相)的增加，会因晶粒边界裂纹和非均匀的结晶结构而造成较低的光发射及不良的光学清晰度。这种非立方晶相结构材料具有明显的光散射和再吸收特性，这是由于此材料有较长的光发射光程，因此降低了外部光探测器可探测到的光量。
在氧化钇-氧化钆闪烁体中加入某些添加剂将有利于减少闪烁体材料中所不希望的发光余辉，这种余辉可能导致再显影象的畸变及出现伪差。加入约0.15％-0.7％摩尔Yb2O3、约0.1-2％摩尔SrO和约0.1-2％摩尔CaO可作用余辉抑制剂。上述的含氧化钇-氧化钆组合物闪烁体粉末可经烧结、烧结加均衡热压和陶瓷热压制备成闪烁体，但在制备陶瓷闪烁体之前，必须预制含有所需闪烁体材料组合物的适用粉末。
本发明方法中，以湿化学法制备含氧化钇-氧化钆组合物的闪烁体粉末。在湿法氢氧化铵工艺中，将选定摩尔百分数的钇、钆、铕、钕、镱、镝、铽、镨、和锶的硝酸盐或氯化物溶于水中，或将这些元素的相应氧化物溶于硝酸或盐酸溶液中，借以形成溶有希土元素的溶液。溶解所得之希土元素溶液经过滤除去不溶性物质，并用蒸馏水释至约0.1-0.2摩尔浓度。搅拌下向此希土元素溶液中加入足够浓度的氢氧化铵溶液，使溶液的pH值达8以上。本文所用术语“氢氧化铵溶液”系指pH值为8以上的氢氧化铵或有机氢氧化铵如四甲基氢氧化铵水溶液。搅拌可采用任何一种不会沾污悬浮液的方法进行，如电磁搅拌、超声波搅拌或机械振动即摇动。形成了希土氢氧化物水悬液和作为氢氧化物共沉淀作用副产品的铵盐。搅拌此混合物约30分钟，直到基本上所有溶解的希土元素都以氢氧化物形式共沉淀出来。
如上所述，在搅拌下向氢氧化物的含水悬浮液中加入足够量的草酸，使氢氧化物转化成草酸盐。发现对应每摩尔希土离子，加入约1.5摩尔的草酸是合适的。草酸的加入量最好足以使含水悬浮液的pH值降到3以下。所得之草酸盐经水洗、中和和过滤以除去过量的草酸及副产品铵盐。草酸盐最好用蒸馏水洗涤直到洗涤前后水的pH值相同为止。洗涤中水的pH值以不超过7为好。过滤所得之草酸盐可在空气中于约75-125℃下干燥约8小时。这种干燥法能形成脆性块状物，该脆性块状物经加压通过网眼约为20目的尼龙筛即可粉碎。
在草酸盐沉淀前加上氢氧化物沉淀步骤可制备出粒度更细的含氧化钇-氧化钆草酸盐粉末。采用本发明方法制备的氧化钇-氧化钆粉末的粒度与在先前已知的方法中经研磨后的粒度相同，如所制备之草酸盐粒度为5微米或更小。因此，由本发明方法制备的粉末，可不经研磨而制得具有同样高光学清晰度的烧结闪烁体。但是，在本发明方法中，也可对草酸盐进行研磨和筛分，以得到具有更佳光学清晰度的烧结闪烁体，例如用经100-325目的尼龙筛进行干式或湿式筛分过的草酸盐粉末，就可得到更佳的清晰度。研磨方法的选用要以不污染草酸盐或氧化物粉末为准，如喷射空气研磨法或采用含刚性有机聚合物研磨介质的高能振动研磨法或用涂有刚性有机聚合物的钢球的金属研磨法。适用的刚性有机聚合物研磨介质的硬度约为肖氏D级硬度40以上，例如包括尼龙、聚乙烯、乙酰和聚酯在内的聚酰胺等有机聚合物。
草酸盐粉末在空气中于约700-900℃下煅烧(即热分解)1-4小时，以形成相应的氧化物，一般在800℃下加热1小时就足够了。氧化物粉末经模压法或模压加均衡热压法压制成块，以进一步提高其坯密度。模具材料应对闪烁体组分呈惰性，以避免引起不良反应和污染。适用的模具材料有氧化铝、碳化硅和某些金属如钼、硬度钢或镍基合金。粉末块是在3000-15000磅/平方吋的压力下模压成型。另一方法是模压成型的粉末块再经10000-60000磅/平方吋的均衡热压处理，以进一步增加粉末压块的坯密度。如果事先已使用了研磨剂、致密剂或润滑剂如石蜡等，则烧结前要进行氧化处理以除去所有的有机添加物。压块在采用钨加热元件的高温炉中于真空或还原气氛(如露点约为23℃的湿的氢气气氛)下烧结。温度提升率约为100-700℃/时，直达烧结温度1800-2100℃，并在烧结温度下保持1小时30分钟，以增加密实化及改善光学清晰度。烧结后的压块在2-10小时内冷却至室温。
烧结陶瓷闪烁体也可采用包括在低于最终烧结温度下保持一段时间的加热程序来制备。通常，粉末压块的加热率为300-400℃/时，直达保持温度1600-1700℃，保持时间约为1-20小时，接着，温度升至约1800-2100℃，进行最终烧结1-10小时。从保持温度到最终烧结温度的升温率为25-75℃/时。最佳加热程序为在5小时内将粉末压块加热至保持温度约1700℃，并在1700℃下保持8小时，然后在4小时内加热到1910℃，并在1910℃下烧结2小时。
本发明方法的各种特征及优点将由下列实例作进一步说明。
                    实例1
将含约67％摩尔氧化钇、30％摩尔氧化钆和3％摩尔氧化铕的约50克氧化物混合物溶解于约200克硝酸和水中，并将溶液体积调至500毫升而制成相应组分的氧化物溶液。所得之氧化物溶液经过滤后用蒸馏水稀释至3升。将100克浓氢氧化铵用蒸馏水稀释至500毫升，并滴加到正在搅拌的氧化物溶液中。搅拌此混合物约30分钟，即制得希土氢氧化物的含水悬浮液，搅拌下混合物的pH值约为9.0。
将约80克草酸溶于1升水中，并加入到搅拌下的氢氧化物沉淀中。约1-2分钟后，混合物的pH值稳定在约2.1。搅拌草酸和氢氧化物沉淀混合物15分钟，以转化氢氧化物沉淀为草酸盐沉淀。用4升蒸馏水滤洗草酸盐，洗涤过的草酸盐在空气中于105℃下干燥3小时，干燥后的草酸盐粉末穿过粗目尼龙筛而粉碎，并在空气中于825℃下煅烧2小时，以制成氧化钇-氧化钆细粉末。
氧化物粉末在钢模中压制成丸片，氧化物丸片在60千磅/平方吋的压力下进行均衡热压法处理。压制成的丸片在使用钨加热元件的加热炉中于流动的湿氢气气氛下加热，其加热程序为：在5小时内加热至1700℃，并在1700℃下保持8小时，然后在4小时内加热至1910℃，并在1910℃下保持2小时以烧结丸片。烧结所得之丸片经可见光准直透射试验测定，其准直透射率为63％/毫米厚度，衰减系数为2.5。
                  实例2
按实例1制备溶解的氧化物溶液。将167克草酸溶于3升蒸馏水中，并慢慢加到搅拌下的氧化物溶液中，以制得相应草酸盐共沉淀。此草酸盐共沉淀悬浮液经搅拌1分钟至沉淀完全。然后用约16升蒸馏水搅拌洗涤，待草酸盐沉降后，将上层清液倾去。这种洗涤及倾泻操作共重复8次。洗涤后的草酸盐沉淀经过滤以除去液体，并在空气中于105℃下干燥数小时以成脆块，使脆块通过20目的尼龙筛粉碎。干燥得的草酸盐粉末按实例1进行煅烧、压制和烧结。以得到氧化钇-氧化钆闪烁体。测定其光学清晰度，其准直透射率小于0.1％/毫米厚度，衰减系数约为70。

Claims (8)

1．一种半透明至透明的多晶型氧化钇-氧化钆闪烁体的制备方法，它包括：
用湿法氢氧化铵工艺制备含氧化钇-氧化钆组分的氢氧化物共沉淀的含水悬浮液；
对所述氢氧化物悬浮液进行搅拌，同时加入足够量的草酸，使氢氧化物转化为草酸盐；
对所述草酸盐进行煅烧至完全氧化该草酸盐，并制成含氧化钇-氧化钆闪烁体组分的粉末；
对该粉末进行冷压使之成块；
在还原气氛或真空中烧结所述压块，以制得半透明至透明的多晶型氧化钇-氧化钆闪烁体。
2．根据权利要求1所述的方法，其中，所述制备氢氧化物共沉淀含水悬浮液的步骤包括：
将含氧化钇-氧化钆组分的氧化物混合物溶于盐酸或硝酸的水溶液中；
搅拌该酸溶液同时与氢氧化铵溶液进行混合，以形成含水悬浮液，
所述氢氧化铵溶液使水悬浮液中的pH值上升至至少7。
3．根据权利要求1所述的方法，其中，将所述搅拌进行到草酸盐悬浮液的pH值稳定为止。
4．根据权利要求3所述的方法，其中，在所述煅烧步骤之前先用水洗涤所述草酸盐沉淀。
5．根据权利要求4所述的方法，其中，在洗涤期间，水不能增加到使pH值在7以上。
6．根据权利要求5所述的方法，其中，所述方法还包括在约75-125℃下干燥草酸盐，以形成脆性块的步骤以及在煅烧步骤之前粉碎该脆性块的步骤。
7．根据权利要求6所述的方法，其中，在所述煅烧步骤之前是研磨草酸盐步骤。
8．根据权利要求7所述的方法，其中，所述研磨步骤是采用含刚性有机聚合物研磨介质的振动研磨法进行。
CN92101172A 1991-02-26 1992-02-26 采用氢氧化物共沉淀法制备氧化钇－氧化钆陶瓷闪烁体的方法 Expired - Fee Related CN1042218C (zh)

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CN1052745C (zh) * 1995-05-19 2000-05-24 中山大学 微波热法合成荧光粉的方法
CN1067708C (zh) * 1996-12-14 2001-06-27 中山大学 微波热法扩散掺杂合成荧光粉
US6361735B1 (en) 1999-09-01 2002-03-26 General Electric Company Composite ceramic article and method of making
US6706212B2 (en) * 2002-04-12 2004-03-16 General Electric Company Cerium-doped alkaline-earth hafnium oxide scintillators having improved transparency and method of making the same
KR100542262B1 (ko) * 2003-10-22 2006-01-11 한국과학기술원 투광성 다결정질 세라믹 섬광체 조성물 및 그 제조방법
US7449128B2 (en) * 2004-06-21 2008-11-11 General Electric Company Scintillator nanoparticles and method of making
CN1958512B (zh) * 2005-10-31 2010-05-12 科发伦材料株式会社 透光性稀土氧化物烧结体及其制造方法
DE102006027958A1 (de) * 2006-06-14 2007-12-20 Schott Ag Optokeramiken, daraus hergestellte optische Elemente sowie Abbildungsoptiken
JP2008143726A (ja) * 2006-12-06 2008-06-26 Japan Fine Ceramics Center 多結晶透明ｙ２ｏ３セラミックス及びその製造方法
US7708968B2 (en) 2007-03-26 2010-05-04 General Electric Company Nano-scale metal oxide, oxyhalide and oxysulfide scintillation materials and methods for making same
US7625502B2 (en) * 2007-03-26 2009-12-01 General Electric Company Nano-scale metal halide scintillation materials and methods for making same
US7608829B2 (en) * 2007-03-26 2009-10-27 General Electric Company Polymeric composite scintillators and method for making same
US7977267B2 (en) * 2008-12-16 2011-07-12 General Electric Company Wetting resistant materials and articles made therewith
WO2010078224A2 (en) 2008-12-30 2010-07-08 Saint-Gobain Ceramics & Plastics, Inc. Ceramic scintillator body and scintillation device
US8872119B2 (en) 2008-12-30 2014-10-28 Saint-Gobain Ceramics & Plastics, Inc. Ceramic scintillator body and scintillation device
CN102265183A (zh) * 2008-12-30 2011-11-30 圣戈本陶瓷及塑料股份有限公司 闪烁装置以及用于生产陶瓷闪烁体本体的方法
WO2010078223A2 (en) 2008-12-30 2010-07-08 Saint-Gobain Ceramics & Plastics, Inc. Ceramic scintillator body and scintillation device
DE102010043749A1 (de) * 2010-11-11 2012-05-16 Siemens Aktiengesellschaft Hybride organische Fotodiode
CN102205985A (zh) * 2011-04-02 2011-10-05 南昌大学 一种不同比表面积氧化钇的制备方法
US10207957B2 (en) 2013-10-08 2019-02-19 Hitachi Metals, Ltd. Ceramic scintillator and its production method, and scintillator array and radiation detector
CN105858706B (zh) * 2015-01-22 2017-09-05 湖南稀土金属材料研究院 氧化钇粉体的制备方法
CN109324339A (zh) * 2018-10-30 2019-02-12 中国工程物理研究院核物理与化学研究所 一种反应堆退役不锈钢材料中Sr-90分析装置和方法
CN109369183B (zh) * 2018-12-13 2020-07-17 东北大学 一种红外透明陶瓷材料及其制备方法
CN111018527A (zh) * 2019-12-26 2020-04-17 江西鑫泰功能材料科技有限公司 一种介电陶瓷电容器用纳米氧化钆的制备方法

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0097295A1 (en) * 1982-06-18 1984-01-04 General Electric Company Rare earth doped yttria-gadolinia ceramic scintillators and methods for making
EP0235387A2 (en) * 1985-12-30 1987-09-09 General Electric Company Radiation detector employing solid state scintillator material and preparation methods therefor

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4466929A (en) * 1982-06-18 1984-08-21 General Electric Company Preparation of yttria-gadolinia ceramic scintillators by vacuum hot pressing
US4525628A (en) * 1982-06-18 1985-06-25 General Electric Company Rare earth ceramic scintillator
US4466930A (en) * 1982-06-18 1984-08-21 General Electric Company Preparation of yttria-gadolinia ceramic scintillators by vacuum hot pressing
US4518545A (en) * 1982-06-18 1985-05-21 General Electric Company Method for sintering high density yttria-gadolinia ceramic scintillators
US4421671A (en) * 1982-06-18 1983-12-20 General Electric Company Rare-earth-doped yttria-gadolinia ceramic scintillators
US4747973A (en) * 1982-06-18 1988-05-31 General Electric Company Rare-earth-doped yttria-gadolina ceramic scintillators
US4755492A (en) * 1986-10-06 1988-07-05 General Electric Company Yttrium oxide ceramic body
DE3801326A1 (de) * 1988-01-19 1989-07-27 Asea Brown Boveri Verfahren zur herstellung einer keramiksuspension

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0097295A1 (en) * 1982-06-18 1984-01-04 General Electric Company Rare earth doped yttria-gadolinia ceramic scintillators and methods for making
EP0235387A2 (en) * 1985-12-30 1987-09-09 General Electric Company Radiation detector employing solid state scintillator material and preparation methods therefor

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IL100510A0 (en) 1992-09-06
DE69205705T2 (de) 1996-06-20
EP0501664A1 (en) 1992-09-02
DE69205705D1 (de) 1995-12-07
EP0501664B1 (en) 1995-11-02
CA2059915A1 (en) 1992-08-27
CA2059915C (en) 2002-01-15
CN1064472A (zh) 1992-09-16
IL100510A (en) 1996-07-23
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US5116559A (en) 1992-05-26

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