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Development of a -detector with barium fluoride crystal

氟化钡晶体α探测器的研制

基本信息

批准号：
62540203
负责人：
SASAO Noboru
金额：
$ 1.34万
依托单位：
Kyoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1987
资助国家：
日本
起止时间：
1987 至 1988
项目状态：
已结题

项目摘要

The purpose of this project is to develop a -detector which satisfies following performance requirements; (1) good energy resolution (<2% at 1 GeV), (2) good position resolution (<8mm), (3) fast response (dead time<100 nsec), (4) large area coverage. Two types of material were considered: barium fluoride (BaF2) and pure cesium iodide (pure CsI).1. BaF2 has two scintillation components. The fast one has a peak emission wave length of =220 nm and a decay time of =0.6 nsec while the slow one has =310 nm and =610 nsec. In order to remove the slow component, which is harmful to our application, we have employed a photomultiplier with a cste photocathode. As a result, the slow component was reduced by factor about 5. A test detector (120mmx120mmx300mm) was constructed and tested with a 0.8-GeV electron beam. The resultant energy resolution was 4.2%, which does not fulfil our requirement above. This is partly due to the crystal size; thus improvement in a crystal-growth technique for longer crystals is needed.2. There are also two scintillation components for pure CsI. The fast one has =310 nm and =10 nsec. Its light yield was found to be about 4% of NaI(TI) scintillators. A -detector (150mmx150mmx300mm) was constructed and tested with a 1.2 GeV electron beam. An energy resolution of 1.84% was obtained. Thus the material has proved to be a promising candidate for a high rate -detector.

本项目的目的是开发一种满足以下性能要求的-检测器；(1)能量分辨率好（1 GeV时<2%），(2)位置分辨率好（<8mm），(3)响应快（死区时间<100 nsec），(4)覆盖面积大。考虑了两种材料：氟化钡（BaF2）和纯碘化铯（纯CsI）。BaF2有两个闪烁元件。其中，快光的峰值发射波长为220 nm，衰减时间为0.6 nsec；慢光的峰值发射波长为310 nm，衰减时间为610 nsec。为了消除对我们的应用有害的慢速元件，我们采用了带阴极的光电倍增管。结果，慢速组件减少了约5倍。搭建了一个尺寸为120mmx120mmx300mm的测试探测器，并用0.8 gev的电子束进行了测试。由此产生的能量分辨率为4.2%，不符合我们上面的要求。这部分是由于晶体的大小；因此，需要改进长晶体的晶体生长技术。对于纯CsI也有两种闪烁成分。快的有=310 nm和=10 nsec。其光产率约为NaI（TI）闪烁体的4%。构造了一个150mmx150mmx300mm的探测器，并在1.2 GeV电子束下进行了测试。能量分辨率为1.84%。因此，该材料已被证明是一个有希望的候选高速率探测器。