Developement of Water Cherenkov Detector for the Giant Air Shower Array(Pierre Auger Project)

皮埃尔·俄歇项目将建造两个大型观测站，研究能量超过10^ eV的宇宙射线<20>。两个探测器将分别在美国的犹他州和阿根廷的门多萨普罗旺斯建造，面积分别为3000平方公里。表面探测器的选择是一个面积为10 m^2、深1.2 m的水箱。每个阵列将由大约1600个这样的坦克组成。为了研究如何有效地实现μ子电磁分离，在世界上唯一运行的Akeno巨型空气簇射阵列（AGASA）部署了两个水箱。1996年秋季安装的第一个水箱的所有表面都覆盖着漫反射器。第二个水箱安装于1997年夏天，除顶部为黑色吸光外，所有表面都有漫反射器。第二槽具有快得多的响应，这可以允许更好的μ子-电磁分离。到目前为止的结果如下：A.横向分布：簇射粒子的横向分布函数（1df）的知识是至关重要的确定簇射能量的表面阵列与广泛的分离的检测器。因此，我们的目标是从AGASA的水箱中得出实验性的1DF，并将其与使用非常相似的探测器单元的Haverah Park实验的1DF进行比较。B.水切伦科夫探测器的自校准：俄歇天文台计划部署3200个探测器站。我们已经证明了在没有额外设备的情况下校准和监测WCD的能力。C.黑顶和白顶WDC的比较：白顶和黑顶WCD的差异已经针对标准μ子信号进行了研究，并且与基于模拟的预期一致。

The Pierre Auger project will construct two large observatories to study cosmic rays with energies in excess of 10^<20>eV.Two detectors will be built of 3000km^2 each in Utah, USA and Mendoza Provence, Argentina. The choice of the surface detector is a water tank of 10 m^2 area and 1.2 m deep. Each array will consist of about 1600 such tanks. In order to study how effectively we can achieve muon-electromagnetic separation, two water tanks were deployed at the Akeno Giant Air Shower Array (AGASA) which is the only operational array in the world. The first tank, installed in fall of 1996 has all surfaces covered with diffuse reflector. The second tank, installed in summer 1997, has diffuse reflector on all surfaceas except the top which is a light absorbing black. The second tank has a much faster response which may permit better muon-electromagnetic separation. The results so far are as follows :A.Lateral Distribution : Knowledge of the lateral distribution function (1df) of shower particles is crucial in the determination of the shower energy in surface arrays with a wide separation of detectors. Thus we aim to derive an experimental 1df from the tanks at AGASA and compare it to the 1df of the Haverah Park experiment which used very similar detector units. The result is in consistent with the expected density distribution from the Haverah Park experiment.B.Self Caliburation of the Water Cherenkov Detectors (WCD) : The Auger Observatory plans to deploy 3200 detector stations. It is not practical to have a scintillation counter telescope attached to each station to calibrate the sensitivity of each detector in VEQ.we have demonstrated the abaility to calibrate and monitor a WCD without additional equipment.C.Comparison of Black-Top and White-Top WDC's : The differences of the white-top and black-top WCD's have been studied for standard muon signals and agree with expectations based on simulation.