Sudbury Neutrino Observatory - Queen's

萨德伯里中微子天文台（SNO）是一个大型的国际项目，研究来自太阳和超新星的中微子。通过证明中微子具有质量，并且在不同类型的中微子之间振荡，天文台已经对理解中微子做出了重大贡献。最常见的中微子被称为电子中微子，它的性质与电子的性质非常相似——除了中微子不带电，质量也小得多。电子和电子中微子是一组被称为轻子的粒子的一部分；其他轻子是μ子和τ子，以及μ子和τ中微子。当中微子穿过物质时，它们很少相互作用——只有一小部分在穿过整个太阳或地球时停止。太阳产生了大量的电子中微子——太阳产生的能量中约有2%是以电子中微子的形式发射的。因为它使用重水作为探测介质，所以SNO能够分别测量电子中微子的通量和所有中微子的总通量。探测器的基础是1000吨重水，位于萨德伯里附近的克雷顿矿地下2公里处。地下位置是过滤掉其他高能宇宙辐射的必要条件。研究工作的很大一部分是尽量减少重水和构成探测器周围的其他物质中自然产生的放射性，这样我们就能清楚地看到相对罕见的中微子事件（每天大约10次）。女王学院以多种方式参与其中。这个项目由女王管理。我们负责校准探测器、光电倍增管、部分高纯水系统、电子设备、数据采集软件和数据分析。我们在了解探测器性能，校准和数据分析方面发挥了重要作用。

The Sudbury Neutrino Observatory (SNO) is a large international project to study neutrinos from the sun and supernova. The observatory has already made a major contribution to the understanding of neutrinos by demonstrating that neutrinos have mass and that they oscillate between different neutrino types. The most common neutrino is called an electron neutrino, and has properties that are very similar to those of an electron- except that the neutrino has no charge and a much smaller mass. Electrons and electron neutrinos are part of a group of particles called leptons; the other leptons are muons and taus, and muon and tau neutrinos. When neutrinos travel through matter they interact only very rarely- only a tiny fraction stop in passing through the entire sun or earth. Electron neutrinos are produced in copious quantities in the sun- about 2% of the energy produced in the sun is emitted in the form of electron neutrinos. Because it uses heavy water as a detection medium, SNO is able to separately measure the flux of electron neutrinos and the total flux of all neutrinos. The detector is based on 1000 tonnes of heavy water, which is located 2 km underground in the Creighton mine near Sudbury. The underground location is necessary to filter out other high energy cosmic radiation. A large part of the research effort has been to minimize the amount of naturally occurring radioactivity in the heavy water and the other materials that make up and surround the detector, so that we can clearly see the relatively rare neutrino events (about 10/day). Queen's is participating in several ways. The administration of the project is Queen's. We are responsible for the calibration of the detector, for the photomultiplier tubes, and for parts of the high purity water system, electronics, data acquisition software, and for analysis of the data. We have taken a major role in understanding the detector performance, calibration and data analysis.