Sudbury Neutrino Observatory Research at Laurentian University

劳伦森大学是加拿大五所机构之一，与来自美国和英国的合作者一起，设计、建造并运行萨德伯里中微子天文台（SNO），以解决一个持久的谜题——“太阳中微子问题”。中微子是由为太阳提供燃料的核反应大量产生的基本粒子。它们与物质的相互作用很小，绝大多数逃离太阳，越过所有障碍物辐射出去。测量这些太阳中微子的通量是出了名的困难，但已经通过几种独立的技术完成了。30多年来，这些测量结果一直与最精确的计算预测相矛盾。SNO通过令人信服地证明所有预测的中微子实际上都存在，解决了这个问题。这个解决方案的美妙之处在于，SNO的测量结果，所有以前的测量结果，以及理论预测，现在在中微子在行进过程中改变其特征的新图景下是一致的。以往的实验只能探测到未变化的中微子，而SNO能够探测到所有的中微子。劳伦森大学的研究人员致力于推进一些基础技术，这些技术在SNO的成功中发挥了重要作用，并且肯定对下一代实验至关重要。这些极其敏感的实验要求在建造中使用的材料中几乎消除放射性，并能够测量残留的微量放射性。推动这些纯度和对放射性污染物的敏感性的前沿是未来实验的一门使能科学。SNO探测器也是一种独特的灵敏仪器，用于探测来自超新星的中微子。Laurentian在SNO的一项令人兴奋的职责是操作SNO的超新星触发器，并参与SNEWS（超新星早期预警系统）的实验合作，该系统将在恒星出现爆炸之前提醒天文学家发现新的银河系超新星。

Laurentian University is one of five Canadian institutions that, along with collaborators from the United States and Great Britain, have designed, built, and now operate the Sudbury Neutrino Observatory (SNO) to solve an enduring enigma - the "solar neutrino problem." Neutrinos are fundamental particles created in large numbers by the nuclear reactions that fuel the sun. They interact with matter to only the slightest degree and the overwhelming majority escape the sun and radiate out traversing all obstacles. Measurements of the flux, of these solar neutrinos, are notoriously difficult and yet have been done by several independent techniques. For over thirty years these measurements have been at odds with the best calculated predictions. SNO has solved this problem by convincingly demonstrating that all of the predicted neutrinos are in fact present. The beauty of this solution is that SNO's measurements, all previous measurements, and the theoretical predictions are now consistent under a new picture in which neutrinos change their character as they travel. Previous experiments were only capable of detecting the unchanged neutrinos whereas SNO detected all neutrinos.    The researchers at Laurentian University are committed to advancing some of the base technologies that have played a large role in the success of SNO and that are certain to be crucial for next generation experiments. These extremely sensitive experiments demand the near elimination of radioactivity from the materials used in their construction and the ability to measure the miniscule amounts that remain. Pushing these frontiers of purity and sensitivity to radioactive contaminants is an enabling science for future experiments.    The SNO detector is also a uniquely sensitive instrument for the detection of neutrinos from supernovae. An exciting Laurentian responsibility within SNO is the operation of SNO's supernova trigger and its participation in the inter-experiment collaboration SNEWS (the Supernova Early Warning System) which would alert astronomers to a new galactic supernova actually in advance of the star having appeared to explode.