Sudbury Neutrino Observatory Research at Laurentian University

劳伦斯大学是与来自美国和英国的合作者一起设计、建造并现在运营萨德伯里中微子天文台(SNO)的五家加拿大机构之一，以解决一个永恒的谜团--“太阳中微子问题”。中微子是为太阳提供燃料的核反应产生的大量基本粒子。它们与物质的相互作用只有很小的程度，绝大多数人躲避太阳，穿过所有障碍辐射出去。测量这些太阳中微子的通量是出了名的困难，但已经有几种独立的技术完成了。三十多年来，这些测量结果一直与最准确的预测不符。Sno令人信服地证明了所有预测的中微子实际上都存在，从而解决了这个问题。这个解决方案的美妙之处在于，SNO的测量结果、之前的所有测量结果和理论预测现在都是一致的，在一幅新的图景下，中微子在移动中改变了自己的特征。以前的实验只能探测到没有变化的中微子，而SNO探测到了所有的中微子。他说，劳伦斯大学的研究人员致力于推进一些基础技术，这些技术在SNO的成功中发挥了很大作用，而且肯定对下一代实验至关重要。这些极其敏感的实验需要几乎消除其建造所用材料中的放射性，并要求有能力测量剩余的微量。推动这些对放射性污染物的纯度和敏感性的前沿是未来实验的一项使能科学。他说，SNO探测器也是探测超新星中微子的唯一灵敏仪器。SNO内部一项令人兴奋的劳伦斯式职责是SNO超新星触发器的操作及其参与超新星预警系统(SNEWS)的实验间合作，SNEWS将在恒星似乎爆炸之前提醒天文学家一颗新的银河系超新星。

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.