A new high-resolution spectrometer for Fermi surface studies

我们理解金属和金属系统行为的能力在很大程度上依赖于我们对它们所含电子行为的了解。金属可以被认为是由电子胶连接在一起的带正电荷的原子核的集合，其中电子可以在原子核之间自由漂移。我们对像铜这样的简单金属的理解是非常好的，尽管它是基于对电子相互作用和原子核相互作用的非常简单的处理。然而，有一类材料，这种简单的描述打破。在这些材料中，每个电子的运动都与其他电子的运动密切相关-我们称之为强相关电子系统。通过测量电子的动量，我们可以大大提高我们对这些材料的理解，并测试为理解它们而开发的最新理论。我们感兴趣的材料种类从超导体到具有重要技术意义的合金，如铝锂合金。我们的研究依赖于我们能够准确地确定伽马射线之间的角度，这意味着我们需要尽可能精确地知道它们击中探测器的位置。我们希望获得一对位置敏感的探测器，其分辨率比我们目前拥有的小五倍。这将使我们能够进行许多新的实验，如果没有这种分辨率的提高，这些实验是不可能的。

Our ability to understand the behaviour of metals and metallic systems relies heavily on our knowledge of the behaviour of the electrons they contain. Metals can be considered as a collection of positively charged nuclei held together by an electron glue , where the electrons are free to wander freely between the nulcei. Our understanding of simple metals like copper is very good even though it based on a very simple treatment of the way in which the electrons interact with each other and the nuclei. However, there is a class of materials where this simple description breaks down. In these materials, the motion of the each electrons is strongly correlated with that of the others - we call these strongly correlated electron systems. By making measurements of the momentum of the electrons, we can substantially improve our understanding of these materials, and test the latest theories that have been developed to understand them. The kinds of materials which we are interested in looking at range from superconductors to technologically important alloys such as Al-Li.Our research relies on us being able to accurately determine the angle between gamma rays, and that means we need to know where they hit our detectors as precisely as possible. We would like to acquire a pair of position-sensitive detectors that offer a resolution about five times smaller than we currently have. This would enable us to perform many new experiments that would be impossible without this improvement in resolution.