A recovery system for helium-3

氦 3 回收系统

• 批准号: 345501-2007
• 负责人: Jäger, Wolfgang
• 金额: $ 4.99万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Research Tools and Instruments - Category 1 (<$150,000)
• 财政年份: 2006
• 资助国家: 加拿大
• 起止时间: 2006-01-01 至 2007-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=325964
• 关键词: recovery; system; helium

In recent years, we have been able to explore the size regime between the microscopic, molecular and the macroscopic, bulk worlds with high resolution spectroscopic techniques. Superfluidity is a particularly interesting bulk property of the helium-4 isotope (spin zero Boson) at low temperatures and manifests itself, for example, in vanishing viscosity. We have studied the evolution of superfluidity from the microscopic scale by investigating molecules embedded in successively larger helium clusters with atom by atom size resolution. The observed decoupling of helium atoms from the rotational motion of the molecule is now accepted to be a manifestation of microscopic superfluidity and occurs in cluster sizes with as few as ten helium atoms. We are proposing to extend these studies to the helium-3 isotope (spin ½ Fermion) which exhibits superfluidity at a much lower temperature than helium-4. It is unclear how the spin ½ of helium-3 will affect the outcome of the experiments. Will the helium-3 stay coupled to the rotational motion of the molecule, and thus provide the 'final proof' that the decoupling in helium-4 indicates indeed the onset of superfluidity? Or will the helium-3 clusters also behave non-classically through the formation of spinless Cooper pairs? These questions have thus far not been addresses experimentally and the results will provide insight into the fascinating quantum properties of systems in the mesoscopic size regime. Helium-3 gas is prohibitively expensive and funds are requested for a recovery system that allows us to recycle the helium-3 in our spectrometer. The heart of the recovery system is a helium compressor that allows us to reach the high pressures of over 150 atm needed for the proposed experiments. Other components include a hermetically sealed pump to avoid contamination with air and vacuum components such as gauges and valves.

近年来，我们已经能够利用高分辨率光谱技术探索微观、分子和宏观、块体世界之间的尺寸范围。超流动性是氦 4 同位素（自旋零玻色子）在低温下的一种特别有趣的整体特性，例如，表现为粘度消失。我们通过逐个原子尺寸分辨率研究嵌入连续较大氦簇中的分子，从微观尺度研究了超流性的演化。观察到的氦原子与分子旋转运动的解耦现在被认为是微观超流性的表现，并且发生在只有十个氦原子的簇大小中。我们建议将这些研究扩展到氦 3 同位素（自旋 1/2 费米子），它在比氦 4 低得多的温度下表现出超流动性。目前尚不清楚氦 3 的自旋 1/2 将如何影响实验结果。氦 3 是否会与分子的旋转运动保持耦合，从而提供“最终证据”，证明氦 4 中的解耦确实表明超流动性的开始？或者，氦 3 星团也会通过形成无自旋库珀对而表现出非经典行为吗？迄今为止，这些问题尚未通过实验得到解决，其结果将提供对介观尺寸体系中系统令人着迷的量子特性的深入了解。 Hel-3 气体非常昂贵，需要资金用于回收系统，以便我们能够回收光谱仪中的 Hel-3。回收系统的核心是氦压缩机，它使我们能够达到拟议实验所需的超过 150 个大气压的高压。其他组件包括密封泵，以避免空气和真空组件（例如仪表和阀门）的污染。