Laboratory helium liquifier for supersolid research

这是一项为低温物理实验室购买小型氦液化器的提议。这种液化器将使研究得以实现，涉及在高压和超低温下对固体氦的实验研究，最近在这种制度下发现了一种新的“超固态”物质相。*由于需要极低的温度(绝对零度以内)，所有这类实验都需要使用强大的“稀释冰箱”。它使用大量的液氦来运行。氦是一种昂贵的不可再生资源，但最近低温技术(脉冲管冰箱)的发展极大地降低了小规模回收和再液化氦的成本。该方案中的氦液化器将允许我们回收液氦沸腾时产生的气体，每天生产多达20升液氦。这将使我们能够继续运行我们的稀释冰箱，并更有效地进行更多的实验。尽管它每年还将节省约200万升氦气体。但这将每年节省约3万美元的液氦成本，在3年内偿还投资。节省的成本将用于支持研究生接受低温和实验凝聚态物理培训。

This is a proposal to acquire a small-scale helium liquifier for a low temperature physics laboratory.  The research that will be enabled by this liquifier involves experimental studies of solid helium at high pressures and ultralow temperatures, a regime where a new "supersolid" phase of matter was recently discovered.  Because of the extremely low temperatures needed (within 0.2 degrees of absolute zero), all such experiments require the use of a powerful "dilution refrigerator", which uses substantial amounts of liquid helium to operate.  Helium is an expensive and non-renewable resource but recent developments in cryogenic technology (pulse tube refrigerators) have dramatically reduced the cost of recovering and reliquifying helium on a small scale.  The helium liquifier in this proposal will allow us to recycle the gas produced as the liquid helium boils off and produce up to 20 liters of liquid helium per day.  This will allow us to continuously operate our dilution refrigerator and perform more experiments, more effectively.  It will also conserve approximately 2 million liters of helium gas each year.  This will save approximately $30,000 per year in liquid helium costs, repaying the investment within 3 years.  The cost savings will be used to support graduate students being trained in low temperature and experimental condensed matter physics.